Preparation of Vortex Porous Graphene Chiral Membrane for Enantioselective Separation
- Hongxin TanHongxin TanCAS Key Laboratory of Chemistry of Northwestern Plant Resources and Key Laboratory for Natural Medicine of Gansu Province, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences, Lanzhou 730000, ChinaUniversity of Chinese Academy of Sciences, Chinese Academy of Sciences, Beijing 100049, ChinaMore by Hongxin Tan,
- Tianqi LiuTianqi LiuCAS Key Laboratory of Chemistry of Northwestern Plant Resources and Key Laboratory for Natural Medicine of Gansu Province, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences, Lanzhou 730000, ChinaMore by Tianqi Liu,
- Xin ZhangXin ZhangSchool of Nuclear Science and Technology, Lanzhou University, Lanzhou 730000, ChinaMore by Xin Zhang,
- Qiang ShanQiang ShanSchool of Nuclear Science and Technology, Lanzhou University, Lanzhou 730000, ChinaMore by Qiang Shan,
- Jia ChenJia ChenCAS Key Laboratory of Chemistry of Northwestern Plant Resources and Key Laboratory for Natural Medicine of Gansu Province, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences, Lanzhou 730000, ChinaMore by Jia Chen,
- Zhan Li*Zhan Li*E-mail: [email protected]CAS Key Laboratory of Chemistry of Northwestern Plant Resources and Key Laboratory for Natural Medicine of Gansu Province, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences, Lanzhou 730000, ChinaMore by Zhan Li,
- Hirotaka IharaHirotaka IharaCAS Key Laboratory of Chemistry of Northwestern Plant Resources and Key Laboratory for Natural Medicine of Gansu Province, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences, Lanzhou 730000, ChinaMore by Hirotaka Ihara, and
- Hongdeng Qiu*Hongdeng Qiu*E-mail: [email protected]CAS Key Laboratory of Chemistry of Northwestern Plant Resources and Key Laboratory for Natural Medicine of Gansu Province, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences, Lanzhou 730000, ChinaUniversity of Chinese Academy of Sciences, Chinese Academy of Sciences, Beijing 100049, ChinaMore by Hongdeng Qiu
Abstract
Chiral materials are usually the key to the separation of chiral membranes. In this work, we propose a new strategy that chiral porous graphene membrane can be fabricated from nonchiral porous graphene by mechanical stirring to induce vortex structure. Porous graphene with controlled, nanosized pores was synthesized by a newly designed, one-pot process directly from graphite as opposed to graphene oxide. Then porous graphene was immobilized on ultrafiltration membrane through filtering while stirring to form porous graphene membrane, which was applied for enantioselective separation toward DL-amino acids: for example, the separation factor of l-/d-phenylalanine reached 4.76. Interestingly, we first observed that the front and back sides of the porous graphene membrane exhibited opposite optical activities.
Chirality plays an essential role in aspects of the origin of life, environment, and drug manufacture.(1,2) As we know, different isomers of chiral compounds have different biological activities and pharmacological effects.(3) Enantioselective synthesis is an ideal way, but this approach is very expensive in practical application. Therefore, the resolution of racemic mixtures of chiral molecules is essential to medication safety and development.(4) Commonly used chromatographic methods require expensive equipment and consume large amounts of solvents.(5) Meanwhile, membrane separation outperforms other chiral resolution techniques due to its no phase change, low energy consumption, highly selective, fast, and easy scale-up.(6) Hence, it is necessary to develop a superior-performance chiral separation membrane.
Porous graphene (PG) and its derivative membranes have been used in various fields including water desalination,(7−9) gas separation and purification,(10,11) and ionic selective separation.(12) PG is a derivative of graphene wherein nanoscale pores with various sizes, shapes, and functionalities are introduced on the sheets of graphene.(13−17) Owing to existing pores, it exhibits unique features as compared to pristine graphene such as higher surface area and mass diffusion rate.(18,19) Interestingly, based on computational simulations, Yan et al. reported that the stacked porous graphene channels with chiral helical profiles can exhibit brilliant enantioselectivity toward molecular transport.(20) Moreover, Kim et al. reported a chiral film of bilayer graphene with a controlled interlayer rotation (θ) and polarity by layer-by-layer deposition of graphene sheets,(21) but the stacking approach is hard to achieve a scalable synthesis of the chiral membrane. Simpler than the above method, physical stirring has been widely used for the facile and rapid preparation of noncovalent chiral materials.(22−24) It is reported that graphene oxide (GO) chirality can be altered by mechanical vortexes, which originate from the chiral structure of GO sheets stacked into a helical shape in the solution. Then, the obtained chirality was successfully transferred to GO support and the host molecules after simply clockwise (CW) and counterclockwise (CCW) dropcast stirring.(25)
Based on the above, here we report a new type of enantioselective porous graphene membrane (PGM) by mechanical stirring. The front and back of the membrane display mirror-image circular dichroism (CD) signals. By rhodamine-B staining, the stripes of the vortex structure can be observed on the membrane. Therefore, our method has some advantageous merits compared with conventional graphene-based functional membranes: for example, (1) no chirality is needed in graphene materials for membrane production because the chiral environment can be provided by simply stirring; (2) chiral function can be adjustable by controlling the mechanical process of stirring; and (3) PG with controlled pores can be produced by the one-pot process and easily immobilized on the ultrafiltration membrane for chiral separation. This work also demonstrates the exceptionally effective enantioselective separation for dl-amino acids.
PG was synthesized by a one-step combustion strategy from graphite. In the Hummers method, the oxidizing agents diffused into graphite galleries for producing the oxidized graphite. The product sulfates (MnSO4 and K2SO4) from the oxidizing reaction would remain and imperfectly cover the surface of the graphite inner layer and then convert to the oxides by heating. The metal oxide nanoparticles as an etcher underwent a carbothermal reaction between the graphite oxide layers for producing PG (Figures 1 and S1). Importantly, we further confirmed that only MnSO4 is the initiator for producing pores in the combustion process (Figures S2–S6). With the decrease of the concentration of the yellow mixture from the Hummers method, the size of the obtained metal oxide nanoparticle decreases (Figures S2 and S3). According to the previous report, the pore size of PG is proportional to the size of the oxide nanoparticle.(26,27) As shown in Figure 2a–c, the pore size of PG is mediated to ∼25, 11, and 3.5 nm by diluting the yellow mixture, respectively. More characterizations are displayed in Figures S7–S10 and Table S1.
Figure 1
Figure 1. Synthesis of PGM with vortex structures. Sulfate is derived from the reaction byproducts in the Hummers method, which forms nanoparticles between layers of graphite oxides in combustion, then the pore is etched by the carbothermal reaction on each layer of graphite oxide at high temperature, and PG is obtained after washing and ultrasound treatment. PGM with vortex structures is prepared by mechanical stirring. The optical activities of the front of PGM are opposite to that of the back.
Figure 2
Figure 2. Characterizations of PG and PGMs with different pore sizes. (a–c) transmission electron microscopy (TEM) images of PG. (d–f) Surface SEM images of PGM. (g–i) Cross-sectional SEM images of PGM. (j) Schematic of chiral separation equipment; the racemic and HCI solution are placed as the feed and permeate solutions, respectively. (k) Photograph of PGM.
PG membranes (PGMs) are prepared by rapid filtration of well-dispersed suspension of PG (pH = 11.4) with different size pores after stirring for 30 min (Figure S11). Figure 2d–f shows the SEM images of PGMs surface morphology with many pores. The cross-section scanning electron microscopy (SEM) images show the layered structures of these PGMs (Figure 2g–i). The schematic diagram of separation equipment and pictures of PGMs with a definite filter area of 1.77 cm2 are shown in Figure 2j and k, respectively. As shown in the typical stress–strain curves of the prepared PGMs (Figure S12), the tensile strength and toughness of the pure polyvinylidene fluoride (PVDF) films are 1.66 MPa and 0.11 MJ m–3, respectively. With the thickness of the PGM increasing from 210 to 415 μm, the tensile strength is increased from 1.65 to 1.78 MPa. More importantly, the toughness of the PGM with a 415 μm thickness is up to 0.45 MJ m–3, which is 4× higher than that of PVDF film. The improvement of mechanical property can be ascribed to the increased π–π conjugated interaction and friction between the PG sheets.(28,29)
Subsequently, the prepared PGMs were used for molecular chiral separation. Figure S13 shows that the larger the pore size on PG causes the higher the permeation toward d-phenylalanine (d-Phe); thus, the PG with the largest pore size of ∼25 nm is selected as a membrane material for the following separation of enantiomers. The permeation dynamics of d-Phe through PGM under 2 and 4 M HCl driven solution are shown in Figure 3a, which suggests that the increase of the acidity in the driven solution can promote the permeation of d-Phe through PGM, also meaning that the permeation processes may be ionic exchange on functional groups between ionized d-Phe and H+.(12) The permeation of l-phenylalanine (l-Phe) through PGM is 1.74 and 1.77 times that of d-Phe under the driven 2 and 4 M HCl at 48 h, respectively (Figure 3b). Figure 3c shows that the permeation of l-/d-Phe reduces, but the separation factor (SF) increases from 1.12 to 1.75 as the thickness of PGM increased from 210 to 415 μm, which is consistent with the existing permeation theory.(30) Importantly, PGM can also be used to separate l-glutamic (l-Glu) and d-glutamic (d-Glu), and the selectivity of PGM to l-/d-Glu is 2.45 and 2.17 at 36 and 48 h, respectively (Figure 3d).
Figure 3
Figure 3. Separation of enantiomer molecules through PGM under an acidic environment. (a) Permeation dynamics of d-Phe through PGM under acidity driven with 2 and 4 M HCl. (b) Separation of l-Phe and d-Phe under acidity driven with 2 and 4 M HCl after 48 h. (c) Separation of l-Phe and d-Phe as a function of the membrane thickness under acidity driven with 4 M HCl after 48 h. (d) Separation of l-Glu and d-Glu under acidity driven with 4 M HCl after 36 and 48 h. The concentration of the initial feed solution is 0.01 M.
To further explore the relation between the stirring vortex and chiral separation, and thus improving the SF of PGM to enantiomer molecules, PGM is prepared by mechanical stirring while filtering after a certain period of time of stirring (Figures 4b and S14). Figure 4a shows the picture of symmetrically folded PGM with a vortex structure, indicating that PGM thickness decreases gradually from the inside to the edge. The stripes of the vortex structure can be seen through the enlarged view of the middle area.
Figure 4
Figure 4. Characterizations and separation performance of PGM prepared by stirring and filtering. (a) Picture of PGM prepared by clockwise stirring. Inset: a high-resolution image of vortex structure on the PGM surface. (b) Schematic diagram of stirring and filtering equipment. (c) Vortex pattern after stirring for different times, observed on rhodamine-B dyed PGM by confocal laser scanning microscope; the yellow arrows identify the vortex structure. (d) CD spectra of stirred PG suspensions at 0, 5, 15, and 30 min, with a stirring speed of 600 rpm. (e) CD spectra of the front and back of PGM. (f) SF of l-/d-Phe through PGM prepared by filtration without stirring, stirring before filtration, and stirring filtration. The feed solution is 0.01 M of racemic l-/d-Phe solution; driven solution is 4 M HCl. (g) Vortex pattern after separation for a different time, and the yellow arrows identify the vortex structure.
As shown in Figure 4c, with the increase of the stirring time, concentric circles (20–100 μm) can be obviously observed by a confocal laser scanning microscope on the rhodamine-B dyed PGM, which confirms the existence of a vortex structure. The CD spectra of PG suspensions after stirring are performed as shown in Figures 4d and S15. A peak at ∼290 nm can be observed, and the magnitude of the CD peak increases with the increase of stirring time from 0 to 30 min, but it is independent of stirring speed. Therefore, 30 min and 600 rpm of stirring were selected to prepare PGM. Moreover, PG deposited on the glass surface under stirring was prepared to perform CD spectra. Mirror image CD signals are observed for the front and back of the glass in Figure 4e, indicating that PGM with vortex structures exhibits chiral properties. Subsequently, the vortex PGM was used to achieve highly selective separation of l-/d-Phe. As shown in Figure S16, the permeation of l-Phe from the front to the back of PGM is higher than that of d-Phe, but permeation of d-Phe from the back of PGM to the front is higher than l-Phe. As a control, the permeation performance of the PG membrane without stirring was also conducted (Figures S17 and S18), displaying no selectivity for l-/d-Phe, and SF remains ∼1 from 24 to 48 h (Figure 4f). However, PGM prepared by stirring before filtration shows SF of ∼2.7 at 24 h, and then SF decreases gradually from 24 to 48 h. More importantly, PGM prepared by stirring and filtration after stirring for 30 min, exhibiting very excellent separation performance toward l-/d-Phe (SF ≈ 4.76 at 24 h). The decrease of SF from 24 to 48 h can be attributed to the decrease of the concentration gradient between feed and driven solutions.(12) Nevertheless, the vortex PGM still maintains higher selectivity for l-/d-Phe after separation for 48 h, and the SF is up to 1.79. As shown in Figure 4g, the vortex structure still existed, indicating the excellent stability of PGM. In particular, the separation performance of vortex PGM is higher than that of chiral molecularly imprinted nanofiber membranes and a homochiral metal–organic framework membrane.(4,31) However, there is no direct evidence that the vortex caused by stirring controls stacking of PG sheets into a chiral shape in this work. Therefore, the mechanism of vortex deposition leading to chiral separation needs further study.
In summary, we have developed a facile, rapid, and low-cost approach for the fabrication of PG from graphite. The byproducts, in the form of salts, from the Hummers method are completely utilized. The preparation measures of PG are simplified from two steps to one step using the combustion of graphite oxides. The resulting PG was successfully used to prepare PGM for achieving selective separation of chiral molecules. We believe this strategy will open an avenue toward the construction of a nanoporous chiral graphene membrane, but further research is still needed about how the vortex causes chiral separations.
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The Supporting Information is available free of charge at https://pubs.acs.org/doi/10.1021/acs.analchem.0c02446.
Experimental; Preparation and formation mechanism of PG; Characterizations of PG; Characterizations and chiral separation performance of PGM (PDF)
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Author Information
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- Hongdeng Qiu - CAS Key Laboratory of Chemistry of Northwestern Plant Resources and Key Laboratory for Natural Medicine of Gansu Province, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences, Lanzhou 730000, China; University of Chinese Academy of Sciences, Chinese Academy of Sciences, Beijing 100049, China;
http://orcid.org/0000-0002-2702-9415;
H.T., Z.L., and H.Q. designed the research. The manuscript was written through the contributions of all authors.
The authors declare no competing financial interest.
Acknowledgments
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This study was conducted with financial assistance from the National Natural Science Foundation of China (Nos. 21974146, 21822407, and 21675164), the Foundation for Sci and Tech Research Project of Gansu Province (18JR3RA387), CAS “Light of West China” Program, and CAS President’s International Fellowship Initiative (2020VBA0009).
References
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This article references 31 other publications.
- 1Rekoske, J. E. Chiral separations. AIChE J. 2001, 47, 2– 5, DOI: 10.1002/aic.690470102[Crossref], [CAS], Google Scholar1https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD3MXmsF2mtw%253D%253D&md5=5e7a20a8c890292aef345d71e114d942Chiral separationsRekoske, James E.AIChE Journal (2001), 47 (1), 2-5CODEN: AICEAC; ISSN:0001-1541. (American Institute of Chemical Engineers)A review with many refs. of chiral sepn. techniques, both those currently in com. practice and emerging technologies. Efficiencies are highlighted, in both time and material resources, which can be exploited by sepn. techniques. Chiral sepn. methodologies, crystn., kinetic resolns., reaction-resoln. combinations, membrane-based sepns., liq. chromatog., and chiral sepns. vs. asym. synthesis are considered.
- 2Sun, P. Z.; Zheng, F.; Zhu, M.; Wang, K. L.; Zhong, M. L.; Wu, D. H.; Zhu, H. W. Realizing Synchronous Energy Harvesting and Ion Separation with Graphene Oxide Membranes. Sci. Rep. 2015, 4, 1– 5, DOI: 10.1038/srep05528
- 3Hauser, A. W.; Mardirossian, N.; Panetier, J. A.; Head-Gordon, M.; Bell, A. T.; Schwerdtfeger, P. Functionalized Graphene as a Gatekeeper for Chiral Molecules: An Alternative Concept for Chiral Separation. Angew. Chem., Int. Ed. 2014, 53, 9957– 9960, DOI: 10.1002/anie.201403145[Crossref], [CAS], Google Scholar3https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2cXhtFGmurfO&md5=beb1a3113e2b491ae2168f2c6094daa7Functionalized Graphene as a Gatekeeper for Chiral Molecules: An Alternative Concept for Chiral SeparationHauser, Andreas W.; Mardirossian, Narbe; Panetier, Julien A.; Head-Gordon, Martin; Bell, Alexis T.; Schwerdtfeger, PeterAngewandte Chemie, International Edition (2014), 53 (37), 9957-9960CODEN: ACIEF5; ISSN:1433-7851. (Wiley-VCH Verlag GmbH & Co. KGaA)The authors propose a new method of chiral sepn. using functionalized nanoporous graphene as an example. Computational simulations based on d. functional theory show that the attachment of a suitable chiral bouncer mol. to the pore rim prevents the passage of the undesired enantiomer while letting its mirror image through.
- 4Wang, W. J.; Dong, X. L.; Nan, J. P.; Jin, W. Q.; Hu, Z. Q.; Chen, Y. F.; Jiang, J. W. A homochiral metal-organic framework membrane for enantioselective separation. Chem. Commun. 2012, 48, 7022– 7024, DOI: 10.1039/c2cc32595k[Crossref], [PubMed], [CAS], Google Scholar4https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC38Xoslaks78%253D&md5=bf0ab19d417e7bc253d9793428a99149A homochiral metal-organic framework membrane for enantioselective separationWang, Wenjin; Dong, Xueliang; Nan, Jiangpu; Jin, Wanqin; Hu, Zhongqiao; Chen, Yifei; Jiang, JianwenChemical Communications (Cambridge, United Kingdom) (2012), 48 (56), 7022-7024CODEN: CHCOFS; ISSN:1359-7345. (Royal Society of Chemistry)For the 1st time, a homochiral metal-org. framework membrane was prepd. for the enantioselective sepn. of important chiral compds., esp. chiral drug intermediates, which will allow for the potential development of a new, sustainable and highly efficient chiral sepn. technique.
- 5Ward, T. J.; Baker, B. A. Chiral Separations. Anal. Chem. 2008, 80, 4363– 4372, DOI: 10.1021/ac800662y[ACS Full Text
], [CAS], Google Scholar5https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD1cXlvFakt7o%253D&md5=e5c48f52c472aef8bc3c43c68204a66eChiral SeparationsWard, Timothy J.; Baker, Beth AnnAnalytical Chemistry (Washington, DC, United States) (2008), 80 (12), 4363-4372CODEN: ANCHAM; ISSN:0003-2700. (American Chemical Society)A review. This fundamental review article covers developments and applications in chiral sepns. from Jan. 2006 to Jan. 2008 and is restricted to the English language literature. Chiral sepns. continue to increase in their importance due to their broad range of applications in drug development in pharmaceutical industries, pesticide development in agricultural industries, and prepn. of additives in the food industry, to name a few. The ability to understand sepn. techniques as well as chiral recognition models is useful to their application in both the anal. and preparative scale. The increase in the no. of reviews published in the past few years as compared to previous years indicates a mastery of the techniques that are commonly used in chiral sepns. While the field continues to progress in the development of new chiral phases and better mechanistic understanding, many of the techniques that are used remain essentially unchanged. However, while the basic techniques are very similar, the expansion of those techniques to include a broader range of applications is noteworthy. Noteworthy growth in the field of chiral sepn. techniques include the increased use of ionic liqs. to achieve chiral sepn. and its extension to countercurrent chromatog. The use of ionic liqs. appears to be widely applicable across various chromatog. fields, including HPLC, SFC, and GC. Also, publications covering preparative chiral sepns. have continued to increase over the past few years, indicating a broad acceptance and mastery of the techniques applied. - 6Xie, R.; Chu, L. Y.; Deng, J. G. Membranes and membrane processes for chiral resolution. Chem. Soc. Rev. 2008, 37, 1243– 1263, DOI: 10.1039/b713350b[Crossref], [PubMed], [CAS], Google Scholar6https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD1cXmtlSisbg%253D&md5=3d4e18f2294f8b786f5beee9bcc99ffdMembranes and membrane processes for chiral resolutionXie, Rui; Chu, Liang-Yin; Deng, Jin-GenChemical Society Reviews (2008), 37 (6), 1243-1263CODEN: CSRVBR; ISSN:0306-0012. (Royal Society of Chemistry)A review is devoted to an active field of research on chiral sepn., membrane-based enantiosepn. technique, which has potential for large-scale prodn. of single-enantiomer compds. Adsorption-type enantioselective membranes and membrane-assisted resoln. systems with non-enantioselective solid membranes have attracted much attention recently. The principles and recent developments of both enantioselective liq. and solid membranes and membrane-assisted processes for chiral resoln. are summarized comprehensively in this review, in which the contents are of interest to a wide range of readers in a variety of fields from anal., org. and medicinal chem., to pharmaceutics and materials, to process engineering for fabricating pharmaceuticals, agrochems., fragrances and foods, etc.
- 7Surwade, S. P.; Smirnov, S. N.; Vlassiouk, I. V.; Unocic, R. R.; Veith, G. M.; Dai, S.; Mahurin, S. M. Water desalination using nanoporous single-layer graphene. Nat. Nanotechnol. 2015, 10, 459– 464, DOI: 10.1038/nnano.2015.37[Crossref], [PubMed], [CAS], Google Scholar7https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2MXlt1aisr8%253D&md5=067d2ba296e0e3bd60417fd43f4c4f07Water desalination using nanoporous single-layer grapheneSurwade, Sumedh P.; Smirnov, Sergei N.; Vlassiouk, Ivan V.; Unocic, Raymond R.; Veith, Gabriel M.; Dai, Sheng; Mahurin, Shannon M.Nature Nanotechnology (2015), 10 (5), 459-464CODEN: NNAABX; ISSN:1748-3387. (Nature Publishing Group)By creating nanoscale pores in a layer of graphene, it could be used as an effective sepn. membrane due to its chem. and mech. stability, its flexibility and, most importantly, its 1-atom thickness. Theor. studies have indicated that the performance of such membranes should be superior to state-of-the-art polymer-based filtration membranes, and exptl. studies have recently begun to explore their potential. We show that single-layer porous graphene can be used as a desalination membrane. Nanometer-sized pores are created in a graphene monolayer using an O plasma etching process, which allows the size of the pores to be tuned. The resulting membranes exhibit a salt rejection rate of ∼100% and rapid water transport. In particular, water fluxes of ≤106 g/m2-s at 40° were measured using pressure difference as a driving force, while water fluxes measured using osmotic pressure as a driving force did not exceed 70 g/m2-s-atm.
- 8Cohen-Tanugi, D.; Grossman, J. C. Water Desalination across Nanoporous Graphene. Nano Lett. 2012, 12, 3602– 3608, DOI: 10.1021/nl3012853[ACS Full Text], [CAS], Google Scholar8https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC38XnvF2ksbw%253D&md5=a1d70f45469490f36bca0e3f5ae3e0d0Water Desalination across Nanoporous GrapheneCohen-Tanugi, David; Grossman, Jeffrey C.Nano Letters (2012), 12 (7), 3602-3608CODEN: NALEFD; ISSN:1530-6984. (American Chemical Society)This work showed nanometer-scale pores in single-layer, free-standing graphene can effectively filter NaCl salt from water. Using classical mol. dynamics, the desalination performance of such membranes as a function of pore size, chem. functionalization, and applied pressure was detd. Results indicate that membrane-prevented salt passage critically depended on pore diam.; adequately sized pores allowed for water flow while blocking ions. An examn. of the role of chem. functional groups bonded to the edge of graphene pores suggested commonly occurring hydroxyl groups roughly doubled water flux due to their hydrophilic character. The increased water flux came at the expense of less consistent salt rejection performance, which was attributed to the ability of hydroxyl functional groups to substitute for water mols. in the ions hydration shell. Overall results indicated the water permeability of this material was several orders of magnitude higher than conventional reverse osmosis membranes; nano-porous graphene may have a valuable role in water purifn.
- 9O’Hern, S. C.; Jang, D.; Bose, S.; Idrobo, J.-C.; Song, Y.; Laoui, T.; Kong, J.; Karnik, R. Nanofiltration across Defect-Sealed Nanoporous Monolayer Graphene. Nano Lett. 2015, 15, 3254– 3260, DOI: 10.1021/acs.nanolett.5b00456[ACS Full Text], [CAS], Google Scholar9https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2MXntF2ksr4%253D&md5=42365a9ee3348f01790f4087aeecc0aaNanofiltration across Defect-Sealed Nanoporous Monolayer GrapheneO'Hern, Sean C.; Jang, Doojoon; Bose, Suman; Idrobo, Juan-Carlos; Song, Yi; Laoui, Tahar; Kong, Jing; Karnik, RohitNano Letters (2015), 15 (5), 3254-3260CODEN: NALEFD; ISSN:1530-6984. (American Chemical Society)A multiscale leakage-sealing process that exploits the nonpolar nature and impermeability of pristine graphene to selectively block defects, resulting in a centimeter-scale membrane that can sep. two fluid reservoirs by an atomically thin layer of graphene, is reported. After introducing subnanometer pores in graphene, the membrane exhibited rejection of multivalent ions and small mols. and water flux consistent with prior mol. dynamics simulations. The results indicate the feasibility of constructing defect-tolerant monolayer graphene membranes for nanofiltration, desalination, and other sepn. processes.
- 10Boutilier, M. S. H.; Sun, C. Z.; O’Hern, S. C.; Au, H.; Hadjiconstantinou, N. G.; Karnik, R. Implications of Permeation through Intrinsic Defects in Graphene on the Design of Defect-Tolerant Membranes for Gas Separation. ACS Nano 2014, 8, 841– 849, DOI: 10.1021/nn405537u[ACS Full Text], [CAS], Google Scholar10https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2cXhvVSiuw%253D%253D&md5=db4f3e1dfc759652b94347fd3acc6e21Implications of Permeation through Intrinsic Defects in Graphene on the Design of Defect-Tolerant Membranes for Gas SeparationBoutilier, Michael S. H.; Sun, Chengzhen; O'Hern, Sean C.; Au, Harold; Hadjiconstantinou, Nicolas G.; Karnik, RohitACS Nano (2014), 8 (1), 841-849CODEN: ANCAC3; ISSN:1936-0851. (American Chemical Society)Gas transport through intrinsic defects and tears is a crit. yet poorly understood phenomenon in graphene membranes for gas sepn. The authors report that independent stacking of graphene layers on a porous support exponentially decreases flow through defects. From exptl. results, the authors develop a gas transport model that elucidates the sep. contributions of tears and intrinsic defects on gas leakage through these membranes. The model shows that the pore size of the porous support and its permeance critically affect the sepn. behavior, and reveals the parameter space where gas sepn. can be achieved regardless of the presence of nonselective defects, even for single-layer membranes. The results provide a framework for understanding gas transport in graphene membranes and guide the design of practical, selectively permeable graphene membranes for gas sepn.
- 11Koenig, S. P.; Wang, L. D.; Pellegrino, J.; Bunch, J. S. Selective molecular sieving through porous graphene. Nat. Nanotechnol. 2012, 7, 728– 732, DOI: 10.1038/nnano.2012.162[Crossref], [PubMed], [CAS], Google Scholar11https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC38XhsVKisbfF&md5=2c239eff3c12d03382b0ca226961831eSelective molecular sieving through porous grapheneKoenig, Steven P.; Wang, Luda; Pellegrino, John; Bunch, J. ScottNature Nanotechnology (2012), 7 (11), 728-732CODEN: NNAABX; ISSN:1748-3387. (Nature Publishing Group)Membranes act as selective barriers and play an important role in processes such as cellular compartmentalization and industrial-scale chem. and gas purifn. The ideal membrane should be as thin as possible to maximize flux, mech. robust to prevent fracture, and have well-defined pore sizes to increase selectivity. Graphene is an excellent starting point for developing size-selective membranes because of its at. thickness, high mech. strength, relative inertness and impermeability to all std. gases. However, pores that can exclude larger mols. but allow smaller mols. to pass through would have to be introduced into the material. Here, we show that UV-induced oxidative etching can create pores in micrometer-sized graphene membranes, and the resulting membranes can be used as mol. sieves. A pressurized blister test and mech. resonance are used to measure the transport of a range of gases (H2, CO2, Ar, N2, CH4 and SF6) through the pores. The exptl. measured leak rate, sepn. factors and Raman spectrum agree well with models based on effusion through a small no. of angstrom-sized pores.
- 12Li, Z.; Liu, Y. Q.; Zhao, Y.; Zhang, X.; Qian, L. J.; Tian, L. L.; Bai, J.; Qi, W.; Yao, H. J.; Gao, B.; Liu, J.; Wu, W. S.; Qiu, H. D. Selective Separation of Metal Ions via Monolayer Nanoporous Graphene with Carboxyl Groups. Anal. Chem. 2016, 88, 10002– 10010, DOI: 10.1021/acs.analchem.6b02175[ACS Full Text], [CAS], Google Scholar12https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC28XhsV2hs7rN&md5=f02a4c0cf5309958703d6339dbeadfd3Selective Separation of Metal Ions via Monolayer Nanoporous Graphene with Carboxyl GroupsLi, Zhan; Liu, Yanqi; Zhao, Yang; Zhang, Xin; Qian, Lijuan; Tian, Longlong; Bai, Jing; Qi, Wei; Yao, Huijun; Gao, Bin; Liu, Jie; Wu, Wangsuo; Qiu, HongdengAnalytical Chemistry (Washington, DC, United States) (2016), 88 (20), 10002-10010CODEN: ANCHAM; ISSN:0003-2700. (American Chemical Society)Graphene-coated plastic substrates, such as polyethylene terephthalate (PET), are regularly used in flexible electronic devices. Here we demonstrate a new application of the graphene-coated nanoporous PET membrane for the selective sepn. of metal ions in an ion exchange manner. Irradn. with swift heavy ions is used to perforate graphene and PET substrate. This process could create graphene nanopores with carboxyl groups, thus forming conical holes in the PET after chem. etching to support graphene nanopores. Therefore, a monolayer nanoporous graphene membrane with a PET substrate is constructed successfully to study its ionic selective sepn. We find that the permeation ratio of ions strongly depends on the temp. and H+ concn. in the driving soln. An elec. field can increase the permeation ratio of ions through the graphene nanopores, but it inhibits the ion selective sepn. Moreover, the structure of the graphene nanopore with carboxyl groups is resolved at the d. functional theory level. The results show the asym. structure of the nanopore with carboxyl groups, and the anal. indicates that the ionic permeation can be attributed to the ion exchange between metal ions and protons on the two sides of graphene nanopores. These results would be beneficial to the design of membrane sepn. materials made from graphene with efficient online and offline bulk sepn.
- 13Sun, P. Z.; Wang, K. L.; Zhu, H. W. Recent Developments in Graphene-Based Membranes: Structure, Mass-Transport Mechanism and Potential Applications. Adv. Mater. 2016, 28, 2287– 2310, DOI: 10.1002/adma.201502595[Crossref], [PubMed], [CAS], Google Scholar13https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC28Xht1ChsLs%253D&md5=4b346f341457da75e0735d90563ce23bRecent Developments in Graphene-Based Membranes: Structure, Mass-Transport Mechanism and Potential ApplicationsSun, Pengzhan; Wang, Kunlin; Zhu, HongweiAdvanced Materials (Weinheim, Germany) (2016), 28 (12), 2287-2310CODEN: ADVMEW; ISSN:0935-9648. (Wiley-VCH Verlag GmbH & Co. KGaA)A review. Significant achievements have been made on the development of next-generation filtration and sepn. membranes using graphene materials, as graphene-based membranes can afford numerous novel mass-transport properties that are not possible in state-of-art com. membranes, making them promising in areas such as membrane sepn., water desalination, proton conductors, energy storage and conversion, etc. The latest developments on understanding mass transport through graphene-based membranes, including perfect graphene lattice, nanoporous graphene and graphene oxide membranes are reviewed here in relation to their potential applications. A summary and outlook is further provided on the opportunities and challenges in this arising field. The aspects discussed may enable researchers to better understand the mass-transport mechanism and to optimize the synthesis of graphene-based membranes toward large-scale prodn. for a wide range of applications.
- 14Wang, L. D.; Boutilier, M. S. H.; Kidambi, P. R.; Jang, D.; Hadjiconstantinou, N. G.; Karnik, R. Fundamental transport mechanisms, fabrication and potential applications of nanoporous atomically thin membranes. Nat. Nanotechnol. 2017, 12, 509– 522, DOI: 10.1038/nnano.2017.72[Crossref], [PubMed], [CAS], Google Scholar14https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2sXpt1Oqur8%253D&md5=9996d427dbca1d7c29f550c0187757d4Fundamental transport mechanisms, fabrication and potential applications of nanoporous atomically thin membranesWang, Luda; Boutilier, Michael S. H.; Kidambi, Piran R.; Jang, Doojoon; Hadjiconstantinou, Nicolas G.; Karnik, RohitNature Nanotechnology (2017), 12 (6), 509-522CODEN: NNAABX; ISSN:1748-3387. (Nature Publishing Group)A review. Graphene and other two-dimensional materials offer a new approach to controlling mass transport at the nanoscale. These materials can sustain nanoscale pores in their rigid lattices and due to their min. possible material thickness, high mech. strength and chem. robustness, they could be used to address persistent challenges in membrane sepns. Here we discuss theor. and exptl. developments in the emerging field of nanoporous atomically thin membranes, focusing on the fundamental mechanisms of gas- and liq.-phase transport, membrane fabrication techniques and advances towards practical application. We highlight potential functional characteristics of the membranes and discuss applications where they are expected to offer advantages. Finally, we outline the major scientific questions and technol. challenges that need to be addressed to bridge the gap from theor. simulations and proof-of-concept expts. to real-world applications.
- 15Jiang, L. L.; Fan, Z. J. Design of advanced porous graphene materials: from graphene nanomesh to 3D architectures. Nanoscale 2014, 6, 1922– 1945, DOI: 10.1039/C3NR04555B[Crossref], [PubMed], [CAS], Google Scholar15https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2cXhsFartrk%253D&md5=23f360c8ae553a84b9e36223e88ba364Design of advanced porous graphene materials: from graphene nanomesh to 3D architecturesJiang, Lili; Fan, ZhuangjunNanoscale (2014), 6 (4), 1922-1945CODEN: NANOHL; ISSN:2040-3372. (Royal Society of Chemistry)A review. In order to make full utilization of the high intrinsic surface area of graphene, recently, porous graphene materials including graphene nanomesh, crumpled graphene and graphene foam, have attracted tremendous attention and research interest, owing to their exceptional porous structure (high surface area, and high pore vol.) in combination with the inherent properties of graphene, such as high electronic cond., good thermal stability, and excellent mech. strength. Interestingly, porous graphene materials and their derivs. have been explored in a wide range of applications in the fields of electronic and photonic devices, energy storage, gas sepn./storage, oil absorption and sensors. This article reviews recent progress in the synthesis, characterization, properties, and applications of porous graphene materials. We aim to highlight the importance of designing different porous structures of graphene to meet future challenges, and the trend on future design of porous graphene materials is analyzed.
- 16Li, Z.; Zhang, X.; Tan, H.; Qi, W.; Wang, L.; Ali, M. C.; Zhang, H.; Chen, J.; Hu, P.; Fan, C.; Qiu, H. Combustion Fabrication of Nanoporous Graphene for Ionic Separation Membranes. Adv. Funct. Mater. 2018, 28, 1805026, DOI: 10.1002/adfm.201805026
- 17Zhang, M.; Bao, W. X.; Liu, X. L.; Yu, B. Z.; Ren, Z. Y.; Bai, J. T.; Fan, H. M. Large-scale synthesis of porous graphene through nanoscale carbothermal reduction etching. J. Mater. Sci. 2015, 50, 7875– 7883, DOI: 10.1007/s10853-015-9309-1[Crossref], [CAS], Google Scholar17https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2MXhsFWhtL3P&md5=ee76bac6208b0ce17ae67d6ae5ef399fLarge-scale synthesis of porous graphene through nanoscale carbothermal reduction etchingZhang, Ming; Bao, Wen Xiao; Liu, Xiao Li; Yu, Bao Zhi; Ren, Zhao Yu; Bai, Jin Tao; Fan, Hai MingJournal of Materials Science (2015), 50 (24), 7875-7883CODEN: JMTSAS; ISSN:0022-2461. (Springer)Porous graphene, which features nanoscaled pores on the sheets, has shown great potential in many technol. important industries. However, the conversional approaches for the synthesis of porous graphene including high-energy techniques and template etching/growth methods are generally conducted on substrates with high cost and low throughput. Herein, we demonstrate a general and scalable synthetic method for porous graphene via carbothermal redn. reaction using monodisperse zinc oxide nanoparticles. The results indicate that ZnO nanoparticles were first attached on graphene oxide nanosheets by electrostatic interaction, and then undergone a carbothermal redn. reaction at 800 °C to produce the pores on the sheets. While graphene oxide nanosheets were thermally reduced to graphene, all the byproducts (carbon monoxide, carbon dioxide, and zinc) escaped from the final products simultaneously. The characterizations of the obtained porous graphene reveal that the pore size is about 11 nm, larger than that of ZnO nanoparticles (∼5 nm), which is ascribed to the aggregation of ZnO nanoparticles (∼20 nm) on the graphene oxide sheets. These results show the certain correlation among the sizes of pores, ZnO nanoparticles and ZnO aggregations, which gain insight into the controlling of pore size by choosing suitable etching agent.
- 18Han, S.; Wu, D. Q.; Li, S.; Zhang, F.; Feng, X. L. Porous Graphene Materials for Advanced Electrochemical Energy Storage and Conversion Devices. Adv. Mater. 2014, 26, 849– 864, DOI: 10.1002/adma.201303115[Crossref], [PubMed], [CAS], Google Scholar18https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3sXhvFCjtr3O&md5=b57290164ca07cad6523404fa95135fePorous graphene materials for advanced electrochemical energy storage and conversion devicesHan, Sheng; Wu, Dongqing; Li, Shuang; Zhang, Fan; Feng, XinliangAdvanced Materials (Weinheim, Germany) (2014), 26 (6), 849-864CODEN: ADVMEW; ISSN:0935-9648. (Wiley-VCH Verlag GmbH & Co. KGaA)A review. Combining the advantages from both porous materials and graphene, porous graphene materials have attracted vast interests due to their large surface areas, unique porous structures, diversified compns. and excellent electronic cond. These unordinary features enable porous graphene materials to serve as key components in high-performance electrochem. energy storage and conversion devices such as lithium ion batteries, supercapacitors, and fuel cells. This progress report summarizes the typical fabrication methods for porous graphene materials with micro-, meso-, and macro-porous structures. The structure-property relationships of these materials and their application in advanced electrochem. devices are also discussed.
- 19Song, L.; Zhang, H.; Cai, T.; Chen, J.; Li, Z.; Guan, M.; Qiu, H. Porous graphene decorated silica as a new stationary phase for separation of sulfanilamide compounds in hydrophilic interaction chromatography. Chin. Chem. Lett. 2019, 30, 863– 866, DOI: 10.1016/j.cclet.2018.10.040[Crossref], [CAS], Google Scholar19https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC1cXit1Cht7rN&md5=06ce42a89141ac4dc39df912e93551f9Porous graphene decorated silica as a new stationary phase for separation of sulfanilamide compounds in hydrophilic interaction chromatographySong, Lijun; Zhang, Haijuan; Cai, Tianpei; Chen, Jia; Li, Zhan; Guan, Ming; Qiu, HongdengChinese Chemical Letters (2019), 30 (4), 863-866CODEN: CCLEE7; ISSN:1001-8417. (Elsevier B.V.)Porous graphene (PG) has potential applications in numerous fields because of the existence of nanopores in the plane. Porous graphene decorated silica microspheres (Sil-PG) were successfully fabricated by assembling PG onto the silica particles surface in deep eutectic solvents (DESs). This new stationary phase can facilitate the sepn. of six sulfonamides compds. in hydrophilic chromatog. conditions. The successful synthesis of the Sil-PG stationary phase provides a basis for the application of porous graphene-modified materials as the stationary phase for liq. chromatog., and offers the possibility to broaden the application of PG in the field of chromatog.
- 20Yan, Y. G.; Li, W.; Kral, P. Enantioselective Molecular Transport in Multilayer Graphene Nanopores. Nano Lett. 2017, 17, 6742– 6746, DOI: 10.1021/acs.nanolett.7b02846[ACS Full Text], [CAS], Google Scholar20https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2sXhsFyqsrzL&md5=86f5c52a3185e721111629beafbe5cd1Enantioselective molecular transport in multilayer graphene nanoporesYan, Youguo; Li, Wen; Kral, PetrNano Letters (2017), 17 (11), 6742-6746CODEN: NALEFD; ISSN:1530-6984. (American Chemical Society)Multilayer superstructures based on stacked layered nanomaterials offer the possibility to design three-dimensional (3D) nanopores with highly specific properties analogous to protein channels. In a layer-by-layer design and stacking, analogous to mol. printing, superstructures with lock-and-key mol. nesting and transport characteristics could be prepd. To examine this possibility, we use mol. dynamics simulations to study elec. field-driven transport of ions through stacked porous graphene flakes. First, highly selective, tunable, and correlated passage rates of monovalent at. ions through these superstructures are obsd. in dependence on the ion type, nanopore type, and relative position and dynamics of neighboring porous flakes. Next, enantioselective mol. transport of ionized L- and D-leucine is obsd. in graphene stacks with helical nanopores. The outlined approach provides a general scheme for synthesis of functional 3D superstructures.
- 21Kim, C. J.; Sanchez-Castillo, A.; Ziegler, Z.; Ogawa, Y.; Noguez, C.; Park, J. Chiral atomically thin films. Nat. Nanotechnol. 2016, 11, 520– 524, DOI: 10.1038/nnano.2016.3[Crossref], [PubMed], [CAS], Google Scholar21https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC28XivFKgt7Y%253D&md5=8029da972deda655159245a18d8ff646Chiral atomically thin filmsKim, Cheol-Joo; Sanchez-Castillo, A.; Ziegler, Zack; Ogawa, Yui; Noguez, Cecilia; Park, JiwoongNature Nanotechnology (2016), 11 (6), 520-524CODEN: NNAABX; ISSN:1748-3387. (Nature Publishing Group)A chiral stacking approach, where 2-dimensional materials are positioned layer-by-layer with precise control of the interlayer rotation (θ) and polarity, resulting in tunable chiral properties of the final stack is reported. Using this method, left- and right-handed bilayer graphene, i.e., a 2-atom-thick chiral film, was produced. The film displays 1 of the highest intrinsic ellipticity values (6.5 deg μm-1) ever reported, and a remarkably strong CD with the peak energy and sign tuned by θ and polarity. These chiral properties originate from the large in-plane magnetic moment assocd. with the interlayer optical transition. The chiral properties of atomically thin films layer-by-layer can be programmed by producing 3-layer graphene films with structurally controlled CD spectra.
- 22Morrow, S. M.; Bissette, A. J.; Fletcher, S. P. Transmission of chirality through space and across length scales. Nat. Nanotechnol. 2017, 12, 410, DOI: 10.1038/nnano.2017.62[Crossref], [PubMed], [CAS], Google Scholar22https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2sXntFahtrk%253D&md5=950a10580a3f3b9d646a87804f8ddb46Transmission of chirality through space and across length scalesMorrow, Sarah M.; Bissette, Andrew J.; Fletcher, Stephen P.Nature Nanotechnology (2017), 12 (5), 410-419CODEN: NNAABX; ISSN:1748-3387. (Nature Publishing Group)Chirality is a fundamental property and vital to chem., biol., physics and materials science. The ability to use asymmetry to operate mol.-level machines or macroscopically functional devices, or to give novel properties to materials, may address key challenges at the heart of the phys. sciences. However, how chirality at one length scale can be translated to asymmetry at a different scale is largely not well understood. In this Review, we discuss systems where chiral information is translated across length scales and through space. A variety of synthetic systems involve the transmission of chiral information between the mol.-, meso- and macroscales. We show how fundamental stereochem. principles may be used to design and understand nanoscale chiral phenomena and highlight important recent advances relevant to nanotechnol. The survey reveals that while the study of stereochem. on the nanoscale is a rich and dynamic area, our understanding of how to control and harness it and dial-up specific properties is still in its infancy. The long-term goal of controlling nanoscale chirality promises to be an exciting journey, revealing insight into biol. mechanisms and providing new technologies based on dynamic phys. properties.
- 23Dzwolak, W. Vortex-induced chiral bifurcation in aggregating insulin. Chirality 2010, 22, E154– E160, DOI: 10.1002/chir.20896[Crossref], [PubMed], [CAS], Google Scholar23https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3cXhtlGrsrnE&md5=2db55b86652fa47c6ad41dc5c80d16c1Vortex-induced chiral bifurcation in aggregating insulinDzwolak, WojciechChirality (2010), 22 (1E), E154-E160CODEN: CHRLEP; ISSN:0899-0042. (Wiley-Liss, Inc.)A review. Chiral symmetry breaking occurs during vortex-assisted crystn. of several simple compds. leading to a stochastically detd. emergence of an enantiomeric excess of one chiral isomer. This article summarizes recent developments in studies of a similar phenomenon obsd. in agitated solns. of aggregating insulin, when a phase transition-pptn. of insol. amyloid fibrils from solns. of the native protein-is coupled to a conformational transition of the native alpha-helical structure into aggregated beta-sheets. In contrast to the previously known cases of chiral bifurcation, the substrate is built of L-amino acids and, therefore, chirally biased. However, under certain conditions, insulin forms fibrils with superstructural chiral features that are independent of the left-handedness of amino acid residues, as revealed by the sign of extrinsic Cotton effect induced in amyloid-bound achiral dye-thioflavin T. The inherent chiral bias of the protein results in a diastereomeric relationship between the two optical isomers of amyloid superstructures and the fact that relative probability of formation of either isomer is temp. dependent. As the formation of amyloid fibrils in vivo is assocd. with several degenerative disorders such as Alzheimer's disease, this newly obsd. phenomenon may have important implications in the context of structural basis of biol. activity of misfolded proteins. Chirality, 2010. © 2010 Wiley-Liss, Inc.
- 24D’Urso, A.; Randazzo, R.; Lo Faro, L.; Purrello, R. Vortexes and Nanoscale Chirality. Angew. Chem., Int. Ed. 2010, 49, 108– 112, DOI: 10.1002/anie.200903543[Crossref], [CAS], Google Scholar24https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD1MXhs1Wlt7bI&md5=8fa0c56bb1e5cb77a7abdaf26213ce15Vortexes and Nanoscale ChiralityD'Urso, Alessandro; Randazzo, Rosalba; Lo Faro, Letizia; Purrello, RobertoAngewandte Chemie, International Edition (2010), 49 (1), 108-112, S108/1-S108/8CODEN: ACIEF5; ISSN:1433-7851. (Wiley-VCH Verlag GmbH & Co. KGaA)The relation between vortexes and chirality of large assemblies is a very intriguing problem, which might lead to understanding fundamentals of nature and from this, to possible technol. applications. Herein the authors describe the behavior under stirring of noncovalent J-aggregates of the protonated form of meso- tetrakis(4-sulfonatophenyl) porphyrin. The hypothesis is that J-aggregates are inherently chiral and exist in aq. soln. as racemate: their distribution is affected by vortexes. This work reports quite strong exptl. evidence that, for the studied systems, stirring is shifting the equil. of a racemic mixt. towards the side chosen by the vortex chirality. It is not clear at the moment if, under the effect of a vortex, there is chiral enrichment and/or a racemate resoln.
- 25Di Mauro, A.; Randazzo, R.; Spano, S. F.; Compagnini, G.; Gaeta, M.; D’Urso, L.; Paolesse, R.; Pomarico, G.; Di Natale, C.; Villari, V.; Micali, N.; Fragala, M. E.; D’Urso, A.; Purrello, R. Vortexes tune the chirality of graphene oxide and its non-covalent hosts. Chem. Commun. 2016, 52, 13094– 13096, DOI: 10.1039/C6CC05177D[Crossref], [PubMed], [CAS], Google Scholar25https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC28XhtlCrtbrF&md5=22d8d2f01701e53ff5c0282be89b995eVortexes tune the chirality of graphene oxide and its non-covalent hostsDi Mauro, A.; Randazzo, R.; Spano, S. F.; Compagnini, G.; Gaeta, M.; D'Urso, L.; Paolesse, R.; Pomarico, G.; Di Natale, C.; Villari, V.; Micali, N.; Fragala, M. E.; D'Urso, A.; Purrello, R.Chemical Communications (Cambridge, United Kingdom) (2016), 52 (89), 13094-13096CODEN: CHCOFS; ISSN:1359-7345. (Royal Society of Chemistry)Graphene oxide (GO) is one of the most appealing bidimensional materials able to interact non-covalently with achiral mols. and to act as chiral inducers. Vortexes can tune chirality and, consequently transfer a specific handedness to non-covalent host mols., either when dispersed in water or when deposited on a solid surface.
- 26Zhou, D.; Cui, Y.; Xiao, P. W.; Jiang, M. Y.; Han, B. H. A general and scalable synthesis approach to porous graphene. Nat. Commun. 2014, 5, 4716, DOI: 10.1038/ncomms5716[Crossref], [PubMed], [CAS], Google Scholar26https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2MXktFensrc%253D&md5=eab43bb01beb357cca7b2f06d37c2701A general and scalable synthesis approach to porous grapheneZhou, Ding; Cui, Yi; Xiao, Pei-Wen; Jiang, Mei-Yang; Han, Bao-HangNature Communications (2014), 5 (), 4716CODEN: NCAOBW; ISSN:2041-1723. (Nature Publishing Group)Porous graphene, which features nano-scaled pores on the sheets, is mostly investigated by computational studies. The pores on the graphene sheets may contribute to the improved mass transfer and may show potential applications in many fields. To date, the prepn. of porous graphene includes chem. bottom-up approach via the aryl-aryl coupling reaction and phys. prepn. by high-energy techniques, and is generally conducted on substrates with limited yields. Here we show a general and scalable synthesis method for porous graphene that is developed through the carbothermal reaction between graphene and metal oxide nanoparticles produced from oxometalates or polyoxometalates. The pore formation process is obsd. in situ with the assistance of an electron beam. Pore engineering on graphene is conducted by controlling the pore size and/or the nitrogen doping on the porous graphene sheets by varying the amt. of the oxometalates or polyoxometalates, or using ammonium-contg. oxometalates or polyoxometalates.
- 27Tan, H. X.; Zhang, X.; Li, Z.; Qiu, H. D. Small-Scale Nanoparticles Pyrolyzed from Layered Hydrotalcite between Graphene Interlayers as Intermediates for Self-Assembly into Metal Oxide Nanosheets and Hollow Nanospheres. ChemNanoMat 2020, 6, 1270– 1275, DOI: 10.1002/cnma.202000224[Crossref], [CAS], Google Scholar27https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BB3cXhsFGhs7jK&md5=b33371a9918f8ff8364349ae956e5c47Small-Scale Nanoparticles Pyrolyzed from Layered Hydrotalcite between Graphene Interlayers as Intermediates for Self-Assembly into Metal Oxide Nanosheets and Hollow NanospheresTan, Hongxin; Zhang, Xin; Li, Zhan; Qiu, HongdengChemNanoMat (2020), 6 (8), 1270-1275CODEN: CHEMSB; ISSN:2199-692X. (Wiley-VCH Verlag GmbH & Co. KGaA)Although significant advances have been made in the synthesis of various two-dimensional (2D) nanomaterials, problems of inefficient and difficult to scale applications remain. Here, a novel strategy is reported for obtaining 2D nanosheets from the 2D interlayer space of a graphene oxide (GO) membrane through combustion, which provides a simple and rapid method for the fabrication of 2D nanosheets as well as hollow nanospheres. Layered hydrotalcite from metal nitrates is formed between GO interlayers, which can be pyrolyzed into small-sized oxide nanoparticles (3-5 nm) and then aggregated as intermediates into large-sized nanosheets by combustion with Co, Ni, and Cr nitrates. However, the oxide intermediates self-assemble into hollow oxide nanospheres for nitrates of more active Cd, Ce, and Eu. Moreover, the intermediates of inactive Ag, Pb, and Bi nitrates are reduced by GO into metal nanoparticles, which can fuse into Ag nanofiber network films, or Pb and Bi composite spheres because of their low m.p. This work is helpful to understand the nature of 2D space and develops a class of micro-scale reactors between graphene layers.
- 28Cheng, Q. F.; Wu, M. X.; Li, M. Z.; Jiang, L.; Tang, Z. Y. Ultratough Artificial Nacre Based on Conjugated Cross-linked Graphene Oxide. Angew. Chem., Int. Ed. 2013, 52, 3750– 3755, DOI: 10.1002/anie.201210166[Crossref], [CAS], Google Scholar28https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3sXitlemsb8%253D&md5=8b465818181e646a26cc720866e03b0cUltratough Artificial Nacre Based on Conjugated Cross-linked Graphene OxideCheng, Qunfeng; Wu, Mengxi; Li, Mingzhu; Jiang, Lei; Tang, ZhiyongAngewandte Chemie, International Edition (2013), 52 (13), 3750-3755CODEN: ACIEF5; ISSN:1433-7851. (Wiley-VCH Verlag GmbH & Co. KGaA)Inspired by natural nacre, we successfully fabricated graphene oxide (GO)-based composites. We have developed a novel strategy for fabricating the ultratough artificial nacre based on 2-D GO sheets by conjugated crosslinking. Highly π-conjugated long-chain polymers made of 10,12-pentacosadiyn-1-ol (PCDO) monomers are cross-linked with the GO sheets, resulting in a huge displacement upon loading and adsorption of much more fracture energy. In comparison with previous prepn. methods, this novel crosslinking strategy demonstrates the following crucial advantages: 1) It dramatically decreases the content of org. polymers in the resultant composites, which is comparable to the natural nacre; 2) it produces the distinct inorg.-org. layered hierarchical nano-/microstructures; 3) it realizes integration of the high tensile strength and excellent toughness; and 4) it creates highly conductive composites based on GO and conjugated mols. The toughness is two times higher than that of the natural nacre. Furthermore, the π-conjugated polymers could add addnl. benefit to the high elec. cond. of the chem. reduced GO (rGO). This study opens the door toward biomimetic prodn. of the GO- or rGO-based composites of superior toughness and high cond., which will have great promising applications in many fields, such as aerospace, flexible supercapacitor electrodes, artificial muscles, and tissue engineering.
- 29Wan, S. J.; Hu, H.; Peng, J. S.; Li, Y. C.; Fan, Y. Z.; Jiang, L.; Cheng, Q. F. Nacre-inspired integrated strong and tough reduced graphene oxide-poly (acrylic acid) nanocomposites. Nanoscale 2016, 8, 5649– 5656, DOI: 10.1039/C6NR00562D[Crossref], [PubMed], [CAS], Google Scholar29https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC28XitFehtrs%253D&md5=94e53ba9d17191678e653dd9bdb6f845Nacre-inspired integrated strong and tough reduced graphene oxide-poly(acrylic acid) nanocompositesWan, Sijie; Hu, Han; Peng, Jingsong; Li, Yuchen; Fan, Yuzun; Jiang, Lei; Cheng, QunfengNanoscale (2016), 8 (10), 5649-5656CODEN: NANOHL; ISSN:2040-3372. (Royal Society of Chemistry)Inspired by the relationship between interface interactions and the high performance mech. properties of nacre, a strong and tough nacre-inspired nanocomposite was demonstrated based on graphene oxide (GO) and polyacrylic acid (PAA) prepd. via a vacuum-assisted filtration self-assembly process. The abundant hydrogen bonding between GO and PAA results in both high strength and toughness of the bioinspired nanocomposites, which are 2 and 3.3 times higher than that of pure reduced GO film, resp. In addn., the effect of environmental relative humidity on the mech. properties of bioinspired nanocomposites is also investigated, and is consistent with previous theor. predictions. Moreover, this nacre-inspired nanocomposite also displays high elec. cond. of 108.9 S cm-1. These excellent phys. properties allow this type of nacre-inspired nanocomposite to be used in many applications, such as flexible electrodes, aerospace applications, and artificial muscles etc. This nacre-inspired strategy also opens an avenue for constructing integrated high performance graphene-based nanocomposites in the near future.
- 30Huang, H. B.; Mao, Y. Y.; Ying, Y. L.; Liu, Y.; Sun, L. W.; Peng, X. S. Salt concentration, pH and pressure controlled separation of small molecules through lamellar graphene oxide membranes. Chem. Commun. 2013, 49, 5963– 5965, DOI: 10.1039/c3cc41953c[Crossref], [PubMed], [CAS], Google Scholar30https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3sXovFWnsL4%253D&md5=ebf37065f080686d03b9403dd54ae90fSalt concentration, pH and pressure controlled separation of small molecules through lamellar graphene oxide membranesHuang, Hubiao; Mao, Yiyin; Ying, Yulong; Liu, Yu; Sun, Luwei; Peng, XinshengChemical Communications (Cambridge, United Kingdom) (2013), 49 (53), 5963-5965CODEN: CHCOFS; ISSN:1359-7345. (Royal Society of Chemistry)For the 1st time, pressure, salt concn. and pH demonstrated advantages for tuning the nanochannels within lamellar graphene oxide (LGO) membranes to control the sepn. of small mols. This provides a new avenue for designing and engineering efficient LGO membranes for mol. sepn.
- 31Sueyoshi, Y.; Fukushima, C.; Yoshikawa, M. Molecularly imprinted nanofiber membranes from cellulose acetate aimed for chiral separation. J. Membr. Sci. 2010, 357, 90– 97, DOI: 10.1016/j.memsci.2010.04.005[Crossref], [CAS], Google Scholar31https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3cXmsVOit7Y%253D&md5=b5af7f9563301bf1dbce3b92db3a76b7Molecularly imprinted nanofiber membranes from cellulose acetate aimed for chiral separationSueyoshi, Yuuki; Fukushima, Chiho; Yoshikawa, MasakazuJournal of Membrane Science (2010), 357 (1-2), 90-97CODEN: JMESDO; ISSN:0376-7388. (Elsevier B.V.)Permselectivity and throughput (flux) are important specificity in membrane sepn. It is an ultimate dream for membranologists to simultaneously enhance not only permselectivity but also flux, which generally show a trade-off relation. A breakthrough in membrane sepn. would be realized by adopting membranes with higher surface area, which leads to higher mol. recognition site concn., and higher porosity. Such sepn. membranes would be obtained by applying an electrospray deposition technique. To this end, molecularly imprinted nanofiber membranes were prepd. from cellulose acetate (CA) and a print mol., a deriv. of optically pure glutamic acid, such as N-α-benzyloxycarbonyl-D-glutamic acid (Z-D-Glu) or N-α-benzyloxycarbonyl-L-glutamic acid (Z-L-Glu). Membrane performance of molecularly imprinted nanofiber membranes and usual molecularly imprinted membranes was compared in terms of adsorption selectivity, affinity const., permselectivity, and flux. The results obtained in the present study revealed that electrospray deposition would be one of plausible methods to construct sepn. membranes to simultaneously enhance permselevtivity and flux.
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- Hongxin Tan, Xin Zhang, Zhan Li, Qing Liang, Jinsheng Wu, Yanli Yuan, Shiwei Cao, Jia Chen, Juewen Liu, Hongdeng Qiu. Nitrogen-doped Nanoporous Graphene Induced by a Multiple Confinement Strategy for Membrane Separation of Rare Earth. iScience 2020, , 101920. https://doi.org/10.1016/j.isci.2020.101920
Abstract
Figure 1
Figure 1. Synthesis of PGM with vortex structures. Sulfate is derived from the reaction byproducts in the Hummers method, which forms nanoparticles between layers of graphite oxides in combustion, then the pore is etched by the carbothermal reaction on each layer of graphite oxide at high temperature, and PG is obtained after washing and ultrasound treatment. PGM with vortex structures is prepared by mechanical stirring. The optical activities of the front of PGM are opposite to that of the back.
Figure 2
Figure 2. Characterizations of PG and PGMs with different pore sizes. (a–c) transmission electron microscopy (TEM) images of PG. (d–f) Surface SEM images of PGM. (g–i) Cross-sectional SEM images of PGM. (j) Schematic of chiral separation equipment; the racemic and HCI solution are placed as the feed and permeate solutions, respectively. (k) Photograph of PGM.
Figure 3
Figure 3. Separation of enantiomer molecules through PGM under an acidic environment. (a) Permeation dynamics of d-Phe through PGM under acidity driven with 2 and 4 M HCl. (b) Separation of l-Phe and d-Phe under acidity driven with 2 and 4 M HCl after 48 h. (c) Separation of l-Phe and d-Phe as a function of the membrane thickness under acidity driven with 4 M HCl after 48 h. (d) Separation of l-Glu and d-Glu under acidity driven with 4 M HCl after 36 and 48 h. The concentration of the initial feed solution is 0.01 M.
Figure 4
Figure 4. Characterizations and separation performance of PGM prepared by stirring and filtering. (a) Picture of PGM prepared by clockwise stirring. Inset: a high-resolution image of vortex structure on the PGM surface. (b) Schematic diagram of stirring and filtering equipment. (c) Vortex pattern after stirring for different times, observed on rhodamine-B dyed PGM by confocal laser scanning microscope; the yellow arrows identify the vortex structure. (d) CD spectra of stirred PG suspensions at 0, 5, 15, and 30 min, with a stirring speed of 600 rpm. (e) CD spectra of the front and back of PGM. (f) SF of l-/d-Phe through PGM prepared by filtration without stirring, stirring before filtration, and stirring filtration. The feed solution is 0.01 M of racemic l-/d-Phe solution; driven solution is 4 M HCl. (g) Vortex pattern after separation for a different time, and the yellow arrows identify the vortex structure.
References
ARTICLE SECTIONSThis article references 31 other publications.
- 1Rekoske, J. E. Chiral separations. AIChE J. 2001, 47, 2– 5, DOI: 10.1002/aic.690470102[Crossref], [CAS], Google Scholar1https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD3MXmsF2mtw%253D%253D&md5=5e7a20a8c890292aef345d71e114d942Chiral separationsRekoske, James E.AIChE Journal (2001), 47 (1), 2-5CODEN: AICEAC; ISSN:0001-1541. (American Institute of Chemical Engineers)A review with many refs. of chiral sepn. techniques, both those currently in com. practice and emerging technologies. Efficiencies are highlighted, in both time and material resources, which can be exploited by sepn. techniques. Chiral sepn. methodologies, crystn., kinetic resolns., reaction-resoln. combinations, membrane-based sepns., liq. chromatog., and chiral sepns. vs. asym. synthesis are considered.
- 2Sun, P. Z.; Zheng, F.; Zhu, M.; Wang, K. L.; Zhong, M. L.; Wu, D. H.; Zhu, H. W. Realizing Synchronous Energy Harvesting and Ion Separation with Graphene Oxide Membranes. Sci. Rep. 2015, 4, 1– 5, DOI: 10.1038/srep05528
- 3Hauser, A. W.; Mardirossian, N.; Panetier, J. A.; Head-Gordon, M.; Bell, A. T.; Schwerdtfeger, P. Functionalized Graphene as a Gatekeeper for Chiral Molecules: An Alternative Concept for Chiral Separation. Angew. Chem., Int. Ed. 2014, 53, 9957– 9960, DOI: 10.1002/anie.201403145[Crossref], [CAS], Google Scholar3https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2cXhtFGmurfO&md5=beb1a3113e2b491ae2168f2c6094daa7Functionalized Graphene as a Gatekeeper for Chiral Molecules: An Alternative Concept for Chiral SeparationHauser, Andreas W.; Mardirossian, Narbe; Panetier, Julien A.; Head-Gordon, Martin; Bell, Alexis T.; Schwerdtfeger, PeterAngewandte Chemie, International Edition (2014), 53 (37), 9957-9960CODEN: ACIEF5; ISSN:1433-7851. (Wiley-VCH Verlag GmbH & Co. KGaA)The authors propose a new method of chiral sepn. using functionalized nanoporous graphene as an example. Computational simulations based on d. functional theory show that the attachment of a suitable chiral bouncer mol. to the pore rim prevents the passage of the undesired enantiomer while letting its mirror image through.
- 4Wang, W. J.; Dong, X. L.; Nan, J. P.; Jin, W. Q.; Hu, Z. Q.; Chen, Y. F.; Jiang, J. W. A homochiral metal-organic framework membrane for enantioselective separation. Chem. Commun. 2012, 48, 7022– 7024, DOI: 10.1039/c2cc32595k[Crossref], [PubMed], [CAS], Google Scholar4https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC38Xoslaks78%253D&md5=bf0ab19d417e7bc253d9793428a99149A homochiral metal-organic framework membrane for enantioselective separationWang, Wenjin; Dong, Xueliang; Nan, Jiangpu; Jin, Wanqin; Hu, Zhongqiao; Chen, Yifei; Jiang, JianwenChemical Communications (Cambridge, United Kingdom) (2012), 48 (56), 7022-7024CODEN: CHCOFS; ISSN:1359-7345. (Royal Society of Chemistry)For the 1st time, a homochiral metal-org. framework membrane was prepd. for the enantioselective sepn. of important chiral compds., esp. chiral drug intermediates, which will allow for the potential development of a new, sustainable and highly efficient chiral sepn. technique.
- 5Ward, T. J.; Baker, B. A. Chiral Separations. Anal. Chem. 2008, 80, 4363– 4372, DOI: 10.1021/ac800662y[ACS Full Text], [CAS], Google Scholar5https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD1cXlvFakt7o%253D&md5=e5c48f52c472aef8bc3c43c68204a66eChiral SeparationsWard, Timothy J.; Baker, Beth AnnAnalytical Chemistry (Washington, DC, United States) (2008), 80 (12), 4363-4372CODEN: ANCHAM; ISSN:0003-2700. (American Chemical Society)A review. This fundamental review article covers developments and applications in chiral sepns. from Jan. 2006 to Jan. 2008 and is restricted to the English language literature. Chiral sepns. continue to increase in their importance due to their broad range of applications in drug development in pharmaceutical industries, pesticide development in agricultural industries, and prepn. of additives in the food industry, to name a few. The ability to understand sepn. techniques as well as chiral recognition models is useful to their application in both the anal. and preparative scale. The increase in the no. of reviews published in the past few years as compared to previous years indicates a mastery of the techniques that are commonly used in chiral sepns. While the field continues to progress in the development of new chiral phases and better mechanistic understanding, many of the techniques that are used remain essentially unchanged. However, while the basic techniques are very similar, the expansion of those techniques to include a broader range of applications is noteworthy. Noteworthy growth in the field of chiral sepn. techniques include the increased use of ionic liqs. to achieve chiral sepn. and its extension to countercurrent chromatog. The use of ionic liqs. appears to be widely applicable across various chromatog. fields, including HPLC, SFC, and GC. Also, publications covering preparative chiral sepns. have continued to increase over the past few years, indicating a broad acceptance and mastery of the techniques applied.
- 6Xie, R.; Chu, L. Y.; Deng, J. G. Membranes and membrane processes for chiral resolution. Chem. Soc. Rev. 2008, 37, 1243– 1263, DOI: 10.1039/b713350b[Crossref], [PubMed], [CAS], Google Scholar6https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD1cXmtlSisbg%253D&md5=3d4e18f2294f8b786f5beee9bcc99ffdMembranes and membrane processes for chiral resolutionXie, Rui; Chu, Liang-Yin; Deng, Jin-GenChemical Society Reviews (2008), 37 (6), 1243-1263CODEN: CSRVBR; ISSN:0306-0012. (Royal Society of Chemistry)A review is devoted to an active field of research on chiral sepn., membrane-based enantiosepn. technique, which has potential for large-scale prodn. of single-enantiomer compds. Adsorption-type enantioselective membranes and membrane-assisted resoln. systems with non-enantioselective solid membranes have attracted much attention recently. The principles and recent developments of both enantioselective liq. and solid membranes and membrane-assisted processes for chiral resoln. are summarized comprehensively in this review, in which the contents are of interest to a wide range of readers in a variety of fields from anal., org. and medicinal chem., to pharmaceutics and materials, to process engineering for fabricating pharmaceuticals, agrochems., fragrances and foods, etc.
- 7Surwade, S. P.; Smirnov, S. N.; Vlassiouk, I. V.; Unocic, R. R.; Veith, G. M.; Dai, S.; Mahurin, S. M. Water desalination using nanoporous single-layer graphene. Nat. Nanotechnol. 2015, 10, 459– 464, DOI: 10.1038/nnano.2015.37[Crossref], [PubMed], [CAS], Google Scholar7https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2MXlt1aisr8%253D&md5=067d2ba296e0e3bd60417fd43f4c4f07Water desalination using nanoporous single-layer grapheneSurwade, Sumedh P.; Smirnov, Sergei N.; Vlassiouk, Ivan V.; Unocic, Raymond R.; Veith, Gabriel M.; Dai, Sheng; Mahurin, Shannon M.Nature Nanotechnology (2015), 10 (5), 459-464CODEN: NNAABX; ISSN:1748-3387. (Nature Publishing Group)By creating nanoscale pores in a layer of graphene, it could be used as an effective sepn. membrane due to its chem. and mech. stability, its flexibility and, most importantly, its 1-atom thickness. Theor. studies have indicated that the performance of such membranes should be superior to state-of-the-art polymer-based filtration membranes, and exptl. studies have recently begun to explore their potential. We show that single-layer porous graphene can be used as a desalination membrane. Nanometer-sized pores are created in a graphene monolayer using an O plasma etching process, which allows the size of the pores to be tuned. The resulting membranes exhibit a salt rejection rate of ∼100% and rapid water transport. In particular, water fluxes of ≤106 g/m2-s at 40° were measured using pressure difference as a driving force, while water fluxes measured using osmotic pressure as a driving force did not exceed 70 g/m2-s-atm.
- 8Cohen-Tanugi, D.; Grossman, J. C. Water Desalination across Nanoporous Graphene. Nano Lett. 2012, 12, 3602– 3608, DOI: 10.1021/nl3012853[ACS Full Text], [CAS], Google Scholar8https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC38XnvF2ksbw%253D&md5=a1d70f45469490f36bca0e3f5ae3e0d0Water Desalination across Nanoporous GrapheneCohen-Tanugi, David; Grossman, Jeffrey C.Nano Letters (2012), 12 (7), 3602-3608CODEN: NALEFD; ISSN:1530-6984. (American Chemical Society)This work showed nanometer-scale pores in single-layer, free-standing graphene can effectively filter NaCl salt from water. Using classical mol. dynamics, the desalination performance of such membranes as a function of pore size, chem. functionalization, and applied pressure was detd. Results indicate that membrane-prevented salt passage critically depended on pore diam.; adequately sized pores allowed for water flow while blocking ions. An examn. of the role of chem. functional groups bonded to the edge of graphene pores suggested commonly occurring hydroxyl groups roughly doubled water flux due to their hydrophilic character. The increased water flux came at the expense of less consistent salt rejection performance, which was attributed to the ability of hydroxyl functional groups to substitute for water mols. in the ions hydration shell. Overall results indicated the water permeability of this material was several orders of magnitude higher than conventional reverse osmosis membranes; nano-porous graphene may have a valuable role in water purifn.
- 9O’Hern, S. C.; Jang, D.; Bose, S.; Idrobo, J.-C.; Song, Y.; Laoui, T.; Kong, J.; Karnik, R. Nanofiltration across Defect-Sealed Nanoporous Monolayer Graphene. Nano Lett. 2015, 15, 3254– 3260, DOI: 10.1021/acs.nanolett.5b00456[ACS Full Text], [CAS], Google Scholar9https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2MXntF2ksr4%253D&md5=42365a9ee3348f01790f4087aeecc0aaNanofiltration across Defect-Sealed Nanoporous Monolayer GrapheneO'Hern, Sean C.; Jang, Doojoon; Bose, Suman; Idrobo, Juan-Carlos; Song, Yi; Laoui, Tahar; Kong, Jing; Karnik, RohitNano Letters (2015), 15 (5), 3254-3260CODEN: NALEFD; ISSN:1530-6984. (American Chemical Society)A multiscale leakage-sealing process that exploits the nonpolar nature and impermeability of pristine graphene to selectively block defects, resulting in a centimeter-scale membrane that can sep. two fluid reservoirs by an atomically thin layer of graphene, is reported. After introducing subnanometer pores in graphene, the membrane exhibited rejection of multivalent ions and small mols. and water flux consistent with prior mol. dynamics simulations. The results indicate the feasibility of constructing defect-tolerant monolayer graphene membranes for nanofiltration, desalination, and other sepn. processes.
- 10Boutilier, M. S. H.; Sun, C. Z.; O’Hern, S. C.; Au, H.; Hadjiconstantinou, N. G.; Karnik, R. Implications of Permeation through Intrinsic Defects in Graphene on the Design of Defect-Tolerant Membranes for Gas Separation. ACS Nano 2014, 8, 841– 849, DOI: 10.1021/nn405537u[ACS Full Text], [CAS], Google Scholar10https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2cXhvVSiuw%253D%253D&md5=db4f3e1dfc759652b94347fd3acc6e21Implications of Permeation through Intrinsic Defects in Graphene on the Design of Defect-Tolerant Membranes for Gas SeparationBoutilier, Michael S. H.; Sun, Chengzhen; O'Hern, Sean C.; Au, Harold; Hadjiconstantinou, Nicolas G.; Karnik, RohitACS Nano (2014), 8 (1), 841-849CODEN: ANCAC3; ISSN:1936-0851. (American Chemical Society)Gas transport through intrinsic defects and tears is a crit. yet poorly understood phenomenon in graphene membranes for gas sepn. The authors report that independent stacking of graphene layers on a porous support exponentially decreases flow through defects. From exptl. results, the authors develop a gas transport model that elucidates the sep. contributions of tears and intrinsic defects on gas leakage through these membranes. The model shows that the pore size of the porous support and its permeance critically affect the sepn. behavior, and reveals the parameter space where gas sepn. can be achieved regardless of the presence of nonselective defects, even for single-layer membranes. The results provide a framework for understanding gas transport in graphene membranes and guide the design of practical, selectively permeable graphene membranes for gas sepn.
- 11Koenig, S. P.; Wang, L. D.; Pellegrino, J.; Bunch, J. S. Selective molecular sieving through porous graphene. Nat. Nanotechnol. 2012, 7, 728– 732, DOI: 10.1038/nnano.2012.162[Crossref], [PubMed], [CAS], Google Scholar11https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC38XhsVKisbfF&md5=2c239eff3c12d03382b0ca226961831eSelective molecular sieving through porous grapheneKoenig, Steven P.; Wang, Luda; Pellegrino, John; Bunch, J. ScottNature Nanotechnology (2012), 7 (11), 728-732CODEN: NNAABX; ISSN:1748-3387. (Nature Publishing Group)Membranes act as selective barriers and play an important role in processes such as cellular compartmentalization and industrial-scale chem. and gas purifn. The ideal membrane should be as thin as possible to maximize flux, mech. robust to prevent fracture, and have well-defined pore sizes to increase selectivity. Graphene is an excellent starting point for developing size-selective membranes because of its at. thickness, high mech. strength, relative inertness and impermeability to all std. gases. However, pores that can exclude larger mols. but allow smaller mols. to pass through would have to be introduced into the material. Here, we show that UV-induced oxidative etching can create pores in micrometer-sized graphene membranes, and the resulting membranes can be used as mol. sieves. A pressurized blister test and mech. resonance are used to measure the transport of a range of gases (H2, CO2, Ar, N2, CH4 and SF6) through the pores. The exptl. measured leak rate, sepn. factors and Raman spectrum agree well with models based on effusion through a small no. of angstrom-sized pores.
- 12Li, Z.; Liu, Y. Q.; Zhao, Y.; Zhang, X.; Qian, L. J.; Tian, L. L.; Bai, J.; Qi, W.; Yao, H. J.; Gao, B.; Liu, J.; Wu, W. S.; Qiu, H. D. Selective Separation of Metal Ions via Monolayer Nanoporous Graphene with Carboxyl Groups. Anal. Chem. 2016, 88, 10002– 10010, DOI: 10.1021/acs.analchem.6b02175[ACS Full Text], [CAS], Google Scholar12https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC28XhsV2hs7rN&md5=f02a4c0cf5309958703d6339dbeadfd3Selective Separation of Metal Ions via Monolayer Nanoporous Graphene with Carboxyl GroupsLi, Zhan; Liu, Yanqi; Zhao, Yang; Zhang, Xin; Qian, Lijuan; Tian, Longlong; Bai, Jing; Qi, Wei; Yao, Huijun; Gao, Bin; Liu, Jie; Wu, Wangsuo; Qiu, HongdengAnalytical Chemistry (Washington, DC, United States) (2016), 88 (20), 10002-10010CODEN: ANCHAM; ISSN:0003-2700. (American Chemical Society)Graphene-coated plastic substrates, such as polyethylene terephthalate (PET), are regularly used in flexible electronic devices. Here we demonstrate a new application of the graphene-coated nanoporous PET membrane for the selective sepn. of metal ions in an ion exchange manner. Irradn. with swift heavy ions is used to perforate graphene and PET substrate. This process could create graphene nanopores with carboxyl groups, thus forming conical holes in the PET after chem. etching to support graphene nanopores. Therefore, a monolayer nanoporous graphene membrane with a PET substrate is constructed successfully to study its ionic selective sepn. We find that the permeation ratio of ions strongly depends on the temp. and H+ concn. in the driving soln. An elec. field can increase the permeation ratio of ions through the graphene nanopores, but it inhibits the ion selective sepn. Moreover, the structure of the graphene nanopore with carboxyl groups is resolved at the d. functional theory level. The results show the asym. structure of the nanopore with carboxyl groups, and the anal. indicates that the ionic permeation can be attributed to the ion exchange between metal ions and protons on the two sides of graphene nanopores. These results would be beneficial to the design of membrane sepn. materials made from graphene with efficient online and offline bulk sepn.
- 13Sun, P. Z.; Wang, K. L.; Zhu, H. W. Recent Developments in Graphene-Based Membranes: Structure, Mass-Transport Mechanism and Potential Applications. Adv. Mater. 2016, 28, 2287– 2310, DOI: 10.1002/adma.201502595[Crossref], [PubMed], [CAS], Google Scholar13https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC28Xht1ChsLs%253D&md5=4b346f341457da75e0735d90563ce23bRecent Developments in Graphene-Based Membranes: Structure, Mass-Transport Mechanism and Potential ApplicationsSun, Pengzhan; Wang, Kunlin; Zhu, HongweiAdvanced Materials (Weinheim, Germany) (2016), 28 (12), 2287-2310CODEN: ADVMEW; ISSN:0935-9648. (Wiley-VCH Verlag GmbH & Co. KGaA)A review. Significant achievements have been made on the development of next-generation filtration and sepn. membranes using graphene materials, as graphene-based membranes can afford numerous novel mass-transport properties that are not possible in state-of-art com. membranes, making them promising in areas such as membrane sepn., water desalination, proton conductors, energy storage and conversion, etc. The latest developments on understanding mass transport through graphene-based membranes, including perfect graphene lattice, nanoporous graphene and graphene oxide membranes are reviewed here in relation to their potential applications. A summary and outlook is further provided on the opportunities and challenges in this arising field. The aspects discussed may enable researchers to better understand the mass-transport mechanism and to optimize the synthesis of graphene-based membranes toward large-scale prodn. for a wide range of applications.
- 14Wang, L. D.; Boutilier, M. S. H.; Kidambi, P. R.; Jang, D.; Hadjiconstantinou, N. G.; Karnik, R. Fundamental transport mechanisms, fabrication and potential applications of nanoporous atomically thin membranes. Nat. Nanotechnol. 2017, 12, 509– 522, DOI: 10.1038/nnano.2017.72[Crossref], [PubMed], [CAS], Google Scholar14https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2sXpt1Oqur8%253D&md5=9996d427dbca1d7c29f550c0187757d4Fundamental transport mechanisms, fabrication and potential applications of nanoporous atomically thin membranesWang, Luda; Boutilier, Michael S. H.; Kidambi, Piran R.; Jang, Doojoon; Hadjiconstantinou, Nicolas G.; Karnik, RohitNature Nanotechnology (2017), 12 (6), 509-522CODEN: NNAABX; ISSN:1748-3387. (Nature Publishing Group)A review. Graphene and other two-dimensional materials offer a new approach to controlling mass transport at the nanoscale. These materials can sustain nanoscale pores in their rigid lattices and due to their min. possible material thickness, high mech. strength and chem. robustness, they could be used to address persistent challenges in membrane sepns. Here we discuss theor. and exptl. developments in the emerging field of nanoporous atomically thin membranes, focusing on the fundamental mechanisms of gas- and liq.-phase transport, membrane fabrication techniques and advances towards practical application. We highlight potential functional characteristics of the membranes and discuss applications where they are expected to offer advantages. Finally, we outline the major scientific questions and technol. challenges that need to be addressed to bridge the gap from theor. simulations and proof-of-concept expts. to real-world applications.
- 15Jiang, L. L.; Fan, Z. J. Design of advanced porous graphene materials: from graphene nanomesh to 3D architectures. Nanoscale 2014, 6, 1922– 1945, DOI: 10.1039/C3NR04555B[Crossref], [PubMed], [CAS], Google Scholar15https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2cXhsFartrk%253D&md5=23f360c8ae553a84b9e36223e88ba364Design of advanced porous graphene materials: from graphene nanomesh to 3D architecturesJiang, Lili; Fan, ZhuangjunNanoscale (2014), 6 (4), 1922-1945CODEN: NANOHL; ISSN:2040-3372. (Royal Society of Chemistry)A review. In order to make full utilization of the high intrinsic surface area of graphene, recently, porous graphene materials including graphene nanomesh, crumpled graphene and graphene foam, have attracted tremendous attention and research interest, owing to their exceptional porous structure (high surface area, and high pore vol.) in combination with the inherent properties of graphene, such as high electronic cond., good thermal stability, and excellent mech. strength. Interestingly, porous graphene materials and their derivs. have been explored in a wide range of applications in the fields of electronic and photonic devices, energy storage, gas sepn./storage, oil absorption and sensors. This article reviews recent progress in the synthesis, characterization, properties, and applications of porous graphene materials. We aim to highlight the importance of designing different porous structures of graphene to meet future challenges, and the trend on future design of porous graphene materials is analyzed.
- 16Li, Z.; Zhang, X.; Tan, H.; Qi, W.; Wang, L.; Ali, M. C.; Zhang, H.; Chen, J.; Hu, P.; Fan, C.; Qiu, H. Combustion Fabrication of Nanoporous Graphene for Ionic Separation Membranes. Adv. Funct. Mater. 2018, 28, 1805026, DOI: 10.1002/adfm.201805026
- 17Zhang, M.; Bao, W. X.; Liu, X. L.; Yu, B. Z.; Ren, Z. Y.; Bai, J. T.; Fan, H. M. Large-scale synthesis of porous graphene through nanoscale carbothermal reduction etching. J. Mater. Sci. 2015, 50, 7875– 7883, DOI: 10.1007/s10853-015-9309-1[Crossref], [CAS], Google Scholar17https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2MXhsFWhtL3P&md5=ee76bac6208b0ce17ae67d6ae5ef399fLarge-scale synthesis of porous graphene through nanoscale carbothermal reduction etchingZhang, Ming; Bao, Wen Xiao; Liu, Xiao Li; Yu, Bao Zhi; Ren, Zhao Yu; Bai, Jin Tao; Fan, Hai MingJournal of Materials Science (2015), 50 (24), 7875-7883CODEN: JMTSAS; ISSN:0022-2461. (Springer)Porous graphene, which features nanoscaled pores on the sheets, has shown great potential in many technol. important industries. However, the conversional approaches for the synthesis of porous graphene including high-energy techniques and template etching/growth methods are generally conducted on substrates with high cost and low throughput. Herein, we demonstrate a general and scalable synthetic method for porous graphene via carbothermal redn. reaction using monodisperse zinc oxide nanoparticles. The results indicate that ZnO nanoparticles were first attached on graphene oxide nanosheets by electrostatic interaction, and then undergone a carbothermal redn. reaction at 800 °C to produce the pores on the sheets. While graphene oxide nanosheets were thermally reduced to graphene, all the byproducts (carbon monoxide, carbon dioxide, and zinc) escaped from the final products simultaneously. The characterizations of the obtained porous graphene reveal that the pore size is about 11 nm, larger than that of ZnO nanoparticles (∼5 nm), which is ascribed to the aggregation of ZnO nanoparticles (∼20 nm) on the graphene oxide sheets. These results show the certain correlation among the sizes of pores, ZnO nanoparticles and ZnO aggregations, which gain insight into the controlling of pore size by choosing suitable etching agent.
- 18Han, S.; Wu, D. Q.; Li, S.; Zhang, F.; Feng, X. L. Porous Graphene Materials for Advanced Electrochemical Energy Storage and Conversion Devices. Adv. Mater. 2014, 26, 849– 864, DOI: 10.1002/adma.201303115[Crossref], [PubMed], [CAS], Google Scholar18https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3sXhvFCjtr3O&md5=b57290164ca07cad6523404fa95135fePorous graphene materials for advanced electrochemical energy storage and conversion devicesHan, Sheng; Wu, Dongqing; Li, Shuang; Zhang, Fan; Feng, XinliangAdvanced Materials (Weinheim, Germany) (2014), 26 (6), 849-864CODEN: ADVMEW; ISSN:0935-9648. (Wiley-VCH Verlag GmbH & Co. KGaA)A review. Combining the advantages from both porous materials and graphene, porous graphene materials have attracted vast interests due to their large surface areas, unique porous structures, diversified compns. and excellent electronic cond. These unordinary features enable porous graphene materials to serve as key components in high-performance electrochem. energy storage and conversion devices such as lithium ion batteries, supercapacitors, and fuel cells. This progress report summarizes the typical fabrication methods for porous graphene materials with micro-, meso-, and macro-porous structures. The structure-property relationships of these materials and their application in advanced electrochem. devices are also discussed.
- 19Song, L.; Zhang, H.; Cai, T.; Chen, J.; Li, Z.; Guan, M.; Qiu, H. Porous graphene decorated silica as a new stationary phase for separation of sulfanilamide compounds in hydrophilic interaction chromatography. Chin. Chem. Lett. 2019, 30, 863– 866, DOI: 10.1016/j.cclet.2018.10.040[Crossref], [CAS], Google Scholar19https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC1cXit1Cht7rN&md5=06ce42a89141ac4dc39df912e93551f9Porous graphene decorated silica as a new stationary phase for separation of sulfanilamide compounds in hydrophilic interaction chromatographySong, Lijun; Zhang, Haijuan; Cai, Tianpei; Chen, Jia; Li, Zhan; Guan, Ming; Qiu, HongdengChinese Chemical Letters (2019), 30 (4), 863-866CODEN: CCLEE7; ISSN:1001-8417. (Elsevier B.V.)Porous graphene (PG) has potential applications in numerous fields because of the existence of nanopores in the plane. Porous graphene decorated silica microspheres (Sil-PG) were successfully fabricated by assembling PG onto the silica particles surface in deep eutectic solvents (DESs). This new stationary phase can facilitate the sepn. of six sulfonamides compds. in hydrophilic chromatog. conditions. The successful synthesis of the Sil-PG stationary phase provides a basis for the application of porous graphene-modified materials as the stationary phase for liq. chromatog., and offers the possibility to broaden the application of PG in the field of chromatog.
- 20Yan, Y. G.; Li, W.; Kral, P. Enantioselective Molecular Transport in Multilayer Graphene Nanopores. Nano Lett. 2017, 17, 6742– 6746, DOI: 10.1021/acs.nanolett.7b02846[ACS Full Text], [CAS], Google Scholar20https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2sXhsFyqsrzL&md5=86f5c52a3185e721111629beafbe5cd1Enantioselective molecular transport in multilayer graphene nanoporesYan, Youguo; Li, Wen; Kral, PetrNano Letters (2017), 17 (11), 6742-6746CODEN: NALEFD; ISSN:1530-6984. (American Chemical Society)Multilayer superstructures based on stacked layered nanomaterials offer the possibility to design three-dimensional (3D) nanopores with highly specific properties analogous to protein channels. In a layer-by-layer design and stacking, analogous to mol. printing, superstructures with lock-and-key mol. nesting and transport characteristics could be prepd. To examine this possibility, we use mol. dynamics simulations to study elec. field-driven transport of ions through stacked porous graphene flakes. First, highly selective, tunable, and correlated passage rates of monovalent at. ions through these superstructures are obsd. in dependence on the ion type, nanopore type, and relative position and dynamics of neighboring porous flakes. Next, enantioselective mol. transport of ionized L- and D-leucine is obsd. in graphene stacks with helical nanopores. The outlined approach provides a general scheme for synthesis of functional 3D superstructures.
- 21Kim, C. J.; Sanchez-Castillo, A.; Ziegler, Z.; Ogawa, Y.; Noguez, C.; Park, J. Chiral atomically thin films. Nat. Nanotechnol. 2016, 11, 520– 524, DOI: 10.1038/nnano.2016.3[Crossref], [PubMed], [CAS], Google Scholar21https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC28XivFKgt7Y%253D&md5=8029da972deda655159245a18d8ff646Chiral atomically thin filmsKim, Cheol-Joo; Sanchez-Castillo, A.; Ziegler, Zack; Ogawa, Yui; Noguez, Cecilia; Park, JiwoongNature Nanotechnology (2016), 11 (6), 520-524CODEN: NNAABX; ISSN:1748-3387. (Nature Publishing Group)A chiral stacking approach, where 2-dimensional materials are positioned layer-by-layer with precise control of the interlayer rotation (θ) and polarity, resulting in tunable chiral properties of the final stack is reported. Using this method, left- and right-handed bilayer graphene, i.e., a 2-atom-thick chiral film, was produced. The film displays 1 of the highest intrinsic ellipticity values (6.5 deg μm-1) ever reported, and a remarkably strong CD with the peak energy and sign tuned by θ and polarity. These chiral properties originate from the large in-plane magnetic moment assocd. with the interlayer optical transition. The chiral properties of atomically thin films layer-by-layer can be programmed by producing 3-layer graphene films with structurally controlled CD spectra.
- 22Morrow, S. M.; Bissette, A. J.; Fletcher, S. P. Transmission of chirality through space and across length scales. Nat. Nanotechnol. 2017, 12, 410, DOI: 10.1038/nnano.2017.62[Crossref], [PubMed], [CAS], Google Scholar22https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2sXntFahtrk%253D&md5=950a10580a3f3b9d646a87804f8ddb46Transmission of chirality through space and across length scalesMorrow, Sarah M.; Bissette, Andrew J.; Fletcher, Stephen P.Nature Nanotechnology (2017), 12 (5), 410-419CODEN: NNAABX; ISSN:1748-3387. (Nature Publishing Group)Chirality is a fundamental property and vital to chem., biol., physics and materials science. The ability to use asymmetry to operate mol.-level machines or macroscopically functional devices, or to give novel properties to materials, may address key challenges at the heart of the phys. sciences. However, how chirality at one length scale can be translated to asymmetry at a different scale is largely not well understood. In this Review, we discuss systems where chiral information is translated across length scales and through space. A variety of synthetic systems involve the transmission of chiral information between the mol.-, meso- and macroscales. We show how fundamental stereochem. principles may be used to design and understand nanoscale chiral phenomena and highlight important recent advances relevant to nanotechnol. The survey reveals that while the study of stereochem. on the nanoscale is a rich and dynamic area, our understanding of how to control and harness it and dial-up specific properties is still in its infancy. The long-term goal of controlling nanoscale chirality promises to be an exciting journey, revealing insight into biol. mechanisms and providing new technologies based on dynamic phys. properties.
- 23Dzwolak, W. Vortex-induced chiral bifurcation in aggregating insulin. Chirality 2010, 22, E154– E160, DOI: 10.1002/chir.20896[Crossref], [PubMed], [CAS], Google Scholar23https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3cXhtlGrsrnE&md5=2db55b86652fa47c6ad41dc5c80d16c1Vortex-induced chiral bifurcation in aggregating insulinDzwolak, WojciechChirality (2010), 22 (1E), E154-E160CODEN: CHRLEP; ISSN:0899-0042. (Wiley-Liss, Inc.)A review. Chiral symmetry breaking occurs during vortex-assisted crystn. of several simple compds. leading to a stochastically detd. emergence of an enantiomeric excess of one chiral isomer. This article summarizes recent developments in studies of a similar phenomenon obsd. in agitated solns. of aggregating insulin, when a phase transition-pptn. of insol. amyloid fibrils from solns. of the native protein-is coupled to a conformational transition of the native alpha-helical structure into aggregated beta-sheets. In contrast to the previously known cases of chiral bifurcation, the substrate is built of L-amino acids and, therefore, chirally biased. However, under certain conditions, insulin forms fibrils with superstructural chiral features that are independent of the left-handedness of amino acid residues, as revealed by the sign of extrinsic Cotton effect induced in amyloid-bound achiral dye-thioflavin T. The inherent chiral bias of the protein results in a diastereomeric relationship between the two optical isomers of amyloid superstructures and the fact that relative probability of formation of either isomer is temp. dependent. As the formation of amyloid fibrils in vivo is assocd. with several degenerative disorders such as Alzheimer's disease, this newly obsd. phenomenon may have important implications in the context of structural basis of biol. activity of misfolded proteins. Chirality, 2010. © 2010 Wiley-Liss, Inc.
- 24D’Urso, A.; Randazzo, R.; Lo Faro, L.; Purrello, R. Vortexes and Nanoscale Chirality. Angew. Chem., Int. Ed. 2010, 49, 108– 112, DOI: 10.1002/anie.200903543[Crossref], [CAS], Google Scholar24https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD1MXhs1Wlt7bI&md5=8fa0c56bb1e5cb77a7abdaf26213ce15Vortexes and Nanoscale ChiralityD'Urso, Alessandro; Randazzo, Rosalba; Lo Faro, Letizia; Purrello, RobertoAngewandte Chemie, International Edition (2010), 49 (1), 108-112, S108/1-S108/8CODEN: ACIEF5; ISSN:1433-7851. (Wiley-VCH Verlag GmbH & Co. KGaA)The relation between vortexes and chirality of large assemblies is a very intriguing problem, which might lead to understanding fundamentals of nature and from this, to possible technol. applications. Herein the authors describe the behavior under stirring of noncovalent J-aggregates of the protonated form of meso- tetrakis(4-sulfonatophenyl) porphyrin. The hypothesis is that J-aggregates are inherently chiral and exist in aq. soln. as racemate: their distribution is affected by vortexes. This work reports quite strong exptl. evidence that, for the studied systems, stirring is shifting the equil. of a racemic mixt. towards the side chosen by the vortex chirality. It is not clear at the moment if, under the effect of a vortex, there is chiral enrichment and/or a racemate resoln.
- 25Di Mauro, A.; Randazzo, R.; Spano, S. F.; Compagnini, G.; Gaeta, M.; D’Urso, L.; Paolesse, R.; Pomarico, G.; Di Natale, C.; Villari, V.; Micali, N.; Fragala, M. E.; D’Urso, A.; Purrello, R. Vortexes tune the chirality of graphene oxide and its non-covalent hosts. Chem. Commun. 2016, 52, 13094– 13096, DOI: 10.1039/C6CC05177D[Crossref], [PubMed], [CAS], Google Scholar25https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC28XhtlCrtbrF&md5=22d8d2f01701e53ff5c0282be89b995eVortexes tune the chirality of graphene oxide and its non-covalent hostsDi Mauro, A.; Randazzo, R.; Spano, S. F.; Compagnini, G.; Gaeta, M.; D'Urso, L.; Paolesse, R.; Pomarico, G.; Di Natale, C.; Villari, V.; Micali, N.; Fragala, M. E.; D'Urso, A.; Purrello, R.Chemical Communications (Cambridge, United Kingdom) (2016), 52 (89), 13094-13096CODEN: CHCOFS; ISSN:1359-7345. (Royal Society of Chemistry)Graphene oxide (GO) is one of the most appealing bidimensional materials able to interact non-covalently with achiral mols. and to act as chiral inducers. Vortexes can tune chirality and, consequently transfer a specific handedness to non-covalent host mols., either when dispersed in water or when deposited on a solid surface.
- 26Zhou, D.; Cui, Y.; Xiao, P. W.; Jiang, M. Y.; Han, B. H. A general and scalable synthesis approach to porous graphene. Nat. Commun. 2014, 5, 4716, DOI: 10.1038/ncomms5716[Crossref], [PubMed], [CAS], Google Scholar26https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2MXktFensrc%253D&md5=eab43bb01beb357cca7b2f06d37c2701A general and scalable synthesis approach to porous grapheneZhou, Ding; Cui, Yi; Xiao, Pei-Wen; Jiang, Mei-Yang; Han, Bao-HangNature Communications (2014), 5 (), 4716CODEN: NCAOBW; ISSN:2041-1723. (Nature Publishing Group)Porous graphene, which features nano-scaled pores on the sheets, is mostly investigated by computational studies. The pores on the graphene sheets may contribute to the improved mass transfer and may show potential applications in many fields. To date, the prepn. of porous graphene includes chem. bottom-up approach via the aryl-aryl coupling reaction and phys. prepn. by high-energy techniques, and is generally conducted on substrates with limited yields. Here we show a general and scalable synthesis method for porous graphene that is developed through the carbothermal reaction between graphene and metal oxide nanoparticles produced from oxometalates or polyoxometalates. The pore formation process is obsd. in situ with the assistance of an electron beam. Pore engineering on graphene is conducted by controlling the pore size and/or the nitrogen doping on the porous graphene sheets by varying the amt. of the oxometalates or polyoxometalates, or using ammonium-contg. oxometalates or polyoxometalates.
- 27Tan, H. X.; Zhang, X.; Li, Z.; Qiu, H. D. Small-Scale Nanoparticles Pyrolyzed from Layered Hydrotalcite between Graphene Interlayers as Intermediates for Self-Assembly into Metal Oxide Nanosheets and Hollow Nanospheres. ChemNanoMat 2020, 6, 1270– 1275, DOI: 10.1002/cnma.202000224[Crossref], [CAS], Google Scholar27https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BB3cXhsFGhs7jK&md5=b33371a9918f8ff8364349ae956e5c47Small-Scale Nanoparticles Pyrolyzed from Layered Hydrotalcite between Graphene Interlayers as Intermediates for Self-Assembly into Metal Oxide Nanosheets and Hollow NanospheresTan, Hongxin; Zhang, Xin; Li, Zhan; Qiu, HongdengChemNanoMat (2020), 6 (8), 1270-1275CODEN: CHEMSB; ISSN:2199-692X. (Wiley-VCH Verlag GmbH & Co. KGaA)Although significant advances have been made in the synthesis of various two-dimensional (2D) nanomaterials, problems of inefficient and difficult to scale applications remain. Here, a novel strategy is reported for obtaining 2D nanosheets from the 2D interlayer space of a graphene oxide (GO) membrane through combustion, which provides a simple and rapid method for the fabrication of 2D nanosheets as well as hollow nanospheres. Layered hydrotalcite from metal nitrates is formed between GO interlayers, which can be pyrolyzed into small-sized oxide nanoparticles (3-5 nm) and then aggregated as intermediates into large-sized nanosheets by combustion with Co, Ni, and Cr nitrates. However, the oxide intermediates self-assemble into hollow oxide nanospheres for nitrates of more active Cd, Ce, and Eu. Moreover, the intermediates of inactive Ag, Pb, and Bi nitrates are reduced by GO into metal nanoparticles, which can fuse into Ag nanofiber network films, or Pb and Bi composite spheres because of their low m.p. This work is helpful to understand the nature of 2D space and develops a class of micro-scale reactors between graphene layers.
- 28Cheng, Q. F.; Wu, M. X.; Li, M. Z.; Jiang, L.; Tang, Z. Y. Ultratough Artificial Nacre Based on Conjugated Cross-linked Graphene Oxide. Angew. Chem., Int. Ed. 2013, 52, 3750– 3755, DOI: 10.1002/anie.201210166[Crossref], [CAS], Google Scholar28https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3sXitlemsb8%253D&md5=8b465818181e646a26cc720866e03b0cUltratough Artificial Nacre Based on Conjugated Cross-linked Graphene OxideCheng, Qunfeng; Wu, Mengxi; Li, Mingzhu; Jiang, Lei; Tang, ZhiyongAngewandte Chemie, International Edition (2013), 52 (13), 3750-3755CODEN: ACIEF5; ISSN:1433-7851. (Wiley-VCH Verlag GmbH & Co. KGaA)Inspired by natural nacre, we successfully fabricated graphene oxide (GO)-based composites. We have developed a novel strategy for fabricating the ultratough artificial nacre based on 2-D GO sheets by conjugated crosslinking. Highly π-conjugated long-chain polymers made of 10,12-pentacosadiyn-1-ol (PCDO) monomers are cross-linked with the GO sheets, resulting in a huge displacement upon loading and adsorption of much more fracture energy. In comparison with previous prepn. methods, this novel crosslinking strategy demonstrates the following crucial advantages: 1) It dramatically decreases the content of org. polymers in the resultant composites, which is comparable to the natural nacre; 2) it produces the distinct inorg.-org. layered hierarchical nano-/microstructures; 3) it realizes integration of the high tensile strength and excellent toughness; and 4) it creates highly conductive composites based on GO and conjugated mols. The toughness is two times higher than that of the natural nacre. Furthermore, the π-conjugated polymers could add addnl. benefit to the high elec. cond. of the chem. reduced GO (rGO). This study opens the door toward biomimetic prodn. of the GO- or rGO-based composites of superior toughness and high cond., which will have great promising applications in many fields, such as aerospace, flexible supercapacitor electrodes, artificial muscles, and tissue engineering.
- 29Wan, S. J.; Hu, H.; Peng, J. S.; Li, Y. C.; Fan, Y. Z.; Jiang, L.; Cheng, Q. F. Nacre-inspired integrated strong and tough reduced graphene oxide-poly (acrylic acid) nanocomposites. Nanoscale 2016, 8, 5649– 5656, DOI: 10.1039/C6NR00562D[Crossref], [PubMed], [CAS], Google Scholar29https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC28XitFehtrs%253D&md5=94e53ba9d17191678e653dd9bdb6f845Nacre-inspired integrated strong and tough reduced graphene oxide-poly(acrylic acid) nanocompositesWan, Sijie; Hu, Han; Peng, Jingsong; Li, Yuchen; Fan, Yuzun; Jiang, Lei; Cheng, QunfengNanoscale (2016), 8 (10), 5649-5656CODEN: NANOHL; ISSN:2040-3372. (Royal Society of Chemistry)Inspired by the relationship between interface interactions and the high performance mech. properties of nacre, a strong and tough nacre-inspired nanocomposite was demonstrated based on graphene oxide (GO) and polyacrylic acid (PAA) prepd. via a vacuum-assisted filtration self-assembly process. The abundant hydrogen bonding between GO and PAA results in both high strength and toughness of the bioinspired nanocomposites, which are 2 and 3.3 times higher than that of pure reduced GO film, resp. In addn., the effect of environmental relative humidity on the mech. properties of bioinspired nanocomposites is also investigated, and is consistent with previous theor. predictions. Moreover, this nacre-inspired nanocomposite also displays high elec. cond. of 108.9 S cm-1. These excellent phys. properties allow this type of nacre-inspired nanocomposite to be used in many applications, such as flexible electrodes, aerospace applications, and artificial muscles etc. This nacre-inspired strategy also opens an avenue for constructing integrated high performance graphene-based nanocomposites in the near future.
- 30Huang, H. B.; Mao, Y. Y.; Ying, Y. L.; Liu, Y.; Sun, L. W.; Peng, X. S. Salt concentration, pH and pressure controlled separation of small molecules through lamellar graphene oxide membranes. Chem. Commun. 2013, 49, 5963– 5965, DOI: 10.1039/c3cc41953c[Crossref], [PubMed], [CAS], Google Scholar30https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3sXovFWnsL4%253D&md5=ebf37065f080686d03b9403dd54ae90fSalt concentration, pH and pressure controlled separation of small molecules through lamellar graphene oxide membranesHuang, Hubiao; Mao, Yiyin; Ying, Yulong; Liu, Yu; Sun, Luwei; Peng, XinshengChemical Communications (Cambridge, United Kingdom) (2013), 49 (53), 5963-5965CODEN: CHCOFS; ISSN:1359-7345. (Royal Society of Chemistry)For the 1st time, pressure, salt concn. and pH demonstrated advantages for tuning the nanochannels within lamellar graphene oxide (LGO) membranes to control the sepn. of small mols. This provides a new avenue for designing and engineering efficient LGO membranes for mol. sepn.
- 31Sueyoshi, Y.; Fukushima, C.; Yoshikawa, M. Molecularly imprinted nanofiber membranes from cellulose acetate aimed for chiral separation. J. Membr. Sci. 2010, 357, 90– 97, DOI: 10.1016/j.memsci.2010.04.005[Crossref], [CAS], Google Scholar31https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3cXmsVOit7Y%253D&md5=b5af7f9563301bf1dbce3b92db3a76b7Molecularly imprinted nanofiber membranes from cellulose acetate aimed for chiral separationSueyoshi, Yuuki; Fukushima, Chiho; Yoshikawa, MasakazuJournal of Membrane Science (2010), 357 (1-2), 90-97CODEN: JMESDO; ISSN:0376-7388. (Elsevier B.V.)Permselectivity and throughput (flux) are important specificity in membrane sepn. It is an ultimate dream for membranologists to simultaneously enhance not only permselectivity but also flux, which generally show a trade-off relation. A breakthrough in membrane sepn. would be realized by adopting membranes with higher surface area, which leads to higher mol. recognition site concn., and higher porosity. Such sepn. membranes would be obtained by applying an electrospray deposition technique. To this end, molecularly imprinted nanofiber membranes were prepd. from cellulose acetate (CA) and a print mol., a deriv. of optically pure glutamic acid, such as N-α-benzyloxycarbonyl-D-glutamic acid (Z-D-Glu) or N-α-benzyloxycarbonyl-L-glutamic acid (Z-L-Glu). Membrane performance of molecularly imprinted nanofiber membranes and usual molecularly imprinted membranes was compared in terms of adsorption selectivity, affinity const., permselectivity, and flux. The results obtained in the present study revealed that electrospray deposition would be one of plausible methods to construct sepn. membranes to simultaneously enhance permselevtivity and flux.
Supporting Information
ARTICLE SECTIONSThe Supporting Information is available free of charge at https://pubs.acs.org/doi/10.1021/acs.analchem.0c02446.
Experimental; Preparation and formation mechanism of PG; Characterizations of PG; Characterizations and chiral separation performance of PGM (PDF)
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