In this study, two extractants, hexakis[(dimethylthiocarbamoyl)oxy]thiacalix[6]arene (1) and tetrakis[(dimethylthiocarbamoyl)oxy]thiacalix[4]arene (2), were synthesized by the reaction of dimethylthiocarbamoyl chloride with p-tert-butylthiacalix[n]arenes (n = 6 and 4) and characterized using 1H NMR and FT-IR spectroscopies, elemental analysis, and fast-atom-bombardment mass spectrometry (FAB-MS). These compounds were extensively evaluated for the extraction of Pd(II) ions from HCl media and solutions of platinum-group metals from automotive catalyst residues, using various solvents. Compounds 1 and 2 were found to have higher Pd(II)-ion extraction abilities (0.57 and 0.48 g/L, respectively) than the native p-tert-butylthiacalix[6]arene (3) and p-tert-butylthiacalix[4]arene (4) (0.46 and 0.20 g/L, respectively), using 1 mM extractant and 9.4 mM Pd(II)-ion solutions in HCl media. The extractant–Pd(II) complexes were characterized using FT-IR spectroscopy, elemental analysis, XRD, Job’s continuous method, and TGA/DTA. Stripping of the Pd(II) ions from the extractants was performed using 1 M thiourea, thereby enabling the reuse of the extractants.

The UVB-induced photocatalytic degradation of Methyl Red and Methyl Orange (azo dyes used in the textile industry) containing solutions was carried out by the use of a laboratory-scale pilot plant where the catalyst, TiO2 (anatase), was immobilized at the bottom of a channel through which the liquid was recirculated under UVB irradiation. The plant was preliminarily characterized hydrodynamically, i.e., flow-rate, hydraulic gradients, and residence time. Photodegradation kinetics were followed by UV–vis absorption measurements of the residual dye concentration in the liquid-phase, and the synergistic effects of the catalyst and radiation in promoting the abatement of dyes was demonstrated in the concentration range 0.3–5.0 mg/L. Kinetic data were correlated by the use of first-order (or pseudo-first-order) models up to the concentration range 0.7 mg/L; at higher concentrations, zero-order models (pure catalytic control) better correlated the experimental data. Photocatalytic degradation of Methyl Red was faster than Methyl Orange, possibly due to the Coulomb repulsion of the negatively charged sulfonate functionalities present on this latter compound. A better hydrodynamic of the liquid recirculating in the channel, i.e., higher flow rate (lower contact time), associated with an improved surface catalyst renovation and a higher frequency of exposition of the substrate to the UVB radiation, together with an improved oxygen dissolution in the liquid-phase, played a positive role in the overall kinetic performance.

PADB was a highly efficient cationic flocculant, which was synthesized through the copolymerization of acrylamide (AM), acryloyloxyethyl trimethyl ammonium chloride (DAC), and butylacrylate (BA) with ultraviolet initiation by micellar polymerization technology. The PADB was the terpolymer of AM, DAC, and BA. In order to observe this flocculant’s structural characteristics, nuclear magnetic resonance hydrogen spectroscopy (1H NMR), Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), and thermal gravimetric analysis (TGA) were used. The most important study was to analyze its physicochemical parameters during dewatering of activated sludge. These tested parameters included residual turbidity of supernatant, dry solid content (DS), extracellular polymeric substances (EPS), specific resistance to filtration (SRF), ζ-potential, floc size, and settling rate. Results demonstrated that the PADB have a superiority over both poly(acrylamide-acryloyloxyethyl trimethyl ammonium chloride) (PAD) and commercially available cationic polyacrylamide (CPAM). However, it was dependent on pH and dosage. A favorable pH was in the neutral range while the appropriate dosage (20 mg·L–1-60 mg·L–1) was crucial to the conditioning process. For the PADB at40 mg·L–1 and pH at 7, the residual turbidity of supernatant, DS, SRF, and settling rate could reach 5.5 NTU, 32.2%, 5.51 × 1012 m·kg–1, and 3.318 cm·min–1, respectively. During the sludge flocculation process, the charge neutralization mechanism and bridging flocculation played an important role in floc’s formation and settlement.

meta-Aminophenol was used during nucleophilic step copolymerization to end-cap partially disulfonated bisphenol A based random copolymers with controlled oligomeric molecular weights. The amine end groups were thermally reacted with a tetrafunctional epoxy reagent to produce networks. Very high gel fractions, up to 99%, and ductile film formation were achieved. The oligomer was further functionalized with acryloyl chloride, phenylethynyl phthalic anhydride, and maleic anhydride to obtain several novel free radically cross-linkable oligomers. The structure and molecular weights (Mn) were established with 1H NMR spectroscopy of the oligomers and end groups. TGA analysis demonstrated the high thermal stability of these oligomers; DSC investigations showed that the oligomers had curing exotherms from 140 to 330 °C and that residual casting solvent during cross-linking was necessary to avoid vitrification during membrane formation. In addition to the thermally cross-linkable systems, photocross-linking was demonstrated with the telechelic acrylamide functionalized oligomers. Two compositions were identified as potential candidates for further development. Cross-linking disulfonated poly(arylene ether sulfone) copolymers limits the high water sorption and swelling of these hydrophilic materials, which enhances several properties for membrane applications. Initial transport results indicate that cross-linking greatly reduces salt permeability while modestly decreasing water permeability, resulting in improved water/NaCl selectivity.

The influence of external clay additive and inherent minerals on the ignition of a Xinjiang lignite and its volatile flame propagation in air versus oxy-fuel combustion have been clarified in this work, through the use of a flat-flame burner reactor (FFBR) coupled with in-situ optical diagnosis tools. As has been confirmed, ignition of the lignite studied in this paper was initiated by homogeneous oxidation of a tarry volatile cloud. The removal of HCl-soluble metals shifted coal devolatilization toward higher temperatures in air and 21% O2 in CO2. The mixing of external clay with coal had little effect on the ignition time. However, it enhanced the decomposition of volatiles, leading to a larger volatile cloud shielding on the particle surface. The oxygen fraction in the bulk gas was found to be most influential. Increasing the oxygen fraction to 30% eliminated all of the discrepencies between raw lignite, acid-washed lignite, and a mixture of raw lignite and clay.

The removal of high-concentration C.I. acid orange 7 (AO7) in aqueous solution by the prepared iron/copper (Fe/Cu) bimetallic particles and zerovalent iron (ZVI) was investigated thoroughly. Fe/Cu bimetallic particles were prepared by planting Cu on the surface of Fe. Experimental results confirmed the superiority of Fe/Cu bimetallic particles for the degradation of AO7 in aqueous solution. Under the optimal conditions ([Fe/Cu]0 = 40 g·L–1, [AO7]0 = 1000 mmol·L–1, initial pH = 6.5, TMLCu = 0.62 g of Cu/g of Fe), the AO7 concentration and chemical oxygen demand (COD) and total organic carbon (TOC) removal efficiencies could reach 94.3%, 61.8%, and 60.8%, respectively, after only 10 min of treatment by Fe/Cu bimetallic particles. Under the same conditions, however, the AO7 concentration and COD and TOC removal efficiencies by ZVI only reached 35.5%, 25.1%, and 21.2%, respectively. Thus, the planting of Cu could improve the reactivity of Fe. The degradation of AO7 was analyzed by UV–vis and Fourier transform infrared spectra, and the results show that the chromophore part (i.e., −N═N−) of AO7 could be destructed by Fe/Cu bimetallic particles. Additionally, its degradation products might be sulfanilamide and 1-amino-2-naphtol, which would be removed by further mineralization of Fe/Cu bimetallic particles or sedimentation of Fe ions. Therefore, the Fe/Cu bimetallic system is a promising process for the toxic and refractory wastewater from the printing and dyeing industry.

In this study three different modeling approaches, with varying levels of sophistication and complexity, on modeling kraft cooking kinetics have been investigated. In the first and second approaches, isothermal conditions were used by converting the heating and cooling times into isothermal time. In the third approach, real temperature and time were used. Donnan theory, accounting for the cation exchange property of the wood fibers, was used in the second and third approaches for estimation of the cooking chemical concentrations in the fiber wall liquid, whereas in the first approach the cooking chemical concentrations in the bulk liquid phase were used. A modification of the Purdue model was used for modeling the delignification kinetics. The parameters of the Purdue model were regressed both with Matlab (commercial software) and Kinfit (in-house software). All three regressions with different modeling approaches provided very good fits to the experimental data. When Donnan theory and real temperature profiles (third approach) were employed, the estimated reaction rates for the faster reacting lignin subcomponent in the Purdue model decreased at all temperatures. On the other hand, the portion of the faster reacting component increased from 24% to 28%. In this way the third modeling approach mimics the reality in the most accurate way. Its implementation is more tedious, but the model should have more predictive capabilities. Furthermore, the effect of anthraquinone on kraft cooking kinetics was studied.

This work focuses on the microwave enhanced catalytic degradation of methyl orange (MO) in aqueous solution over CuO/CeO2 catalyst in the absence and presence of H2O2. The prepared CuO/CeO2 catalysts were characterized with X-ray diffraction, Brunnauer-Emmett-Teller analysis, temperature-programmed reduction, and temperature-programmed desorption techniques to elucidate the effect of calcination temperature on its properties and catalytic performance. The results show that calcination temperature exerts remarkable influence on the catalytic performance of CuO/CeO2, with that calcined at 300 °C displaying the highest MO degradation ability. On the basis of Fourier transform infrared spectroscopy, ultraviolet–visible spectroscopy, and X-ray photoelectron spectroscopy measurement results, the mechanism of MO degradation under microwave irradiation in the presence of both CuO/CeO2 and H2O2 was suggested. A synergistic rather than additive effect of catalyst, microwave irradiation, and H2O2 contributes to the high degradation activity toward MO.

We have explored C–O bond cleavage in different lignin model compounds in high-temperature water using catalytic amounts of water-tolerant Lewis acids. Experiments comparing indium triflate, scandium triflate, ytterbium triflate, and indium chloride indicate that indium triflate is the most active catalyst for this cleavage in guaiacol. Reactions of guaiacol at 225, 250, and 275 °C were consistent with first-order kinetics for guaiacol disappearance. The conversion reached 96% at 275 °C after 2 h using indium triflate. Milder temperatures (175, 200, and 225 °C) were sufficient for selective cleavage of the weaker C–O bond in benzyl phenyl ether. The conversion reached 99% at 225 °C after 3 h using indium triflate. The activation energies for guaiacol and benzyl phenyl ether hydrolysis were found to be 134 ± 5 and 98 ± 5 kJ·mol–1, respectively. As expected, diphenyl ether was more resistant to C–O cleavage, but even its very strong aryl–O–aryl bond can be hydrolyzed to form phenol at 330 °C with indium triflate as the catalyst. These results point to the potential application of water-tolerant Lewis acids as catalysts for lignin depolymerization.

Photocatalysis is attracting more and more interest because it offers efficient environmental friendly exploitation of solar energy for several end uses. In this context, research into the reactivity of photocatalysts on surfaces is of considerable importance. In this paper, the introduction of ammonium carbonate, a cost-effective and nontoxic reagent, is shown to influence preferential crystal growth of the photocatalyst BiVO4 along its {040} facet at high pH, thereby increasing the concentration of OH species on its surface, resulting in a substantial improvement in its visible-light-induced photocatalytic activity. As a result, 6 times higher rate of photoinduced degradation of ethylene has been measured compared to the best rate obtained with TiO2 photocatalyst ever produced by our group and even 10 times higher than with the reference Degussa P25 titania.

Novel Mn–Zr mixed oxide catalysts have been prepared by the citric acid method for the low-temperature selective catalytic reduction (SCR) of NOx with ammonia in the presence of excess oxygen. They have been characterized by a series of techniques, specifically N2 adsorption–desorption, X-ray diffraction (XRD), temperature programmed reduction (TPR), temperature programmed desorption (TPD), and X-ray photoelectron spectroscopy (XPS). It was found that an Mn(0.5)–ZrOx-450 (Mn/(Mn + Zr) mole ratio of 0.5) catalyst showed the highest activity, giving 100% NOx conversion at 100 °C with a space velocity of 30 000 h–1. XRD results suggested that an Mn–Zr solid solution was formed in the Mn(0.5)–ZrOx-450 catalyst, with highly dispersed MnOx. TPR data indicated a strong interaction between the zirconium oxide and manganese oxide, which improved the reduction ability of the MnOx. The TPD results indicated that an appropriate NH3 adsorption ability was beneficial for the low-temperature SCR. The catalyst showed a certain level of sulfur tolerance and water resistance. The effect of H2O could be quickly eliminated after its removal, whereas deactivation by SO2 proved to be irreversible.

This paper aims at finding the effect of harsh weather on corrosion repair of reinforced concrete slabs at the rebar intersections. Concrete slabs were tested to get an insight into the existence of macro-cell phenomenon in the rehabilitated patches of the corroded reinforced concrete members and the durability of repairs under the coupled effect of high constant humidity and high temperature. The specimens were prepared having a total chloride concentration in mixing water as 3% and 5% by mass of binder and the intersection steel areas simulating the patch repairs that were kept uncontaminated. After two years of corrosion potential observations, the specimens were broken to find the gravimetric mass loss and to get the true picture of the corrosion of steel at the intersection of the repaired patches of reinforced concrete.

Expanded graphites (EGs) or modified EGs (eEGs) were blended with multiwalled carbon nanotubes (MWCNTs) in a big weight ratio to prepare low-cost composites, coded as (EG-MWCNT)/cyanate ester (CE) or (eEG-MWCNT)/CE. The structures and properties of the composites are closely related to the loading of total conductors (f). When f < 0.75 wt %, EGs are beneficial for preparing high-k composites with low dielectric loss; however, when f ≥ 1.05 wt %, eEGs have superior advantages. When f = 1.5 wt %, the dielectric constant and loss of (eEG-MWCNT)1.5/CE composite are about 1.6 and 0.6 times that of the (EG-MWCNT)1.5/CE composite, respectively. The origin behind these interesting results was intensively discussed. Attractively, (EG-MWCNT)/CE and (eEG-MWCNT)/CE composites have similar percolation thresholds, so the surface modification of EGs does not increase the percolation threshold; moreover, ternary composites prepared herein have much better dielectric properties than both traditional EG/CE and MWCNT/CE composites.

The solubility and diffusivity of CO2 in polymer matrix play crucial roles in controlling the nucleation and growth of bubbles in the polymer/CO2 foaming process. In this work, the effects of polymeric aggregation states (solid and melt states) and layered filler with one-dimensional nanostructures on the solubility and diffusivity of CO2 in isotactic polypropylene (iPP)/nanomontmorillonite (nano-MMT) composites were investigated. The results show that the solubility in the iPP composites has little change with an increase of nano-MMT concentration while the diffusivity of CO2 decreases with increasing nano-MMT content. Considering the effects of a one-dimensional nanostructure filler and a polymeric crystalline region on the free volume and the diffusion path, two models on the basis of the free volume theory were established and used to well correlate the experimental diffusion coefficients of CO2 in melt-state iPP composites and predict the CO2 diffusivity in solid-state iPP composites.

Simultaneously overcoming the poor UV resistance and surface inertness of aramid fibers while maintaining their excellent mechanical and thermal properties is a challenge. New grafted Kevlar fibers (HSi-g-KFs) were facilely prepared by in situ synthesizing hyperbranched polysiloxane with double bonds and epoxy groups on Kevlar fibers (KFs). As the molar ratio of water to silane was adjusted from 1.1 to 1.4, the surface morphology of HSi-g-KFs successively changed from unconnected dots to condensed dots and to a compact coating of hyperbranched polysiloxane. Compared with KFs, all HSi-g-KFs were found to have remarkably improved surface wettability and UV resistance. After 168 h of UV irradiation, the retentions of the modulus and break extension of the HSi-g-KFs were as high as 95–97%. In addition, the HSi-g-KFs were found to have much higher thermal stabilities than KFs. These attractive results demonstrate that the method proposed herein is a new and facile approach for preparing high-performance aramid fibers for cutting-edge industries.

Viscoelastic properties of N,N-dimethylformamide (DMF) solutions of softwood kraft lignin (SKL) containing small amounts of poly(ethylene oxide) (PEO) were investigated. Of interest is the relationship between viscoelastic properties of the spinning solutions and their corresponding electrospinning behavior. Although it is well established that fiber diameter is critical in determining the material properties of nanofibers, lignin solutions have been observed to display poor electrospinnability in many instances. Thus, the motivation behind this work was to understand and exert control over the relevant fluid properties that control the fiber diameter of SKL/PEO fibers, The results of dynamic shear and capillary breakup extensional rheometry (CaBER) experiments indicated that SKL solutions were weakly elastic in shear and Newtonian in elongational flow. SKL solutions were not electrospinnable at concentrations of 25–45 wt % but form fibers at 50 wt % concentration. The addition of PEO to SKL solutions led to an increase in shear moduli and pronounced strain hardening in elongational flow. The characteristic time scales of tensile stress growth (λ) measured with CaBER were dependent on the SKL concentration, PEO concentration, and PEO molecular weight. In contrast to SKL solutions, SKL/PEO solutions are electrospinnable over the concentration range of 25–45 wt % SKL depending on the combination of SKL concentration, PEO concentration, and PEO molecular weight. Correlation between the fiber diameters obtained during electrospinning and the measured value of λ are discussed.

This article reports a study of the addition of black wattle tannin to a phosphating bath as an environmentally friendly grain refiner additive. Scanning electron microscopy (SEM), X-ray diffraction (XRD) analysis, and electrochemical impedance spectroscopy analysis were carried out to verify the tannin effect. Adhesion was measured according to the ASTM D3359 standard. The presence of tannin in the zinc phosphating bath changed the direction of phosphate crystal growth and favored phosphophylite phase formation (XRD analyses). SEM images showed a reduction in the size of the zinc phosphate crystals when tannin was present in the bath. Because of this decrease in size, the adherence of the final coating improved. The optimal concentration of black wattle tannin in the zinc phosphating bath used in this work was 2 g L–1, as higher values reduced the corrosion resistance of the coating. Grain size reduction was also observed in iron phosphating.

CaAlSiN3:Eu2+ fine powder phosphors were successfully synthesized from the fully oxidic system CaO/Al2O3/SiO2 using the gas-reduction–nitridation (GRN) method. The GRN reaction was conducted at low temperatures of ∼1370 °C to obtain nitrided precursor powders that could be converted into nearly single-phase CaAlSiN3 by a moderate heat treatment at 1600 °C for 4 h in a N2 atmosphere of 0.92 MPa. Highly efficient CaAlSiN3:Eu2+ red-emitting phosphors were obtained using a fluoride activator, with external quantum efficiencies of up to 72%.

From the standpoint of green chemistry, tris(pentafluorophenyl)gallium (7) and tris(pentafluorophenyl)aluminum (8) outperform all previously explored perfluoroarylated Lewis acids (PFLAs) for the polymerization of isobutene. In comparison to other PFLA based systems, 7 and 8 do not require ultrahigh purity monomer, toxic chlorinated solvents, or expensive and highly sensitive initiators (e.g., metallocenes). Moreover, compared to other PFLA based initiator systems they provide much larger yields of high to medium molecular weight polyisobutene even at polymerization temperatures up to ambient. Stopping experiments indicate that strong Brønsted acids formed in situ by reaction with adventitious moisture (9 and 10, respectively) induce cationic polymerization protonically. Unlike other PFLA compounds which require expensive and/or energetically unstable precursors, 7 and 8 are readily synthesized from their corresponding group 13 halides in conjunction with bis(pentafluorophenyl)zinc (6), thereby lending themselves to commercial implementation.

Nanoparticulate drugs show promise for a variety of reasons, including novel targeted delivery mechanisms, enhanced in vitro diagnostics, and increased bioavailability. However, there are often practical limitations to using nanoparticles, such as nanoparticle agglomeration and processing. Inkjet printing provides a viable method to produce nanocomposites from nanoparticles. A simple technique for producing and processing naproxen nanoparticle colloids for use in inkjet printing is presented in this report. Naproxen nanoparticles predominantly 50 nm in diameter and coated in polyvinylpyrrolidone were produced using a supercritical solution-based method, the rapid expansion of a supercritical solution into a liquid solvent (RESOLV) process. The viscosity and surface tension of the RESOLV suspensions were then modified to 10.6 cSt and 34.2 mN/m, respectively, to demonstrate the feasibility of turning the RESOLV suspension into a printable ink. The results suggest that combining the RESOLV and inkjet platforms can overcome the processing and agglomeration issues often associated with producing true nanocomposites.

A novel superstructure-based approach for synthesizing sustainable trigeneration systems (i.e., heating, cooling, and power generation cycles) integrated with heat exchanger networks is presented in this paper. The trigeneration system accounts for steam and organic Rankine cycles and an absorption refrigeration cycle. The steam Rankine cycle can be driven by multiple primary energy sources (i.e., solar, biofuels, and fossil fuels) for sustainable generation of power and process heating. The waste energy from the steam Rankine cycle and/or the excess of process heat can be used to drive both the organic Rankine cycle and the absorption refrigeration cycle to produce power and process cooling below the ambient temperature, respectively. The synthesis problem is formulated as a multiobjective mixed-integer nonlinear programming problem for the simultaneous consideration of the economic, environmental, and social dimensions of sustainability. Two example problems are presented to show the applicability of the proposed methodology.

Distillation technology, which is applied in most chemical and process industries in general, is an energy-intensive process, and this has a significant effect on the overall cost of production. Batch distillation, in particular, is one of the most important unit operations for small-scale production of specialty and fine chemicals. This unit operation is a strong unifying factor and the main support of pharmaceutical and perfume industries. This paper investigates a novel approach of minimizing energy consumption of a simple conventional binary batch distillation process by applying the attainable region theory for a binary batch boiling process. The fundamental processes considered are boiling and mixing. It is shown that the trajectory of a simple batch distillation process is convex in the concentration–energy space and that there is no room for minimizing energy consumption by any simple mixing policy.

The design and optimization of a gas-to-liquids technology (GTL) is considered, mostly from the view of an optimal choice of a synthesis gas (syngas) production method. Material balance and energy efficiency are calculated for a number of flowsheets, which comprise syngas production by various techniques and Fischer–Tropsch (FT) synthesis of liquid hydrocarbons (LHs). Three different methods are considered for syngas production: combined steam and dry reforming; autothermal reforming; and partial oxidation. The FT process is considered in the version, which produces LHs, not waxes. The results of modeling manifest that the choice of syngas production method influences dramatically the efficiency of overall GTL technology. Ways to improve the efficiency of GTL technology are discussed.

We propose a method for the automatic tuning of the feedforward compensator for proportional-integral-derivative control loops in order to reject disturbances acting on the process. The parameters of the compensator are automatically computed after estimating the disturbance transfer function by using closed-loop routine operating data. Simulation and experimental results show the effectiveness of the methodology.

This work presents both the design of a novel process to produce microparticles with a shell–core structure and a bench scale apparatus purposely realized. The developed process was designed to respond to mandatory needs of process intensification. It involved the coupling of two emergent technologies: atomization assisted by ultrasonic energy and microwave heating. The former was used to atomize polymeric solutions; the latter was applied to stabilize the produced droplets by drying. Both operations were performed in the same vessel with the aim to have a single-pot process chamber and were carried out by a semicontinuous procedure. Basic design criteria and advantages of the ultrasonic–microwave coupled operations in the realized apparatus are presented and discussed. Results of testing and of operating runs to produce shell–core microparticles are also reported, emphasizing the main features of the produced particles.

This work introduces the preparation of zeolite-filled porous mixed matrix membranes (MMMs) and discusses their potential use for air separation. Porous polysulfone (PSF) matrix membranes were prepared using the nonsolvent-induced phase separation process. Scanning electron microscope and gas permeation experiments suggested the presence of closed pores in the porous matrix membranes. Furthermore, porous MMMs containing zeolite 4A particles as filler were prepared and characterized. The permeation properties of porous MMMs were highly dependent on the zeolite content. The introduction of zeolite particles distorted the closed pores in the PSF matrix and formed nonselective voids which resulted in very high oxygen flux but low O2/N2 selectivity. The annealing technique for modifying the nonselective pores present in the polymer–zeolite interface is also described in this study. The resulting annealed porous MMMs had the ability to separate O2 from N2 more effectively than traditional dense MMMs.

It is a focus to reduce the energy consumption and operating cost of CO2 capture from low-pressure flue gas streams of power plants using an aqueous amine-based absorbent. In this study, CO2 capture experiments were conducted in an absorption–desorption loop system using amine-based absorbents. The gas mixture containing CO2, O2, SO2, and N2 in the composition range of flue gas from coal-fired power plant after flue gas desulfurization was selected as the feed gas. For an aqueous amine solution, the largest contribution to monoethanolamine (MEA) loss was made by evaporation during desorption, followed by the formation of sulfate and heat-stable salts. To reduce MEA loss and meanwhile decrease the energy consumption during CO2 desorption, an aqueous amine solution mixed with ionic liquid (30 wt % MEA + 40 wt % [bmim][BF4] + 30 wt % H2O) was proposed. The energy consumption of the mixed ionic liquid solution for absorbent regeneration was 37.2% lower than that of aqueous MEA solution. The MEA loss per ton of captured CO2 for the mixed solution was 1.16 kg, which is much lower than that of 3.55 kg for the aqueous amine solution. No ionic liquid loss was detected. In addition, the mixed ionic liquid solution showed a low viscosity of 3.54 mPa s at 323 K, indicating that the ionic liquid disadvantage of high viscosity can be overcome for absorbent delivery of CO2 capture.

Hydrodynamic modeling of gas–solid bubbling fluidization is of significance to the development of gas–solid bubbling reactors since it still remains at the stage of experimental and empirical science. As is the role of particle clusters in gas–solid fast fluidization, gas bubbles characterize the structural heterogeneity of gas–solid bubbling fluidization, and their evolution is mainly subject to the constraints of the stability and boundary conditions of the system. By considering the expansion work of gas bubbles against the normal pressure stress in the emulsion phase, an improved necessary stability condition is proposed to close a gas–solid bubbling model. Applying the upgraded gas–solid bubbling model at the scale of vessels, the steady-state hydrodynamics of gas–solid bubbling fluidization can be reproduced without introducing bubble-specific empirical correlations such as for diameter and/or acceleration. The unified modeling of the entire gas–solid fluidization regime from bubbling to fast fluidization is performed by integrating the upgraded gas–solid bubbling model with the original energy-minimization multiscale (EMMS) model. Incorporating the upgraded gas–solid bubbling model into commercial computational fluid dynamics (CFD) software at the scale of computational cells, the unsteady-state simulation of gas–solid bubbling fluidization is realized with a higher accuracy than that based on homogeneous drag models.

The nucleation kinetics and crystal growth rates of both middle distillates and their blends with a model biodiesel were determined. As middle distillates are complex mixtures of hydrocarbons, a strategy was taken to define the solute and solvent. Different mixtures were prepared from different fuels, and a mixture law was used to calculate the mass percentages of each n-paraffin in the mixture; the difference between experimental and estimated compositions was negligible. An experimental device was set up to obtain the solubility curve of a distillate, for the first time. The application of classical homogeneous nucleation theory and Nývlt’s semiempirical approach allowed the nucleation rate, interfacial tension, and nucleation order to be obtained. The presence of esters did not have an influence on the solubility curve slope, but they had higher kinetic parameters and influenced the interfacial tension. The values found using the Nývlt law were typical for organic systems. Images were taken as a function of temperature and time, using thermomicroscopy, and image analysis enabled the crystal growth rates to be obtained. In general, the mixtures containing esters had higher growth rates. The solvent nature was found to play an important role in the growth, as the other alternative fuels studied have considerably higher growth rates.

In this paper, a simple model, but with high accuracy for a packed column liquid desiccant regenerator, to describe the heat and mass transfer process is developed. By lumping fluids’ thermodynamic properties and the geometric specifications as constants, two equations related with seven identified parameters are developed to predict the heat and mass transfer rate for solution regeneration processes in the regenerator. Commissioning information and the Levenberg–Marquardt method are employed to determine the unknown parameters. Compared with previous models, the presented model is simply constructed and accurate and requires no iterative computations while applied in predicting the heat and mass transfer rate once the parameters of the proposed model are determined. Experimental results demonstrate that the current model is effective to predict the performance of desiccant regeneration in the regenerator over wide working conditions. The proposed model promises to have wide application for real-time performance monitoring, optimization, and control for liquid desiccant regeneration.

In this work, we investigated the turbulent airflow field of a solution-blowing annular jet using the computational fluid dynamic approach, captured the fiber flapping motion with a high-speed camera, and then correlated the fiber morphology with the physical quantities of the airflow field and fiber motion. The characteristics of the average flow fields of various nozzle configurations under different air pressures were calculated and compared. The simulations demonstrated that higher air pressure results in higher velocity and turbulent fluctuations. The experiments showed that polymer jet attenuation is due to the effects of stretching, bending instability, flapping motion, and solvent evaporation. The fiber diameters were found to decrease and become more uniform as the air pressure increased. However, the fiber morphology became worse, with the emergence of some fiber strands under even higher air pressures.

A simple, cost-effective approach is presented for producing exfoliated films of pure graphene or polymer–graphene composite with high yield, high conductivity, and processability. The approach combines supercritical CO2 with ultrasonics. Characterization by Raman spectroscopy combined with atom force field microscopy demonstrates that the graphene sheets were obtained with 24% as monolayers, 44% as bilayers, and 26% as trilayers. The layer number and lateral size of graphene sheets can be controlled by adjusting the process parameters. The yield of graphene sheets with a lateral size of about 0.5–5.0 μm is about 16.7 wt % under optimum conditions, which can be easily raised to 40–50 wt % by repeated exfoliation of the sediment that remained in the reactor. The resultant pure graphene film made by filtration has a high electrical conductivity of 2.8 × 107 S/m. The electrical conductivity of the film of polyvinyl alcohol–graphene composite is 300 S/m.

The aim of present study was to measure and correlate the mole fraction solubility of olmesartan medoxomil (OLM) in six green solvents, namely, water, ethanol, propylene glycol (PG), polyethylene glycol-400 (PEG-400), ethylene glycol (EG), and Transcutol from (295.15 to 330.15) K at atmospheric pressure using the shake flask method. The experimental solubilities of OLM were correlated with the Apelblat equation. The root-mean-square deviations between experimental and calculated solubility were observed in the range of 3.360 × 10–8 to 0.013 × 10–3 in all green solvents. However, the correlation coefficients in water, ethanol, PG, PEG-400, EG, and Transcutol were observed in the range of 0.996–0.998, indicating a good fit. The solubility of OLM was found to be higher in PEG-400 (2.58 × 10–3 at 298.15 K) and Transcutol (2.48 × 10–3 at 298.15 K) as compared to water (2.32 × 10–7 at 298.15 K), ethanol (4.67 × 10–4 at 298.15 K), PG (9.23 × 10–5 at 298.15 K) and EG (6.73 × 10–5 at 298.15 K).