Do All Carbonized Charcoals Have the Same Chemical Structure? 1. Implications of Thermogravimetry−Mass Spectrometry Measurements

A half century ago, Rosalind Franklin identified two distinct families of organic materials: those that become graphitic during carbonization at high temperatures and those that do not. According to Franklin, sucrose-derived biocarbons showed “no trace of homogeneous development of the true graphitic structure, even after heating to 3000 °C” [Proc. R. Soc. A 1951, 209, 196-218]. Franklin concluded that “non-graphitizing” carbons (e.g., sucrose biocarbons) are typically formed from oxygen-rich or hydrogen-poor substances that develop a “strong system of cross-linking, which immobilizes the structure and unites the crystallites in a rigid mass”. In this work, we show that there is a spectrum of non-graphitizing biocarbons ranging from those that release little CO during carbonization at temperatures approaching 1000 °C to those that strongly and persistently emit CO during carbonization at temperatures approaching 1000 °C. Typically, very low-ash biocarbons are not persistent CO emitters, but biocarbons with moderate ash contents can also be a member of this class if their ash lacks the catalytic species K, P, Mg, and/or Na that appear to be responsible for persistent CO evolution at 1000 °C.