Enhancement of hydrothermal carbonization of chitin by combined pretreatment of mechanical activation and FeCl 3

In this work, a combined mechanical activation and FeCl (MA + FeCl ) method was applied to pretreat chitin to enhance the degree of hydrothermal carbonization. MA + FeCl pretreatment significantly disrupt the crystalline region of chitin and Fe entered into the molecular chain, resulting in the destruction of the stable structure of chitin. The chemical and structural properties of hydrochars were characterized by EA, SEM, FTIR, XRD, XPS, C solid state NMR, and N adsorption-desorption analyses. The results showed that the H/C and O/C atomic ratios of HC-MAFCT/230 (the hydrochar derived from MA + FeCl pretreated chitin with hydrothermal reaction temperature of 230 °C) were 0.96 and 0.34, respectively. Van Krevelen diagram indicated that the hydrothermal carbonization of chitin underwent a series of reactions such as dehydration, decarboxylation, and aromatization. HC-MAFCT/230 had abundant oxygen- and nitrogen-containing functional groups. HC-MAFCT/230 exhibited a porous structure, with the specific surface area of 128 m g , which was a promising carbon material.