Environmental performances of hydrochar-derived magnetic carbon composite affected by its carbonaceous precursor

The effects of hydrochar properties on the environmental performances of its derived magnetic carbon composites have been overlooked. In the present work, various hydrochars (produced at different hydrothermal carbonization temperatures, 160–300 °C) were selected as the carbonaceous precursors. Then, magnetic carbon composites were fabricated by simultaneously carbonizing hydrochar, ZnCl2 and FeCl3 (namely simultaneous activation and magnetization). It was observed that a magnetic carbon composite with high porosity, acid resistance and adsorption capacity for roxarsone, and low graphitization degree was prepared from a hydrochar with low hydrothermal carbonization temperature. More importantly, strong linear correlations were obtained between hydrochar properties (recalcitrance index, H/C and O/C atomic ratios) and the environmental performances of its derived magnetic carbon composites (porosity, acid resistance, degree of graphitization, and adsorption capacity for roxarsone). The adsorption of ROX molecules onto the as-prepared magnetic carbon composites were mainly regulated by the pores of materials under certain pH of the solution. This work provides novel insights into the role of hydrochar properties in determining the environmental performances of its derived magnetic carbon composites.