g-C3N4 Modified biochar as an adsorptive and photocatalytic material for decontamination of aqueous organic pollutants

Abstract Converting the waste biomasses with high-carbon content into value-added materials is an environmental-friendly way for their utilization. In this study, a leaf-derived biochar is modified with graphitic C 3 N 4 to fulfill an affordable composite material capable of removing organic pollutants via adsorptive and photocatalytic processes simultaneously. The preparation process includes a carbonization process of chestnut leaf biomass and a followed condensation reaction of melamine at 520 °C. The characterization shows that biochar and C 3 N 4 existed in the composites in their pristine status, and the effective connection of C 3 N 4 and biochar was established. The adsorptive performance of the composites is governed by the biochar content in the composite, thus showing favorable performance for the removal of cationic dye methylene blue (MB). The condensation reaction of the melamine precursor has a coalescing effect on the dispersed biochar, resulting in the growth of particle size of composite. The composites prepared at different biochar/melamine ratios all show a photocatalytic activity on decolorization of MB. In terms of the specific photocatalytic activity of C 3 N 4 in the composite, biochar/melamine ratio of 0.5:1 is the best. Unlike the conventional adsorptive carbon materials which have saturated adsorption capacity, the composite in this study retain a sustaining decontamination capability due to the photocatalytic degradation of adsorbed organic pollutants under irradiation.