▎ 摘　　要

Biochar is a stabilized carbon-rich product, and has drawn scientists' interest because of its specific properties and potential use in many environmental areas. It is emphasized that innovative technologies comprised of engineered nanoparticles in conventional biochar systems could ameliorate the functions of biochar to some extent, such as carbon sequestration, soil fertility and wastewater treatment. As a result, it enables an enhanced sorption of both inorganic and organic pollutants to their surfaces, reducing environmental fate and mobility. In this study, biochar and graphene-coated biochars were prepared by dip-coating of biomass by slow pyrolysis. Batch sorption experiments were performed on the resultant biochars to evaluate sorption ability. The graphene covering on biochar surface changes to increase the surface properties of the biochars, exhibiting the greatest surface area, pore volume and carbon content. Graphene-coated biochars had the ultimate sorption ability compared to their corresponding chars. The sorption data indicated that electrostatic attraction, pi-pi interaction between graphene sheets on the char surface and aromatic domain, was the controlling mechanism for the sorption of organic chemicals onto the chars. Graphene-coated biochars can thus be used as a stable, cheap sorbent, biomaterial for the removal of organic pollutants from aqueous media.