Biochar has played an important role in mitigating global climate change,water environment protection,soil improvement and soil biochemistry.At present,the modification and application of biochar is still a hot point.Surface modification of biochar by organic or other modifiers can alter the surface characteristics of biochar,thereby enhancing the adsorption properties of biochar.Biological carbon surface negative charge dominates,the adsorption capacity of cation,at present there are many researches focuse...