Abstract:Biochar composite adsorbent (MBC) loaded with manganese slag was prepared by mixed-co-pyrolysis method using biogas slag and manganese slag as raw materials. The effects of pyrolysis temperature, mass ratio of manganese slag to biogas residue, initial pH value of solution and material dosage on the adsorption of Sb3+ were investigated by static adsorption experiments. The adsorption mechanism was explored by XRF, XRD, FTIR, SEM-EDS and XPS. The results show that the surface pore structure of MBC is rich and loaded with many iron, manganese and calcium compounds. SiO2, CaCO3 and CaS are the main crystal phases of MBC. Under the conditions of pyrolysis temperature of 600 °C, mass ratio of mM : mB of 6 : 4, initial pH value of 3 and dosage of 20 mg, the maximum adsorption capacity of MBC to Sb3+ was 28.71 mg g-1, which was 60.82 % higher than that before modification. The adsorption mechanism of Sb3+ on MBC mainly includes co-precipitation, redox reaction, complexation and ion exchange.