China Nonferrous Metallurgy

In order to investigate the adsorption capacity of heavy metal Pb(Ⅱ) from agricultural and forestry waste walnut shell, modified walnut shell biochar was prepared by microwaveH2O2 coupling modification method, and analyzed by scanning electron microscope, Xray diffraction and infrared absorption spectrum. The effects of pH, adsorption time, temperature, amount of adsorbent and initial concentration on the adsorption of Pb(Ⅱ) from simulated aqueous solution with modified walnut shell activated carbon were investigated. The characterization results showed that the modified biochar had amorphous carbon structure, uneven surface of carbon particles and abundant pore structures of different sizes and shapes. The contents of C[FY=,1]O, C—O, C[FY=,1]C groups increased compared with those before modification. Under the conditions of initial ion concentration of 400mg/L, dosage of 16mg/L, pH 4.0, temperature of 25℃ and adsorption time of 180min, the adsorption rate of Pb(Ⅱ) by modified biochar reaches 99.5%. The results of adsorption experiments show that the microwaveH2O2 coupling modified walnut shell biochar has good adsorption effect on high concentration Pb(Ⅱ)containing wastewater.