微纳米生物炭对镉和镍的吸附特性OA

The aim of this study was to explore the heavy metal adsorption performance of micro-nano-scale biochar(MNBC)and provide a theoretical basis for the effective removal of cadmium and nickel by MNBC.Rice straw was used as the raw material,which was pyrolyzed with oxygen-limited condition at 500℃to produce biochar(BC).The biochar was ground to obtain MNBC.MNBC were characterized using transmission electron microscopy(TEM),elemental analyses(EA),Fourier transformed-infrared spectroscopy(FTIR),etc.Combined with adsorption kinetics and adsorption iso-therm experiments,the single adsorption and mixed adsorption of Cd and Ni by MNBC were com-pared and the adsorption mechanism was discussed.The results showed that the adsorption kinetics of Cd and Ni by BC and MNBC were better fitted by the quasi-second-order kinetic equation.In a single system,the adsorption rate constants K2 of MNBC for Cd and Ni were 2.24 and 2.91 times higher than that of BC,respectively.In the mixed system,the K2 of MNBC for Cd and Ni were 2.09 and 2.24 times higher than that of BC,respectively.The adsorption isotherms all conformed to the Langmuir model.In a single system,the saturated adsorption capacity Qm of MNBC for Cd and Ni were 1.81 and 1.41 times higher than that of BC,respectively.In the mixed system,the Qm of MNBC for Cd and Ni were 1.44 and 1.35 times higher than that of BC,respectively.In the mixed system,MNBC promoted the competition of Cd and inhibited Ni.