The Removal Of Lead,Copper And Uranium By Amino Modified Magnetic Biochar From Aqueous Solutions

In this study,a magnetic and amino modified rice husk biochar were successfully prepared by a hydrothermal method.Then,the modified biochars were used to remove Pb(?),Cu(?),and U(?)from aqueous solutions.The effect of biochar loading,pH of solution,adsorption time,ionic strength,temperaure and coexited metal ions on the adsorption of Pb(?),Cu(?)and U(?)by different biochars were investigated.SEM,FTIR,XRD and XPS were used to analyze the characteristics of before and after biochars modification and the adsorption mechanism.The results showed that the adsorption site,specific surface area and hydrophobic of biochar were significantly improved and enhanced after being modified.The adsorption data fitted well to pseudo-second-order kinetic.The adsorption isotherm of Pb(?)and U(?)on biochar(BC)and magnetic biochar(MBC)fitted to Langmuir model.The adsorption isotherm of Pb(?)and U(?)on amino modified biochar(NBC)and magnetic ally amino modified biochar(NMBC)were in line with the Freundlich model,and the adsorption isotherm of Pb(?),Cu(?)and U(?)on all kinds of biochars were accorded with the Freundlich model.The increase rate of adsorption quantity of Cu(?)and U(?)on NMBC were significantly higher than the Pb(?)and the increase rate were 78.51%,33.34%and 8.42%,respectively.The adsorption mechanism of biochars were mainly attributed to the action of surface functional groups,ion exchange,and electrostatic interaction.The adsorption of Pb(?),Cu(?),and U(?)on NBC,MBC,and NMBC mainly occurred in the functional groups of N-H and Fe3O4,but that on BC was mainly in the functional groups of-OH,C=C and-COOH.