Mg-modified biochar was prepared by aquatic plants Vallisneria and Myriophyllum.The specific surface,porosity analysis,elemental analysis,pHpzc,FTIR,XPS and XRD characterization of the biochar were carried out,and the adsorption of microcystin-LR(MC-LR)was studied.The results showed that the Mg-modified biochar had larger specific surface area and mesopore volume,and its surface was loaded with MgO and Mg(OH)2,and had higher oxygen-containing group content and pHpzc.Biochar soaked with 2.0 mol·L-1 MgCl2 had the best removal effect on MC-LR.The adsorption kinetics could be well described by pseudo-first order,pseudo-second order,Elovich and intra-particle diffusion models.The adsorption isotherms were consistent with the Langmuir and Freundlich models,and higher temperature facilitated the adsorption of MC-LR.Higher pH and higher molecular weight of DOM would inhibit adsorption.Intra-particle diffusion and mesoporous filling were the important mechanisms of adsorption.Hydrogen bonding,electrostatic attraction andπ+-π EDA interaction forces may also exist.This study provides new ideas for the resource utilization of wetland aquatic plant residues.
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