EDTA-LDH/zeolite制备及其对重金属离子的吸附

Preparation of EDTA-LDH/Zeolite and Its Adsorption of Heavy Metal Ions

用水热法和焙烧还原法两步合成了乙二胺四乙酸-水滑石/沸石(EDTA-LDH/zeolite)复合材料,并将其用于去除水溶液中的Cd^(2+)、Pb^(2+)、Cu^(2+),系统研究不同条件下EDTA-LDH/zeolite对单一及混合重金属离子溶液中Cd^(2+)、Pb^(2+)、Cu^(2+)的吸附效果与吸附机制。结果表明,当EDTA-LDH/zeolite投加量为0.05 g、重金属离子浓度为1500 mg/L、pH值为6.5、吸附时间为24 h时,EDTA-LDH/zeolite吸附性能最佳。重金属离子间存在竞争吸附,EDTA-LDH/zeolite对Cd^(2+)、Pb^(2+)、Cu^(2+)的最大吸附容量分别为65.33、98.35和108.51 mg/g。去除过程中沉淀作用、表面络合、螯合反应等多种机制协同作用,去除行为均符合Langmuir等温模型与拟二阶动力学模型。

EDTA-LDH/zeolite composite material was synthesized in two steps by hydrothermal and reconstruction method and used for the removal of Cd^(2+),Pb^(2+),and Cu^(2+)from aqueous solution.The adsorption effect and mechanism of EDTALDH/zeolite on Cd^(2+),Pb^(2+)and Cu^(2+)in single and mixed heavy metal ion solutions under different conditions were systematically investigated.The results show that the best adsorption performance of EDTA-LDH/zeolite is achieved when the dosage of EDTA-LDH/zeolite is 0.05 g,the concentration of heavy metal ions is 1500 mg/L,the pH value is 6.5,and the adsorption time is 24 h.Competing adsorption between heavy metal ions,the maximum adsorption capacities of EDTALDH/zeolite for Cd^(2+),Pb^(2+),and Cu^(2+)are 65.33,98.35,and 108.51 mg/g,respectively.During the removal process,various mechanisms such as precipitation,surface complexation,and chelation work synergistically.The removal behavior of EDTA-LDH/zeolite are all consistent with Langmuir isotherm model and pseudo second-order kinetic model.