EDTA对新型多胺螯合树脂选择性吸附Cu(Ⅱ)的影响机制  

INSIGHT INTO THE EFFECT OF EDTA ON SELECTIVE ADSORPTION OF COPPER ONTO A NOVAL POLYAMINE CHELATING RESIN

作　　者：赵伟[1] 刘福强[1] 刘自成 袁媛 凌晨[1] 李爱民[1] ZHAO Wei;LIU Fuqiang;LIU Zicheng;YUAN Yuan;LING Chen;LI Aimin(State Key Laboratory of Pollution Control and Resources Reuse School of the Environment,Nanjing University,Nanjing 210046,China)

机构地区：[1]污染控制与资源化研究国家重点实验室,南京大学环境学院,南京210046

出　　处：《离子交换与吸附》2019年第4期289-299,共11页Ion Exchange and Adsorption

基　　金：国家自然科学基金(No.51878334,51378253,BK20170647).

摘　　要：结合溶液体系Cu-EDTA形态分析,研究了广泛pH值下EDTA对多胺螯合树脂(PAMD)选择性吸附Cu(Ⅱ)的影响规律。酸性条件(2.0<pH<7.0)下,随pH值升高,Cu(Ⅱ)的吸附量先增大后减小,显示出受游离EDTA离子形态变化的明显影响,这与阴离子络合态铜(CuHEDTA-和CuEDTA2-)与质子化氨基的静电作用相关。碱性条件(7.0<pH<12.0)下,随pH值升高,Cu(Ⅱ)的吸附量逐步增大并趋于稳定,这主要是因为作用机制由去质子化氨基与EDTA络合态铜形成三元络合物(7.0<pH<9.5)转变为去质子化氨基直接置换EDTA络合态铜中EDTA配体的方式(9.5<pH<12.0),进而增加了PAMD树脂对Cu(Ⅱ)的选择性吸附性能。另外,无机盐离子促进了PAMD树脂对EDTA络合态铜的配体置换作用,提高了Cu(Ⅱ)的选择性吸附性能。在盐、碱共存体系中Cu(Ⅱ)对EDTA的选择性系数高达73.1,可作为常见有机络合重金属离子选择性去除的新方法。The effect of EDTA on the selective adsorption of Cu(Ⅱ)with the noval polyamine chelate resin(PAMD)was explored with the help of speciation analysis for EDTA and Cu(Ⅱ).Under the acidic condition(2.0<pH<7.0),the adsorpiton amount of Cu(Ⅱ)firstly increases and then decreases with the increase of pH,which is obviously affected by the species of free EDTA ions.This is mainly due to difference in the electrostatic effect between the species of copper(CuHEDTA-and CuEDTA2-)and proton amino sites.Under alkaline conditions(7.0<pH<12.0),the adsorpiton amount of Cu(Ⅱ)increases and then keep constant with the increase of pH.The transformation from the deprotonated amino coordinated with the complex of Cu(Ⅱ)and EDTA to form ternary complex(7.0<pH<9.5)into exchange of the EDTA ligand in the complex of Cu(Ⅱ)and EDTA with the deprotonated amino(9.5<pH<12.0),increased the PAMD resin for copper selective adsorption performance.In addition,the inorganic ions enhance the interaction EDTA ligand with the deprotonated amino and improve the selective adsorption to Cu(Ⅱ).In the salt and alkali solution,the selectivity coefficient of Cu(Ⅱ)versus EDTA is up to 73.1,which provides a new method to selective removal of heavy metals from common organnic complex systems.

关 键 词：多胺螯合树脂 Cu(Ⅱ) EDTA 配体置换 选择性吸附 

分 类 号：X703[环境科学与工程—环境工程] O647.3[理学—物理化学]