Ni/GO^(0.2)-PAC^(0.8)粒子电极的制备及其降解CuEDTA络合物效能

Preparation of Ni/GO_(0.2)-PAC_(0.8) particle electrode and its degradation performance of Cu-EDTA complex

Cu-EDTA在水中具有很强的稳定性,且难以用常规化学沉淀法去除。以粉末活性炭(PAC)和氧化石墨烯(GO)为载体、Ni为催化剂,采用浸渍焙烧法制备了粒子电极,用于Cu-EDTA的电催化降解。采用XRD和SEM-EDS对电极表面的组成和形态进行了表征;探讨了Cu-EDTA解络和铜回收的效能及机制。结果表明,粒子电极最佳制备条件为:焙烧温度为600℃、焙烧时间为4 h、PAC与GO质量比为8:2。粒子电极上的镍主要以Ni^(0)存在,并含有少量NiO。Cu-EDTA和总络合态铜(TCCu)的解络率分别为99.6%和99.4%,总铜(TCu)的回收率为93.7%,解络和铜回收均符合拟一级动力学规律。自由基淬灭和循环伏安扫描实验结果表明,Cu-EDTA的解络是通过电还原完成的,Cu-EDTA中的Cu^(2+)先还原为Cu^(+),再还原为Cu^(0)并沉积在粒子电极表面。

Cu-EDTA has strong stability in water and is hard to remove by conventional chemical precipitation methods.The particle electrode that was applied in the electrocatalytic degradation of Cu-EDTA was prepared by impregnation roasting method,using the powdered activated carbon(PAC)and graphene oxide(GO)as the carrier,and nickel as the catalyst.XRD and SEM-EDS were performed to characterize the composition and morphology of the electrode surface.The efficiency and mechanism of Cu-EDTA decomplexation and copper recovery were investigated.The results showed that the optimal conditions of the preparation of particle electrode were:the calcination temperature of 600℃,the calcination time of 4 h,and the mass ratio of PAC to GO of 8:2.The nickel on the particle electrode existed mainly as Ni^(0),and a small amount of Ni^(O).The decomplexation efficiencies of Cu-EDTA and total complexing copper(TCCu)were 99.6%and 99.4%,respectively.The recovery efficiency of total copper(TCu)was 93.7%.The decomplexation and copper recovery processes were in accordance with pseudo-first order reaction kinetical model.The results of free radical quenching and cyclic voltammetry scanning experiments showed that the decomplexation of Cu-EDTA was completed by electro-reduction.Cu^(2+)in Cu-EDTA was first reduced to Cu^(+),then reduced to Cu^(0) and deposited on the particle electrodes.