Enhanced Photoelectrocatalytic Decomplexation of Cu-EDTA and Cu Recovery by Persulfate Activated by UV and Cathodic Reduction
Enhanced Photoelectrocatalytic Decomplexation of Cu-EDTA and Cu Recovery by Persulfate Activated by UV and Cathodic Reduction
复制标题
紫外和阴极还原活化过硫酸盐增强 Cu-EDTA 光电催化解络和铜回收
DOI：
10.1021/acs.est.6b00632
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发表时间：
2016
影响因子：
11.4
通讯作者：
Zhao Xu
中科院分区：
文献类型：
--
作者：
Zeng Huabin;Liu Shanshan;Chai Buyu;Cao Di;Wang Yan;Zhao Xu
为了通过光电催化(PEC)过程促进铜-EDTA的分解和铜的阴极回收，将S2O82-引入到以二氧化钛/钛为光阳极的光电催化体系中。在电流密度为0.2 mA/cm2、初始溶液pH为3.0的条件下，加入5 mM的S2O82-后，铜络合物的解配率从PEC的47.5%提高到98.4%。相应地，铜的回收率在60min内从47.4%提高到98.3%。在10min的初始反应时间内，几乎没有铜的回收。结合ESR和电化学LSV曲线的分析，认为S2O82-发生了阴极还原活化为SO4·-自由基，先于释放出来的Cu2+离子还原。S2O82-的紫外光照射也导致SO4·-的产生。生成的SO4·-自由基促进了铜-EDTA的氧化。消耗S2O82-后，阴极还原回收铜的速度较快。SO4·-转化为OH·引起的酸化有利于铜的阴极回收。PEC/S2O82-组合工艺对实际电镀废水中的TOC也有较好的去除效果，铜的回收率在80%以上。
In order to enhance Cu–EDTA decomplexation and copper cathodic recovery via the photoelectrocatalytic (PEC) process, S2O82–was introduced into the PEC system with a TiO2/Ti photoanode. At a current density of 0.2 mA/cm2and initial solution pH of 3.0, the decomplexation ratio of Cu complexes was increased from 47.5% in the PEC process to 98.4% with 5 mM S2O82–addition into the PEC process (PEC/S2O82–). Correspondently, recovery percentage of Cu was increased to 98.3% from 47.4% within 60 min. It was observed that nearly no copper recovery occurred within the initial reaction period of 10 min. Combined with the analysis of ESR and electrochemical LSV curves, it was concluded that activation of S2O82–into SO4·–radicals by cathodic reduction occurred, which was prior to the reduction of liberated Cu2+ions. UV irradiation of S2O82–also led to the production of SO4·–. The generated SO4·–radicals enhanced the oxidation of Cu–EDTA. After the consumption of S2O82–, the Cu recovery via cathodic reduction proceeded quickly. Acidification induced by the transformation of SO4·–to OH· favored the copper cathodic recovery. The combined PEC/S2O82–process was also efficient for the TOC removal from a real electroplating wastewater with the Cu recovery efficiency higher than 80%.