Photoelectrocatalytic oxidation of Cu(II)-EDTA at the TiO2 electrode and simultaneous recovery of Cu(II) by electrodeposition.
Photoelectrocatalytic oxidation of Cu(II)-EDTA at the TiO2 electrode and simultaneous recovery of Cu(II) by electrodeposition.
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DOI：
10.1021/es3046982
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发表时间：
2013-04
影响因子：
11.4
通讯作者：
Xu Zhao;Libao Guo;Baofeng Zhang;Huijuan Liu;J. Qu
中科院分区：
文献类型：
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作者：
Xu Zhao;Libao Guo;Baofeng Zhang;Huijuan Liu;J. Qu
以TiO 2/Ti为阳极，不锈钢为阴极，在光电催化（PEC）体系中实现了Cu-EDTA的同时脱络和Cu（2+）的电沉积回收。在0.5 mA/cm（2）的电流密度，去除效率为0.05 mM Cu-EDTA的反渗透，电氧化，和PEC过程被确定为15，43，和72%，在3小时，分别。Cu（2+）离子的回收率分别为10%、33%和67%。结果表明，在PEC过程中，Cu-EDTA的脱络合和Cu（2+）的回收存在协同效应，且协同效应有利于酸性条件，且随电流密度的增大而增大。Cu-EDTA和Cu（2+）离子的去除符合准一级动力学模型。Ca（2+）离子的加入显著提高了Cu-EDTA的去除率和Cu（2+）的回收率。中间体，包括Cu-NTA，Cu-EDDA，乙酸，甲酸，草酸被确定，并提出了一个Cu-EDTA的解络合途径。Cu-EDTA在阳极通过氧化羟基自由基的解络合被揭示。根据X射线光电子能谱分析，讨论了Cu（2+）离子在阴极的还原途径。本研究为金属络合物的破坏和金属离子的回收提供了一种有前途的替代方法。
The simultaneous decomplexation of Cu-EDTA and electrodeposition recovery of Cu(2+) ions was attempted in a photoelectrocatalytic (PEC) system using TiO2/Ti as the anode and stainless steel as the cathode. At a current density of 0.5 mA/cm(2), removal efficiencies of 0.05 mM Cu-EDTA by photocatalysis, electrooxidation, and PEC processes were determined to be 15, 43, and 72% at 3 h, respectively. Recovery percentages of Cu(2+) ions were determined to be 10, 33, and 67%, respectively. These results indicated that a synergetic effect in the decomplexation of Cu-EDTA and recovery of Cu(2+) ions occurred in the PEC process, which favored acid conditions and increased with the current densities. The removal of Cu-EDTA and Cu(2+) ions can be described by a pseudo-first-order kinetics model. Ca(2+) ions significantly increase the removal of Cu-EDTA and recovery of Cu(2+) ions. Intermediates, including Cu-NTA, Cu-EDDA, acetic acid, formic acid, and oxalic acid, were identified, and a decomplexation pathway of Cu-EDTA was proposed. The Cu-EDTA decomplexation at the anode via oxidation of hydroxyl radicals was revealed. On the basis of X-ray photoelectron spectra analysis, a reduction pathway of Cu(2+) ions at the cathode was discussed. The present study may provide a promising alternative for destruction of the metal complex and recovery of metal ions.