王义,黄先锋,郑向勇,李玉宝,张业健,金展,贝克,赵敏.UV/氯降解铜络合物的特性与机理[J].环境科学学报,2019,39(6):1763-1771
UV/氯降解铜络合物的特性与机理
- Performance and mechanism of Cu(II)-organic complexes degradation by UV/chlorine advanced oxidation process
- 基金项目：国家自然科学基金项目（No.51808406）；温州市水污染控制与治理科技创新项目（No.W2017004）；浙江省教育厅一般科研项目（No.Y201635237）
- 王义
- 温州大学生命与环境科学学院, 温州 325035
- 黄先锋
- 温州大学生命与环境科学学院, 温州 325035
- 郑向勇
- 温州大学生命与环境科学学院, 温州 325035
- 李玉宝
- 温州大学生命与环境科学学院, 温州 325035
- 张业健
- 温州大学生命与环境科学学院, 温州 325035
- 金展
- 温州大学生命与环境科学学院, 温州 325035
- 贝克
- 温州大学生命与环境科学学院, 温州 325035
- 赵敏
- 温州大学生命与环境科学学院, 温州 325035
- 摘要：本研究选取Cu-EDTA、Cu-NTA、Cu-柠檬酸和Cu-酒石酸4种典型的铜络合物来探讨UV/氯工艺在酸性和中性条件下降解重金属络合污染物的潜力，并以Cu-EDTA为代表物详细考察了[NaClO]0/[Cu]0（物质的量比）、初始溶液pH值和NO3-、SO42-等共存物质对UV/氯破络性能的影响.结果表明，UV/氯对多种铜络合物具有高效的氧化破络能力，可将Cu浓度从初始的19.2 mg·L-1降至1.0 mg·L-1以下.在[NaClO]0/[Cu]0为60、初始溶液pH为3.0~5.0的条件下，UV/氯对Cu-EDTA的破络效果较好，Cu和TOC的去除率分别高于95%和70%，但共存的NO3-、SO42-、Ca2+和NOM对Cu-EDTA的破络有一定抑制作用.自由基捕获实验和竞争动力学研究结果表明，UV/氯通过HO·和Cl·两者的共同作用实现Cu-EDTA破络，在pH=5.0时的贡献分别为60%和40%.产物鉴定结果证明，Cu-EDTA降解为N-C键逐步断裂的脱羧过程，其中，-N-（CH2-COOH）2和-N-CH2-CH2-N-基团上的N-C键断开生成Cu-ED3A和Cu-NTA，分别贡献约80%和20%.UV/氯对实际络合铜废水仍具有良好的处理效果，Cu浓度由初始的20.4 mg·L-1降至约1.0 mg·L-1.
- Abstract：The applicability of UV/chlorine advanced oxidation process for the decomplexation of heavy metal complexes was performed using four typical Cu(Ⅱ)-organic complexes including Cu(Ⅱ)-EDTA, Cu(Ⅱ)-NTA, Cu(Ⅱ)-citrate and Cu(Ⅱ)-tartrate under acidic and neutral pH. As well, the effects of the molar ratio of initial NaClO to initial Cu ([NaClO]0/[Cu]0), initial solution pH and co-existing matters (e.g., NO3- and SO42-) on the process were systematically investigated using Cu(Ⅱ)-EDTA as a representative compound. The results indicated that those Cu(Ⅱ)-organic complexes can be efficiently destructed by UV/chlorine, with the residual Cu(Ⅱ) below 1.0 mg·L-1 from 19.2 mg·L-1. Efficient decomplexation of Cu(Ⅱ)-EDTA was achieved by UV/chlorine, with higher than 95% of Cu(Ⅱ) removal and 70% of TOC elimination, at the[NaClO]0/[Cu]0 of 60 and initial solution pH of 3.0~5.0. However, the efficiency was slightly inhibited by the co-existing matters of NO3-, SO42-, Ca2+ and NOM. The radical scavenging and competitive kinetics experiments proved that the degradation of Cu(Ⅱ)-EDTA was attributed to the combined oxidation by HO·and Cl·, and their relative contributions at pH 5.0 were about 60% and 40%, respectively. Based on the analysis of degradation products using HPLC, a decarboxylation process through stepwise cleavage of N-C bond was found to be responsible for the degradation of Cu-EDTA, wherein the separate cleavage of N-C bond from -N-(CH2-COOH)2 to form Cu-ED3A and -N-CH2-CH2-N-to Cu-NTA contributed about 80% and 20% to the overall process. Efficient removal of Cu(Ⅱ) from a realistic electroplating effluent was also achieved using UV/chlorine method, with the residual Cu(Ⅱ) concentration decreasing to 1.0 mg·L-1 from 20.4 mg·L-1.
