title: Decomplexation efficiency and mechanism of Cu(II)-EDTA by H2O2coupled internal micro-electrolysis process.
abstract: Internal micro-electrolysis (IE) coupled with Fenton oxidation (IEF) was a very effective technology for copper (Cu)-ethylenediaminetetraacetic acid (EDTA) wastewater treatment. However, the mechanisms of Cu2+removal and EDTA degradation were scarce and lack persuasion in the IEF process. In this paper, the decomplexation and removal efficiency of Cu-EDTA and the corresponding mechanisms during the IEF process were investigated by batch test. An empirical equation and the oxidation reduction potential (ORP) index were proposed to flexibly control IE and the Fenton process, respectively. The results showed that Cu2+, total organic carbon (TOC), and EDTA removal efficiencies were 99.6, 80.3, and 83.4%, respectively, under the proper operation conditions of iron dosage of 30 g/L, Fe/C of 3/1, initial pH of 3.0, Fe2+/H2O2molar ratio of 1/4, and reaction time of 20 min, respectively for IE and the Fenton process. The contributions of IE and Fenton to Cu2+removal were 91.2 and 8.4%, respectively, and those to TOC and EDTA removal were 23.3, 25.1, and 57, 58.3%, respectively. It was found that Fe2+-based replacement-precipitation and hydroxyl radical (•OH) were the most important effects during the IEF process. •OH played an important role in the degradation of EDTA, whose yield and productive rate were 3.13 mg/L and 0.157 mg/(L min-1), respectively. Based on the intermediates detected by GC-MS, including acetic acid, propionic acid, pentanoic acid, amino acetic acid, 3-(diethylamino)-1,2-propanediol, and nitrilotriacetic acid (NTA), a possible degradation pathway of Cu-EDTA in the IEF process was proposed. Graphical abstract The mechanism diagram of IEF process.
authors.affiliation: Ministry of Education Key Laboratory of Pollution Control and Ecological Remediation for Industrial Agglomeration Area, College of Environment and Energy, South China University of Technology, Guangzhou, 510006, People's Republic of China.
authors.forename: Dongfang
authors.initials: D
authors.lastname: Zhou
authors.affiliation: Ministry of Education Key Laboratory of Pollution Control and Ecological Remediation for Industrial Agglomeration Area, College of Environment and Energy, South China University of Technology, Guangzhou, 510006, People's Republic of China. ppyyhu@scut.edu.cn.
authors.forename: Yongyou
authors.initials: Y
authors.lastname: Hu
authors.affiliation: Ministry of Education Key Laboratory of Pollution Control and Ecological Remediation for Industrial Agglomeration Area, College of Environment and Energy, South China University of Technology, Guangzhou, 510006, People's Republic of China.
authors.forename: Qian
authors.initials: Q
authors.lastname: Guo
authors.affiliation: Zhujianghai Institute of Salty Water Desalination, Dongguan, 523000, People's Republic of China.
authors.forename: Weiguang
authors.initials: W
authors.lastname: Yuan
authors.affiliation: Institute of Dongguan Environmental Science, Dongguan, 523009, People's Republic of China.
authors.forename: Jiefan
authors.initials: J
authors.lastname: Deng
authors.affiliation: Ministry of Education Key Laboratory of Pollution Control and Ecological Remediation for Industrial Agglomeration Area, College of Environment and Energy, South China University of Technology, Guangzhou, 510006, People's Republic of China.
authors.forename: Yapan
authors.initials: Y
authors.lastname: Dang
mesh_terms: D003300:Copper / Q000737:chemistry*; D004492:Edetic Acid / Q000737:chemistry*; D004572:Electrolysis / Q000379:methods*; D006861:Hydrogen Peroxide / Q000737:chemistry*; D006863:Hydrogen-Ion Concentration; D007501:Iron / Q000737:chemistry; D010084:Oxidation-Reduction; D014865:Waste Disposal, Fluid / Q000379:methods; D014874:Water Pollutants, Chemical / Q000737:chemistry*
chemical_list: D014874:Water Pollutants, Chemical; D003300:Copper; D004492:Edetic Acid; D006861:Hydrogen Peroxide; D007501:Iron
keywords: Cu–EDTA; Decomplexation; Degradation; Fenton; Internal micro-electrolysis