Journal
ENVIRONMENTAL SCIENCE & TECHNOLOGY
Volume 53, Issue 4, Pages 2036-2044Publisher
AMER CHEMICAL SOC
DOI: 10.1021/acs.est.8b05346
Keywords
-
Categories
Funding
- National Natural Science Foundation of China [51808406]
- Science and Technology Project of Zhejiang Province [2017C33036]
- Wenzhou Science and Technology Innovation Project in the Control and Management of the Contaminated Water
- Natural Science Foundation of Jiangsu Province [BK20160653]
Ask authors/readers for more resources
Traditional processes usually cannot enable efficient water decontamination from toxic heavy metals complexed with organic ligands. Herein, we first reported the removal of Cu(II)-EDTA by a UV/chlorine process, where the Cu(II)-EDTA degradation obeyed autocatalytic two-stage kinetics, and Cu(II) was simultaneously removed as CuO precipitate. The scavenging experiments and EPR analysis indicated that Cl-center dot accounted for the Cu(II)-EDTA degradation at diffusion-controlled rate (similar to 10(10) M(-1)s(-1)). Mechanism study with mass spectrometry evidence of 11 key intermediates revealed that the Cu(II)-EDTA degradation by UV/chlorine was an autocatalytic successive decarboxylation process mediated by the Cu(II)/Cu(I) redox cycle. Under UV irradiation, Cu(I) was generated during the photolysis of the Cl-center dot-attacked complexed Cu(II) via ligand-to-metal charge transfer (LMCT). Both free and organic ligand-complexed Cu(I) could form binary/ternary complexes with ClO-, which were oxidized back to Cu(II) via metal-to-ligand charge transfer (MLCT) with simultaneous production of Cl-center dot, resulting in the autocatalytic effect on Cu(II)-EDTA removal. Effects of chlorine dosage and pH were examined, and the technological practicability was validated with authentic electroplating wastewater and other Cu(II)-organic complexes. This study shed light on a new mechanism of decomplexation by Cl-center dot and broadened the applicability of the promising UV/chlorine process in water treatment.
Authors
I am an author on this paper
Click your name to claim this paper and add it to your profile.
Reviews
Recommended
No Data Available