EDTA, oxalate, and phosphate ions enhanced reactive oxygen species generation and sulfamethazine removal by zero-valent iron

Yuwei Pan; Minghua Zhou; Qi Wang; Jingju Cai; Yusi Tian; Ying Zhang

doi:10.1016/j.jhazmat.2020.122210

EDTA, oxalate, and phosphate ions enhanced reactive oxygen species generation and sulfamethazine removal by zero-valent iron

J Hazard Mater. 2020 Jun 5:391:122210. doi: 10.1016/j.jhazmat.2020.122210. Epub 2020 Jan 31.

Authors

Yuwei Pan¹, Minghua Zhou², Qi Wang³, Jingju Cai³, Yusi Tian³, Ying Zhang⁴

Affiliations

¹ College of Biology and the Environment, Nanjing Forestry University, Nanjing, 210037, China; Key Laboratory of Pollution Process and Environmental Criteria, Ministry of Education, College of Environmental Science and Engineering, Nankai University, Tianjin, 300350, China; Tianjin Key Laboratory of Environmental Technology for Complex Trans-Media Pollution, College of Environmental Science and Engineering, Nankai University, Tianjin, 300350, China; Tianjin Key Laboratory of Urban Ecology Environmental Remediation and Pollution Control, College of Environmental Science and Engineering, Nankai University, Tianjin 300350, China.
² Key Laboratory of Pollution Process and Environmental Criteria, Ministry of Education, College of Environmental Science and Engineering, Nankai University, Tianjin, 300350, China; Tianjin Key Laboratory of Environmental Technology for Complex Trans-Media Pollution, College of Environmental Science and Engineering, Nankai University, Tianjin, 300350, China; Tianjin Key Laboratory of Urban Ecology Environmental Remediation and Pollution Control, College of Environmental Science and Engineering, Nankai University, Tianjin 300350, China. Electronic address: zhoumh@nankai.edu.cn.
³ Key Laboratory of Pollution Process and Environmental Criteria, Ministry of Education, College of Environmental Science and Engineering, Nankai University, Tianjin, 300350, China; Tianjin Key Laboratory of Environmental Technology for Complex Trans-Media Pollution, College of Environmental Science and Engineering, Nankai University, Tianjin, 300350, China; Tianjin Key Laboratory of Urban Ecology Environmental Remediation and Pollution Control, College of Environmental Science and Engineering, Nankai University, Tianjin 300350, China.
⁴ Key Laboratory of Pollution Process and Environmental Criteria, Ministry of Education, College of Environmental Science and Engineering, Nankai University, Tianjin, 300350, China; Tianjin Key Laboratory of Environmental Technology for Complex Trans-Media Pollution, College of Environmental Science and Engineering, Nankai University, Tianjin, 300350, China; Tianjin Key Laboratory of Urban Ecology Environmental Remediation and Pollution Control, College of Environmental Science and Engineering, Nankai University, Tianjin 300350, China. Electronic address: zhangying04@nankai.edu.cn.

PMID: 32044636
DOI: 10.1016/j.jhazmat.2020.122210

Abstract

The activation rate of oxygen by zero-valent iron (Fe°) was very low. In this study, ethylenediaminetetraacetic acid (EDTA), oxalate (Ox), and phosphate ions (Na₂HPO₄) were used to enhance the oxygen activation by Fe° for sulfamethazine (SMT) removal. The addition of these ligands could significantly enhance the SMT degradation. SMT removal was improved from 10.5 % in the Fe° system (360 min) to 70.3 %, 85.2 % and 77.8 % in the Fe°/EDTA (60 min), Fe°/Ox (180 min) and Fe°/phosphate (360 min) systems, respectively. Scanning electron microscopy with energy dispersive X-ray (SEM-EDX), Fourier transform infrared reflection (FTIR), contact angle and X-ray photoelectron spectra (XPS) of Fe° in different systems were recorded. The presence of chelating agents hydroxylated Fe°, inhibited the iron oxide formation on the Fe° surface and promoted iron ion release from the solid. Moreover, the agents improved the recovery of surface Fe²⁺ which could subsequently enhance the activation of O₂ to produce more H₂O₂ and reactive oxygen radicals for SMT removal. OH radical produced mainly through H₂O₂ decomposition was primarily responsible for removing SMT in all three systems. The Fe° system added with chelating agents is a new and promising approach for treating wastewaters containing ligands.

Keywords: Ethylenediaminetetraacetic acid; Fe(0); Oxalate; Oxygen activation; Phosphate ions.

Publication types

Research Support, Non-U.S. Gov't