1. Oxalic acid enhanced removal of heavy metal and pesticide by peroxymonosulphate activation with a green biochar iron composite: Reactivity and mechanism.
- Author
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Chen, Man-Li, Yao, Xiao-Wen, Diao, Zeng-Hui, Jin, Jian-Chao, Qian, Wei, Yi, Yun-Qiang, Chen, Xie, and Kong, Ling-Jun
- Subjects
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OXALIC acid , *IRON composites , *CHROMIUM removal (Water purification) , *ACOUSTIC emission testing , *HEAVY metals , *PESTICIDES , *PESTICIDE pollution , *WASTE recycling , *BIOCHAR - Abstract
[Display omitted] • Oxalic acid (OA) maintain a high dissolved Fe2+ in the PC-ZVI/PMS process. • Peroxymonosulfate (PMS) greatly improve atrazine (AE) removal. • The contribution order of reactive species followed as HO• > SO 4 •- greater than1O 2 > O 2 •−. • The possible degradation pathways of AE by PC-ZVI/PMS/OA process proposed. • Enhanced mechanism of Cr6+ and AE removal by PC-ZVI/PMS/OA process was proposed. Nowadays, clean-up of heavy metals and pesticides from environment has received great attention. A green biochar iron composite (PC-ZVI) was successfully synthesized using pomelo peel residues and FeCl 3 solution. Peroxymonosulfate (PMS) was introduced into the PC-ZVI system for Cr(VI) and atrazine (AE) removal, and results showed that PMS greatly promoted Cr(VI) and AE removal. The presence of oxalic acid (OA) could maintain a relatively high dissolved Fe2+ species for Cr(VI) reduction and AE oxidation in the PC-ZVI/PMS process. The contribution order of reactive oxygen species followed as HO• > SO 4 •- greater than1O 2 > O 2 •− in both Cr(VI) and AE removal by PC-ZVI/PMS/OA process. A total of six intermediates products of AE degradation were detected, and AE molecular was effectively degraded into CO 2 , H 2 O, inorganic N and Cl through hydroxylation, substitution and de-alkylation processes. The underlying mechanism of Cr(VI) and AE removal by PC-ZVI/PMS/OA process was also proposed. Most Cr(VI) species were transformed into Cr 2 O 3 and Cr(OH) 3 through reduction and precipitation processes. PC-ZVI has a relatively high recyclability toward both Cr(VI) and AE removal from solutions. The potential toxicity of PC-ZVI solution was small at three PC-ZVI dosages levels, and the corresponding toxicity of AE reaction solution by PC-ZVI/PMS/OA process decreased as reaction time increased. The order of both Cr(VI) and AE removal in different water systems was tap water > river water > lake water > wastewater, and this PC-ZVI/PMS/OA process exhibited the better adaptability in application for several actual water environments. [ABSTRACT FROM AUTHOR]
- Published
- 2023
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