A controllable reduction-oxidation coupling process for chloronitrobenzenes remediation: From lab to field trial. (30th June 2022)

• Record Type: Journal Article
• Authors: Wei, Kai; Wan, Yanyan; Liao, Minzi; Cao, Shiyu; Zhang, Hao; Peng, Xing; Gu, Huayu; Ling, Cancan; Li, Meiqi; Shi, Yanbiao; Ai, Zhihui; Gong, Jingming; Zhang, Lizhi
• Is Part Of: Water research. Volume 218(2022)
• Publication Date: 2022-06-30
• Subjects: Reduction-oxidation coupling -- Zero-valent iron -- H2O2 -- Chloronitrobenzenes -- Environmental remediation; Water -- Pollution -- Research -- Periodicals; 363.7394
• DOI: 10.1016/j.watres.2022.118453
• Languages: English
• ISSNs: 0043-1354

Abstract

Highlights: ZVI/H2O2 delivers a controllable reduction-oxidation coupling process for CNBs remediation. ZVI pre-reduction significantly accelerates CNBs mineralization rate by ·OH. The performance of ZVI/H2O2 based reduction-oxidation process is controlled by the addition time of H2O2. The efficiency of this controllable reduction-oxidation process has been validated in remediating real site contaminated by CNBs. Abstract: Chloronitrobenzenes (CNBs) are typical refractory aromatic pollutants. The reduction products of CNBs often possess higher toxicity, and the electron-withdrawing substituent groups are detrimental to the ring-opening during the oxidation treatment, leading to ineffective removal of CNBs by either reduction or oxidation technology. Herein we demonstrate a controllable reduction-oxidation coupling (ROC) process composed of zero-valent iron (ZVI) and H2 O2 for the effective removal of CNBs from both water and soil. In water, ZVI first reduced p-CNB into 4-chloronitrosobenzene and 4-chloroaniline intermediates, which were then suffered from the subsequent oxidative ring-opening by ·OH generated from the reaction between Fe(II) and H2 O2 . By controlling the addition time of H2 O2, the final mineralization rate of p-CNB reached 6.6 × 10 −1 h −1, about 74 times that of oxidation alone (9.0 × 10 −3 h −1 ). More importantly, this controllable ROC process was also applicable for the site remediation of CNBs contaminated soil by either ex-situ treatment or in-situ injection, and, respectively decreased the concentrations of p-CNB, m-CNB, and o-CNB from 1105, 980, and 94 mg/kg to 3, 1, and < 1mg/kg, meeting the remediation goals (p-CNB: < 32.35 mg/kg, o-CNB and m-CNB: < 1.98 mg/kg). These laboratory and field trial results reveal that this controllable ROC strategy is very promising for the treatment of electron-withdrawing groups substituted aromatic contaminates. Graphical abstract: Image, graphical abstract