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High-efficiency As(III) oxidation and electrocoagulation removal using hematite with a charge-discharge technique TEXT SIZE: A A A
Arsenite (As(III)) is generally removed by adsorption or coprecipitation after being oxidized to arsenate (As(V)). Electrocoagulation is regarded as an effective and environment-friendly method for arsenic (As) removal from wastewater. However, some disadvantages including the passivation of electrode and high energy consumption limit its wide application. Herein, a multi-cycle galvanostatic charge?discharge technique was employed to remove aqueous As(III) using hematite prepared through a microwave-assisted hydrothermal reaction. When charge?discharge experiments were conducted at the potential window of ?0.8–0 V (vs. SCE) in As(III) solution with NaCl as the background electrolyte, ClO? intermediates and the counter electrode at high potential contributed much to As(III) oxidation. As(V) was adsorbed on ferrihydrite generated from the re-oxidation of released Fe2+, forming FeAsO4 precipitate. A higher removal ratio of As(T) was achieved at initial pH 7.0 compared with that at initial pH 5.0 and 9.0. When the hematite mass was 4, 10 and 15 mg, the removal ratio of As(T) reached 55.2%, 79.6% and 98.6% after 600 cycles of charge?discharge. The periodic redox reactions of hematite electrodes occurred in each charge?discharge process, effectively avoiding the passivation of electrode. Additionally, the electrochemical system can be used as a supercapacitor for power output. The present work provides a novel strategy for high-efficiency As(III) immobilization and removal from aqueous solution.
 

Publication name

 Science of The Total Environment Volume 703, 10 February 2020, 135678

Author(s)

 Liu, Lihu; Chen, Hanchen; Yang, Xiong; Tan, Wenfeng; Liu, Chengshuai; Dang, Zhi; Qiu, Guohong

Corresponding author(s) 

 QIU Guohong
 qiugh@mail.hzau.edu.cn  
 Key Laboratory of Arable Land Conservation (Middle and Lower Reaches of Yangtse River), Ministry of Agriculture and Rural Affairs, Hubei Key Laboratory of Soil Environment and Pollution Remediation, College of Resources and Environment, Huazhong Agricultural University, Wuhan 430070, China

Author(s) from IGCAS   LIU Chengshuai

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