标题: Metal-Free Electro-Activated Sulfite Process for As(III) Oxidation in Water Using Graphite Electrodes

作者: Luo, T (Luo, Tao); Peng, Y (Peng, Ying); Chen, L (Chen, Long); Li, JJ (Li, Jinjun); Wu, F (Wu, Feng); Zhou, DN (Zhou, Danna)

来源出版物: ENVIRONMENTAL SCIENCE & TECHNOLOGY 卷: 54 期: 16 页: 10261-10269 DOI: 10.1021/acs.est.9b07078 出版年: AUG 18 2020

摘要: Transition-metal-activated sulfite [S(IV)] processes for water decontamination have recently received intense attention in the field of decontamination by advanced oxidation processes (AOPs). However, the drawback with respect to the secondary metal sludge contamination involved in various AOPs has been argued often. In this work, we developed a novel electro-sulfite (ES) process using stable and low-cost graphite electrodes to address that concern. Arsenite [As(III)] was used as the target compound for removal by the ES process because of its wide presence and high toxicity. Parameters, including cell voltage, S(IV) concentration, solution pH, and water matrix, and the mechanisms for reactions on anode and cathode were investigated in electrolytic cells containing one or two compartments, respectively. The results show that the ES process using 1 mM S(IV) and 2 V cell voltage oxidizes 5 mu M As(III) at a rate of 0.127 min(-1), which is 15-fold higher than mere electrolysis without S(IV) addition (0.008 min(-1)) at pH 7. Further studies using radical scavengers and electron spin resonance assays demonstrated that oxysulfur radicals (i.e., SO5 center dot- and SO4 center dot-) and HO center dot are responsible for As(III) oxidation in the ES process. However, HO2 center dot produced via the oxygen reduction reaction in the EO process plays a major role in As(III) oxidation, which explains the lower reaction rate in the absence of S(IV). The effectiveness of the ES process was moreover evidenced by 60-82% As(III) oxidation in field water within 40 min. Overall, this work realizes the metal-free activation of S(IV) and significantly leverages the S(IV)-based water treatment technologies.

入藏号: WOS:000563025000053

PubMed ID: 32806915

语言: English

文献类型: Article

KeyWords Plus: ACID ORANGE 7; SULFUR-DIOXIDE; ELECTROCHEMICAL OXIDATION; BACTERIAL INACTIVATION; CATALYZED OXIDATION; HYDROGEN-PEROXIDE; HYDROXYL RADICALS; DEGRADATION; OXYGEN; PERSULFATE

地址: [Luo, Tao; Peng, Ying; Li, Jinjun; Wu, Feng] Wuhan Univ, Sch Resources & Environm Sci, Wuhan 430079, Peoples R China.

[Chen, Long] Northeastern Univ, Dept Civil & Environm Engn, Boston, MA 02115 USA.

[Zhou, Danna] China Univ Geosci, Fac Mat Sci & Chem, Wuhan 430074, Peoples R China.

通讯作者地址: Wu, F (corresponding author)，Wuhan Univ, Sch Resources & Environm Sci, Wuhan 430079, Peoples R China.

Zhou, DN (corresponding author)，China Univ Geosci, Fac Mat Sci & Chem, Wuhan 430074, Peoples R China.

影响因子：7.864