Transformation of iodide by Fe(II) activated peroxydisulfate

Zijun Dong; Chengchun Jiang; Jingxin Yang; Xi Zhang; Weili Dai; Pengwei Cai

doi:10.1016/j.jhazmat.2019.03.063

Transformation of iodide by Fe(II) activated peroxydisulfate

J Hazard Mater. 2019 Jul 5:373:519-526. doi: 10.1016/j.jhazmat.2019.03.063. Epub 2019 Mar 15.

Authors

Zijun Dong¹, Chengchun Jiang², Jingxin Yang³, Xi Zhang⁴, Weili Dai⁵, Pengwei Cai¹

Affiliations

¹ Department of Building and Environmental Engineering, Shenzhen Polytechnic, Shenzhen 518055, China.
² Department of Building and Environmental Engineering, Shenzhen Polytechnic, Shenzhen 518055, China. Electronic address: jiangcc@szpt.edu.cn.
³ Key Laboratory for Water Quality and Conservation of the Pearl River Delta, Ministry of Education, Institute of Environmental Research at Greater Bay, Guangzhou University, Guangzhou 510006, China. Electronic address: yangjx@gzhu.edu.cn.
⁴ Department of Building and Environmental Engineering, Shenzhen Polytechnic, Shenzhen 518055, China; Key Laboratory for Jiangxi Province for Persistent Pollutants Control and Resources Recycle, Nanchang Hangkong University, Nanchang 330063, China.
⁵ Key Laboratory for Jiangxi Province for Persistent Pollutants Control and Resources Recycle, Nanchang Hangkong University, Nanchang 330063, China.

PMID: 30951996
DOI: 10.1016/j.jhazmat.2019.03.063

Abstract

This work investigates the transformation of iodide (I^-) by Fe(II)-activated peroxydisulfate (PDS). The transformation of I^- into iodate (IO₃^-) is a two-step process, involving reactive iodine species, such as hypoiodous acid (HOI), as a key intermediate, and IO₃^- as the final product. In the first step, SO₄^•- produced by Fe(II)-activated PDS is mainly responsible for the transformation of I^- into HOI. In the second step, Fe(IV) formed by the reaction of Fe(III) with PDS is required, to facilitate the further oxidation of HOI to IO₃^-. The disproportionation of HOI and the oxidation by PDS alone contribute negligibly to IO₃^- formation. The IO₃^- yield increases to a maximum, before decreasing gradually, with increased PDS and Fe(II) dosages. The transformation of I^- into IO₃^- is favored by lower pH and higher temperature, due to the greater SO₄^•- production by the reaction of Fe(II) with PDS under these conditions. Humic acid, as a representative natural organic matter, scavenges the formed HOI to form iodinated disinfection byproducts, which largely inhibit the transformation of I^- into IO₃^-. In addition, the transformation of I^- into IO₃^- and iodinated disinfection byproducts by Fe(II) activated PDS was confirmed in the natural waters.

Keywords: Fe (II); Iodate; Iodide; Peroxydisulfate (PDS); Reactive iodine species; Sulfate radicals (SO(4)(•)-).

Publication types

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