Treatment of iodine-containing water by the UV/NH2Cl process: Dissolved organic matters transformation, iodinated trihalomethane formation and toxicity variation

Jing Wang; Jie Zhang; Shi-Qi Huang; Yi Hu; Yang Mu

doi:10.1016/j.watres.2021.117256

Treatment of iodine-containing water by the UV/NH₂Cl process: Dissolved organic matters transformation, iodinated trihalomethane formation and toxicity variation

Water Res. 2021 Jul 15:200:117256. doi: 10.1016/j.watres.2021.117256. Epub 2021 May 17.

Authors

Jing Wang¹, Jie Zhang², Shi-Qi Huang¹, Yi Hu¹, Yang Mu³

Affiliations

¹ CAS Key Laboratory of Urban Pollutant Conversion, Department of Environmental Science and Engineering, University of Science and Technology of China, Hefei, China.
² CAS Key Laboratory of Urban Pollutant Conversion, Department of Environmental Science and Engineering, University of Science and Technology of China, Hefei, China; Instrumental Analysis Center of Shanghai Jiao Tong University, Shanghai Jiao Tong University, Shanghai, China.
³ CAS Key Laboratory of Urban Pollutant Conversion, Department of Environmental Science and Engineering, University of Science and Technology of China, Hefei, China. Electronic address: yangmu@ustc.edu.cn.

PMID: 34062404
DOI: 10.1016/j.watres.2021.117256

Abstract

UV/NH₂Cl process is becoming increasingly important for water treatment, while its impact on iodine-containing water remains unknown. In this study, the structure transformation of dissolved organic matters (DOMs), generation of iodinated trihalomethanes (I-THMs), and variation of acute toxicity were evaulated during the UV/NH₂Cl treatment of iodine-containing water. The combination of exciation emission matrix-parallel factor analysis and two-dimensional correlation spectroscopy integrated with synchronous fluorescence and infrared absorption spectroscopy showed that fulvic-like fraction of DOM was more susceptible to UV/NH₂Cl process and particularly iodo and polysaccharide groups gave the fastest resopnses. Consequently, UV fluence lower than 60 mJ/cm² promoted the production of I-THMs, while excessive UV exhausted NH₂Cl and reactive iodine species and subsequently reduced I-THM generation. Moreover, DOM concentration and source, NH₂Cl dosage, and I^- concentration had significant impacts on I-THM formation in the UV/NH₂Cl process. Additionally, a positive correlation was found between acute toxicity variation and I-THM formation when treating iodine-containing waters with UV/NH₂Cl. These results together provide a comprehensive understanding on UV/NH₂Cl treatment of iodine-containing water.

Keywords: DOM; Iodinated trihalomethanes (I-THMs); Toxicity; UV/NH(2)Cl.

MeSH terms

Disinfection
Iodine*
Trihalomethanes
Water
Water Pollutants, Chemical* / analysis
Water Purification*

Substances

Trihalomethanes
Water Pollutants, Chemical
Water
Iodine