Effect of pH on the formation of disinfection byproducts in ferrate(VI) pre-oxidation and subsequent chlorination

Significance Statement

Chlorination is the most widely used disinfectant around the world to control microbial pathogens in drinking water. However, chlorination has raised a public health concern with the determination of potential toxic disinfection byproducts (DBPs). Among the pre-oxdiants to control the disinfection byproduct formation, Ferrate((VI) (FeVIO42-) is regarded as a greener oxidant in sustainable treatment processes. In this study, the effect of pH on the formation of a variety group of disinfection byproducts, including trihalomethanes, chloral hydrate, haloacetonitriles, and trichloronitromethane during pre-oxidation with ferrate (VI) and subsequent chlorination of water samples has been investigated. The results provide guidance for water treatment plant for better disinfection byproducts control.  

About The Author

Dr. Xin Yang is an associate professor of School of Environmental Science & Engineering at Sun Yat-sen University, Guangzhou, China. She holds B.S. Degree from Nankai University (2002) and M.Phil. (2004) and Ph.D. (2007) Degrees from the Hong Kong University of Science & Technology. She also worked as a postodoctoral scholar at the University of North Carolina at Chapel Hill. Her research interests include the formation and control of disinfection byproducts, the fate and transport of organic contaminants in the environment, such as pharmaceuticals and personal care products, and advanced water treatment technologies for water safety.  

About The Author

Dr. Virender K. Sharma received his Ph.D. from Rosenstiel School of Marine and Atmospheric Science, University of Miami, Florida.  His postdoctoral work was at SUNY, Buffalo and Brookhaven National Laboratory, New York.  He is currently a professor at Department of Environmental and Occupational Health and a director of Program for Water Sustainability and Public Health Research, School of Public Health at Texas A&M University, College Station, Texas.  His research focuses on fundamental chemistry and environmental applications of high-valent iron species, synthesis and environmental applications of magnetic nanomaterials, and understanding formation mechanism, fate, and toxicity of natural nanoparticles.  He has published more than 230 peer-reviewed journal publications and authored and edited seven books.  

 Effect of pH on formation of disinfection byproducts in Ferrate(VI) pre-oxidation and subsequent chlorination

Journal Reference

Separation and Purification Technology, Volume 156, Part 3, 17 December 2015, Pages 980–986.

Xin Yang1,2, Wenhui Gan1, Xing Zhang1, Huang Huang1, Virender K. Sharma3

Show Affiliations
  1. SYSU-HKUST Research Center for Innovative Environmental Technology, School of Environmental Science and Engineering, Sun Yat-sen University, Guangzhou 510275, China
  2. Research Institute of Sun Yat-sen University in Shenzhen, Shenzhen, China
  3. Department of Environmental and Occupational Health, School of Public Health, Texas A&M University, 1266 TAMU, College Station, TX 77843, USA

Abstract

This study investigated the effect of pH on the formation of disinfection byproducts (DBPs) during pre-oxidation with ferrate(VI) (FeVIO42−, Fe(VI)) and subsequent chlorination of either a source water from a treatment plant, or a representative solution of natural organic matter from the Suwannee River NOM (SRNOM). The studied DBPs include trihalomethanes (THMs), chloral hydrate (CH), haloacetonitriles (HANs), and trichloronitromethane (TCNM). The results show that increasing pH from 5.0 to 9.0 increased THMs formation during chlorination of source water and Fe(VI) pre-oxidation generally decreased the concentration of THMs, except pH 9.0. The formation of CH and TCNM were not greatly influenced by pH in chlorination. But Fe(VI) pretreatment before chlorination enhanced CH and TCNM formation in acidic pH while lessened their formation in alkaline pH. HANs were detected in acidic pH whereas almost no formation of HANs was observed in basic pH. Similar experiments were conducted with SRNOM water to assess the variation of disinfection byproducts at different pHs with/without Fe(VI) pre-oxidation. Reactivity, products of fractions, and moieties of organic matter involved in Fe(VI) per-oxidation and subsequent chlorination reasonably explained the trends of the formation of disinfection by-products under acidic to basic conditions.

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