Effect of capacitive deionization on disinfection by-product precursors.
Formation of brominated disinfection by-products (DBPs) from bromide and natural organic matter upon chlorination imposes health risks to drinking water users. In this study, capacitive deionization (CDI) was evaluated as a potential process for DBP precursor removal. Synthetic humic acid and bromide containing saline water was used as model water prior to CDI treatment. Batch experiments were conducted at cell voltages of 0.6-, 0.9-, and 1.2V to study the influence of CDI on the ratio of bromide and dissolved organic carbon, bromine substitution factor, and DBP formation potential (FP). Results showed beneficial aspects of CDI on reducing the levels of these parameters. A maximum DBPFP removal from 1510 to 1160μg/L was observed at the cell voltage of 0.6V. For the removed DBPFP, electro-adsorption played a greater role than physical adsorption. However, it is also noted that there could be electrochemical oxidations that led to reduction of humic content and formation of new dichloroacetic acid precursors at high cell voltages. Because of the potential of CDI on reducing health risks from the formation of less brominated DBPs upon subsequent chlorination, it can be considered as a potential technology for DBP control in drinking water treatment.
Department of Water Engineering and Science, College of Civil Engineering, Hunan University, Changsha, Hunan 410082, China.
Danyang
D
Liu
State Key Joint Laboratory of Environmental Simulation and Pollution Control, School of Environment, Tsinghua University, Beijing 100084, China.
Xiaomao
X
Wang
State Key Joint Laboratory of Environmental Simulation and Pollution Control, School of Environment, Tsinghua University, Beijing 100084, China; Environmental Engineering Programs, Pennsylvania State University, Middletown, PA 17057, USA.
Yuefeng F
YF
Xie
Department of Water Engineering and Science, College of Civil Engineering, Hunan University, Changsha, Hunan 410082, China; Department of Chemistry, Indiana University of Pennsylvania, Indiana, PA 15705, USA. Electronic address: tang@minnwater.com.
Hao L
HL
Tang
D000327:Adsorption; D001965:Bromides / Q000737:chemistry*; D004202:Disinfectants / Q000737:chemistry*; D054879:Halogenation; D006812:Humic Substances; D018508:Water Purification / Q000379:methods*
D001965:Bromides; D004202:Disinfectants; D006812:Humic Substances
Bromide; Bromine substitution factor (BSF); Capacitive deionization (CDI); Disinfection by-product precursor (DBP precursor); Humic acid