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Comparative evaluation of iodoacids removal by UV/persulfate and UV/H2O2 processes.
Water Res. 2016 10 01; 102:629-639.WR

Abstract

To develop a cost-effective method for post-formation mitigation of iodinated disinfection by-products, degradation of iodoacids by UV, UV/PS (persulfate), and UV/H2O2 was extensively investigated in this study. UV direct photolysis of 4 iodoacids followed first-order kinetics with rate constants in the range of 2.43 × 10(-4)-3.02 × 10(-3) cm(2) kJ(-1). The derived quantum yields (Ф254) of the 4 iodoacids range from 0.13 to 0.34, respectively. A quantitative structure-activity relationship (QSAR) model was subsequently established and applied to predict the direct photolysis rates of 6 other structurally similar iodoacids whose standards are commercially unavailable. At a UV dose of 140 mJ cm(-2) which is typically applied for disinfection of drinking water, the removal percentages of 4 iodoacids were only between 3.35% and 34.7%. Thus, ICH2CO2H (IAA), the most photo-recalcitrant species, was selected as the target compound for removal in the UV/PS and UV/H2O2 processes. The IAA degradation rates decreased with increasing pH from 3 to 11 in both processes. Humic acid (HA) and HCO3(-) had inhibitory effects on IAA degradation in both processes. Cl(-) adversely affected the IAA degradation in the UV/PS process but had no effect in the UV/H2O2 process. Generally, in the deionized (DI) water, surface water, treated drinking water, and secondary effluent, UV/PS process is more effective than UV/H2O2 process for IAA removal, based on the same molar ratio of oxidant: IAA. SO4(-) generated in the UV/PS process yields a greater mineralization of IAA than HO in the UV/H2O2 process. IO3(-) was the predominant end-product in the UV/PS process, while I(-) was the major end-product in the UV/H2O2 process. The respective contributions of UV, HO, and SO4(-) for IAA removal in the UV/PS process were 7.8%, 14.7%, and 77.5%, respectively, at a specific condition (1.5 μM IAA, 60 μM oxidant, and pH 7). Compared to UV/H2O2 process, UV/PS was also observed as more cost-effective process based on the electrical energy per order (EE/O) and chemical cost.

Authors+Show Affiliations

School of Civil and Environmental Engineering, Nanyang Technological University, 50 Nanyang Avenue, Singapore, 639798, Republic of Singapore; Water Research Analytical Laboratories, Water Quality Office, Public Utilities Board, 82 Toh Guan Road East, #04-03, Singapore, 608576, Republic of Singapore.Water Research Analytical Laboratories, Water Quality Office, Public Utilities Board, 82 Toh Guan Road East, #04-03, Singapore, 608576, Republic of Singapore.Water Research Analytical Laboratories, Water Quality Office, Public Utilities Board, 82 Toh Guan Road East, #04-03, Singapore, 608576, Republic of Singapore.Water Research Analytical Laboratories, Water Quality Office, Public Utilities Board, 82 Toh Guan Road East, #04-03, Singapore, 608576, Republic of Singapore.School of Physical and Mathematic Sciences, Nanyang Technological University, 21 Nanyang Link, Singapore, 637371, Republic of Singapore.School of Civil and Environmental Engineering, Nanyang Technological University, 50 Nanyang Avenue, Singapore, 639798, Republic of Singapore; Nanyang Environment and Water Research Institute (NEWRI), Nanyang Technological University, 1 Cleantech Loop, CleanTech One, Singapore 637141, Republic of Singapore. Electronic address: cttlim@ntu.edu.sg.

Pub Type(s)

Journal Article

Language

eng

PubMed ID

27479295

Citation

Xiao, Yongjun, et al. "Comparative Evaluation of Iodoacids Removal By UV/persulfate and UV/H2O2 Processes." Water Research, vol. 102, 2016, pp. 629-639.
Xiao Y, Zhang L, Zhang W, et al. Comparative evaluation of iodoacids removal by UV/persulfate and UV/H2O2 processes. Water Res. 2016;102:629-639.
Xiao, Y., Zhang, L., Zhang, W., Lim, K. Y., Webster, R. D., & Lim, T. T. (2016). Comparative evaluation of iodoacids removal by UV/persulfate and UV/H2O2 processes. Water Research, 102, 629-639. https://doi.org/10.1016/j.watres.2016.07.004
Xiao Y, et al. Comparative Evaluation of Iodoacids Removal By UV/persulfate and UV/H2O2 Processes. Water Res. 2016 10 1;102:629-639. PubMed PMID: 27479295.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Comparative evaluation of iodoacids removal by UV/persulfate and UV/H2O2 processes. AU - Xiao,Yongjun, AU - Zhang,Lifeng, AU - Zhang,Wei, AU - Lim,Kok-Yong, AU - Webster,Richard D, AU - Lim,Teik-Thye, Y1 - 2016/07/05/ PY - 2016/01/11/received PY - 2016/06/27/revised PY - 2016/07/02/accepted PY - 2016/8/2/entrez PY - 2016/8/2/pubmed PY - 2017/5/6/medline KW - Hydroxyl radical KW - Iodinated disinfection by-product KW - QSAR model KW - Sulfate radical KW - UV/H(2)O(2) KW - UV/PS SP - 629 EP - 639 JF - Water research JO - Water Res VL - 102 N2 - To develop a cost-effective method for post-formation mitigation of iodinated disinfection by-products, degradation of iodoacids by UV, UV/PS (persulfate), and UV/H2O2 was extensively investigated in this study. UV direct photolysis of 4 iodoacids followed first-order kinetics with rate constants in the range of 2.43 × 10(-4)-3.02 × 10(-3) cm(2) kJ(-1). The derived quantum yields (Ф254) of the 4 iodoacids range from 0.13 to 0.34, respectively. A quantitative structure-activity relationship (QSAR) model was subsequently established and applied to predict the direct photolysis rates of 6 other structurally similar iodoacids whose standards are commercially unavailable. At a UV dose of 140 mJ cm(-2) which is typically applied for disinfection of drinking water, the removal percentages of 4 iodoacids were only between 3.35% and 34.7%. Thus, ICH2CO2H (IAA), the most photo-recalcitrant species, was selected as the target compound for removal in the UV/PS and UV/H2O2 processes. The IAA degradation rates decreased with increasing pH from 3 to 11 in both processes. Humic acid (HA) and HCO3(-) had inhibitory effects on IAA degradation in both processes. Cl(-) adversely affected the IAA degradation in the UV/PS process but had no effect in the UV/H2O2 process. Generally, in the deionized (DI) water, surface water, treated drinking water, and secondary effluent, UV/PS process is more effective than UV/H2O2 process for IAA removal, based on the same molar ratio of oxidant: IAA. SO4(-) generated in the UV/PS process yields a greater mineralization of IAA than HO in the UV/H2O2 process. IO3(-) was the predominant end-product in the UV/PS process, while I(-) was the major end-product in the UV/H2O2 process. The respective contributions of UV, HO, and SO4(-) for IAA removal in the UV/PS process were 7.8%, 14.7%, and 77.5%, respectively, at a specific condition (1.5 μM IAA, 60 μM oxidant, and pH 7). Compared to UV/H2O2 process, UV/PS was also observed as more cost-effective process based on the electrical energy per order (EE/O) and chemical cost. SN - 1879-2448 UR - https://www.unboundmedicine.com/medline/citation/27479295/Comparative_evaluation_of_iodoacids_removal_by_UV/persulfate_and_UV/H2O2_processes_ L2 - https://linkinghub.elsevier.com/retrieve/pii/S0043-1354(16)30508-5 DB - PRIME DP - Unbound Medicine ER -