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Transformations of dissolved organic matter induced by UV photolysis, Hydroxyl radicals, chlorine radicals, and sulfate radicals in aqueous-phase UV-Based advanced oxidation processes.
Water Res. 2018 05 15; 135:22-30.WR

Abstract

Considering the increasing identification of trace organic contaminants in natural aquatic environments, the removal of trace organic contaminants from water or wastewater discharge is an urgent task. Ultraviolet (UV) and UV-based advanced oxidation processes (AOPs), such as UV/hydrogen peroxide (UV/H2O2), UV/free chlorine and UV/persulfate, are attractive and promising approaches for the removal of these contaminants due to the high reactivity of active radical species produced in these UV-AOPs with a wide variety of organic contaminants. However, the removal efficiency of trace contaminants is greatly affected by the presence of background dissolved organic matter (DOM). In this study, we use ultrahigh resolution mass spectrometry to evaluate the transformation of a standard Suwanee River fulvic acid DOM isolate in UV photolysis and UV-AOPs. The use of probe compounds allows for the determination of the steady-state concentrations of active radical species in each UV-AOP. The changes in the H/C and O/C elemental ratios, double bond equivalents, and the low-molecular-weight transformation product concentrations of organic acids reveal that different DOM transformation patterns are induced by each UV-AOP. By comparison with the known reactivities of each radical species with specific organic compounds, we mechanistically and systematically elucidate the molecular-level DOM transformation pathways induced by hydroxyl, chlorine, and sulfate radicals in UV-AOPs. We find that there is a distinct transformation in the aliphatic components of DOM due to HO• in UV/H2O2 and UV/free chlorine. Cl• induced transformation of olefinic species is also observed in the UV/free chlorine system. Transformation of aromatic and olefinic moieties by SO4•- are the predominant pathways in the UV/persulfate system.

Authors+Show Affiliations

Department of Civil and Environmental Engineering, Michigan Technological University, 1400 Townsend Drive, Houghton, MI 49931-1295, USA. Electronic address: pvaranas@mtu.edu.Department of Civil and Environmental Engineering, Michigan Technological University, 1400 Townsend Drive, Houghton, MI 49931-1295, USA. Electronic address: eacoscar@mtu.edu.Chemical Advanced Resolution Methods Laboratory, Michigan Technological University, 1400 Townsend Drive, Houghton, MI 49931-1295, USA; Department of Chemistry, Michigan Technological University, 1400 Townsend Drive, Houghton, MI 49931-1295, USA. Electronic address: mkhaksar@mtu.edu.Chemical Advanced Resolution Methods Laboratory, Michigan Technological University, 1400 Townsend Drive, Houghton, MI 49931-1295, USA; Department of Chemistry, Michigan Technological University, 1400 Townsend Drive, Houghton, MI 49931-1295, USA. Electronic address: lrmazzol@mtu.edu.Department of Civil and Environmental Engineering, Michigan Technological University, 1400 Townsend Drive, Houghton, MI 49931-1295, USA. Electronic address: dminakat@mtu.edu.

Pub Type(s)

Journal Article
Research Support, Non-U.S. Gov't
Research Support, U.S. Gov't, Non-P.H.S.

Language

eng

PubMed ID

29454238

Citation

Varanasi, Lathika, et al. "Transformations of Dissolved Organic Matter Induced By UV Photolysis, Hydroxyl Radicals, Chlorine Radicals, and Sulfate Radicals in Aqueous-phase UV-Based Advanced Oxidation Processes." Water Research, vol. 135, 2018, pp. 22-30.
Varanasi L, Coscarelli E, Khaksari M, et al. Transformations of dissolved organic matter induced by UV photolysis, Hydroxyl radicals, chlorine radicals, and sulfate radicals in aqueous-phase UV-Based advanced oxidation processes. Water Res. 2018;135:22-30.
Varanasi, L., Coscarelli, E., Khaksari, M., Mazzoleni, L. R., & Minakata, D. (2018). Transformations of dissolved organic matter induced by UV photolysis, Hydroxyl radicals, chlorine radicals, and sulfate radicals in aqueous-phase UV-Based advanced oxidation processes. Water Research, 135, 22-30. https://doi.org/10.1016/j.watres.2018.02.015
Varanasi L, et al. Transformations of Dissolved Organic Matter Induced By UV Photolysis, Hydroxyl Radicals, Chlorine Radicals, and Sulfate Radicals in Aqueous-phase UV-Based Advanced Oxidation Processes. Water Res. 2018 05 15;135:22-30. PubMed PMID: 29454238.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Transformations of dissolved organic matter induced by UV photolysis, Hydroxyl radicals, chlorine radicals, and sulfate radicals in aqueous-phase UV-Based advanced oxidation processes. AU - Varanasi,Lathika, AU - Coscarelli,Erica, AU - Khaksari,Maryam, AU - Mazzoleni,Lynn R, AU - Minakata,Daisuke, Y1 - 2018/02/08/ PY - 2017/11/24/received PY - 2018/01/26/revised PY - 2018/02/06/accepted PY - 2018/2/18/pubmed PY - 2018/9/25/medline PY - 2018/2/18/entrez KW - Active radical species KW - Dissolved organic matter KW - UV/Free chlorine KW - UV/H(2)O(2) KW - UV/Persulfate KW - Ultrahigh resolution mass spectrometry SP - 22 EP - 30 JF - Water research JO - Water Res. VL - 135 N2 - Considering the increasing identification of trace organic contaminants in natural aquatic environments, the removal of trace organic contaminants from water or wastewater discharge is an urgent task. Ultraviolet (UV) and UV-based advanced oxidation processes (AOPs), such as UV/hydrogen peroxide (UV/H2O2), UV/free chlorine and UV/persulfate, are attractive and promising approaches for the removal of these contaminants due to the high reactivity of active radical species produced in these UV-AOPs with a wide variety of organic contaminants. However, the removal efficiency of trace contaminants is greatly affected by the presence of background dissolved organic matter (DOM). In this study, we use ultrahigh resolution mass spectrometry to evaluate the transformation of a standard Suwanee River fulvic acid DOM isolate in UV photolysis and UV-AOPs. The use of probe compounds allows for the determination of the steady-state concentrations of active radical species in each UV-AOP. The changes in the H/C and O/C elemental ratios, double bond equivalents, and the low-molecular-weight transformation product concentrations of organic acids reveal that different DOM transformation patterns are induced by each UV-AOP. By comparison with the known reactivities of each radical species with specific organic compounds, we mechanistically and systematically elucidate the molecular-level DOM transformation pathways induced by hydroxyl, chlorine, and sulfate radicals in UV-AOPs. We find that there is a distinct transformation in the aliphatic components of DOM due to HO• in UV/H2O2 and UV/free chlorine. Cl• induced transformation of olefinic species is also observed in the UV/free chlorine system. Transformation of aromatic and olefinic moieties by SO4•- are the predominant pathways in the UV/persulfate system. SN - 1879-2448 UR - https://www.unboundmedicine.com/medline/citation/29454238/Transformations_of_dissolved_organic_matter_induced_by_UV_photolysis_Hydroxyl_radicals_chlorine_radicals_and_sulfate_radicals_in_aqueous_phase_UV_Based_advanced_oxidation_processes_ L2 - https://linkinghub.elsevier.com/retrieve/pii/S0043-1354(18)30114-3 DB - PRIME DP - Unbound Medicine ER -