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Removal of sulfonamides from wastewater in the UV/TiO2 system: effects of pH and salinity on photodegradation and mineralization.
Water Sci Technol. 2019 Jan; 79(2):349-355.WS

Abstract

The effects of salinity on the photodegradation and mineralization of sulfonamides in the UV/TiO2 system were investigated. The goals of this study were to analyze the effects of pH and salinity on the sulfonamide concentration and total organic carbon (TOC) during the removal of sulfonamides in a UV/TiO2 system. Four sulfonamides - sulfadiazine (SDZ), sulfamethizole (SFZ), sulfamethoxazole (SMX) and sulfathiazole (STZ) - were selected as parent compounds. The photodegradation and mineralization rates of sulfonamides in the UV/TiO2 system satisfy pseudo-first-order kinetics. Direct photolysis degraded sulfonamides but sulfonamides cannot be mineralized. The photodegradation and mineralization rate constants in all experiments followed the order pH 5 > pH 7 > pH 9. At pH 5, the mineralization rate constants of SMX, SFZ, SDZ and STZ were 0.015, 0.009, 0.012 and 0.011 min-1, respectively. The addition of NaCl inhibited the mineralization of the four tested sulfonamides more than it inhibited their photodegradation. The inhibitory effect of chloride ions on the removal of sulfonamides in the UV/TiO2 system was attributed to the scavenging by chloride ions of hydroxyl radicals (HO•) and holes and the much lower reactivity of chlorine radicals thus formed, even though the chlorine radicals were more abundant than HO•.

Authors+Show Affiliations

Department of Chemical and Materials Engineering, National Kaohsiung University of Science and Technology, Kaohsiung, Taiwan E-mail: wuch@nkust.edu.tw.Department of Environmental and Safety Engineering, National Yunlin University of Science and Technology, Yunlin, Taiwan.Department of Chemical and Materials Engineering, National Kaohsiung University of Science and Technology, Kaohsiung, Taiwan E-mail: wuch@nkust.edu.tw.Department of Chemical and Materials Engineering, National Kaohsiung University of Science and Technology, Kaohsiung, Taiwan E-mail: wuch@nkust.edu.tw.Department of Chemical and Materials Engineering, National Kaohsiung University of Science and Technology, Kaohsiung, Taiwan E-mail: wuch@nkust.edu.tw.

Pub Type(s)

Journal Article

Language

eng

PubMed ID

30865606

Citation

Wu, C H., et al. "Removal of Sulfonamides From Wastewater in the UV/TiO2 System: Effects of pH and Salinity On Photodegradation and Mineralization." Water Science and Technology : a Journal of the International Association On Water Pollution Research, vol. 79, no. 2, 2019, pp. 349-355.
Wu CH, Kuo CY, Dong CD, et al. Removal of sulfonamides from wastewater in the UV/TiO2 system: effects of pH and salinity on photodegradation and mineralization. Water Sci Technol. 2019;79(2):349-355.
Wu, C. H., Kuo, C. Y., Dong, C. D., Chen, C. W., & Lin, Y. L. (2019). Removal of sulfonamides from wastewater in the UV/TiO2 system: effects of pH and salinity on photodegradation and mineralization. Water Science and Technology : a Journal of the International Association On Water Pollution Research, 79(2), 349-355. https://doi.org/10.2166/wst.2019.053
Wu CH, et al. Removal of Sulfonamides From Wastewater in the UV/TiO2 System: Effects of pH and Salinity On Photodegradation and Mineralization. Water Sci Technol. 2019;79(2):349-355. PubMed PMID: 30865606.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Removal of sulfonamides from wastewater in the UV/TiO2 system: effects of pH and salinity on photodegradation and mineralization. AU - Wu,C H, AU - Kuo,C Y, AU - Dong,C D, AU - Chen,C W, AU - Lin,Y L, PY - 2019/3/14/entrez PY - 2019/3/14/pubmed PY - 2019/5/17/medline SP - 349 EP - 355 JF - Water science and technology : a journal of the International Association on Water Pollution Research JO - Water Sci Technol VL - 79 IS - 2 N2 - The effects of salinity on the photodegradation and mineralization of sulfonamides in the UV/TiO2 system were investigated. The goals of this study were to analyze the effects of pH and salinity on the sulfonamide concentration and total organic carbon (TOC) during the removal of sulfonamides in a UV/TiO2 system. Four sulfonamides - sulfadiazine (SDZ), sulfamethizole (SFZ), sulfamethoxazole (SMX) and sulfathiazole (STZ) - were selected as parent compounds. The photodegradation and mineralization rates of sulfonamides in the UV/TiO2 system satisfy pseudo-first-order kinetics. Direct photolysis degraded sulfonamides but sulfonamides cannot be mineralized. The photodegradation and mineralization rate constants in all experiments followed the order pH 5 > pH 7 > pH 9. At pH 5, the mineralization rate constants of SMX, SFZ, SDZ and STZ were 0.015, 0.009, 0.012 and 0.011 min-1, respectively. The addition of NaCl inhibited the mineralization of the four tested sulfonamides more than it inhibited their photodegradation. The inhibitory effect of chloride ions on the removal of sulfonamides in the UV/TiO2 system was attributed to the scavenging by chloride ions of hydroxyl radicals (HO•) and holes and the much lower reactivity of chlorine radicals thus formed, even though the chlorine radicals were more abundant than HO•. SN - 0273-1223 UR - https://www.unboundmedicine.com/medline/citation/30865606/Removal_of_sulfonamides_from_wastewater_in_the_UV/TiO2_system:_effects_of_pH_and_salinity_on_photodegradation_and_mineralization_ L2 - https://iwaponline.com/wst/article-lookup/doi/10.2166/wst.2019.053 DB - PRIME DP - Unbound Medicine ER -