Degradation of 3, 5-dichlorophenol by UV-C photolysis and UV-C-activated persulfate oxidation process in pure water and simulated tertiary treated urban wastewater. Issue 25 (10th November 2021)

• Record Type: Journal Article
• Authors: Ucun, Olga Koba; Montazeri, Bahareh; Arslan-Alaton, Idil; Olmez-Hanci, Tugba
• Is Part Of: Environmental technology. Volume 42:Issue 25(2021)
• Page Start: 3877
• Page End: 3888
• Publication Date: 2021-11-10
• Subjects: Chlorophenols -- UV-C light activation of peroxydisulfate -- acute toxicity -- advanced oxidation products -- simulated urban wastewater; Environmental engineering -- Periodicals; Environmental protection -- Periodicals; 628.05
• DOI: 10.1080/09593330.2020.1732478
• Languages: English
• ISSNs: 0959-3330

Abstract

ABSTRACT: UV-C and UV-C/peroxydisulfate (PS) treatments of 3, 5-dichlorophenol (3, 5-DCP), a model industrial pollutant, were comparatively investigated in two different water matrices namely distilled water (DW) and simulated treated urban wastewater (SWW). The treatment performance of the selected treatment processes was comprehensively examined by following changes in 3, 5-DCP, dissolved organic carbon (DOC), PS consumption, Cl − release, aromatic/aliphatic degradation products and acute toxicities towards the marine photobacterium Vibrio fischeri and freshwater microalga Pseudokirchneriella subcapitata . The treatability of 2 mg/L (12.3 µM) 3, 5-DCP in DW was investigated under different operating conditions such as initial PS concentrations (0.00–1.00 mM) and pH values (3–11) at a fixed light intensity (0.5 W/L). Increasing the pH and PS concentration exhibited positive effects on 3, 5-DCP degradation. Even 10 mg/L 3, 5-DCP was completely degraded with UV-C/PS treatment in 40 min in the presence of 0.03 mM PS at pH 6.3 accompanied with 95% DOC removal that was achieved after 120 min treatment. The second-order rate constant of 3, 5-DCP (10 mg/L) with SO 4 ⋅ − was determined as 1.77×10 9 M −1 s −1 using competition kinetics. Cl − release and formation of hydroquinone were evidences of 3, 5-DCP degradation involving SO 4 ⋅ − . 3, 5-DCP (2 mg/L) was also subjected to UV-C and UV-C/PS treatments in SWW. 3, 5-DCP (100% after 60 min) and in particular DOC (26% after 120 min treatment) removal efficiencies observed in DW decreased dramatically in SWW. The original and UV-C/PS-treated samples were non-toxic towards Vibrio fischeri ; however, Pseudokirchneriella subcapitata toxicity increased from 20% to 47% through 80 min UV-C/PS treatment of 3, 5-DCP. GRAPHICAL ABSTRACT: UF0001