Elucidating the performance of UV-based photochemical processes for the removal of trace organic contaminants: Degradation and toxicity evaluation

Arbab Tufail; Jawad Al-Rifai; William E Price; Jason P van de Merwe; Frederic D L Leusch; Faisal I Hai

doi:10.1016/j.chemosphere.2023.140978

Elucidating the performance of UV-based photochemical processes for the removal of trace organic contaminants: Degradation and toxicity evaluation

Chemosphere. 2024 Feb:350:140978. doi: 10.1016/j.chemosphere.2023.140978. Epub 2023 Dec 20.

Authors

Arbab Tufail¹, Jawad Al-Rifai¹, William E Price², Jason P van de Merwe³, Frederic D L Leusch³, Faisal I Hai⁴

Affiliations

¹ Strategic Water Infrastructure Laboratory, School of Civil, Mining, Environmental and Architectural Engineering, University of Wollongong, Wollongong, NSW, 2522, Australia.
² Strategic Water Infrastructure Laboratory, School of Chemistry and Molecular Bioscience, University of Wollongong, Wollongong, NSW, 2522, Australia.
³ Australian Rivers Institute and School of Environment and Science, Griffith University, Gold Coast, QLD, 4222, Australia.
⁴ Strategic Water Infrastructure Laboratory, School of Civil, Mining, Environmental and Architectural Engineering, University of Wollongong, Wollongong, NSW, 2522, Australia. Electronic address: faisal@uow.edu.au.

PMID: 38135125
DOI: 10.1016/j.chemosphere.2023.140978

Abstract

In this study, the performance of standalone ultraviolet (UV) photolysis and UV-based advanced oxidation processes (AOPs), namely, UV/hydrogen peroxide, UV/chlorine, UV/persulphate, and UV/permonosulphate, were investigated for the degradation of 31 trace organic contaminants (TrOCs). Under the tested conditions, standalone UV photolysis did not achieve effective removal of TrOCs. To improve the degradation efficiency of UV photolysis, four different oxidants were added individually to the test solution. The effect of these oxidants in the absence of UV irradiation was also explored and only chlorine showed promising degradation of some contaminants. During the chlorination of 31 investigated TrOCs, only six demonstrated greater than 50% degradation. The combined UV-based AOPs demonstrated much improved degradation (ranging from 65 to 100%) depending on TrOC-structure and oxidant concentration. The UV/hydrogen peroxide process showed similar degradation of TrOCs, irrespective of the functional groups (i.e., electron withdrawing groups, EWGs and electron donating groups, EDGs) present in their structures. Conversely, the UV/sulphate and UV/chlorine based processes achieved better degradation of the TrOCs with EDGs in their structures. TrOCs degradation improved up to 40% when oxidants concentrations were increased from 0.1 to 1 mM, and further increasing the concentration to 2 mM did not improve degradation. Toxicity evaluation using bioluminescence test (BLT assay) demonstrated that except for UV/hydrogen peroxide, all UV-based AOPs increased the toxicity of the treated effluent, indicating generation of toxic by-products. This study elucidates the performance of four different UV-based AOPs for the removal of commonly detected diverse TrOCs for the first time.

Keywords: Toxicity; TrOCs degradation; Trace organic contaminants; UV photolysis; UV-Based photochemical treatment.

MeSH terms

Chlorine
Hydrogen Peroxide / chemistry
Oxidants
Oxidation-Reduction
Photolysis
Ultraviolet Rays
Water Pollutants, Chemical* / analysis
Water Purification*

Substances

Hydrogen Peroxide
Chlorine
Water Pollutants, Chemical
Oxidants