Combined analytical study on chemical transformations and detoxification of model phenolic pollutants during various advanced oxidation treatment processes

Kravos, Aleksander (author), Žgajnar Gotvajn, Andreja (author), Lavrenčič Štangar, Urška (author), Malinović, Borislav N. (author), Prosen, Helena (author)

Advanced oxidation processes (AOPs) have been introduced to deal with different types of water pollution. They cause effective chemical destruction of pollutants, yet leading to a mixture of transformation by-products, rather than complete mineralization. Therefore, the aim of our study was to understand complex degradation processes induced by different AOPs from chemical and ecotoxicological point of view. Phenol, 2,4-dichlorophenol, and pentachlorophenol were used as model pollutants since they are still common industrial chemicals and thus encountered in the aquatic environment. A comprehensive study of efficiency of several AOPs was undertaken by using instrumental analyses along with ecotoxicological assessment. Four approaches were compared: ozonation, photocatalytic oxidation with immobilized nitrogen-doped TiO$_2$ thin films, the sequence of both, as well as electrooxidation on boron-doped diamond (BDD) and mixed metal oxide (MMO) anodes. The monitored parameters were: removal of target phenols, dechlorination, transformation products, and ecotoxicological impact. Therefore, HPLC–DAD, GC–MS, UHPLC–MS/MS, ion chromatography, and 48 h inhibition tests on Daphnia magna were applied. In addition, pH and total organic carbon (TOC) were measured. Results show that ozonation provides by far the most suitable pattern of degradation accompanied by rapid detoxification. In contrast, photocatalysis was found to be slow and mild, marked by the accumulation of aromatic products. Preozonation reinforces the photocatalytic process. Regarding the electrooxidations, BDD is more effective than MMO, while the degradation pattern and transformation products formed depend on supporting electrolyte.

• Language: English
• Keywords: chlorophenols, phenol, electrooxidation, ozonation, photocatalysis, photooxidation, gas chromatography, liquid chromatography, ion chromatography, mass spectrometry, total organic carbon, ecotoxicology, Daphnia magna
• Work type: Article
• Typology: 1.01 - Original Scientific Article
• Organization: FKKT - Faculty of Chemistry and Chemical Technology
• Publication status: Published
• Publication version: Version of Record
• Year: 2022
• Number of pages: 20 str.
• Numbering: Vol. 27, iss. 6, art. 1935
• PID: 20.500.12556/RUL-137534
• UDC: 628.349:66.094.3:543.544
• ISSN on article: 1420-3049
• DOI: 10.3390/molecules27061935
• COBISS.SI-ID: 101261315
• Publication date in RUL: 21.06.2022

Record is a part of a journal

• Title: Molecules
• Shortened title: Molecules
• Publisher: MDPI
• ISSN: 1420-3049
• COBISS.SI-ID: 18462981

Licences

• License: CC BY 4.0, Creative Commons Attribution 4.0 International
• Link: http://creativecommons.org/licenses/by/4.0/
• Description: This is the standard Creative Commons license that gives others maximum freedom to do what they want with the work as long as they credit the author.
• Licensing start date: 16.03.2022

Secondary language

• Language: Slovenian
• Keywords: klorofenoli, fenol, elektroksidacija, ozonacija, fotokataliza, fotooksidacija, plinska kromatografija, tekočinska kromatografija, ionska kromatografija, masna spektrometrija, celokupni organski ogljik, ekotoksikologija, Daphnia magna