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Antonopoulou M, Bika P, Papailias I, Zervou SK, Vrettou A, Efthimiou I, Mitrikas G, Ioannidis N, Trapalis C, Dallas P, Vlastos D, Hiskia A. Photocatalytic degradation of organic micropollutants under UV-A and visible light irradiation by exfoliated g-C 3N 4 catalysts. Sci Total Environ 2023:164218. [PMID: 37211132 DOI: 10.1016/j.scitotenv.2023.164218] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/08/2023] [Revised: 05/02/2023] [Accepted: 05/13/2023] [Indexed: 05/23/2023]
Abstract
In the present study, the photocatalytic performance of exfoliated graphitic carbon nitride (g-C3N4) catalysts, with enhanced properties and response in UV and visible light irradiation, was evaluated for the removal of selected contaminants i.e., diuron, bisphenol A and ethyl paraben. Commercial TiO2 Degussa P25 was also used as a reference photocatalyst. g-C3N4 catalysts demonstrated good photocatalytic activity which in some cases is comparable to TiO2 Degussa P25 leading to high removal percentages of the studied micropollutants under UV-A light irradiation. In contrast to TiO2 Degussa P25, g-C3N4 catalysts were also able to degrade the studied micropollutants under visible light irradiation. For all the studied g-C3N4 under both UV-A and visible light irradiation, the overall degradation rate decreases in the order of bisphenol A > diuron > ethyl paraben. Among the studied g-C3N4, the chemically exfoliated catalyst (g-C3N4-CHEM) showed superior photocatalytic activity under UV-A light irradiation due to its enhanced characteristics, such as pore volume and specific surface area and ~ 82.0 in 6 min, ~75.7 in 15 min and ~ 96.3 % in 40 min removals were achieved for BPA, DIU and EP, respectively. Under visible light irradiation, the thermally exfoliated catalyst (g-C3N4-THERM) demonstrated the best photocatalytic performance and the degradation ranged from ~29.5 to 59.4 % after 120 min. EPR data revealed that the three g-C3N4 semiconductors generate mainly O2•-, whereas TiO2 generates both HO• and O2•-, the latter only under UV-A light irradiation. Nevertheless, the indirect formation of HO• in the case of g-C3N4 should also be considered. Hydroxylation, oxidation, dealkylation, dechlorination and ring opening were the main degradation pathways. The process proceeded without significant alterations in toxicity levels. Based on the results, heterogeneous photocatalysis using g-C3N4 catalysts is a promising method for the removal of organic micropollutants without the formation of harmful transformation products.
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Affiliation(s)
- Maria Antonopoulou
- Department of Sustainable Agriculture, University of Patras, 30100, Agrinio, Greece.
| | - Panagiota Bika
- Institute of Nanoscience & Nanotechnology, NCSR "Demokritos", Patr. Gregoriou E' & 27 Neapoleos Str, 15341 Agia Paraskevi, Athens, Greece
| | - Ilias Papailias
- Institute of Nanoscience & Nanotechnology, NCSR "Demokritos", Patr. Gregoriou E' & 27 Neapoleos Str, 15341 Agia Paraskevi, Athens, Greece
| | - Sevasti-Kiriaki Zervou
- Institute of Nanoscience & Nanotechnology, NCSR "Demokritos", Patr. Gregoriou E' & 27 Neapoleos Str, 15341 Agia Paraskevi, Athens, Greece
| | - Androniki Vrettou
- Institute of Nanoscience & Nanotechnology, NCSR "Demokritos", Patr. Gregoriou E' & 27 Neapoleos Str, 15341 Agia Paraskevi, Athens, Greece
| | - Ioanna Efthimiou
- Department of Sustainable Agriculture, University of Patras, 30100, Agrinio, Greece
| | - George Mitrikas
- Institute of Nanoscience & Nanotechnology, NCSR "Demokritos", Patr. Gregoriou E' & 27 Neapoleos Str, 15341 Agia Paraskevi, Athens, Greece
| | - Nikolaos Ioannidis
- Institute of Nanoscience & Nanotechnology, NCSR "Demokritos", Patr. Gregoriou E' & 27 Neapoleos Str, 15341 Agia Paraskevi, Athens, Greece
| | - Christos Trapalis
- Institute of Nanoscience & Nanotechnology, NCSR "Demokritos", Patr. Gregoriou E' & 27 Neapoleos Str, 15341 Agia Paraskevi, Athens, Greece
| | - Panagiotis Dallas
- Institute of Nanoscience & Nanotechnology, NCSR "Demokritos", Patr. Gregoriou E' & 27 Neapoleos Str, 15341 Agia Paraskevi, Athens, Greece
| | - Dimitris Vlastos
- Department of Biology, Section of Genetics Cell Biology and Development, University of Patras, 26500 Patras, Greece
| | - Anastasia Hiskia
- Institute of Nanoscience & Nanotechnology, NCSR "Demokritos", Patr. Gregoriou E' & 27 Neapoleos Str, 15341 Agia Paraskevi, Athens, Greece
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