Ethylene glycol-assisted microwave synthesis of bismuth-rich oxychlorides photocatalysts with oxygen vacancies for efficient degradation of bisphenol A and oxidation of arsenite

Luangwanta, Tawanwit, Chachvalvutikul, Auttaphon, Watwiangkham, Athis, Jungsuttiwong, Siriporn and Kaowphong, Sulawan 2024. Ethylene glycol-assisted microwave synthesis of bismuth-rich oxychlorides photocatalysts with oxygen vacancies for efficient degradation of bisphenol A and oxidation of arsenite. Journal of Environmental Chemical Engineering 12 (5) , 114100. 10.1016/j.jece.2024.114100 Item availability restricted.

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Abstract

The bismuth-rich strategy, which involves increasing the bismuth content within the BiOCl structure, offers an effective approach for tailoring the physicochemical and optoelectrical properties of BiOCl photocatalysts for enhanced photocatalytic performance. In this study, BiOCl, Bi12O15Cl6, and Bi12O17Cl2 were selectively synthesized using the ethylene glycol (EG)-assisted microwave irradiation method by regulating the pH of the reaction solution. Photocatalytic performance was evaluated by studying bisphenol A (BPA) degradation and arsenite (As(III)) oxidation under visible-light irradiation. The energy structures and bandgaps of the materials were tuned according to their chemical compositions, affecting their photocatalytic activity. Bi12O17Cl2 (EG-pH 9) exhibited superior photo-efficiency: 85.4 % of BPA and 97.6 % of As(III) were removed by Bi12O17Cl2 (EG-pH 9) at rates 17.7 and 18.4 times higher than those of BiOCl (EG-initial pH 3), respectively. This superior performance attributed to the synergistic effect between the bismuth-rich nature and oxygen vacancies (OVs) induced by EG, along with the presence of OH− ions in the reaction solution. The increased number of OVs in Bi12O17Cl2 led to enhanced photocurrent density and charge transfer efficiency. Trapping experiments, DMPO-ESR spin-trapping, nitroblue tetrazolium transformation, terephthalic acid photoluminescence probing, and o-tolidine oxidation experiments identified holes (h+), superoxide radicals (•O2−), superoxide radicals (•OH) and electrons (e−) as the reactive species. Density functional theory calculations further highlight the OV of Bi12O17Cl2 as the active site for O2 adsorption. This study not only developed an effective method for fabricating bismuth-rich oxychlorides with OVs but also demonstrated the potential of these photocatalysts for wastewater treatment.

Item Type:	Article
Date Type:	Publication
Status:	Published
Schools:	Chemistry
Publisher:	Elsevier
ISSN:	2213-3437
Date of First Compliant Deposit:	1 November 2024
Date of Acceptance:	8 September 2024
Last Modified:	11 Nov 2024 11:30
URI:	https://orca.cardiff.ac.uk/id/eprint/173596

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