Photocatalytic degradation of sulfadiazine in suspensions of TiO2 nanosheets with exposed (001) facets

• Published in: Chinese chemical letters Vol. 32; no. 10; pp. 3215 - 3220
• Main Authors: Xiang, Xiaofan, Wu, Laiyan, Zhu, Junjiang, Li, Jiazhou, Liao, Xi, Huang, Hongcheng, Fan, Jiajie, Lv, Kangle
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01.10.2021; Key Laboratory of Resources Conversion and Pollution Control of the State Ethnic Affairs Commission,College of Resources and Environmental Science,South-Central University for Nationalities,Wuhan 430074,China%Hubei Key Laboratory of Biomass Fibers and Eco-Dyeing & Finishing,College of Chemistry and Chemical Engineering,Wuhan Textile University,Wuhan 430200,China%School of Materials Science and Engineering,Zhengzhou University,Zhengzhou 450001,China
• Subjects: Antibiotics; Degradation pathway; Photocatalytic degradation; Sulfadiazine; TiO2 nanosheets; Sulfadiazine; Photocatalytic degradation; Antibiotics; TiO2 nanosheets; Degradation pathway
• ISSN: 1001-8417; 1878-5964
• DOI: 10.1016/j.cclet.2021.03.064

Photocatalytic oxidation mechanism of sulfadiazine over TiO2 nanosheets (TiO2-NSs) with exposed high energy (001) facets was systematically studied. [Display omitted] Antibiotics such as sulfonamides are widely used in agriculture as growth promoters and medicine in treatment of infectious diseases. However, the release of these antibiotics has caused serious environmental problems. In this paper, photocatalytic oxidation technology was used to degrade sulfadiazine (SDZ), one of the typical sulfonamides antibiotics, in UV illuminated TiO2 suspensions. It was found that TiO2 nanosheets (TiO2-NSs) with exposed (001) facets exhibit much higher photoreactivity towards SDZ degradation compared to TiO2 nanoparticles (TiO2-NPs) with a rate constant increases from 0.017 min−1 to 0.035 min−1, improving by a factor of 2.1. Under the attacking of reactive oxygen species (ROSs) such as superoxide radicals (O2–) and hydroxyl radicals (OH), SDZ was steady degraded on the surface of TiO2-NSs. Based on the identification of the produced intermediates by LC–MS/MS, possible degradation pathways of SDZ, which include desulfonation, oxidation and cleavage, were put forwards. After UV irradiation for 4 h, nearly 90% of the total organic carbon (TOC) can be removed in suspensions of TiO2-NSs, indicating the mineralization of SDZ. TiO2-NSs also exhibits excellent stability in photocatalytic degradation of SDZ in wide range of pH. Even after recycling used for 7 times, more than 91.3% of the SDZ can be efficiently removed, indicating that they are promising to be practically used in treatment of wastewater containing antibiotics.