Photocatalytic degradation of clofibric acid by g-C3N4/P25 composites under simulated sunlight irradiation: The significant effects of reactive species. (April 2017)

• Record Type: Journal Article
• Authors: Chen, Ping; Wang, Fengliang; Zhang, Qianxin; Su, Yuehan; Shen, Lingzhi; Yao, Kun; Chen, Zhi-Feng; Liu, Yang; Cai, Zongwei; Lv, Wenying; Liu, Guoguang
• Is Part Of: Chemosphere. Volume 172(2017)
• Page Start: 193
• Page End: 200
• Publication Date: 2017-04
• Subjects: Photocatalysis -- Clofibric acid -- g-C3N4/P25 -- Reactive species -- Pathways; Pollution -- Periodicals; Pollution -- Physiological effect -- Periodicals; Environmental sciences -- Periodicals; Atmospheric chemistry -- Periodicals; 551.511
• DOI: 10.1016/j.chemosphere.2017.01.015
• Languages: English
• ISSNs: 0045-6535

Abstract

Abstract: Pharmaceutically emerging micropollutants have become an environmental concern in recent years. In the present paper, the reactive species (RSs)-induced degradation mechanism of clofibric acid (CA) was investigated using a newly sunlight-driven g-C3 N4 /P25 photocatalyst. A very low g-C3 N4 content of 8.0 weight percent resulted in a 3.36 and a 2.29 times faster reaction rate for CA photodegradation than for pristine g-C3 N4 and P25, respectively. Electron spin resonance and quenching experiments demonstrated the participation of HO, h +, e −, 1 O2 and O2 ·- in the photocatalytic system, and the contribution rates were calculated to 73.3%, 15.3%, 5.1%, 6.7% and 33.1%, respectively. According to the pulse radiolysis measurements and the competitive kinetics approaches, the bimolecular reaction rate constants for HO, e −, and 1 O2 with CA were (8.47 ± 0.33) × 10 9 M −1 s −1, (6.41 ± 0.48) × 10 9 M −1 s −1 and (6.6 ± 0.37) × 10 6 M −1 s −1, respectively. RSs were found to significantly influence the degradation of CA, and the degradation pathways occurred primarily via e − reduction, HO addition and 1 O2 attack reactions on the basis of mass spectrometry and theoretical calculations. Graphical abstract: Highlights: Synthesis and characterization of a sunlight-driven g-C3 N4 /P25 photocatalyst. Photocatalytic activity for degradation of clofibric acid under simulated sunlight irradiation. Significant roles of reactive species during the photocatalytic process. Degradation pathways of clofibric acid via g-C3 N4 /P25.