Photodegradation of Alachlor Using BiVO4 Photocatalyst Under Visible Light Irradiation

Chang, Yi-Kuo; Wu, Yu-Shen; Lu, Chung-Shin; Lin, Pei-Feng; Wu, Tsung-Yen

Photodegradation of Alachlor Using BiVO4 Photocatalyst Under Visible Light Irradiation

2015

Chang, Yi-Kuo | Wu, Yu-Shen | Lu, Chung-Shin | Lin, Pei-Feng | Wu, Tsung-Yen

In this study, BiVO₄ powder is prepared and used as a visible-light catalyst for the photocatalytic degradation of alachlor. The as-prepared BiVO₄ photocatalyst is characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), UV–vis diffuse reflectance spectra (DRS), and BET surface area analysis. Alachlor could be successfully degraded in the presence of both H₂O₂ and BiVO₄ catalyst under visible-light irradiation. With optimal operating parameters, its degradation efficiency could reach 97 % in 6 h. Factors such as solution pH, catalyst dosage, and the presence of anions are found to influence the degradation rate. To scrutinize the mechanistic details of the alachlor photodegradation, the intermediates of the process are separated, identified, and characterized by solid-phase microextraction (SPME) and gas chromatography/mass spectrometry (GC/MS). Results suggest that possible transformation pathways may include oxidation of the arylethyl group, cleavage of the N-methoxymethyl group, and N-chloroacetyl moiety.

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