Photocatalytic Degradation of Bisphenol A in Aqueous Suspensions of Titanium Dioxide

Abstract

Abstract

Photocatalytic degradation of bisphenol A (BPA) in aqueous solution under UV irradiation with 253.7 nm, by nano titanium dioxide (TiO₂) as a photocatalyst, was investigated in a batch photocatalytic reactor. The degradation effect was studied under different conditions such as TiO₂ dosage, irradiation time, pH, and BPA initial concentration. Results show that the photodegradation efficiency of BPA increases with irradiation time, but decreases with increasing BPA initial concentration. Alkaline conditions are favorable for the degradation. When TiO₂ was dosed at 1.0 g/L and a BPA initial concentration of 10 mg/L with pH ≥ 9.5, BPA degradation was almost complete after UV irradiation for 90 min. Photocatalytic degradation of BPA by UV/TiO₂ exhibited pseudo-first-order reaction kinetics. According to the results of determining the intermediate degradation products using gas chromatography/mass spectrometry, there are multiple pathways of BPA degradation that involve reactions not only between ·OH and BPA or the intermediates but also between various unstable intermediates such as carboxylic, phenolic, and other types of intermediates.