Enhanced photocatalytic degradation performance of bisphenol A over TiO₂-SiO₂ photocatalyst by improving specific surface area under simulation natural light

Abstract

The application of natural light in photocatalytic process is a potential energy source. In this study, TiO2-SiO2 nanoparticles with outstandingly enhanced photocatalytic activity have been fabricated by sol-gel method. The prepared photocatalysts with different molar ratio of TiO2:SiO2 as 100:0; 95:5; 85:15 and 75:25 were denoted as TiO2, TS5, TS15 and TS25, respectively. Characterization of these photocatalysts was evaluated using transmission electron microscopy (TEM), X-ray diffraction (XRD), N2 Adsorption and Desorption isotherms method (Brunauer–Emmet–Teller, BET). The specific surface area was improved in TiO2-SiO2 photocatalyst namely 193.9 m2.g-1 (at molar ratio of TiO2:SiO2 of 95:5) compared to 33.6 m2.g-1 of TiO2. The crystallite size was calculated around 5 nm from XRD data and uniform particle size distribution was observed in TEM image. The photocatalytic experiments were performed with bisphenol A (BPA) as model compound of organic pollutant. The effect of various operation parameters such as initial concentration, initial solution pH and photocatalyst dosage has been investigated. The kinetic studies of the photocatalytic degradation BPA over TS5 followed the pseudo-first order (k=1.09×10-2 min-1) and degradation yield to be 82.4% BPA, at pH6.23, initial concentration to be 10 ppm and photocatalyst dosage to be 1.0 g.L-1. The photocatalyst TS5 maintained activity after four cycles and remained 78%. The TiO2-SiO2 composite photocatalyst has shown to be a promising heterogeneous photocatalyst for organic degradation.