Photodegradation screening on chlorpyrifos and benzoic acid using titania-based photocatalyst supported on pulasan peel activated carbon

Abstract

Chlorpyrifos and benzoic acid are harmful and toxic organic compounds which contribute to the damage of the environment and human health. Therefore, any organic or inorganic pollutants present in water system should be treated in an appropriate way and low-cost before they can be safely disposed to the environment. In this research, TiO₂ modified with PPW activated carbon, TiO₂/AC was synthesized. The pulasan peel was treated with sulphuric acid to obtain activated carbon. Various ratios of TiO₂/AC (90:10, 50:50, 10:90) with various calcination temperatures (500, 600 and 700℃) were   prepared by physical mixing.   Titania-silver oxide was also prepared with various ratios (90:10, 50:50 and 10:90) and calcined at 500℃ and prepared by wet-impregnation method. All the prepared photocatalysts were screened on chlorpyrifos and benzoic acid degradations under   UV irradiation (l=365 nm), monitored by UV-Vis spectrophotometer. The main absorption measured at wavelength ℷ_max=210 nm for chlorpyrifos and ℷ_max= 227 nm for benzoic acid were recorded. Among the photocatalysts prepared, the catalyst which gave maximum percent degradation was 5T/3SAC (50:50) compared to single TiO₂ and other modified photocatalysts. The best photocatalyst was assessed on the effect of various catalysts loading (0.1, 0.2 and 0.3 g) on the benzoic acid solution and result shows that as catalyst loading increase, the rate of degradation was also increased. The prepared photocatalysts were characterized by X-ray diffractometer (XRD), Brunauer-Emmett-Teller (BET) and field emission scanning electron microscopy-energy dispersive X-ray (FESEM-EDX). It is proven that (5T/3SAC 50:50) is the most efficient photocatalyst with the presence of anatase phase, and homogenous distributed porous surface with average size (1.48 µm) and from BET surface area of 4SAC showed highest surface 228.49 m²/g.