Photo Degradation of Organophosphate Pesticides (Acephate & Omethoate) with N-Doped TiO2 in Presence and Absence of Visible Light

Abstract

Rising demand for the crop production is increasing the use of pesticides and herbicides. Organophosphorous pesticides like acephate and omethoate are the most harmful chemicals and are playing the main role in the water and soil pollution. These are slow biodegradable organic compounds and are contaminating the environment. The increasing awareness for the environmental remediation has made human to investigate novel researches for the photo degradation of such toxic compounds. In the present work nanoparticles of TiO2 were synthesized by sol gel method using titanium tetraisopropoxide, 2-propanol in distilled water. The nanoparticles so formed were then doped with nitrogen by using urea as nitrogen source. Different ratios of TiO2 to urea i-e (1:0), (1:0.1), (1:0.5), (1:1), (1:2) and (1:3) were used to synthesize six different types of nanocatalysts. The catalysts were symbolized as SN-0, SN-0.1, SN-0.5, SN-1, SN-2 and SN-3 respective to the ratio of urea used. These as prepared N-doped catalysts were then characterized with various techniques i-e SEM, EDS, XRD UV-visible spectroscopy and BET. From SEM the spherical morphology of all the catalysts was seen and particle size within nano range was investigated. The EDS showed the elemental composition. Through XRD the anatase phase and tetragonal structure was confirmed and the crystallite sizes were also calculated. From UV-visible spectra band gap was calculated by Tauc plot. From BET analysis the surface area and pore size of each catalyst was found. The photo catalytic activity of all the catalysts was evaluated from the degradation study of acephate and omethoate pesticides. The decrease in concentration was found from UV visible spectrophotometer. As compared to all the synthesized and bulk TiO2, SN-3 nanocatalyst showed the highest activity due to its smaller crystallite size, lower band gap and larger surface area.