Photocatalytic degradation of paraoxon-ethyl in aqueous solution using titania nanoparticulate film

• Published in: Thin solid films 2012-06, Vol.520 (17), p.5597-5601
• Main Authors: Prasad, G.K., Ramacharyulu, P.V.R.K., Kumar, J. Praveen, Srivastava, A.R., Singh, Beer
• Format: Article
• Language: English
• Subjects: Chemistry; Cross-disciplinary physics: materials science; rheology; Degradation; Exact sciences and technology; General and physical chemistry; General, apparatus; Liquid phase epitaxy; deposition from liquid phases (melts, solutions, and surface layers on liquids); Materials science; Methods of deposition of films and coatings; film growth and epitaxy; Nano particulate film; Nano titania; Nanocomposites; Nanomaterials; Nanostructure; Paraoxon-ethyl; Phosphonic acids; Photocatalysis; Physics; Rate constants; Sol–gel deposition; Surface physical chemistry; Titanium dioxide
• ISSN: 0040-6090; 1879-2731
• DOI: 10.1016/j.tsf.2012.04.033

Photocatalytic degradation of paraoxon-ethyl (o,o-diethyl o-(4-nitrophenyl) phosphate), a well known surrogate of chemical warfare agents, in aqueous solution was studied by using titania nanoparticulate film. Reaction followed pseudo first order behaviour. Photolytic degradation reaction of paraoxon-ethyl demonstrated relatively low rate with a value of rate constant of 2.5×10−3min−1. Whereas, degradation reaction in the presence of titania nanoparticulate film and UV light displayed enhanced rate with a value of rate constant of 6.9×10−3min−1 due to photocatalysis. Gas chromatography–mass spectrometry analysis showed the formation of p-nitrophenol, o,o-diethyl phosphonic acid, o-ethyl, diphosphonic acid, phosphoric acid, dimerized product of o,o-diethyl phosphonic acid, acetaldehyde, and carbon dioxide due to photocatalytic degradation of paraoxon-ethyl. It indicates that, photocatalytic degradation reaction begins with destruction of P–O–C bonds. Subsequently, P, C atoms were found to be oxidized gradually, and contributed to its photocatalytic degradation. ► Synthesis of titania nanoparticles by sol–gel method. ► Fabrication of titania nanoparticulate film by dip coating. ► Paraoxon ethyl degradation reactions followed pseudo first order behaviour. ► Paraoxon-ethyl degraded to non toxic compounds like CO2, acetaldehyde, and nitrophenol.