Reactive adsorption of toxic organophosphates parathion methyl and DMMP on nanostructured Ti/Ce oxides and their composites

Abstract

Pure titanium and cerium oxides and their composites were prepared by the modified method of homogeneous hydrolysis with urea as the precipitating agent. The as-synthesized nanostructured oxides were examined by XRD, XPS, microscopic techniques (SEM, HRTEM), nitrogen physisorption, and vibrational spectroscopies (FTIR, Raman). Decontamination ability of the samples towards the toxic organophosphorus compounds was determined by two methods. The reactive adsorption of the warfare agent simulant Dimethyl methylphosphonate (DMMP) was observed by in situ FTIR spectroscopy. The degradation of the pesticide parathion methyl in a liquid medium was investigated by liquid chromatography (HPLC). Nano-ceria exhibited substantially higher degradation ability compared to nano-titania. The highest degradation efficiency was achieved with the composites with Ti:Ce 2:8 and 1:1 molar ratio. The strong interaction of Ti with Ce led to an increase of Ce3+ and formation of Ti<4+ states and changed surface area and porosity which may cause improved degradation efficacy for both DMMP and parathion methyl.