Adsorption of diethylchlorophosphate on metal oxide nanoparticles under static conditions

Nanoparticles of MgO, Al2O3, CaO and SiO2 were synthesized using aerogel route, and characterized by N2-BET, SEM, TEM, XRD, TGA and FT-IR techniques. Characterization indicated 2-75 nm diameter nanoparticles with 135-887 m2/g surface area and microporous-mesoporous characteristics. Prepared nanoparticles were tested for their adsorptive potential by conducting studies on kinetics of adsorption of diethylchlorophosphate under static conditions. The kinetic parameters such as equilibration constant, equilibration capacity, diffusional exponent and adsorbate-adsorbent interaction constant have been determined using linear driving force model and Fickian diffusion model. AP-MgO and AP-CaO showed the maximum (1011 mg/g) and minimum (690 mg/g) uptake of DEClP, respectively. All nanoparticles showed the values of diffusional exponent to be >0.5, indicating the diffusion mechanism to be anomalous. Hydrolysis reaction (identified using GC/MS technique) was found to be the route of degradation of DEClP.