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Abstract: Metal oxide nanoparticles such as silica, alumina, magnesium oxide and calcium oxide were synthesized using sol–gel process followed by super critical drying. In order to increase reactivity, nanoparticles were loaded with zero valent iron. Nanoparticles were then characterized for their surface area, porosity, particle size, surface morphology, compositions, thermal stability, etc. Nanoparticles showed particle diameter in the range of 5–60nm, surface area 23–673m2/g and microporous–mesoporous characteristics. Adsorption of nitrobenzene on prepared nanoparticles was performed in closed glass chamber and the kinetics parameters such as equilibration constant, equilibration capacity, diffusional exponent and adsorbate–adsorbent interaction constant have been determined using linear driving force and Fickian diffusion model. Zero valent iron loaded silica nanoparticles showed maximum adsorption potential (1155mg/g) and considerable ratio for adsorption capacity to surface area (3.14mg/m2) among impregnated systems. [Copyright &y& Elsevier]

Abstract: 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 2–75nm diameter nanoparticles with 135–887m2/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 (1011mg/g) and minimum (690mg/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. [Copyright &y& Elsevier]

Abstract: Nanoparticles of AP-Al2O3 (aero-gel produced alumina) have been produced by an alkoxide based synthesis involving aluminum powder, methanol, toluene and water. Thus produced alumina nanoparticles were characterized and the data indicated the formation of nanoparticles of alumina in the size range of 2–30nm with high surface area (375m2/g). Thereafter, these nanoparticles were impregnated with reactive chemicals. Adsorptive removal kinetics for DEClP (diethylchlorophosphate) and GB (isopropylmethylphosphonofluoridate, sarin) was monitored by GC–FID (gas chromatograph coupled with flame ionization detector) technique and found to be following pseudo first order reaction kinetics. Among impregnated AP-Al2O3 nanoparticles based sorbent systems AP-Al2O3 impregnated with 9-molybdo-3-vanadophosphoric acid (10%, w/w) was found to be the most reactive with least half-life values of 7 and 30min for the removal of DEClP and GB, respectively, whereas unimpregnated AP-Al2O3 nanoparticles showed the best adsorption potential among all studied systems. In addition to this, hydrolysis reaction {identified using GC/MS (gas chromatograph coupled with mass spectrometer) technique} was found to be the route of degradation of DEClP and GB on impregnated alumina nanoparticles. [Copyright &y& Elsevier]

Abstract: Alumina nanoparticles in the size range of 2–30nm and surface area 375m2/g were synthesized using aerogel route and then characterized using N2–BET, SEM, TEM, XRD, FTIR and TGA techniques. Thereafter, these were impregnated with reactive chemicals and tested for their potential by conducting studies on kinetics of adsorption of 2-chloroethylethylsulphide (2-CEES) under static conditions. Kinetics was studied using linear driving force and Fickian diffusion model. The kinetics parameters such as equilibration constant, equilibration capacity, diffusional exponent and adsorbate–adsorbent interaction constant were also determined. AP-Al2O3 with 10% impregnation of MoVPA (V3) and NaOH showed the maximum (574mg/g) and minimum (88mg/g) uptake of 2-CEES among impregnated systems respectively. All impregnated systems except NaOH impregnation showed the values of diffusional exponent to be <0.5, indicated the diffusion mechanism to be Fickian, whereas AP-Al2O3 with and without NaOH impregnation showed the diffusional mechanism to be anomalous. Hydrolysis and dehydrohalogenation reactions (identified using GC/MS technique) were found to be the route of degradation of 2-CEES. [Copyright &y& Elsevier]