[Show abstract][Hide abstract] ABSTRACT: Sorbent decontaminant based on molecular sieves supported with Ag2O nanoparticles was synthesized by ion exchange, precipitation, and subsequent calcination. It was characterized by transmission electron microscopy, X-ray diffraction, nitrogen adsorption, and gravimetric
techniques. Transmission electron microscopy data indicated the formation of silver oxide nanoparticles of size varying from 1 to 25 nm on the external surface of molecular sieves. X-ray diffraction revealed the preservation of the host structure during the synthesis. Reduction in surface
areas and pore sizes indicated the partial blocking of pores of molecular sieves by silver oxide nanoparticles. This sorbent decontaminant was used for decontamination of sarin and the data was compared with that of bare molecular sieve and bare silver oxide nanoparticles. Molecular sieve
supported with Ag2O nanoparticles showed greater decontamination efficiency when compared to bare molecular sieve or bare silver oxide nanoparticles. It degraded 100 % of sarin within 80 min. Whereas, bare molecular sieves decontaminated 78% of sarin within 24 h and bare silver
oxide nanoparticles decontaminated 100% of sarin in 16 h.
[Show abstract][Hide abstract] ABSTRACT: Sun light assisted photocatalytic decontamination of sulfur mustard (HD) was studied by using ZnO nanoparticles and the data was compared with those carried out in the presence of UVA and visible light radiation. In the presence of Sun light, 100% of HD was decontaminated in 12h. Whereas, in the presence of UVA light 90%, and in visible light 80% of HD was decontaminated in 12h. GC–MS data indicated the formation of thiodiglycol, hemisulfur mustard, divinyl sulfide, 2-chloro ethyl vinyl sulfide, etc., on the surface of ZnO nanoparticles in the case of dark and visible light irradiation experiments. However, in Sun light and UVA light irradiation experiments, GC–MS data indicated the formation of HD sulfoxide, HD sulfone, 1,3-dithiane, 2-chloro ethanol, acetaldehyde, carbon dioxide, etc. along with hydrolysis and elimination products. Under the illumination of visible light and in dark hydrolysis, elimination and surface complexation reactions have contributed to decontamination of HD. Whereas, in the presence of Sun light and UVA light, photocatalytic reactions like C–S bond cleavage, oxidation of C, S atoms were observed to have contributed to decontamination of HD in addition to hydrolysis and elimination reactions.
No preview · Article · Oct 2011 · Journal of Molecular Catalysis A Chemical
[Show abstract][Hide abstract] ABSTRACT: Mixed metal oxide nanocrystals of AP-Al(2)O(3), AP-Al(2)O(3)-Fe(2)O(3), AP-Al(2)O(3)-V(2)O(5) and AP-Al(2)O(3)-CuO have been prepared by aerogel process. XRD data of prepared materials revealed the formation of nanocrystals with a size range of 3-15 nm diameters. N(2) BET investigations on these materials revealed larger values of surface area ranging from 350 to 540 m(2)/g. Reactivity of these nanocrystalline materials against Yperite was examined by gas chromatography, gas chromatography-mass spectrometry and infrared spectroscopy techniques. AP-Al(2)O(3)-Fe(2)O(3), AP-Al(2)O(3)-V(2)O(5) and AP-Al(2)O(3)-CuO nanocrystals exhibited superior decontamination properties against Yperite than AP-Al(2)O(3). The reactions exhibited pseudo first order behaviour. 100% of Yperite was found to be decontaminated on Al(2)O(3)-Fe(2)O(3), Al(2)O(3)-V(2)O(5) and Al(2)O(3)-CuO where only 75% of the same was found to be decontaminated on AP-Al(2)O(3) within 40 h.
No preview · Article · Nov 2010 · Journal of hazardous materials
[Show abstract][Hide abstract] ABSTRACT: Mesoporous manganese oxide nanobelts were synthesized by hydrothermal-ion exchange method and characterized by transmission electron microscopy, scanning electron microscopy, X-ray diffraction, N2-BET, thermogravimetry and FT-IR techniques. Decontamination reactions of sarin (GB), sulphur mustard (HD) and chloro ethyl ethyl sulphide (CEES) were studied on obtained mesoporous material by using gas chromatography (GC) and gas chromatography coupled with mass spectrometry (GC–MS) techniques. Decontamination products formed via hydrolysis were non-toxic methyl phosphonic acid, thiodiglycol and hydroxyl ethyl ethyl sulphide. Decontamination reactions exhibited pseudo first order behavior and the values of rate constant and half life were found to be 0.43h−1 and 1.6h for GB, 0.01h−1 and 69.32h for HD, and 0.02h−1 and 34.66h for CEES, respectively.
No preview · Article · Jul 2010 · Microporous and Mesoporous Materials
[Show abstract][Hide abstract] ABSTRACT: Versatile adsorbents were prepared by modifying whetlerite carbon for intended application against both non-persistent and persistent chemical warfare agents. Whetlerite carbon was modified by impregnating with basic inorganic compounds such as sodium hydroxide, potassium carbonate, sodium carbonate, cesium carbonate, etc. and oxidizing inorganic compounds such as ammonium heptamolybdate, ceric ammonium nitrate, etc. These carbons were explored for their reactivity against sulphur mustard and data was compared with that of impregnated carbons consisted of above basic and oxidizing compounds. On modified whetlerites and impregnated carbons comprised of basic compounds, sulphur mustard was transformed into hemisulphur mustard, thiodiglycol, vinyl-2-chloroethyl sulphide, divinyl sulphide, etc. On those comprised of oxidizing compounds sulphur mustard was converted into sulphur mustard sulphoxide.