title: Adsorption of dimethyl methylphosphonate on metal impregnated carbons under static conditions.
abstract: Active carbon, grade 80 CTC, of surface area 1199m(2)/g, 12x30 BSS particle size and coconut shell origin was impregnated (5%, W/W) with various impregnants such as Cu(II) 1,1,1,5,5,5-hexafluoroacetylacetonate, Cu(II) 1,1,1-trifluoroacetylacetonate, 1-phenylbute-1,3-dione-2-oxime plus Cu(II) using incipient wetness technique. These impregnated carbons along with active carbon (Grade 80 CTC) and whetlerite were studied for the adsorption of dimethyl methylphosphonate (DMMP) at 33+/-1 degrees C under static conditions. Cu(II) 1,1,1,5,5,5-hexafluoroacetylacetonate impregnated carbon system showed highest uptake (68.5%, W/W) of DMMP amongst all the carbon systems, however, active carbon with higher surface area could adsorb 61.5% (W/W) of DMMP under same conditions. It indicated that the adsorption by Cu(II) 1,1,1,5,5,5-hexafluoroacetylacetonate impregnated carbon was not only due to physisorption but chemisorption as well. Kinetics of adsorption was also studied and various parameters such as equilibration time, equilibration capacity, rate constant (k), diffusional exponent (n) and constant (K) were determined. Carbons with and without DMMP exposure were also studied using IR and TGA techniques. Reaction products were analyzed using gas chromatography coupled with mass spectrometry (GC/MS) and found to be methyl methylphosphonic acid (MMPA) and methylphosphonic acid (MPA) for Cu(II) 1,1,1,5,5,5-hexafluoroacetylacetonate impregnated carbon.
authors.affiliation: Defence Research and Development Establishment, Jhansi Road, Gwalior 474002, Madhya Pradesh, India.
authors.forename: Amit
authors.initials: A
authors.lastname: Saxena
authors.forename: Beer
authors.initials: B
authors.lastname: Singh
authors.forename: Abha
authors.initials: A
authors.lastname: Sharma
authors.forename: Vinita
authors.initials: V
authors.lastname: Dubey
authors.forename: Rajendra Prasad
authors.initials: RP
authors.lastname: Semwal
authors.forename: Malladi Venkata Satya
authors.initials: MV
authors.lastname: Suryanarayana
authors.forename: Vepa Kameswara
authors.initials: VK
authors.lastname: Rao
authors.forename: Krishnamurthy
authors.initials: K
authors.lastname: Sekhar
mesh_terms: D000327:Adsorption; D002244:Carbon / Q000737:chemistry*; D007700:Kinetics; D013058:Mass Spectrometry; D008670:Metals / Q000737:chemistry*; D009943:Organophosphorus Compounds / Q000737:chemistry*; D013055:Spectrophotometry, Infrared; D013696:Temperature
chemical_list: D008670:Metals; D009943:Organophosphorus Compounds; C031116:dimethyl methylphosphonate; D002244:Carbon