| || Effect of Surface Oxygen Complexes of Activated Carbon on the Adsorption of 2 4 6 Trinitrophenol
Author : Bansal, R.C. ;Bhalla, A.K.;Kapoor, S.K.;Misra, Kshipra;Aggarwal, Preeti
Source : Defence Science Journal ; Vol:48(2) ; 1998 ; pp 219-222
Subject : 66 Chemical Technology;547 Organic Chemistry
Keywords : Activated carbons ;Adsorption isotherms
Abstract : "The adsorption isotherms for 2,4,6-trinitrophenol (picric acid) on five samples of coconut-based activated carbons (ACs) with varying surface area have been studied. The results obtained show that adsorption depends upon surface area but is not linearly related to it. The adsorption increases on oxidation with ammonium persulphate ((NH/sub 4/)/sub 2/ S/sub 2/ O/sub 8/) as well as on degassing at 600 °C. The results have been explained on the basis of the existence of surface carbonyl groups, where the O/sub 2/ of the carbonyl group interacts with pi electrons of the benzene ring of picric acid."
| || Evaluation of NBC canisters against phosgene : Chemical warfare agent
Author : Singh, Beer;Saxena, Amit;Sharda, Dileep;Yadav, S. S.;Chintamani;Pandey, D;Sekhar, K.
Source : Defence Science Journal ; Vol:55(4) ; 2005 ; pp 437-445
Subject : 623.459 Chemical Weapons
Keywords : Activated carbon;Adsorption isotherms;Chemical warfare agent;Phosgene;NBC canisters;Blister agents;Nerve agents
Abstract : Indigenously developed and bulk produced NBC canisters from eight different sources containing carbon (100 g) carbon impregnated with Cu (II), Cr (VI), Ag (I), NaOH, and pyridine were evaluated for their protective potential against phosgene (COCl2), a highly toxic chemical warfare agent. Protection time (COCl2 breakthrough time) was found to be 84 min for canisters of six different sources at 4.0 mg/l COCl2 concentration and 30 l/min airflow under wet conditions of 30 ± 1 oC and 50 per cent RH. Protection time, however, varied from 63 min to 116 min for the canisters of other two sources under the similar conditions. Phosgene breakthrough time was also studied under dry conditions of 30 °C and 0.2 per cent RH (dry air was used from air cylinder) and found to be 37 min at 4.0 mg/l COCl2 concentration and 30 l/min airflow. Effect of COCl2 concentration on breakthrough time indicated that the canisters made by six out of eight manufacturers were similar, while canisters from other two sources had slight variations in carbon compactness, which was exemplified by the phosgene breakthrough behaviour. The study indicated that phosgene breakthrough time not only depends upon chemical degradation but is also influenced by carbon compactness. The results were supported by the CCl4 breakthrough times of the canisters.