Mechanistic Study of the Effect of Sulphur Dioxide and Nitrogen Dioxide Exposure of ASC/T, Whetlerised BPL and Whetlerised Chlorinated BPL Activated Carbons on the Chemisorption of Hydrogen Cyanide from Air

Autor: A. Keaney, J.F. Alder
Jazyk: angličtina
Rok vydání: 1998
Předmět:
Zdroj: Adsorption Science & Technology, Vol 16 (1998)
Druh dokumentu: article
ISSN: 0263-6174
2048-4038
02636174
DOI: 10.1177/026361749801600204
Popis: Three activated carbons, ASC/T, Whetlerised BPL and Whetlerised chlorinated BPL (BPL/C) (4.5 %w/w chlorine/carbon) were tested extensively on their adsorption behaviour towards HCN in air, before and after exposure to SO 2 and NO 2 in air at pressures from 2 to 500 mbar. Whetlerite impregnation solutions of carefully controlled compositions were made up to treat the BPL and BPL/C. ASC/T and the resulting Whetlerised carbons BPL/W and BPL/WC were examined. Nitrogen isotherm data were obtained for these carbons before and after exposure to SO 2 and NO 2 . The carbons were also analysed by ICP-AES and AAS for total Cr, and by alkaline extraction then spectrophotometric analysis using diphenylcarbazide reagent, for the determination of Cr VI . The ASC/T, BPL/W and BPL/WC were challenged by 2 mg/l HCN in air at 22°C/80% relative humidity (RH) before and after exposure to SO 2 and NO 2 . Surface area, microporous volume N 2 adsorption energy and pore size distribution data were obtained for the range of carbons from the nitrogen isotherms. Adsorption rate constants, adsorption capacity and adsorption site densities for HCN and (CN) 2 were obtained. Analysis of the results for all three carbons shows that the principal effects of SO 2 and NO 2 are in reducing the fraction of Cr as Cr VI and in blocking the micropore adsorption sites for HCN and (CN) 2 . There is little obvious correlation between SO 2 or NO 2 loading and the N 2 adsorption rate constants and N 2 adsorption energies. There is an overall reduction in microporous area and volume on exposure of ASC/T to both SO 2 and, to a lesser but still marked degree, to NO 2 . The biggest reduction is in the fraction of pores
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