Studies of activated charcoal cloth. III. Mesopore development induced by phosphate impregnants

✍ Scribed by J.J. Freeman; F.G.R. Gimblett; R.A. Roberts; K.S.W. Sing

• Publisher: Elsevier Science
• Year: 1988
• Tongue: English
• Weight: 554 KB
• Volume: 26
• Category: Article
• ISSN: 0008-6223
• DOI: 10.1016/0008-6223(88)90003-6

✦ Synopsis

Nitrogen adsorption isotherms have been determined at 77 K on samples of activated charcoal cloth prepared from viscose rayon cloth after impregnation of the latter with aqueous solutions containing various phosphate compounds. The results obtained indicate that a much wider range of isotherm type and hysteresis loop may be achieved with phosphate impregnants than with the borates studied previously. Analyses of the isotherms employing the a, method indicate that although all the adsorbents were highly microporous (pore width <2 nm), an appreciable mesoporosity (pore width 2-50 nm) could be superimposed upon the micropore structure by employing suitable combinations of phosphate salts. The addition of 3-3-3 mix (3% w/v AlC& + 3% w/v ZnCl* + 3% w/v N&Cl) to the impregnating solution led to better control in the development of the mesopore volume at higher degrees of burnoff when 5% w/v sodium dihydrogen phosphate was employed. A comparison of the a, plots obtained with those reported for charcoal cloths derived from borate-impregnated precursors suggests that the mesopore structure developed in the presence of phosphate impregnants is better defined and more rigid. Reasons for this are advanced in terms of a model for mesopore development suggested by us previously.