Carbon 40 (2002) 1929–1936 The effect of impregnation of activated carbon with SnCl .2H O on its porosity, surface composition and 2 2 CO gas adsorption a a, b b * Ma’an. F. Al-Khatib , Sunny E. Iyuke , Abu Bakar Mohamad ,Wan R.W. Daud , b c d Abdul Amir H. Kadhum , Azmi M. Shariff , Mohd A. Yarmo a Department of Chemical and Environmental Engineering, Faculty of Engineering, Universiti Putra Malaysia, 43400, UPM Serdang, Selangor, Darul Ehsan, Malaysia b Department of Chemical and Process Engineering, Universiti Kebangsaan Malaysia, 43600, UKM Bangi, Selangor, Darul Ehsan, Malaysia c Department of Chemical Engineering, Universiti Teknologi Petronas, 31750 Tronoh, Perak, Malaysia d Department of chemistry, XPS Laboratory, Universiti Kebangsaan Malaysia, 43600, UKM Bangi, Selangor, Darul Ehsan, Malaysia Received 10 October 2001; accepted 31 December 2001 Abstract Activated carbon was impregnated with different concentrations of SnCl .2H O. Unimpregnated and impregnated 2 2 activated carbons were analysed by means of physical adsorption and XPS and were tested for CO gas adsorption in a PSA system. The adsorption isotherms of N at 77 K were measured and showed a Type I isotherm indicating microporous 2 carbon for all the samples. The surface area, pore volume and pore size distribution were reduced with impregnation. XPS analysis showed an increase in the intensity of Sn3d peak with impregnation. The impregnated activated carbon showed a very good adsorption ability of CO gas compared to the unimpregnated sample. The adsorptive species responsible for CO gas adsorption was confirmed to be SnO instead of SnO due to the former’s comparative thermodynamic stability. 2  2002 Elsevier Science Ltd. All rights reserved. Keywords: A. Activated carbon; B. Impregnation; C. Adsorption; BET surface area; X-ray photoelectron spectroscopy 1. Introduction carbon with nine kinds of metal halides and tested their adsorption ability to CO. They deduced that the amounts Activated carbon is a common and popular adsorbent of CO adsorbed by PdCl and CuCl -impregnated carbons 2 2 that has been used extensively in separation and purifica- were around eight and 20 times that adsorbed on the tion processes due to its high adsorption capacity, high unimpregnated activated carbon, respectively. However, surface area and adequate pore size distribution. Yet in the the micropore volume and specific surface area were case of gases with low molecular weight, low boiling point greatly decreased. Other materials such as the salts of and appreciable polarity, the adsorption capacity is low Cr(VI) and Cu(II) have been used by Molina-Sabio et al. and activated carbon is no more effective [1]. [3] for the impregnation of activated carbon. Activated An improvement on the adsorption capacity is observed carbon produced showed a decrease in the volume of when activated carbon is impregnated with metal halides micro and mesopores as well as in the mean micropore and salts. However, this headway in adsorption capacity is size. Tin, on the other hand, in its oxide form such as associated with changes in the porous structure of the SnO , normally has the ability of adsorbing CO to produce 2 activated carbon. Tamon et al. [2] impregnated activated CO on the adsorbent surface [4]. Durrant et al. [5] 2 reported that tin reacts with steam at high temperature to produce SnO and H . This result could imply that at high *Corresponding author. Tel.: 160-3-89466294; fax: 160-3- 2 2 temperature in humid environment with enough air, tin 8656-7099. E-mail address: iyuke@yahoo.com (S.E. Iyuke). could easily be oxidised to tin(VI) oxide. They also 0008-6223 / 02 / $ – see front matter  2002 Elsevier Science Ltd. All rights reserved. PII: S0008-6223(02)00026-X