Effect of Acidification on the Adsorption Profile for Ester on Zeolite, Diatomite and Activated Carbon

In this paper we report on the adsorption and catalytic properties of zeolite, diatomite and activated carbon. It is observed that, adsorption of ethyl acetate on zeolite, diatomite and charcoal is enhanced significantly on acidification, in the case of zeolite but suppressed in the case of diatomite and activated carbon. The adsorption efficiencies of zeolite, diatomite and activated charcoal are above 93% and is independent of the amount of solid used. Infra-red spectra showed that the C=O stretching vibration of the adsorbed molecules shifted to lower frequencies compared to carbonyl band at 1700cm -1 observed in the spectra of pure ester. The Lewis and Bronsted acid sites on zeolite samples were also identified from the infra-red spectra of ethyl acetate adsorbed on both raw and acidified samples. Quantitative elemental analysis shows changes in the amounts of cations on increased acidification which correlates to the amount of ester adsorbed. water in the interlayer sites. 2, 3, 4 Quantitative analytical determinations of the amount substance adsorbed at a fixed temperature (adsorption isotherm), has facilitated/enabled studies on replacement of inorganic by organic cations. It is thus now possible to estimate the number of neutral molecules associated with each exchangeable cation. Mechanisms of interaction between adsorbed molecules and the silicate surfaces have been postulated with the help of chemical and x-ray studies. 1 .