FTIR study of modification of transition metal on zeolites for adsorption

Abstract

Adsorption of 1-propanethiol on Co²⁺ and Cd²⁺ modified, synthetic (3A, 4A and 13X) zeolites were studied by FTIR (Fourier Transform Infrared) spectroscopy and SEM-EDX (Scanning Electron Microscope-Energy Dispersive X-Ray) graphics. Amount of metal cations on mentioned zeolites was measured by AAS (Atomic Absorption Spectrometer). Based on divalent cations of zeolites, it was assumed that cations may affect their adsorption properties. The nature of the cations present in a given type zeolite markedly affects the physical and chemical feature of the system, for instance, valance and size of cations and their location in the zeolite framework influence adsorption, molecular sieving and catalytic properties. In this study, we used cation exchanged zeolites as adsorbents due to their high surface area. Zeolites with divalent cations show an affinity to adsorp 1-propanethiol comparing to their ordinary positions with monovalent cations. The lack of S-H band in IR spectra gives an idea, that sulphur may make a bond to metal (Cd²⁺ or Co²⁺) or it makes a bond to H atom of isolated OH groups of zeolite surface.