Desulfurization by an economically adsorption technique

Removal of organic sulfur compounds from its solution has been investigated by using adsorption. The objective is to find an economically attractive alternative method for desulfurization of petroleum fraction and to select a suitable adsorbing material for this purpose. The solid materials; acid-activated kaolinite, acid-activated bentonite, charcoal, petroleum coke and cement kiln dust are selected to verify this purpose, Dimethyl disulfide compound has been used as a sulfur model compound to evaluate the adsorption efficiency of these solid materials. The solid materials have been characterized by applying different techniques: X-ray analyses to study the crystalline structure (X-ray diffraction) and the constituents of the solid materials (X-ray fluorescence), and thermal analysis to trace the structural change that accompanying the thermal treatment. In addition, acidity was also measured to study the effect of acid treatment on the acidity of the protonated materials. The acid-activated bentonite was found to be the most suitable adsorbent studied, at the lowest reaction temperature 30 degreesC. The higher efficiency of the activated-clay towards sulfur adsorption may be attributed to that, the silicate-silicate bentonite structure possesses Bronsted acid sites, which resulted from the dissociation of the water molecule in between silicate sheets. In addition, the clay surface, after acid treatment would possess positive hydrogen sites. Therefore, the increase in acid sites, disturbs the charge equilibrium in the bentonite-clay lattice, creates strain that arises new active sites for adsorption, which would interact more favorably with the basic sulfur compounds. (C) 2002 Elsevier Science B.V. All rights reserved.