Effect of activation factors on adsorption of cationic dye, methylene blue, by activated bentonite

The aim of this investigation was to study the relationship between activation factors and adsorption of cationic dye, methylene blue MB, by activated bentonite. The adsorption index was investigated as a function of acid type, time and temperature. A commercial bentonite was selected as a starting material and the effect of heat treatment on MB adsorption were determined in a batch setup. Though the adsorption index of activated adsorbents by choleric, sulfuric and nitric acids are higher than that for starting bentonite but this parameter depends on activation condition. The results clearly indicated that the maximum adsorption index is achieved when activation is carried out in the presence of 0.5 mol/l nitric acid at 98 C during 60 min. The finding results were confirmed by the measurement of the specific surface area of adsorbents with nitrogen adsorption technique and X-ray diffraction.