Ionic Strength Effect on Green Malachite Adsorption onto Moroccan Montmorillonite Clay: Experimental Study and Theoretical Investigation

Abstract

The equilibrium adsorption process of Malachite green(MG) from an aqueous solution using Sodic Moroccan Montmorillonite Clay (Na-MMC) has been investigated under various experimental conditions. The effect of several inorganic salts (LiCl, NaCl, KCl, and CsCl) on malachite green adsorption at different ionic strength by sodic montmorillonite as well as the pH effect were investigated through a number of batch adsorption experiments. The dye concentration in the solution before and after adsorption was measured spectrophotometrically. The experimental isotherm data show that the maximum removal of MG was observed at pH in the rang 8-10. The adsorbed amount increases with the concentration of the sodium or lithium, however it decrease with cesium or potassium salts. A theoretical explanation of MG adsorption and ionic strength effect was given based on data modeling developed by Nir and Co. also. Geometry optimizations of MG molecule to get a better insight into structure geometry and reactivity were carried out by DFT calculations.