Adsorption of Naphthol Green B Dye on to Ca-Montmorillonite and Nano-Composite Ca-Montmorillonite Clay

Abstract

In this work Iraqi Ca-montmorillonite clay was converted to Fe-Ca-montmorillonite nano composite for enhancing the adsorption capacity of the clay for adsorbing the anionic dye Naphthol Green B using batch method for adsorption. The equilibrium adsorption parameters which affects the removal efficiency of the dyes including clay dose, starting dye concentration, pH of the dyes solutions, time of adsorption and temperature were studied for the both clays. The adsorption isotherms at optimum operating conditions were described using various adsorption isotherm models such as: Langmuir, Freundlich, Temkin and Dubinin-Radushkevich isotherms and the values of the adsorption constants for these isotherms were evaluated. The equilibrium data were fitted by Freundlich isotherm .The values of the mean free energy calculated from Dubinin-Radushkevich isotherm show that the adsorption of NGB dye onto both clays was physi-sorption. The values of the ΔG_Ad, ΔH_Ad and ΔS_Ad suggest that the adsorption process of NGB dye is spontaneous, exothermic occurs with increasing in the disorder.