Methylene blue and crystal violet dyes removal (as a binary system) from aqueous solution using local soil clay: kinetics study and equilibrium isotherms

Abstract

IN THIS PAPER, local soil clay as a low cost and affordable adsorbent was employed for the successful removal of methylene blue (MB) and crystal violet (CV) dyes from an aqueous binary system. The effect of various experimental conditions like adsorbate concentrations, time, temperature, and pH has been investigated. To know the adsorption performance of the dye molecules upon soil clay, the kinetics of the adsorption data were analyzed using various models such as pseudo-first-order and pseudo-second-order. This kind of study shows that the maximum adsorption reached at 2 min and uses the pseudo- second-order kinetics. The adsorption Kinetics have been investigated in the pH range of 2, 3.7, 7, and 8.7 at 25˚C and analyzed with two different models namely Langmuir and Freundlich. The interaction of dye molecules with soil clay has been investigated by SEM, EDS, FTIR, and XRD. Maximum removal of MB and CV up to 47.82 and 35.71 mg g-1, respectively was achieved by dye molecules adsorption onto soil clay. This effective removal method may provide a promising solution for eliminating of CV and MB dyes from wastewater.