REMOVAL OF SOME ADVANCED DYES FROM AQUEOUS SOLUTION USING MODIFIED KAOLINITE CLAY

Kaolin mineral and its modified forms were used for dye removal from aqueous solutions. The affecting parameters such as pH, dye concentration and contact time on the removal performance were investigated. Three different dyes (acid Green 25, Basic Blue 3 and Disperse Orange 13) were studied. The removal has a higher rate at initial period of contact time. The equilibrium is achieved at 120 min. The adsorption is occurring through transport of dye molecules from solution to solid surface. Then, they diffused into the pores. The order of adsorption was: Basic blue 3 > Acid Green 25 > Disperse Orange 13. The adsorption process follows the pseudo-second-order kinetics. The rate controlling step is not depending on the intra-particle diffusion. A Freundlich isotherm model could describe the adsorption. The calculated (RL) factor confirmed the variability of the adsorption process.