Adsorption of direct green 6 dye onto modified power plant ASH

Abstract

Power plant ash and modified ash were used as the adsorbent, in this study, for the removal of textiledye direct green 6 (DG6) from aqueous solutions. The adsorbent was prepared by the alkaline attack in aqueous medium and characterized by scanning electron microscopy (SEM-EDX), X-ray diffraction (XRD) and Brunauer- Emmett -Teller (BET) methods. The adsorbent in this study had a specific surface area of 7, for power plant ash and 40 m2g -1 for modified ash. Effects of various experimentalparameters, such as initialpH solution,adsorbent dosage, contact time and initial dye concentration are studied. The removal of DG6 effluent is a relatively rapid process. At pH 2 and ambient temperature, the adsorption equilibrium was reached after 4 hours and thekinetics follow a pseudo-second order model. The highest removal rate was obtained at pH 4, and was about 94% at ambient temperature. The adsorption isotherm is in goodagreement with the Langmuir model, the adsorption of dye on thesurface of new adsorbent materials was done in monolayer. The results obtained in this study confirm the potential of modified ash to be used as efficient adsorbent for the removal of direct green 6 dye from aqueous solution.