Kinetic and isotherm modeling of adsorption of dyes onto rice husk carbon

Abstract

Rice husk carbon (RHC) has the ability to adsorb the dyestuff from aqueous solution. It may be useful low cost adsorbent for the treatment of effluents, discharged from textile industries. The effectiveness of RHC have been tested for the removal of colour from the wastewater samples containing three dyes namely crystal violet, direct orange and magenta. Effect of various parameters such as agitation time, pH, temperature, adsorbent dose and concentration have been investigated in the present study. The adsorption of dyes have been best described by pseudo first order mechanism and Freundlich adsorption isotherms. The rate constant of adsorption (Kad) have been determined, which are found to be 6.8 × 10-3, 8 × 10-3 and 10 × 10 -3 min-1 for crystal violet, direct orange and magenta respectively. Similarly the Freundlich constants related to the adsorption capacity (Kf) are found to be 0.74, 0.44 and 0.68 g l-1 and intensity of adsorption (n) are found to be 0.41, 0.73 and 0.33 mg g -1 for above dyes respectively. © Copyright 2010 Global NEST Printed in Greece. All rights reserved.