Sorption Kinetics and Isotherm Studies of Basic Dye Using Agricultural Waste: Silk Cotton Hull

Abstract

Finding out the effectiveness of Malachite Green dye removal is the aim of the present work by using Silk cotton hull an agricultural waste as an activated carbon. Even if various materials are used in the making of activated carbons ample availability and low cost of agricultural by-products create excellent source of raw materials for activated carbon. The Silk cotton hull activated carbon was prepared in the laboratory by carbonization followed by activation. To evaluate the influence of various experimental parameters like initial solution pH, contact time, initial concentration of dye and adsorbent dosage on the removal of Malachite Green dye from aqueous solution batch adsorption studies was performed. The concentration of the residual due was measured using UV visible spectrometer corresponding to the maximum adsorption for the dye solution. The equilibrium of adsorption data was interpreted by using the Langmuir and Freundlich isotherm and Kinetic studies for malachite green- Silk cotton hull batch adsorption system. Batch test showed that maximum of 92% of dye was removed when the dye concentration was 5 mg/L, at an adsorbent dose of 0.5 gm/L at dye pH 8 in 40 minutes. From the studies it is confirmed that the equilibrium data fitted very well with the both Freundlich and Langmuir isotherms. The maximum adsorption capacity of Silk cotton hull carbon was found to be 4.85 mg/g and pseudo second order kinetic model is more likely to predict the behavior over the whole experimental range of adsorption than pseudo-first order model. The intra particle diffusion model indicates that the intra particle diffusion is not the sole- rate determining step and also regression results indicate that the linear regression model give the best results. The above findings suggest that silk cotton hull can be effectively used for decontamination of dye containing wastewater.