STUDIES ON THE ISOTHERMS, KINETICS AND THERMODYNAMICS OF ADSORPTION OF CRYSTAL VIOLET ON LOW COST MATERIALS

Abstract

The low cost adsorbent namely Cassia Siamea (CS), Albizia Labbeck (AL), Nerium Indicum (NI), Durauta Erecta (DE), and Potato Husk (PH) have been tested for the effectiveness in declourisation of wastewater containing a crystal violet dye (CV) by an adsorption technique. The various parameters such as contact time, dye concentration, temperature, adsorbent dosage, pH and ionic strength were applied for the study. The equilibrium was attained within 50 min, the adsorption of the dye on solution was studied in the pH range 2-7, the salt dosage was increased from 0.05 to 0.5 g. Adsorption was carried out at different temperature in the range of 293 to 333 K±0.5K It was observed that the adsorption increase with increasing in time, solution pH and dosage (g). It was also observed that adsorption decreases with increase in CV concentration and the addition of salt. The kinetic data were then fitted using both Pseudo –first order model and second order model, Langmuir and Freundlich models were often used to describe equilibrium adsorption isotherms and the thermodynamic parameters, change in enthalpy (ΔH) (KJ/mol) and change in entropy (ΔS) (J/mol) which related to the Gibbs free energy (ΔG).