Equilibrium, Kinetics and Thermodynamic of Dye Adsorption by Low — Cost Adsorbents

Abstract

This work is to study the adsorption of a commercial dye (magenta color) for silk yarn by low-cost adsorbents such as green perlite and shrimp shell (Macrobrachium rosenbergii). The adsorption experiments were carried out in batch process without adjusting pH. The various parameters, such as contact time, initial dye concentration and adsorbent doses were evaluated at the natural pH. The equilibrium data at various concentrations were analyzed using Langmuir, Freundlich and Temkin isotherms. The results showed that the maximum adsorption capacities of Langmuir isotherm valued 14.805 mg/g for green perlite and 5.621 mg/g for shrimp shell at 30°C. The kinetic data was better fitted with pseudo-second order for the adsorbents. Thermodynamic properties such as free energy (ΔG), enthalpy (ΔH) and entropy (ΔS) indicated spontaneous and endothermic in nature of adsorption for all adsorbents. The study revealed that green perlite and shrimp shell can be used as an efficient adsorbents for the removal of dye solution. ISSN : 2010-0221