Adsorption, Kinetic, Equilibrium and Thermodynamic studies on the removal of basic dye Rhodamine-B from aqueous solution by the use of natural adsorbent perlite

This paper presents the feasibility of removal of basic dye Rhodamine-B from aqueous solutions by using a low cost natural adsorbent perlite. Batch adsorption experiments were carried out as a function of pH, contact time, initial concentration of the adsorbate, adsorbent dosage and temperature. Dye adsorption equilibrium was rapidly attained after 50 minutes of the contact time, and it was described by the Langmuir and Freundlich adsorption isotherms over the entire concentration ranges from 20-100 mgL-1. Adsorption dataʹs are used for modelling, from the first and second order kinetic equation and intra-particle diffusion models. Thermodynamic parameters such as AH°, AS°, and AG°were calculated, which indicated that the adsorption was spontaneous and exothermic nature, which was evident by decreasing the randomness of the dye at the solid and liquid interface. Adsorbent used in this study, characterized by FT-IR and SEM before and after the adsorption of Rhodamine-B. The characteristic results and dimensionless separation factors (RL) showed that perlite can be employed as an alternative to commercial adsorbents in the removal of Rhodamine-B from aqueous solution and waste water.