Adsorption of Rhodamine-B and Congo red dye from Aqueous Solution using Activated Carbon: Kinetics, Isotherms, and Thermodynamics

Abstract

The present work aims to investigate the removal of dye Rhodamine-B (RB) and Congo red (CR) dye from aqueous solutions by low cost bio-waste adsorbents, such as Maranta arundinacea activated carbon (MAC) under various experimental conditions. The effect of dye concentrations, contact time, temperature and adsorbent dose on the removal of dyes was studied. The kinetic experimental data were fitted to pseudo-first-and pseudo-second – order model. Results imply that adsorption of RB and CR on these adsorbents nicely followed the second order kinetics model and maximum adsorption capacity was found to be 88.4 mg/g for RB and 79.3 mg/g for CR, however it increase with increase in temperature for both dyes. Equilibrium adsorption was investigated by the Langmuir, Freundlich, Temkin, D-R and Jovanoic isotherms. The thermodynamics parameters of adsorption systems indicated spontaneous and exothermic process.