Comparative studies on adsorptive removal of indole by granular activated carbon and bagasse fly ash

Abstract

In the present article, comparative studies were performed for the adsorptive removal of indole by granular activated carbon (GAC) and bagasse fly ash (BFA) in batch system. Experiments were conducted to study and optimize various operational parameters such as adsorbent dose, contact time, pH, and temperature. BFA was found to work more effectively over wide pH range for indole removal than GAC. Optimum dose and equilibrium time for GAC were found to be 20 g L−1 and 7 h, whereas, respective values for BFA were 7 g L−1 and 3 h. The adsorption equilibrium was well described by Redlich and Peterson isotherm. Kinetic data was best represented for pseudo-second order kinetic model. Indole adsorption onto GAC and BFA was found to be endothermic in nature. Values for entropy change and heat of adsorption for GAC were found as 101.30 kJ mol−1 K−1 and 12.42 kJ mol−1 whereas for BFA respective values were 198.88 kJ mol−1 K−1 and 32.22 kJ mol−1. © 2014 American Institute of Chemical Engineers Environ Prog, 34: 492–503, 2015