Utilization of agricultural waste chestnut shell for the removal of Reactive Brilliant Red K-2G from aqueous solution

Abstract

Chestnut shell, an agricultural residue, was used as a low-cost adsorbent to remove Reactive Brilliant Red K-2G (RBR) from aqueous solution. Batch adsorption experiments were conducted to study the effects of initial solution pH value, adsorbent dosage, initial dye concentration and temperature on the adsorption. It was proved that strong acidic condition was favorable for the adsorption process and the optimal pH value was 1.0. Freundlich isotherm was appropriate for describing the experimental data. The kinetics study revealed that the adsorption of RBR onto chestnut shell followed the pseudo-second order model well. The external mass transfer mainly governed the adsorption rate. Thermodynamic studies demonstrated the spontaneous and exothermic natures of the adsorption process. The FTIR analysis indicated that functional groups such as amine, hydroxyl and phenolic compounds on the chestnut shell may be the active binding sites for the adsorption of RBR.