Removal of reactive dye (BEZAKTIV Red S-MAX) from aqueous solution by adsorption onto activated carbons prepared from date palm rachis and jujube stones

Abstract

In this study, activated carbons were prepared from date palm rachis (RPK) and jujube stones (NJK), by-product agricultural wastes which have been tested for the elimination of reactive dye BEZAKTIV Red S-MAX (BRSM) from aqueous solutions by batch adsorption method. Both activated carbons were prepared using chemical activation by KOH as an impregnating agent (rate of KOH/biomass (w/w) of 0.74) at 800°C in the presence of inert gas (N2). RPK and NJK were characterized using BET, SEM, FTIR and Boehm titration mass. The results show that RPK possess the higher specific surface area (1160m2/g). The effect of contact time, solution temperature and solution pH on the adsorption of BRSM dye were also studied. The experimental data were analysed using Langmuir, Freundlich and Temkin isotherm models. The equilibrium data fitted well with the Langmuir isotherm model, and the adsorption capacities were calculated to be 128.21 and 28.49mg/g using RPK and NJK, respectively. The kinetic data were fitted to pseudo-first order, pseudo-second order, elovich and intra-particle diffusion model. Thermodynamic parameters such as ∆G°, ∆H° and ∆S° were also estimated for the adsorption study and they were found to be spontaneous and endothermic processes. Desorption and regeneration study was made to test the viability of reusing the adsorbents. Lastly, it was found that RPK is efficient in dyes removal from real wastewater.