Langmuir, Freundlich Adsorption Isotherms and Kinetics for the Removal of Methylene Blue Dye from Aqueous Solution using Activated Carbon Derived from Pods of Acacia nilotica var astringens (Sunt tree) by Chemical Activation with ZnCl2

Abstract

Adsorption of Methylene Blue dye from aqueous solution onto Activated carbon derived from   Acacia nilotica (Sunt tree) by chemical activation with ZnCl2, (SUNT-C2) has been studied using batch-adsorption techniques. This study was carried out to examine the adsorption capacity of the low-cost adsorbent (SUNT-C2) for the removal of Methylene Blue dye from aqueous solution. The influence of pH, initial dye concentration, adsorbent particle size, adsorbent dose and contact time on the adsorption process were also studied. Results revealed that adsorption rate initially increased rapidly, and the optimal removal efficiency was reached within about 100 mins. Further increase in contact time did not show significant change in equilibrium concentration; that is, the adsorption phase reached equilibrium. The adsorption isotherms could be fitted well by the Langmuir and Freundlich models. Also the adsorption process followed pseudo first order rate kinetics. Results indicate that, a new, environment friendly, freely abundant, locally available, lw-cost adsorbent, (SUNT-C2) was an attractive candidate for the removal of cationic dyes from dye wastewater.

Keywords: Adsorption, Acacia nilotica, (SUNT-C2) activated carbon, Methylene Blue dye, pseudo first order rate kinetics, FTIR.