Brown Sea Bean (Mucuna Sloanei) Shell, an Effective Adsorbent for Cationic Dye Removal

Brown sea bean (mucuna sloanei) shell has been used as an alternative adsorbent for removing cationic dye from aqueous medium. The effects of pH, initial dye concentration, temperature, and contact time were investigated using the batch technique. The result indicated that the adsorption was strongly dependent on the four factors. The FTIR analysis of the functional groups present on both the precursor and the activated carbon revealed that many peaks present on the precursor disappeared on the activated carbon while those remaining were weak. This is as a result of breakage of many bonds on the KOH impregnated precursor leading to the liberation of volatile species. The kinetic data were fitted to first order model, second order model and Boyd model. Dye uptake process followed the Boyd kinetic model more appropriately. The isotherm data were fitted to Langmuir and Freundlich isotherm models, the Freundlich isotherm best fitted the process. Thermodynamic parameters such as: Gibb’s free energy change (?G), standard enthalpy change (?H), standard entropy change (?S) calculated, indicated spontaneous and endothermic nature of the process.