Preparation, characterization and adsorption studies of the chemically modified Luffa aegyptica peel as a potential adsorbent for the removal of malachite green from aqueous solution

摘要

In the present work, the proficiency of Luffa aegyptica peel (LAP) and NaOH modified Luffa aegyptica peel (NaOH/LAP) was explored for the adsorption of malachite green (MG) from aqueous solution. Prepared adsorbents were characterized by a number of techniques such as SEM, EDAX, BET, FTIR, TGA, proximate, component analyses and pH(pzc) (point of zero charge). The experiments were conducted by varying batch parameters such as contact time, pH, initial dye concentration and temperature. Adsorption equilibrium of MG removal was reached after 150 min and 60 min with an adsorption capacity of 70.21 mg g(-1) and 78.79 mg g(-1) for LAP and NaOH/LAP, respectively. The experimental data were examined in light of different isotherm and kinetic models. The isothermal and kinetics data for both the adsorbents were observed to be best represented by Langmuir adsorption isotherm and pseudo-second-order kinetics model. The thermodynamic study reveals that adsorption of MG on both the adsorbents has been found to be thermodynamically feasible, endothermic and accompanying with an enhancement in entropy. Adsorption-desorption cycle of the MG laden LAP and NaOH/LAP was effectively performed using HCl as an eluant The results suggest that NaOH/LAP could be used as an effective adsorbent than the LAP for the removal of MG from aqueous solution. (C) 2018 Elsevier B.V. All rights reserved.