Removal of malachite green dye from aqueous solution with adsorption technique using Limonia acidissima (wood apple) shell as low cost adsorbent

Abstract

In the present study, the use of low-cost, abundantly available, highly efficient and eco-friendly adsorbent wood apple shell (WAS) has been reported as an alternative to the current expensive methods of removing of malachite green (MG) dye from aqueous solution. The effects of different variables, adsorbent dosage, initial dye concentration, pH, contact time, temperature etc. were investigated and optimal experimental conditions were ascertained. The Langmuir isotherm model has given a better conformity than the Freundlich model with 80.645 mg/g as maximum adsorption capacity at 299 K. The adsorption of MG on WAS was confirmed by FTIR, SEM study, as it showed the change in characterization before and after adsorption. It was found that the Lagergren’s model could be used for the prediction of the system’s kinetics, while intraparticle diffusion study and Boyd plot were used to furnish the mechanistic study. Thermodynamic study concluded the spontaneous and endothermic nature of the adsorption. Present investigation and comparison with other reported adsorbents concluded that, WAS may be applied as a low-cost attractive option for removal of MG from aqueous solution.

Keywords

• Wood apple shell
• Biosorption
• Adsorption isotherm
• Kinetic study
• FTIR study