Sustainable removal of Pb (II) from aqueous medium by using chitosan functionalized <i>Citrus limetta</i> peels biomass
Veer Singh, Jyoti Singh, Nidhi Singh, Manoj Verma, Sarva Mangala Praveena, Vishal Mishra
Abstract
In this investigation, chitosan functionalized Citrus limetta peel biomass (ChCLP) was synthesized for adsorption of Pb (II). Results of energy dispersive X-ray (EDX) and X-ray photoelectron spectroscopic (XPS) confirmed the chitosan coating and adsorption of Pb (II). Functional groups like -NH2, C-H and -OH groups were present on the ChCLP surface. The surface of ChCLP was observed to be rough and porous. Langmuir isotherm was best fitted in the adsorption data. This indicated toward the monolayer adsorption of Pb (II) onto the homogeneous surface of the adsorbent. The suitability of pseudo-second order (PSO) kinetic model indicated chemisorption of Pb (II) onto ChCLP. Thermodynamic study revealed endothermic and spontaneous Pb (II) adsorption. Values of the diffusion coefficient and dimensionless numbers indicated that Pb (II) adsorption was mix diffusion and transfer controlled. It was found that both the experimental and predicted values for ChCLP was close to each other showing a high R2 value in the range of 0.94 − 0.98. Results showed that ChCLP has high Pb (II) removal capacity (99.8%) at 100 mg/L and 10 g/L ChCLP dosage. ChCLP adsorbent showed a high regeneration capacity in five consecutive adsorption-desorption cycles.