Chemically modified Quercus dilatata plant leaves for Pb (II), Cd (II), and Cr (VI) ions remediation from aqueous solution

Abstract

Abstract The current investigation deals with the removal of Pb (II), Cd (II), and Cr (VI) ions by using chemically modified Quercus dilatata leaves (CMQDL) treated with nitric acid (HNO3), and calcium chloride (CaCl2). Batch biosorption experiments were performed to determine the optimal conditions of pH, biomass dose, temperature, contact time, and initial metal concentration for the utmost removal of heavy metals from water. The structural morphology and functionalities were explained by SEM and FTIR analysis. The maximum biosorption capacities for remediation of Pb (II), Cd (II), and Cr (VI) ions via CMQDL were 17.54, 20.408, 20.83 mg g−1, respectively at the optimal conditions. The Langmuir and Freundlich isotherm were applied to explore the equilibrium data however Freundlich isotherm model best evaluate the equilibrium data with high regression correlation coefficient (R2) values of 0.985, 0.826, and 0.919 for the elimination of Pb (II) Cd (II), and Cr (VI) ions, respectively. The kinetic study proposed that the remediation operation best obeyed the kinetic pseudo 2nd order model. The calculated thermodynamics functions like change in entropy (ΔS°), change in enthalpy (ΔH°) and Gibbs free energy (ΔG°) revealed that the removal of Pb (II) ions via the CMQDL was viable, exothermic and spontaneous, Cd (II) was endothermic and spontaneous and Cr (VI) was endothermic and non-spontaneous. The current study explored that CMQDL can be used for the remediation of Pb (II), Cd (II), and Cr (VI) ions, respectively.