Methyl acrylate modified apple pomace as promising adsorbent for the removal of divalent metal ion from industrial wastewater.

Polymerized apple pomace (PoAP) surface was evaluated as adsorbent for the removal of Pb+2, Cd+2, and Ni+2 ions from aqueous solution. PoAP was characterized by FTIR, SEM, EDS, XRD, and BET surface area analyzer. Furthermore, the adsorption influencing parameters such as dose, pH, time, concentration, and temperature were optimized for maximum removal of metal ions from aqueous solution. The maximum monolayer adsorption capacity of PoAP was found to be 106, 34.12, and 19.45 mg g-1, for Pb+2, Cd+2, and Ni+2 ions respectively, using the Langmuir isotherm model. The rate of adsorption was evaluated using pseudo-second order kinetics and intra-particle diffusion. The adsorption data followed pseudo-second order kinetic with the correlation coefficient (r 2) from 0.99-1 at all concentration. Thermodynamic study revealed endothermic nature of Pb+2 and Cd+2 adsorption and exothermic for Ni+2 ions. The rate of adsorption for binary and tertiary mixtures of Pb+2, Ni+2, and Cd+2 metal ion was studied using the ideal adsorbed solution theory. The regeneration study revealed that PoAP could be re-utilized up to 4 cycles for Pb+2 and 2 cycles for Cd+2 and Ni+2 ions. PoAP was successfully applied to real industrial wastewater for the removal of Pb+2, Cd+2, and Ni+2 ions.