l-Methionine modified Dowex-50 ion-exchanger of reduced size for the separation and removal of Cu(II) and Ni(II) from aqueous solution

Reduced size Dowex-50 (RDS-50) ion-exchanger was developed via a simple thermal treatment of commercial Dowex-50 in presence of l-methionine. Fourier transform infrared spectroscopy, scanning electron microscopy, energy dispersive X-ray spectroscopy and N2 adsorption/desorption isotherms studies were performed to confirm functional groups, surface morphology, BET surface area and pore size of RDS-50 ion-exchanger. RDS-50 ion-exchanger was applied for the removal of Ni(II) and Cu(II) from aqueous solution under different experimental conditions such as contact time, solution pH, initial metal ion concentration and temperature. The equilibrium adsorption data were analyzed in detail using Langmuir, Freundlich and Temkin models. Adsorption kinetic study was conducted to fit the pseudo-first-order, pseudo-second-order and the intra-particle diffusion models. The adsorption isotherm experiments revealed that adsorption of Ni(II) and Cu(II) from aqueous solution onto RDS-50 ion-exchanger was fitted for Langmuir model. The maximum adsorption of Ni(II) and Cu(II) onto the RDS-50 ion-exchanger from aqueous solution was found to be 83.33 and 71.43 mg g−1. The adsorption of Ni(II) and Cu(II) onto the RDS-50 ion-exchanger followed the pseudo second order kinetic model. The 87% Cu(II) and 93% Ni(II) were desorbed in 0.10 M HCl solution.

• l-Methionine functionalized reduced size Dowex-50 (RDS-50) has been prepared.
• RDS-50 had maximum sorption capacitates 83.3 and 71.4 mg g−1 for Ni(II) and Cu(II).
• Langmuir model and pseudo second order kinetics described the adsorption.
• The 93% and 87%, Ni(II) and Cu(II) were regenerated from used RDS-50.