Investigation of the cationic resin Am®IRC-50 as a potential adsorbent of Co (II): Equilibrium isotherms and thermodynamic studies

Abstract

In this work, we study the removal of metal ions among of Co (II) by adsorption on the resin Am®IRC-50 artificial biopolymer. The characterization of the adsorbent was exploited out by X-ray diffraction, EDX and SEM. The influence of the physicochemical parameters on the adsorption capacity of the cationic resin for Co (II) ions, namely the dose of adsorbent, the contact time, the initial pH imposed on the aqueous solution and the concentration of the cobalt solution was studied. Experiments have shown that the adsorption at a mass greater than 1 g and 100% is obtained, which shows the total exhaustion of the solution. Equilibrium is reached after 120 min for the cationic resin. The pH of the aqueous phase, optimal for this adsorption is 5.5, increasing the temperature of the aqueous phase-adsorbate mixture from 25 to55 °C decreases the extraction yield and the sorption capacity. On the other hand, kinetic measurements exploited the pseudo 1St order model, the pseudo 2 Sec order and Elovich model's explained that the process is fast following the pseudo 2 Sec order model. Adsorption equilibrium studies, using several isothermal models such as Freundlich, Langmuir and Temkin, have seeing that the adsorption of cobalt Co (II) ions by cationic resin to the Langmuir model (R 2 = 0.9999). Finally, various thermodynamic technics indicate as well ΔG° (−1. 34 at −6.90 kJ. mol −1 ), ΔH° (52. 80 kJ. mol −1 ) and ΔS° (182 J.mol −1 k −1 ) that the adsorption is impetuous and endothermic.