Competitive adsorption characteristics of rhenium in single and binary (Re-Mo) systems using Purolite A170

In this study adsorption of rhenium ions from single and bi-component solutions (Re-Mo) by Purolite A170 was studied experimentally and described by isotherm, kinetic and thermodynamic modeling. Considering coefficient of determination (R2) and values of root mean squared error (RMSE) for the multicomponent isotherms, the extended model of Freundlich isotherm was found to be successful. Moreover, fitting the time-dependent data into different mechanisms showed that the data comply well with the pseudo-second order model. Results from the binary systems demonstrated that the presence of the secondary metal ions in the system causes a decrease in the adsorption capacity of rhenium, which is mainly due to the competitive effects of metals for adsorption sites. Furthermore, evaluation of thermodynamic parameters showed that the reaction mechanisms are different for both systems; however, due to negative values of ΔH, in competitive condition the adsorption of rhenium becomes more feasible with increasing the temperature.