Equilibrium and kinetic studies of palladium(II) ions sorption onto Dowex resins

Palladium(II) sorption was studied in hydrochloric acid solutions with sodium chloride addition onto Dowex MSA-1 and Dowex MSA-2 resins by means of the static method. The dependence between the amount of palladium(II) ions sorbed at time tin a disequilibrium state (qt) as well as the sorption capacities (qe) and phases contact time were obtained. The results were applied in kinetic studies using the pseudo-fi rst (Lagergren equation) and pseudo-second order kinetic equations (linear form of Blanchard equation proposed by Ho, PSO). Moreover, the equilibrium studies were caried out at ambient temperature and fitted to the Langmuir and Freundlich isotherms. The AFM pictures of the surface of anion exchange resins before and after the loading process were also recorded. Both resins exhibit high selectivity towards palladium(II) ions. The sorption capacities are in the range 7–10 mg/g for both resins under discussion in all examined solutions. Th e pseudo-second order kinetic equation and the Langmuir isotherm show the best fit with the experimental data.