Equilibrium Studies of Sorption of Strontium Ions by Different Pectin Compounds

Strontium binding activity of different water soluble pectin compounds varying according to their degree of esterification and insoluble calcium pectate beads in aqueous solution was studied in a batch sorption system. The strontium uptake by all pectin compounds was highest within the pH range from 4.0 to 6.0. The binding capacities and rates of strontium ions by pectin compounds were evaluated. The Langmuir, Freundlich and BET sorption models were applied to describe the isotherms and constants. Sorption isothermal data could be well interpreted by the Langmuir and Freundlich equations. The results obtained through the study suggest that pectin compounds are favorable sorbents. The largest amount of strontium ions is bound by pectin with the degree of esterification lower 20%. Therefore, it can be concluded that low esterified pectins are more effective substances for elimination of strontium ions from nuclear disposals.