Influence of the concentrations of potassium, sodium, and ammonium ions on the cesium sorption with mixed nickel potassium ferrocyanide sorbent based on hydrated titanium dioxide

Abstract

The effect of single-charged cations (Na+, K+, NH +4 ) on the cesium sorption with mixed nickel potassium ferrocyanide sorbent based on hydrated TiO2 was studied. The K+ and Na+ ions exert no effect at their concentrations of up to 0.5 M; the Cs+ distribution coefficients from KCl and NaCl solutions are (1.1 ± 0.5) × 105 and (8 ± 3) × 104 mL g−1, respectively. The sorbent is highly specific to Cs+ in the presence of ammonium ions. The sorption mechanisms were studied. The concentration ranges in which Cs+ and NH +4 are sorbed by independent mechanisms (Cs+, by the ferrocyanide phase; NH +4 , by the phase of hydrated TiO2) and in which the Cs+ distribution coefficient decreases owing to competitive filling of the ferrocyanide phase with ammonium ions were determined. At cesium concentrations in solution exceeding 50 mg L−1, Cs+ and NH +4 are absorbed jointly owing to coprecipitation in the mixed ferrocyanide phase in the pore space of the sorbent.