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) Ч 105 and (8 ± 3) Ч 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. © 2013 Pleiades Publishing, Ltd.