Studying the kinetics of 137Cs selective sorption by the dynamic method with the measurement of radioactivity in the sorbent solid phase

Abstract The dynamic method was proposed for studying the kinetics of 137Cs selective sorption by the measurement of the 137Cs activity directly in the sorbent solid phase. A thin layer of the sorbent in a disposable syringe membrane filter (MF) was eluted with a 137Cs solution containing $ K^{+} $...
Ausführliche Beschreibung

Abstract The dynamic method was proposed for studying the kinetics of 137Cs selective sorption by the measurement of the 137Cs activity directly in the sorbent solid phase. A thin layer of the sorbent in a disposable syringe membrane filter (MF) was eluted with a 137Cs solution containing $ K^{+} $ and $ Ca^{2+} $ ions with a gradual decrease in the solution flow rate from 6 to 0.2 $ cm^{3} $/min. The activity of the sorbed 137Cs was determined periodically by placing the same MF in the detector well of a Wizard 1480 gamma counter. It was shown that the masses of the sorbent and water in the MF had no effect on the efficiency of the 137Cs measurement. A linear relationship between the RIP(K) value and the square root of the time for the period between 4 and 30 days was revealed using this method. The relative increase in the RIP(K) with time changed by 6 times (from 0.034 to 0.208 $ days^{−0.5} $) for the soils and by 20 times (from 0.008 to 0.153 $ days^{−0.5} $) for the mineral sorbents. The RIP(K) values measured for the interaction of soddy-podzolic soils with 137Cs during 24 hours using the standard limited volume method were lower than the values determined by the proposed dynamic method for the interaction period of 30 days by 50–100%. Ausführliche Beschreibung