ISM-S Sorbent: Properties and Tests in a Sorption Process for Treatment of Water from Accumulating Basin of the Mayak Production Association To Remove ~(90)Sr

摘要

ISM-S hydrated oxide sorbent, showing the most promise for strontium sorption, and its analog ISM-SP were studied under static and dynamic conditions. The optimal pH ranges for sorption (pH 6-10) and desorption (pH <1.2) of strontium, the total exchange capacities for strontium of various forms of the sorbent, and the dependences of the degree of strontium sorption on concentrations of supporting electrolytes were determined. The limiting stage of sorption, rate constants of ion exchange, diffusion coefficients, and calculated and experimental exchange half-times were determined in kinetic experiments. Based on these data, the optimal productive capacity of the ion-exchange apparatus was suggested: up to 30 and up to 25 column volumes per hour with ISM-SP and ISM-S, respectively. Rig trials of a sorption process for treatment of water from accumulating basin to remove ~(90)Sr were performed. The working installation included a mechanical filter and two series-connected sorption columns (h∶d=10∶1) packed with ISM-SP (V=3.5 l). In the course of the tests, more than 7 m~(3) of the surface layers of radioactively contaminated water with the initial ~(90)Sr activity of about 3.0×10~(-8) Ci l~(-1) and total hardness of 4.5-5.4 mg-equiv l~(-1) was treated, with the ~(90)Sr content being reduced to the level of 10UV~(water) according to NRB-99 (UV, interference level; NRB, radiation safety regulations valid in Russia).