Revista de ciencia de la energía nuclear y tecnología de generación de energía

Selective Removal of Cs⁺ and Sr²⁺ in Seawater by Novel Zeolite Honeycomb Modeling

Md. Shakilur Rahman, Hitoshi Mimura, Minoru Matsukura and Fatema Binte Amin

The sorption removal of cesium and strontium ions from chemically synthesized fibrous mordenite (M) and zeolite type ‘A’ in the form of honeycomb in seawater consisting of competing cations Na⁺, Mg²⁺, Ca²⁺, and K⁺ have been investigated. The batch experiments were carried out for the effect of various parameters such as initial contact time, uptake with volume mass ratio, distribution coefficients (K_d) factor, and effect on temperature. The uptake (%) of Cs⁺ ions for mordenite honeycomb at V/m=100 cm³/g was measured to be 86.8% and 57.9% within 18 h in pure water and 15 h in seawater media, respectively. On the other hand, the uptake (%) of Sr²⁺ ions for type ‘A’ zeolite honeycomb was 99.2% within 24 h and 69.0% within 3 h in pure water and seawater media, respectively. The adsorption of Cs⁺ and Sr²⁺ by compact column on mordenite and type ‘A’ zeolite honeycomb at a flow rate of 1 cm³/min, and 3 cm³/ min were observed and found increasing with circulating time and flow rate that reaches maximum 64.5%, and 70.3% for Cs and 52.7% and 71.2% for Sr after 7 d, respectively. The adsorption increases with increasing flow rate indicates that the overall kinetics was dominated by external mass transfer with time of the sorption process in the column which is a favorable indicator. A mathematical relationship of adsorption with respect to time and mass volume ratio has been established. The solidification of zeolite shows an excellent immobilization of less than 1% at 1200ºC for both the zeolite has been obtained.