Removal of 137Cs on a Niigata Montmorillonite Clay by Column Technique
1964 Volume 13 Issue 6 Pages 455-461
Details
1964 Volume 13 Issue 6 Pages 455-461
Natural clay in rod of 1 mm dia. × 2-5 mm was prepared from a predominately Ca saturated montmorillonite (100%), which is a commercial bleaching earth from Omi, Niigata prefecture, with polyvinyl acetate (10%) as a binder. Portions of the natural clay in rod were converted to Na- and H-forms by treating with 1N solutions of the corresponding chloride. Through a column (2 cm dia.) of 20 g of natural, H-, or Na-clay in rod, the test solutions containing 137Cs 1.0×10-2 μc/ml were percolated at a flow rate of 10 ml/min at room temperatures. The cesium capacities of the three clay columns were measured by the effluent volume (ml/g of clay) at a specific activity ratio (C/ C0) of 0.05. Na-Clay column was incomparatively superior in cesium capacity to natural and H-clay columns, and the pH value of the feed most suitable for 137Cs removal on Na-clay was a range of 6 to 9, as was also indicated for 90Sr removal. Comparative effects of competing various rations on the cesium capacity of Na-clay column are in the order: K+ >Na+ >Ba2+ ( >Al3+ (pH 2.3) ) >Ca2+ >Sr2+ for neutral 1, 0×10-1N aqueous solutions of the corresponding chloride, because the effluent volume values at C/C0 of 0.05 for the above systems in the presence of these cation were found to be 30, 170, 440, 770 (pH 2. 2), 2, 400 and 3, 900 ml/g, respectively. Effects of increasing K, Na and Ca concentrations on the cesium capacity of Na-clay column can be expressed as the linear relations between the effluent volume in ml/g at C/C0 of 0.05, x, and log (the initial concentration of the corresponding chloride in N, y) :
log y=log (1.07×10-1) - (2.58×10-3) x, for 0.01-0.1N KCl, neutral;
log y=log (1. 06×10-1) - (1.48×10-4) x, for 0.05-0.1N NaCl, neutral;
log y=log 1.32- (4.66×10-4) x, for 0.1-0.5 N CaCl2, neutral.
