Removal of radionuclides and corrosion products from neutral and weakly alkaline solutions by microfiltration

Abstract

The use of microfiltration for removing from solutions Cs, Sr, Co, Zr, Ce, and Pu radionuclides and corrosion products, Fe(III) compounds, was studied. The microfiltration method is efficient for removing radionuclides of readily hydrolyzable elements (Co, Zr, Ce, Pu, etc.) from neutral or weakly alkaline solutions. In the presence of freshly precipitated iron(III) hydroxide, the decontamination efficiency is still higher, reaching 97–99%. High (99.5%) efficiency of the retention of the apparatus corrosion product, finely dispersed precipitate of iron(III) hydroxide, by a microfiltration membrane in treatment of lithium salt solutions was demonstrated. The microfiltration is inefficient in removal of ionic species of Cs and Sr radionuclides. For the removal of these radionuclides by microfiltration, the use of collectors capable of specific adsorption of these radionuclides was suggested, namely, the use of potassium nickel ferrocyanide precipitate for Cs radionuclides and of manganese dioxide and barium sulfate precipitates for Sr radionuclides. The efficiency of the removal of ¹³⁷Cs and ⁸⁵Sr radionuclides using specific collectors reaches 97–99%.