Cesium removal in freshwater using potassium cobalt hexacyanoferrate-impregnated fibers

•Dimethylaminoethyl methacrylate was grafted onto a 6-nylon fiber.•Potassium cobalt hexacyanoferrate compounds were precipitated onto the grafted fibers.•With increasing KCl concentration, the rate of cesium removal from cesium chloride solution increased.•To achieve the practical use, we established the manufacturing equipment on a scale of 100 kg.

Potassium cobalt hexacyanoferrate compounds (KCo-HCFe's) were impregnated onto a 6-nylon fiber by radiation-induced graft polymerization and subsequent chemical modifications. First, dimethylaminoethyl methacrylate was graft-polymerized onto the nylon fiber. Second, hexacyanoferrate ions were bound to graft chains via an anion-exchange interaction. Third, KCo-HCFe's were formed on the nylon fiber via the precipitation reaction of hexacyanoferrate ions with cobalt ions in the presence of potassium chloride. The resulting KCo-HCFe-impregnated fiber had an impregnation percentage of the fiber for KCo-HCFe's of 7%. The cesium concentration in 10 ppm cesium chloride solution with the immersion of this fiber decreased to 0.6 ppm within 60 min at a ratio of liquid volume (10 mL) to fiber mass (0.1 g). The fiber was fabricated into a braid with a length of 100 cm and a diameter of 8 cm for practical use at sites contaminated with cesium.