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.