Sorbents Based on Ni(OH)2/chitosan, Immobilization of Metal Hexacyanoferrates, and Application for Removal of Radionuclide Cs from Aqueous Solutions

In the present work, in-situ formed nickel(II) hydroxide particles have been immobilized in a chitosan matrix with subsequent introduction of potassium hexacyanoferrate into this hybrid material, which has resulted in the formation of advanced composite sorbents for 137Cs removal. The immobilization of microcrystalline nickel(II) hydroxide particles has been carried out via homogeneous alkalization of nickel(II) chloride solutions by urea hydrolysis. Intercalation of the Fe(CN)64− ion into nickel hydroxide has been performed at the stage of formation of nickel hydroxide in the chitosan gel. In the process of anion exchange sorption of Fe(CN)64− ions with nickel hydroxide, a composite sorbent Ni(OH)2–CS–KNiFe(CN)6 has been formed. According to X-ray diffraction analysis, the composite sorbent also contains α-Ni(OH)2. Both types of sorbents can be used to remove cesium from wastewaters.