Nickel hexacyanoferrate multilayers on functionalized mesoporous silica supports for selective sorption and sensing of cesium

The preparation and characterization of a novel material, multilayers of nickel hexacyanoferrate immobilized on mesoporous propyl-ethylenediamine triacetate functionalized silica supports, and its uses as a cesium sorbent and a cesium sensing material is reported. The preparation of nickel hexacyanoferrate multilayers is based on multiple sequential adsorption of Ni2+ and Fe(CN)64-. This material was evaluated for selective removal of cesium ions in the presence of competing metal ions from water. Loading capacity of at least 2.25 mg (1.69 mmol) per gram of sorbent material has been achieved, making it potentially useful for the removal of cesium from nuclear wastes and contaminated groundwater. This material was also coated on a glassy carbon electrode for voltammetric sensing of cesium ions. The Nernst plot for the film has a linear range between 10−6 and 1 M and a slope of 31 mV/decade. The material was characterized through infrared spectroscopy, nitrogen adsorption, X-ray powder diffraction, cyclic voltammetry, and the Ni and Fe precursors and a reaction complex were modeled computationally by the PM3™ semiempirical method.