Thermodynamics and Mechanism Studies on Electrochemical Removal of Cesium Ions from Aqueous Solution Using a Nanoparticle Film of Copper Hexacyanoferrate

Abstract

Nanoparticle (NPs) film of copper hexacyanoferrate (CuHCF(III)) was developed for electrochemically cesium separation from wastewater. Different form the electro- or chemical deposited films, CuHCF(III) NPs were firstly covered with ferrocyanide anions, so that they can be well dispersed in water and formed ink. Then CuHCF(III) NPs can be uniformly coated by simple wet printing methods, so it is feasible to prepare NPs film of any sizes, or any patterns at low cost. This process provided a promising technology for preparing large scale electrodes for sequential removal of Cs from wastewater in the columns. Cs separation can be controlled by an electrically switched ion exchange (ESIX) system. Effect of temperatures, and ionic strength on Cs removal was investigated. Thermodynamics results showed that Cs adsorption process was exothermic in nature and favored at low temperature. Ionic strength study indicated the CuHCF(III) film can selectively separate Cs in wide ionic strength range from 1 × 10(-4) to 1 × 10(-1) M Na(+). XPS results demonstrated that the electrochemical oxidation-reduction of Fe (II/III) made contributions to Cs separation.

Solvent-assisted synthesis of potassium copper hexacyanoferrate embedded 3D-interconnected porous hydrogel for highly selective and rapid cesium ion removal

“…which are often present in contaminated effluents [1,4,5,[16][17][18]. Since metal HCF has a well-known perovskite-like face-centered cubic crystal structure, with a channel diameter of around 3.2 Å, small hydrated cations such as Cs + can be inserted, whereas the larger hydrated ions such as Na + are selectively rejected [4,19].…”

“…Since metal HCF has a well-known perovskite-like face-centered cubic crystal structure, with a channel diameter of around 3.2 Å, small hydrated cations such as Cs + can be inserted, whereas the larger hydrated ions such as Na + are selectively rejected [4,19]. Particularly, copper hexacyanoferrate has been widely used due to its simple preparation, low cost, superior Cs + capture properties, and chemical stability over a wide pH range [3,17,18,20].…”

“…1(a)). Immobilization of Cu in the polymer hydrogel matrix was performed, followed by the acetone-assisted evaporative diffusion of K 4 [Fe(CN) 6 ] into the preformed film structure to induce the formation of KCuHCF in the matrix. Therefore, the hydrogel film structure was entirely maintained and KCuHCF nanoparticles were well dispersed in the 3D-interconnected network.…”

“…Next, both acetone-treatment and heat-treatment were used according to the conditions presented in Table 1. Acetone was used as a non-solvent to restrict the reverse diffusion of deposited Cu from the CPC polymer matrix, and heat-treatment was applied to drive the fast diffusion of K 4 [Fe(CN) 6 ] into the CPC structure.…”

“…Among all the radioactive elements, gamma ray emitters 134 Cs and 137 Cs are the richest and the most hazardous nuclear fission products of uranium [4][5][6]. Both isotopes are considerably harmful to humans and can easily destroy the environmental habitat since they can quickly migrate through ground and sea waters, accumulating in the biosphere for hundreds of years [5].…”