Battery-type column for caesium ions separation using electroactive film of copper hexacyanoferrate nanoparticles

We reported a novel and compact battery-type column using nanoparticles film of copper hexacyanoferrate (CuHCF NPs film) for sequential removal of Cs from wastewater. Different from the electrochemical deposition, chemical spray or chemical bath deposition, our film was prepared by coating water dispersed CuHCF NPs ink on the electrode surface through a simple wet process similar to ink printing. The battery-type column indicated Cs adsorption and desorption can be achieved by electrochemical redox of CuHCF NPs film, through switching the potentials between two sandwiched electrodes. Kinetic studies revealed both the static attraction and electrochemical oxidation-reduction of Fe (II/III) contributed to Cs separation. Insignificant change in the current after 100 cycles of durability test indicated the CuHCF NPs film is relatively stable, suggesting the battery-type column has a long service life for Cs removal from wastewater.