Abstract: Nickel hexacyanoferrate (NiHCF) films were synthesized on porous three-dimensional carbon felt (PTCF) substrates by repetitious batch chemical deposition, and the NiHCF/PTCF was investigated as electrochemically switched ion exchange (ESIX) electrode of packed bed for continuous cesium ion separation. Scanning electron microscopy (SEM) and cyclic voltammetry (CV) technique were used to characterize the prepared electrodes. CV investigation confirmed the effects of solution concentration on the ion-exchange capacity of NiHCF/PTCF electrodes. The cycling stability and long-term storage stability of NiHCF/PTCF electrodes were also studied. Ion exchange ability of NiHCF/PTCF electrodes was used to assemble a diaphragm-isolated ESIX reactor for cesium separation. The continuous operation of cesium separation and regeneration process of NiHCF/PTCF electrodes based on the diaphragm-isolated reactor was tested in a two-electrode system of laboratory scale. This is of particular interest from an industrial point of views for scaling up to meet requirements for practical application.