High-efficiently and rapidly capturing cesium from water with Prussian blue@expanded graphite as adsorbent

The removal of radioactive 137Cs from nuclear wastewater is still needed to mitigate their high radiological toxicity to living creatures. However, the industrial application of adsorbents is still challenging owing to the complex and costly preparation and slow adsorption rate for Cs wastewater with low concentration. Herein, cost-effective and fast removal of Cs+ is achieved by vermiform expanded graphite (EG) immobilized with potassium copper hexacyanoferrate (KCuHCF) via the in-situ synthesis method. We revealed that the nano-scale KCuHCF granules are dispersed homogeneously on the EG interlayers. With this design, it achieves an excellent Cs removal capacity of 16.24 mg/g within 30 min in ultralow Cs concentration and shows high selectivity among various competing ions. We systematically studied the associated adsorption mechanism by XPS and ICP, which revealed that ion exchange between the lattice K and Cs played critical roles. Our work paves the way for the design of economical adsorbents for radioactive Cs remediation.