Preparation of Acid‐Resistant Ammonium Molybdophosphate Spheres for Removal of Cs ⁺ From Analog High‐Level Liquid Wastewater

ABSTRACT The selective removal of radionuclide 137 Cs from high‐level liquid wastewater (HLLW) remains a big challenge due to its high radioactivity, high acidity, and complex constitution. Ammonium molybdophosphate (AMP) is considered to be an excellent adsorbent for efficient removal of Cs + from complex systems, but it is challenging to use in practical HLLW contexts due to its fine powder size. To solve the issue, a new AMP‐polytetrafluoroethylene (AMP‐PTFE) composite was prepared by loading AMP particles onto the surface of PTFE sphere and possessed a larger specific area, which favors to column separation in the practical process. Remarkably, this composite also exhibited the considerable stability and adsorption properties under high concentrations of HNO 3 , and the maximum adsorption capacity of Cs + onto AMP‐PTFE in 3 mol L −1 HNO 3 solution fitted by a Langmuir model is 53.42 mg g −1 , which was higher than that of similar adsorbents. In addition, kinetic studies indicated that Cs + adsorption on AMP‐PTFE was fast and reached adsorption equilibrium within 60 min in 3 mol L −1 of HNO 3 , and the adsorption data had a good fit to pseudo‐second‐order kinetics, which were attributed to the loading and dispersing of AMP on the surface of PFTE spheres, providing much more adsorption sites favorable to ion‐exchange between NH 4 + and Cs + . Notably, the adsorption performance of AMP‐PTFE hardly decreases after five cycles of adsorption–desorption. These results demonstrated that loading of AMP onto PTFE spheres was an effective way to promote AMP material application in a stronger acidic environment, and the prepared AMP‐PTFE material presented a promising potential for the removal of 137 Cs from the actual HLLW systems.