Facile structuring of crystalline porous framework beads for deep purification of nuclear wastewater

Abstract Trace of radionuclide residual in ground water poses tremendous threats with combined radiotoxicity and chemotoxicity to human health and environment. Crystalline porous frameworks (CPFs), including metal-organic frameworks (MOFs), covalent organic frameworks (COFs), and hydrogen-bonded organic frameworks (HOFs), have demonstrated considerable promise as efficient adsorbents for deep purification processes. However, their microcrystalline nature often limits their practicality for industrial-scale applications. In this study, we present a facile and scalable structuring strategy to shape seventeen CPFs into thirty-four hydrophilic and hydrophobic microbead composites using poly(acrylic acid) (PAA)-sodium alginate and polyether sulfone (PES) as co-polymers, respectively. To validate the effectiveness of this approach, the beads were employed for the sequestration of ReO4− (a nonradioactive surrogate of 99TcO4−) from contaminated tap water and simulated Hanford low activity waste (LAW). Notably, they achieved one of the highest levels of purification in treating pre-treated LAW streams, allowing purification of drinking water to nearly 5000 times their own weight under continuous flow conditions. The purified water contained only 0.026 ppb of Tc (calculated from Re), meeting both WHO (0.159 ppb) and U.S. EPA (0.053 ppb) drinking water standards. Furthermore, the beads can be conveniently and rapidly regenerated through cycling. This study provides a universal structuring strategy of CPFs beads for deep purification of nuclear wastewater.