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

Traces of radionuclide residuals in ground water, with combined radiotoxicity and chemotoxicity, poses a tremendous threat to human health and the 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 17 CPFs into 34 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 CPF beads for deep purification of nuclear wastewater.