Thick Hydrogel Membrane With Macro‐Channel for Rapid Uranium Extraction From Seawater

Abstract The growing demand for uranium driven by nuclear power development necessitates the creation of macroscale, cost‐effective, and efficient adsorbents for uranium extraction from seawater, a challenge yet to be fully addressed. Amidoxime‐based hydrogel adsorbents are promising candidates but suffer from performance limitations due to bound water obstructing pore channels and impeding uranyl ion migration. Herein, a thick macro‐channel poly(amidoxime)‐polyvinyl alcohol hydrogel membrane (MCHM) with a double cross‐linking structure is introduced, designed to enhance uranium adsorption. Unlike traditional powders and microfibers, the macroscale thick membrane facilitates deployment and recovery in marine environments, while its directional channel structure improves mass transfer properties and accessibility to amidoxime groups. Using COMSOL Multiphysics, design parameters such as channel size, membrane thickness, and arrangement are optimized, significantly enhancing performance while reducing costs. In natural seawater, the optimized MCHM with 2.0 mm channels, 20 times thicker than ultra‐thin hydrogel membranes demonstrated improvements of 99% in adsorption capacity and 179% in adsorption rate compared to non‐channel counterparts. This method uniquely combines material innovation with computational modeling, providing valuable insights into how the internal channel structure of adsorbents influences their performance. The findings provide a scalable design solution for hydrogel adsorbents, enabling sustainable uranium extraction from seawater.