Molecularly cooperative bifunctional polymers enable speciation resilient uranium removal in continuous flow wastewater systems

Abstract

Uranium contamination of water is a persistent environmental challenge, constrained by its complex speciation across cationic and anionic forms and regulated at <30 µg L⁻¹ (IAEA/ICRP). Conventional treatments struggle under high flow and often rely on mixed bed ion-exchange resins, which suffer from poor regenerability, phase separation, and high chemical demand. Here, we introduce BA-PPSD, a bifunctional polymeric resin designed to overcome these limitations through molecular-level integration of amidoxime (cation-exchange) and pyridinium (anion-exchange) groups via a tailored carbon spacer. Guided by theoretical modeling, this cooperative architecture enables rapid and selective uranium capture across diverse aqueous matrices, achieving high capacities of 81.4, 45.8, and 37.4 mg g⁻¹ in nitrate, sulfate, and carbonate media, respectively, with >90% uptake in under five minutes. In continuous-flow columns, BA-PPSD reduces uranium from ∼2500 µg L⁻¹ to below potable limits (<30 µg L⁻¹) at 50 BV h⁻¹ while retaining performance over multiple regenerations. This new concept of molecularly guided cooperation establishes a scalable, versatile platform for tackling other challenging contaminants having diverse speciation, providing a blueprint for the rational design of next-generation water purification materials.