Speaker
Description
The sustainable management of nuclear power necessitates advanced technologies for the efficient recovery of uranium(Ⅵ) from highly acidic radioactive waste streams (e.g., 4 M HNO3), a challenge exacerbated by the extreme acidity, which degrades the stability and efficacy of conventional adsorbents. This study presents a comprehensive and progressive materials development campaign aimed at overcoming this challenge. Initially, an ordered mesoporous carbon (CMK-3) supported composite CMK-3/P(DMVP) was synthesized via in-situ polymerization. By leveraging CMK-3’s robust scaffold for mechanical stability and mass transfer, this composite established a baseline for U(Ⅵ) capture in strong acid. To decouple the roles of porosity and ligand chemistry, a non-porous yet highly functionalized organic polymer, P(VPA-TEGDMA), was subsequently prepared via solvothermal copolymerization. This material exhibited an unexpectedly high adsorption capacity, underscoring the paramount importance of phosphonic acid ligand density even in the absence of traditional pore pathways. Building on this insight, a strategic enhancement was achieved through compositional engineering by incorporating a second phosphonic acid ligand, dimethyl vinylphosphonate (DMVP), to create the P(VPA-TEGDMA-DMVP) copolymer series. This mixed-ligand strategy induced synergistic effects, optimizing the polymer’s affinity and selectivity for U(Ⅵ). To address the intrinsic kinetic limitations of dense polymer networks, the final stage of the study employed Pluronic F127 as a soft template. This resulted in the successful synthesis of porous polymers, denoted as P(VPA-TEGDMA-DMVP)-F127-x, which feature tailored mesoporous structures. The introduced porosity significantly accelerated uranium ion diffusion, enhancing adsorption kinetics while preserving the high capacity endowed by the optimized chemical composition. Collectively, this research delineates a logical trajectory from composite materials to compositionally and structurally optimized polymers, culminating in a novel class of acid-stable, high-capacity, and kinetically robust adsorbents tailored for uranium recovery from highly acidic nuclear waste streams.
Keywords: Phosphonic acid-functionalized; Uranium; Adsorption; Strongly acidic waste; Soft template.