Synergistic effects between phytic acid (PA) and urea on the extraction of uranium with porous polyvinyl alcohol (PVA) xerogel films

A novel porous xerogel of phytic acid (PA)-modified polyvinyl alcohol (PVA) was fabricated via a straightforward condensation reaction between PVA, urea, and PA. Besides serving as crosslinking agents, urea and PA also act as the pore forming agents and adsorptive functional groups of this xerogel, respectively. The decomposition and gasification of urea during synthesis formed an interconnected porous structure, dramatically raising the content of PA groups in the material as well as expose more adsorptive groups on its surface. This resultant structural characteristic allows the material to display outstanding adsorption capacity and rapid adsorption rate. Furthermore, the utilization of a compound crosslinker (urea/PA) can provide PVA with a sturdier crosslinking structure compared to the use of the two agents separately. As a result, the material shows excellent reusability, and its adsorption capacity can reach up to 89% of its initial adsorption capacity after five adsorption-desorption cycles. Density function theory (DFT) calculations demonstrated that there is a strong interaction between PA and uranium ions, conferring the material an impressive selectivity for uranium. This work could broaden in-sights into the tailored design and synthesis of polymer materials for the extraction of uranium.