Phytic acid-decorated porous organic polymer for uranium extraction under highly acidic conditions

Abstract

Although various kinds of adsorbents have good uranium adsorption capacity, they still meet the challenge in capturing uranium under highly acidic condition. Therefore, efficiently extracting uranium under strong acidic condition become the pursuit of researchers. In this study, a new phytic acid decorated porous organic polymers (POPs) named MA-U-PA was prepared by synthesizing a organic framework (MA-U) using melamine and uracil and with subsequent phytic acid modification. The results showed that the excellent stability of the prepared organic framework and strong uranium chelating ability of phytic acid endowed the as-prepared material being an excellent adsorbent under strong acidic condition. The adsorption capacity achieved 106.7 mg·g -1 at the pH of 1 which was much higher than that of MA-U and most of other adsorbents. The study of modification mechanism confirmed that the hydrogen bonds interaction of phytic acid with MA-U lead to the successful modification. In addition, the phosphonate groups of PA was mainly the active groups chelated with uranium. Moreover, the uranium adsorption process of MA-U-PA was in accordance with the pseudo-second-order kinetic and Langmuir isothermal model. The newly prepared phytic acid decorated porous organic material could achieve efficient uranium capturing from highly acidic nuclear wastewater. • The raw materials were melamine, uracil and phytic acid which were relatively green and nontoxic. • The organic framework made the adsorbent stable and phosphoric groups on the surface endowed the adsorbent capturing uranium efficiently under strong acidic conditions. • The uranium adsorption capacity of MA-U-PA attained to 106.7 mg·g -1 under pH of 1, higher than most of other adsorbents.