Fabrication of novel pectin-based adsorbents for extraction of uranium from simulated seawater: Synthesis, performance and mechanistic insight

Efficient extraction of uranium from seawater is of great significance to the stable development of nuclear energy. The graft modification of pectin is expected to realize the efficient extraction of uranium through the dual action of aminoxime and carboxyl groups. In this work, novel biomimetic pectin adsorbents were developed and their performance on the adsorption performance of uranium from seawater was investigated. The physical structure and morphology were characterized by employing FT-IR, BET, SEM and elemental analysis. The skeleton structure and surface functional groups of the pectin-derived adsorbents, which were modified to improve the adsorption selectivity, favored the adsorption of uranium in simulated seawater. The modified apple pectin (MPA) adsorbents exhibited the highest adsorption capacity of 212.27 mg/g at optimal conditions. The thermodynamic results showed that the adsorption of uranium on MPA surface followed the Langmuir single-layer model, and the theoretical maximum adsorption capacity could reach up to 296.25 mg/g. The adsorption process conformed to the pseudo-second-order model. Furthermore, the synergistic mechanism between aminoxime and carboxyl groups of the pectin-based adsorbents was proposed. In conclusion, this work provides a new bio-based adsorbent with high efficiency for uranium extraction from concentrated seawater.