Novel Phytic Acid-Based Supramolecular Material for Uranium Removal from Highly Acidic Media: Synthesis, Performance, and Mechanistic Insights

The efficient adsorption and removal of U(VI) from nuclear wastewater is fetching growing interest due to its importance for the ecological environment and human health. In this study, we report a facile ionic self-assembly method to synthesize a phytic acid-based material denoted PE-x using phytic acid and ethylenediamine. PE-x was applied to remove U(VI) from a highly acidic aqueous solution with pH = 1.0. In batch adsorption experiments, PE-x showed fast removal kinetics for U(VI) with an equilibrium time around 10 min, excellent selectivity for An-Ln and U(VI) with a maximum selectivity of 97.8% and 76.2%, and a remarkable maximum adsorption capacity of 689.7 mg/g toward U(VI). Additionally, PE-x exhibited a considerable adsorption capacity of 282.6 mg/g in the fixed bed column test. The adsorption mechanism was investigated by using scanning electron microscopy (SEM), X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), and X-ray photoelectron spectroscopy (XPS). The results indicate a unique mechanism based on the reconstruction of the self-assembly framework involving U(VI) building blocks driven by positively charged species exchange. This study provides new insights and strategies for the design of enhanced uranium adsorbents under highly acidic conditions and extends the potential practical application of phytic acid for uranium capture from radioactive wastewater.