Chemically and physically dual Cross-Linked phosphorylated cellulose hydrogel for uranium removal from aqueous solution

Abstract

Cellulose-based hydrogel materials have emerged as a highly promising candidate for the adsorption and removal of uranium from aqueous solutions. However, the subpar mechanical properties of cellulose hydrogels pose a significant obstacle to their practical implementation. In this study, a radiation-induced graft polymerization (RIGP) technique is employed to fabricate the hydrogel matrix, and subsequently, a phosphorylated modified cellulose-based hydrogel (PTCH) uranium adsorbent is synthesized through a one-step phytic acid modification process. Micro-Raman imaging is utilized to meticulously characterize and analyze the distribution and density of cross-linking domains within the hydrogel network. The findings reveal that the modified PTCH boasted both a loose chemical cross-linking network and a compact physical cross-linking network formed by hydrogen bond reconstruction, leading to a remarkable enhancement in its mechanical properties. It exhibits a compressive strength of up to 0.13 MPa and a strain of 49.20 %. Concurrently, the U(VI) adsorption performance of the hydrogel is investigated. The synergistic complexation effect of phosphate and carboxyl groups on U(VI) substantially augment the adsorption capacity of the hydrogel, with a theoretical maximum adsorption capacity for U(VI) reaching 449.5 mg·g⁻¹. In summary, PTCH effectively overcomes the limitations of traditional cellulose-based adsorbent materials, presenting a novel avenue for the development of cost-effective and efficient uranium adsorbents.