Spider-web-inspired phosphorylated aerogel engineered via Schiff base linkages for efficient uranium capture

With the increasing global utilization of nuclear energy, the accumulation of uranium-containing wastewater has become a critical environmental concern, which has consequently led to significant attention being attracted to the development of high-performance adsorbents for efficient uranium separation. Herein, a phosphorylated biosorbent, P-gelatin/G2.0, was developed by integrating phosphorylated polyamidoamine (PAMAM) dendrimers (G2.0) with eco‑friendly gelatin via a spider‑web‑inspired strategy that mimics the hierarchical web architecture of spider webs, coupled with Schiff base crosslinking, yielding effective uranium capture from aqueous media. The biosorbent exhibited exceptional uranium adsorption performance, reaching a maximum capacity of 1103.20 mg·g^-1 at pH 6.0, as evidenced by the Langmuir isotherm and pseudo-second-order kinetics. Thermodynamic investigations indicated a spontaneous adsorption mechanism. XPS spectra revealed that phosphate groups played a dominant role in U(VI) coordination, synergistically interacting with amino and hydroxyl groups. The P-gelatin/G2.0 biosorbent demonstrated outstanding selectivity in multi-ion systems and maintains 84.94% adsorption efficiency after five regeneration cycles, revealing its robust reusability. The DFT study confirms that the phosphorylation introduces phosphate groups which dominate the uranyl ion coordination, thereby elucidating the fundamental adsorption mechanism. This study displays the potential of P-gelatin/G2.0 as a sustainable, high-capacity material for uranium recovery in nuclear wastewater treatment and environmental remediation applications.