Phosphorus-functionalized Porphyra toward uranium removal from water

The high-value utilization of marine biomass has garnered significant attention in recent years, particularly the application of biomass-based adsorbents in water environment remediation. In this study, we innovatively combined ball-milling treatment with phosphorylation modification to construct a phosphorus-functionalized Porphyra (P-Porphyra) adsorbent, which can be applied for uranium adsorption from water. Systematic characterization and batch adsorption experiments revealed that P-Porphyra exhibited optimal uranium adsorption at pH 4.0, with the adsorption process fitted the pseudo-second-order kinetic model and Langmuir isotherm well. Under optimal conditions, the maximum adsorption capacity reached 262.76 mg·g⁻¹, almost unaffected by common ions in natural waterbody. Fourier-transform infrared (FTIR) spectroscopy and X-ray photoelectron spectroscopy (XPS) analyses demonstrated that the adsorption mechanism primarily relied on the complexation between phosphate groups and uranium ions, enabling efficient uranium enrichment. P-Prophyra exhibited the fast uranium adsorption in the real seawater, and the adsorption capacity reached to be 0.90 mg·g⁻¹. This work proposes a green, low-cost, and scalable strategy for converting Porphyra into phosphorylated biomass materials towards uranium enrichment from water, also offering significant potential for sustainable marine resource utilization.