Bifunctional lignin-based hydrogel membrane with enhanced structural stability for synergistic uranium uptake

Area of Science:

• Materials Science
• Environmental Science
• Nuclear Engineering

Background:

• Developing efficient biomass-based adsorbents for uranium removal is crucial for sustainable nuclear energy.
• Lignin, a renewable biomass, presents potential but requires modification for enhanced uranium adsorption.

Purpose of the Study:

• To construct a novel, stable, and highly efficient lignin-based adsorbent for uranium (U(VI)) removal.
• To investigate the synergistic effects and adsorption mechanisms of the modified lignin adsorbent.

Main Methods:

• A two-step modification strategy was used to phosphorylate lignin, creating a dual-functionalized adsorbent (DLP@PAO) with polyamidoxime.
• Characterization of the adsorbent's structure, including its porous honeycomb morphology and stability in acidic conditions.
• Experimental studies and density functional theory (DFT) calculations to determine U(VI) uptake capacity, selectivity, and adsorption mechanisms.

Main Results:

• The DLP@PAO adsorbent exhibited a high U(VI) uptake capacity of 701.02 mg g⁻¹ and excellent selectivity (Kd = 1.45 × 10⁵ mL g⁻¹).
• The adsorbent demonstrated robust structural stability and high U(VI) removal efficiency (>91.07%) in dynamic wastewater treatment simulations.
• DFT calculations and experimental data confirmed synergistic coordination between UO₂²⁺ ions and oxygen/nitrogen atoms as the primary uptake mechanism.

Conclusions:

• The developed DLP@PAO adsorbent offers a highly effective and selective solution for uranium removal from wastewater.
• This research highlights a new pathway for the value-added utilization of lignin in environmental remediation and nuclear energy applications.