Uranium contamination in water remains a pressing global challenge, driven by nuclear energy production, mining activities, and legacy waste from nuclear development. In aquatic environments, uranium predominantly exists as hexavalent uranium, U(VI), a form that is highly soluble, highly toxic and easy migration. Uranium presents serious threats to ecosystems and human health, driving the need for more effective and sustainable remediation technologies.

Among current approaches, photocatalytic reduction has emerged as a promising strategy because it can transform U(VI) into tetravalent uranium, U(IV) with low toxicity and fluidity. Graphitic Carbon Nitrides (CNs) with high molecular properties have been applied as the substrate of various inorganic nanoparticles, organic molecules and functional species for U(VI) photoduction due to their flexible polymer structure. Beyond efficiency alone, the use of sorbents and photocatalysts in powder form commonly produces water-adsorbed residues following treatment. Recovering these fine particles from solution is often costly and technically challenging, creating a major barrier to large-scale and industrial application.

This study introduces a multifunctional membrane designed to meet these demands. The researchers developed phosphorus-modified graphitic carbon nitride nanosheets (PCNNs) and integrated them into cellulose nanofiber membranes (CL/PCNNs) using an electrospinning technique. The purpose of this work was to create a scalable material that could selectively capture U(VI), efficiently drive its photoreduction under visible light, and be reused multiple times without significant performance loss.

Performance testing revealed that the composite membranes rapidly adsorb U(VI), reaching equilibrium within five hours and achieving high uptake capacities (153.8–243.3 mg/g) compared to many existing sorbents. In term of selectivity, the membranes preferentially bind U(VI) over a wide range of competing metal ions, including those commonly found in seawater and simulated nuclear wastewater. This selectivity is due to the strong chemical coordination between uranium ions and the phosphate groups on the membrane surface. Moreover, CL/PCNNS membranes showed an enhanced photoreduction rate of U(VI) (0.018–0.078 min^{− 1}). After six cycles of sorption and photoreduction, the membranes retain 82% of its performance, highlighting their durability and potential for long-term application.

In summary, integration of selective adsorption, efficient photocatalytic reduction, and membrane-based architecture in a single system has overcomes key barriers that have limited the practical use of photocatalysts for uranium remediation. This membrane strategy offers a promising pathway toward safer and more sustainable treatment of uranium-contaminated water.

Source:

Xuan Du, Suraya Abdul Rashid, Luqman Chuah Abdullah, Norizah Abdul Rahman, Bin Li, Phosphorous graphitic carbon nitride nanosheets integrated cellulose nanofiber membranes via electrospinning for efficiently selective sorption and photoreduction of U(VI), Journal of Environmental Chemical Engineering, Volume 13, Issue 3, 2025, 116213

https://doi.org/10.1016/j.jece.2025.116213

Date of Input: 08/01/2026 | Updated: 08/01/2026 | roslina_ar