Functional polysaccharide-based biosorbents as efficient green alternatives for radionuclide removal from radioactive waste: a review.

Radioactive waste presents persistent environmental and health challenges, creating an urgent need for remediation materials that are not only effective and selective but also sustainable. Conventional treatment methods often suffer from high cost, limited selectivity, and secondary waste generation, prompting growing interest in biopolymer-based alternatives. Polysaccharides including chitosan, alginate, cellulose, starch, carrageenan, and pectin have emerged as highly promising platforms for radioactive ion removal due to their natural abundance, biodegradability, and rich surface chemistry. Their functional groups (hydroxyl, amino, carboxyl, and sulfate) enable strong coordination with diverse radionuclides, including actinides, fission products, and activation products. This review critically examines the structure-property relationships governing radionuclide adsorption by polysaccharide-based materials, with particular attention to chemical modification strategies, including grafting, cross-linking, phosphorylation, and hybridization. These approaches significantly enhance adsorption capacity, selectivity, and stability, with reported Uranium(vi) uptake exceeding 600 mg g-1 for engineered systems. Advanced composites, including polysaccharide-polysaccharide hybrids and polysaccharide-based metal-organic frameworks, are highlighted for their potential in treating complex radioactive waste streams. Future perspectives focus on multifunctional material design, regeneration efficiency, and scalability to advance polysaccharide-based adsorbents toward practical nuclear waste management applications.