Seaweed-derived bioadsorbent and composite materials for efficient aquatic pollutant removal

Accelerating anthropogenic activity has resulted in widespread exposure of aquatic ecosystems to hazardous pollutants, including heavy metals, synthetic dyes, and emerging pharmaceuticals, yielding severe ecotoxicological impacts ranging from oxidative stress to reproductive failure in aquatic biota. This review critically presents the toxicological nexus between these contaminants and aquatic health while evaluating the remediation efficacy of sustainable seaweed-derived materials. Unlike conventional energy intensive treatments, seaweed biosorbents utilizing functional polysaccharides like alginate, carrageenan, and ulvan offer a cost effective, renewable solution driven by mechanisms such as ion exchange and surface complexation. While raw biomass exhibits limitations related to mechanical stability, variable composition, and organic leaching, this article highlights the superior performance of engineered derivatives, particularly functionalized biochars, cross-linked hydrogels, and nanocomposites, which mitigate these drawbacks through enhanced porosity and stability. The distinct strength of this review lies in bridging the gap between ecotoxicological impact and sustainable material engineering, offering a comprehensive eco-friendly perspective often absent in singular adsorption studies. Conclusively, future research must transition from synthetic simulations to real world effluent testing and explore hybrid photocatalytic adsorptive systems to maximize regeneration potential, thereby establishing seaweed valorization as a cornerstone of the circular blue economy.