Sodium Alginate-Based Functional Materials toward Sustainable Applications: Water Treatment and Energy Storage

Most synthetic materials used in water treatment andenergy storageare nonbiodegradable and nonrenewable, causing the generation of massiveelectronic wastes and discarded separation materials. Sodium alginate(SA) has the features of abundant sources, low cost, renewability,and biodegradability. To achieve sustainable development and minimizeenvironmental impact, SA is well designed into high-performance hydrogels,aerogels/foams, films, and binders used in water treatment and energystorage components via low-energy, low-toxicity, and low-cost ways.This review summarizes the preparation methods of SA composites andhighlights the advantages of composites applied in water treatmentand energy storage. In water treatment, challenges and solutions tothe separation, regeneration, and waste disposal process of SA compositesare introduced, aiming to simplify the separation process, reducesecondary pollutants, and achieve high-value utilization of waste.Conventional and nonbiodegradable components in energy storage materialswere replaced with renewable SA to improve electrochemical performances,decrease manufacturing costs, and reduce the generation of solid-stateelectronic wastes. Finally, a summary and perspectives are proposed.