Alginate-Based Ternary Composites for Water Treatment: Synthesis, Mechanisms, and Applications

Alginate, as a natural polymer, has been widely used in the removal of pollutants in water due to its renewability, biocompatibility and abundant functional groups. However, it still has some limitations such as low specific surface area, poor mechanical strength and single function. Introducing metal oxides can effectively enhance their adsorption capacity and multi-functionality. Nevertheless, binary composites remain insufficient for treating complex water bodies. Therefore, the construction of structurally stable and functionally diverse ternary composites has become an important research direction. The review is based on alginate/metal oxide binary composites, analyzing their deficiencies in structural stability, nanoparticle dispersion and functional synergy. On this basis, the synthetic strategy and structural characteristics for constructing ternary composites by incorporating inorganic non-metallic frameworks, metal nanoparticles, porous carbon-based materials, and other natural polymers are discussed. The synergistic mechanism and performance enhancements of various components during pollutant removal are primarily summarized. Although the ternary composite system has a promising application prospect, it still faces challenges such as complex synthesis processes, insufficient interfacial stability, limited reusability, and poor adaptability to complex water bodies. Therefore, future efforts should focus on structural optimization, green preparation and resource utilization of waste materials to promote their engineering application and sustainable development in the field of water treatment.