Polydopamine-based polysaccharide materials for water treatment

Low-cost polysaccharides, such as cellulose, chitosan, chitin and alginate, have come into sight for water treatment. Nevertheless, their treatment efficiency and capability are sometimes unsatisfactory because of the lack of active sites and functionalities. In recent years, more and more attention has been paid to the integration of polydopamine (PDA) into polysaccharide-based materials to develop high-performance products for wastewater treatment. PDA modification can endow polysaccharides with plentiful functional moieties (including catechol, amine, and phenyl groups) for binding heavy metals and organic pollutants. PDA coatings may increase interfacial stability and hydrophilicity for oil/water separation. PDA also may anchor various catalysts for catalytic degradation of organic pollutants. Furthermore, the good light-harvesting capability and photothermal transformation feature of PDA are available for solar-driven water purification. This review aims to give the comprehensive overview on the development of PDA-based polysaccharide materials for water treatment. PDA-based polysaccharide materials can be made into cost-effective and high-performance products (including hydrogels, aerogels, membranes, beads and nanocomposites) for adsorption of heavy metals and organic pollutants, oil/water separation, catalytic degradation of organic pollutants, and solar-driven water purification. This review will give valuable information for the design and exploitation of PDA-based polysaccharide materials in water treatment.