Progress in Polysaccharide/Zeolites and Polysaccharide Hydrogel Composite Sorbents and Their Applications in Removal of Heavy Metal Ions and Dyes

Design of composite biosorbents based either on polysaccharides as biopolymer matrix embedded with natural or synthetic zeolites or composite hydrogels having polysaccharides as one component and their applications in sorption processes of heavy metal ions and dyes has been reviewed based on the most recent publications in the field. It was demonstrated that polysaccharide-zeolite composites exhibit higher performance in sorption of environmental pollutants comparative with natural or synthetic zeolites or pristine biopolymers. The polysaccharide-zeolite composites are economically feasible because they are easy to prepare and involve inexpensive chemical reagents, which are coming from renewable resources. On the other hand, the polysaccharide based composite hydrogels present stiffer and tougher mechanical properties and more efficient sorption/desorption properties compared to conventional hydrogels. Interpenetrating polymer network composite hydrogels based on chitosan, alginate, starch, cellulose, and other polysaccharides, reported mainly in the last decade, and their sorption properties for heavy metal ions and dyes are discussed in this review.