Chitosan as adsorbent for removal of some organic dyes: a review

Water pollution is a significant problem that affects the environment and human life. There are a lot of pollutant types, such as chlorophenols, dioxins, benzofuran, polychlorinated compounds, and organic dyes. Among them, organic dyes gained a lot of interest recently, because of their wide usages, chemical stability, harmful effects on water bodies, and resistance to biodegradation. Various water treatment techniques have been used to reduce organic dyes dangerous effects, including biological, physical, and chemical techniques. Adsorption is a one favorable technique, due to its relatively low cost, availability, simple operation, and rapid results. Modifications done on chitosan can enhance its physio-chemical properties and adsorption capacity. They also allowed the use of chitosan in various forms, such as chitosan compositions with metals, clays, and other polymers, hydrogels, aerogels, gel beads, and Schiff base derivatives. The core of the ongoing review will discuss the synthesis, characterization, physical and chemical properties of some chitosan-based adsorbents which used for the adsorption of three organic dyes: methylene blue, methyl orange, and sunset yellow.