Application of chitosan for treatment of wastewaters.

Research has clearly demonstrated that the biopolymer chitosan (deacetylated chitin) can be used as an effective coagulating agent for organic compounds, as a chelating polymer for binding toxic heavy metals, as well as an adsorption medium for dyes and small concentrations of phenols and PCBs present in various industrial wastewaters. In these specific applications, chitosan appears more effective than other polymers such as synthetic resins, activated charcoal, and even chitin itself. In addition, the amino group in chitosan is an effective functional group that can be altered chemically for production of other chitinous derivatives with specific useful characteristics as effective absorptive agents. Chitosans exhibiting different physicochemical characteristics, i.e., molecular weight, crystallinity, deacetylation, particle size, and hydrophilicity, differ in their effectiveness as waste treatment agents. The specific relationship between methods and the particular crustacean species used in preparation of chitosan for wastewater treatment needs further examination. Use of bioremediation approaches, combined with immobilization of specific microorganisms on immobilized chitinous columns, is an extremely promising area of current research and actual plant operation.