Wastewater treatment chitin

Environmental requirements are assuming great importance, since there is an increased interest in the industrial use of renewable resources such as starch and chitin. Considerable efforts are now being made in the research and development of polysaccharide derivatives as the basic materials for new applications. In particular, the increasing cost of conventional adsorbents undoubtedly makes chitin and chitosan-based materials one of the most attractive biosorbent for wastewater treatment. Chitin and chitosan biopolymers have demonstrated outstanding removal capabilities for certain pollutants such as dyes and metal ions as compared to other low-cost sorbents and commercial-activated carbons. Biopolymer adsorbents are efficient and can be used for the decontamination of effluents (removal of pollutants) and for separation processes (recovery of valuable metals). 

Santosa, S.J., Siswanta, D., Sudiono, S., Utarianingrum, R. Chitin-humic acid hybrid as adsorbent for Cr(III) in effiuent of tannery wastewater treatment. Journal of Photochemistry and Photobiology. App. Surf. Sci. 254, 7846-7850 (2008)... 

The industrial and pharmacological applications of chitin and chitosan have been known for many years and have become an important industrial pursuit because these materials have the three advantages of being abundant, nontoxic, and biodegradable. Chitin and chitosan are produced on an industrial scale from the shells of crustaceans. Chitosans are strong chelators of arsenic and heavy cations, and are used for this purpose in wastewater treatment and in the paper industry (Da Sacco and Masotti, 2010). They have many other applications, however, particularly in the biomedical field, either unaltered or after chemical transformation (depolymerization, alkylation. 

This review summarizes the industrial applications of natural polysaccharides such as Chitin and Chitosan based materials in wastewater treatment. In addition, this review also opens up various factors affecting the adsorption and desorption processes. We expect that this chapter will provide insights on the use of these natural polysaccharides for researchers woiking to discover new materials with new properties for the valuable applications. 

Chitosan and chitosan with immobilized enzymes found application in a large range of applications due to the original properties of chitosan itself [190, 215]. A review for applications in food was published previously but it seems that this domain is not in development [216,217], Packaging [218] and paper industry are also concerned [98, 219-221], In paper fabric, it may be used for paper reinforcement or as coagulant of wastewater. In textile industry, some application of chitosan is also mentioned in the literature as it was for chitin [61, 63, 222], Another field where the specificity of chitosan still is to be recognized is cosmetics (especially for hair treatment in relation with electrostatic interaction) (Table 4.5) [1],... 

Recently, numerous approaches have been studied for the development of cheaper and most effective adsorbents containing biopolymers. The most widespread biopolymers are polysaccharides [190], chitin [167, 139, 7] and cyclodextrin [157, 26, 32]. These biopolymers reach the increasing demand for treatment of industrial wastewater before their use or disposal. Because the pollutants creates environmental and health diffieulties, associated with heavy metals and pesticides and their deposit through the food chain [39]. Traditional methods for the elimination of heavy metals from industrial wastewater may be inefficient or costly, particularly when metals are present at low concentrations [30, 184]. Chitin, chitosan and oligosaccharides represent interesting and attractive alternative adsorbents because of their particular structure, physico-chemical characteristics, chemical stability, high reactivity and excellent selectivity towards metals. Moreover, Ihey are abundant, renewable and biodegradable resources and have a capacity to associate by physical and chemical interactions with a wide variety of molecules [22, 131]. 

---