Abstract: In this study, a white powder of chitosan was produced from its chitin, which was extracted from the fish scale of Tilapia (Tilapia nilotica). Proximate analysis (moisture and ash) and average molecular weight (~69 kDa) of the chitosan were determined. Structural data of the chitosan determined by FT-IR were compared with those of chitin concerning the degree of deacetylation. For dye binding study, the chitosan soluble in 2% (v/v) lactic acid was mixed with each of dye solutions (Congo red, Methylene blue and Sunset yellow FCF). The visible absorption resulting in the interactions of the dye-chitosan complex was monitored at their maximum wavelengths; 483, 488 and 662 nm for Congo red, Methylene blue and Sunset yellow FCF, respectively. The following parameters attributed to their interactions including concentration of dye and chitosan, pH, ionic strength, incubation time and temperature were investigated in detail. These results are due insight of the molecular interactions of these dye-chitosan complexes, and can further be implied for the removal efficiency of toxic waste dyes.

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KEYWORDS: Dye adsorption, Interactions, Chitin, Chitosan, FT-IR.