| Summary: | 碩士 === 國立臺灣海洋大學 === 食品科學系 === 98 === Preparation of water-soluble chitosan derivatives including carboxymethyl chitosan (CMC), N-methylene phosphonic chitosan (NMPC) and half acetylated chitosan (HCS). These water-soluble chitosan derivatives were tested for their chemical and physical properties. Also, their chelation capacities for Zn(II) were determined. Furthermore, their adsorption capacities for Zn(II) was also investigated at different conditions. The degrees of acetylation (DA) for CMC, NMPC, and HCS were 11.78%, 14.55%, and 50.14%, and their solubilities were 36.29, 79.46 and 9.33 mg/mL, respectively. These water-soluble chitosan derivatives were soluble over a wide pH range (pH 7~11). The chelating capacities of water-soluble chitosans for Zn(II) were evaluated at different chitosan concentrations. The results indicated that the chelating capacities of water-soluble chitosan derivatives increased with greater concentrations and leveled off to a saturated chelating capacity when the chitosan concentration reached to 0.2%. In addition, water-soluble chitosans exhibited higher chelating capacity than the non-water-soluble chitosan. The adsorption properties of water-soluble chitosan derivatives for Zn(II) were studied at different zinc concentrations, adsorption times, temperatures, and pH. The optimal adsorption time for CMC, NMPC, and HCS were 3, 1, and 6 hours, respectively. The maximum adsorption capacities for CMC, NMPC, and HCS were 1.97, 0.55, and 1.03 mmol Zn(II)/g adsorbent, respectively.
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