| Summary: | 碩士 === 國立臺灣大學 === 化學工程學研究所 === 96 === In this study, chitosan mixed matrices and sulfonic chitosan matrices were prepared for copper ion adsorption process. Ion exchange resins (Amberjet 1200H, Rohm & Haas) were incorporated into the stereo structure of chitosan matrices to fabricate chitosan mixed matrices. The porous structure of chitosan matrices could make the copper ion solution flowing though the matrices. The copper ions would be easily caught by the amino groups of chitosan matrices or sulfonic groups of ion exchange resins. The specific surface area of chitosan mixed matrices are 72.26m2/g due to the formation of bi-continuous structure, which has considerable surface area and can enhance the copper ion adsorption capacities. Results of copper ion adsorption experiments showed that adsorption capacities of chitosan matrices were obviously improved at low ion concentrations and could be utilized in various ranges of ion concentrations. The copper ion adsorption isotherm of chitosan mixed matrices fitted well with both Langmuir and Freundlich models.
In sulfonation process, chitosan matrices were cross-linked and sulfonated by epichlorohydrin(ECH) and 1,3-propane sultone(1,3-PS) solutions respectively. Chitosan matrices with different degree of sulfonation can be composed by reacting chitosan matrices with different volume ratio of the 1,3-PS/EtOH solution. By the results of elementary analysis, the degree of sulfonation of sulfonic chitosan matrices (without EtOH) was 100.00%. The sulfonic chitosan matrices which reacted with 0.1/50, 0.5/50 and 2.5/50 of volume ratio of 1,3-PS/EtOH solutions were 35.05%, 57.40% and 96.05% respectively. SEM images revealed that the external structure of sulfonic chitosan matrices were suppressed and sheltered by dense layer after cross-linking and sulfonation processes. The results of copper ion adsorption experiments showed that the copper ion adsorption capacity of sulfonic chitosan matrix (14.5mg/g) is lower than that of chitosan matrix (28.4mg/g) at an initial ion concentration of 100mg/L. The possible reasons may include: 1) Based on the same weight of chitosan adsorbents, increasing molecular weight of matrices after sulfonation process could decrease the number of functional groups feasible reacting with copper ions; 2) Cross-linking process decrease the density of amino groups available chelate with copper ions; 3) Structure transformation of the sulfonic chitosan matrices could decrease the attainable surface area for adsorption processes.
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