幾丁聚醣改質吸附劑處理含銅離子溶液與脫附回收之研究

The Adsorption and Recovery Study of Copper Ion in Aqueous Solution Using Chitosan-Coated Sand as Absorbent

幾丁聚醣是甲殼類生物體經由萃取、加工製造成的天然陽離子型高分子聚合物，可應用於處理汙染水體中的重金屬離子之吸附；且生物分解材料使用後會在自然界中進行循環，原料可在自然界中取得，符合永續利用之原則。本研究利用具生物可分解特色之生物高分子聚合物（Biopolymer）：幾丁聚醣（Chitosan），作為傳統吸附劑改質之基質。過濾銅金屬之實驗分別使用：石英砂（Sand）、幾丁聚醣固化於石英砂（CCS）、幾丁聚醣固化於石英砂交聯環氧氯丙烷（CCS-ECH）做為吸附劑進行管柱過濾吸附，並以pH=3、pH=5及100ml與200ml反洗脫附液進行反洗脫附試驗。實驗結果顯示，石英砂對於銅離子的吸附能力極低，而其他兩種改質吸附劑之吸附量能力為CCS比CCS-ECH良好，但由於使用交聯劑的條件下，反洗脫附後CCS-ECH之吸附劑可再重覆使用的次數上較CCS來的多，相對亦提升了銅的總回收濃度。

Chitosan can be derived from crustaceans, such as: shrimp, crabs and other arthropods, by the deacetylation of chitin formation. Chitosan is also recognized as a powerful heavy metal chelating agent. Chitosan and its modification of as an additional or replacement to traditional filter media is employed to treat heavy metal contaminated soil and water. In this study, adsorption of copper ions using quartz sand （Sand）, chitosan cured in quartz sand （CCS）, chitosan cured in quartz sand and cross-linked epichlorohydrin （CCS -ECH） as an adsorbent at different backwash solution pH was investigated and evaluated. Copper wastewater concentration of 100ppm flowing at a rate of 5ml/min is used for the filtration and adsorption experiments. HCl solution of pH 3 and pH5 with volumes of 100 ml and 200 ml is used as a backwash solution.Research reveal quartz sand exhibits the lowest adsorption capacity as compared to the adsorption capacity of CCS and CCS-ECH. In terms of breakthough time, quartz sand also show the fastest time of breakthough of 200 minutes as compared to the 600 minutes breakhtrough time for CCS and CCS-ECH. This is because the cross linking material used for both chitosan-modified media enhanced the coordination between the components and have made the structure of the two adsorbents stronger than ordinary quartz sand. As to the number of times of reuse, CCS-ECH proved to be more economical since at shows the most number of reuse at pH 5 （4 times） and pH 3 （3 times）.