| 摘要: | 本研究從文獻中得知幾丁質的應用非常廣泛，使用在食品、醫學、美容、環境...等用途，而幾丁質經由去乙醯後的幾丁聚醣具有良好的吸附效果，運用在環境上可以吸附水中之重金屬離子，經由螯合作用易與重金屬離子形成配位鍵。另外幾丁質結構類似於纖維素，在地球上含量是非常豐富，是自然界上第二多高分子纖維，它來自於甲殼類動物如:蝦、蟹、等節肢動物。本實驗使用微量之幾丁聚醣附著於石英砂探討其吸附Cu2+效果，並且使用不同之交聯劑如環氧氯丙烷(ECH)、縮水甘油醚(EGDE)，改變幾丁聚醣型態，探討未交聯與交聯過後之吸附劑之吸附差別的影響及在不同pH值狀態下之吸附及脫附情形。進階探討等溫吸附Langmuir Isotherm、Freundlish Isotherm之適用性及動力吸附擬一階動力吸附、擬二階動力吸附之探討。
本實驗在吸附劑吸附銅離子試驗中，使用石英砂(Sand)、幾丁聚醣(Chitosan)、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)、幾丁聚醣固化於石英砂交聯縮水甘油醚(CCS-EGDE)做吸附，進行批次吸附研究，銅離子濃度範圍在100-2000mg/L。研究得知，石英砂吸附劑對於吸附銅離子的吸附能力低，而其他四種吸附劑對於銅離子有具良好的吸附效果。套用等溫吸附模式實驗結果顯示Langmuir等溫吸附模式，R2值均可達0.980以上；此外，在Freundlich等溫吸附式中，所有吸附劑之n值均大於1，亦驗證此吸附劑有利於金屬吸附現象的發生。套用動力模式下數據顯示吸附劑對於銅之吸附符合擬二階動力學模式。而在不同pH值狀態下之吸附及脫附情形，不同交聯劑添加使用對於銅的吸附與脫附效果亦不一樣，本實驗中添加EGDE交聯劑比ECH之交聯劑效果好，使用交聯劑可以提升吸附效果及提高抗酸能力。
From the literature, Chitosan was found to be highly use in many industries, such as, food industry, medicine industry, cosmetic industry, environment and other uses. Chitosan is from the deacetylation of Chitin. It has a very good absorption, can be used in environment and also can use to absorb heavy metal ions from solution. Chitosan is easy to have coordination bond with metal ions by sequestration. Chitin structure is similar to cellulose which is abundant on earth. Chitin can be extracted from shrimps, crabs and much more. It was found to be the second most abundant resource in the nature after cellulose.
In this study, the small amount of chitosan were coated on sand and using two cross-linking agents which are Epichlorohydrin (ECH) and Ethylene glycol diglycidyl ether (EGDE) to change the structure of chitosan. Then, the cross-linking and non cross-linking on the adsorption capacity of adsorbent and the effect of different pH conditions of adsorption and desorption were determined. Moreover, the appilication of Langmuir and Freundlich Isoterm and the kinetic study (first and second order) were used for further explanation of the research results.
In this research, the adsorption of copper (II) ions on sand, chitosan, chitosan-coated sand (CCS), crosslinked chitosan intercalated sand using ECH as cross-linking agent (CCS-ECH), and crosslinked chitosan intercalated sand using EGDE as cross-linking agent (CCS-EGDE) were examined. The experiments were carried out in batch mode with the copper ion concentration range from 100-2000 mg/L. The study showed that sand has low adsorption capacity, while, the others adsorbents have high copper ions adsorption capacity. The equilibrium adsorption data were analyzed using Langmuir and Freundlich isotherm model. Langmuir isotherm model on the adsorption shows the R2 values more than 0.980 and Freundlich isotherm revealed that all adsorbents have n value greater than 1. These verified that all adsorbents were response for the adsorption phenomenon of the metal. The kinetics of the adsorption capacity was followed that second-order behavior. The effect of different pH values on the adsorption and desorption were not the same when using different cross-linking agent. Results showed that EGDE has more effect than ECH. The use of cross-linking agent was found to be an important parameter, since it can enhance the adsorption capacity and also increase the acid-resistance ability. |
