官能基化活性碳纖維布對二氧化碳氣體之吸附貫穿研究

Study on Adsorption Breakthrough Curves of Carbon Dioxide on Functionalized Activated Carbon Fiber Fabrics

江右君(Yu-Chun Chiang) ； 吳政諺(Cheng-Yen Wu) ； 陳宥任(Yu-Jen Chen)

《燃燒季刊》 94期 (2016/08) Pp. 47-59

https://doi.org/10.30041/CQ.201608_(94).0004

摘要

本研究將商用活性碳纖維布予以表面官能基化，包含KOH活化和TEPA胺化，評估對CO_2之吸附貫穿效能。以材料檢測技術分析樣本的特性，並量測對CO_2之吸附貫穿曲線；探討樣本表面和材料性質對CO_2吸附貫穿效能之影響，並進一步提出適合的吸附貫穿模式，估算平衡吸附量、吸附速率係數和吸附貫穿時間。研究發現，表面改質處理後各纖維樣本的表面並未受到明顯破壞，可在細小紋路或溝槽中發現微小孔隙。KOH高溫活化處理使纖維直徑變小、氮含量流失、比表面積和孔隙體積顯著增加。TEPA的胺化確實可有效增加纖維的含氮量，但可能因阻塞原有孔隙，使得比表面積和總孔體積均減少。此外，本研究發現傳統的Wheeler equation經修正後，可以更適當的模擬貫穿曲線的轉折處；但此新增的參數需依樣本特性調整。各樣本對15 % CO_2的平衡吸附量依序為KOH-ACF ＞ACF ＞ TEPA-ACF，此結果顯示比表面積和孔隙體積應是主要關鍵因素。此外，隨著吸附溫度的增加，各樣本對CO_2的平衡吸附量和貫穿時間均出現降低的現象；顯示各樣本對CO_2的吸附應屬於放熱反應。

關鍵字

活性碳纖維 ； 二氧化碳 ； 表面改質 ； 特性分析 ； 吸附貫穿曲線

並列摘要

The objective of this study was to functionalize the surface of activated carbon fiber fabrics (ACF) by potassium hydroxide (KOH) activation or tetraethylenepentamine (TEPA) amination and discuss their adsorption breakthrough for carbon dioxide (CO2). The properties of the samples were characterized using several techniques. The adsorption breakthrough curves at different temperatures were measured, and the key parameters affecting the breakthrough performance were discussed. The adsorption breakthrough model was proposed, and the equilibrium adsorption capacity, the overall adsorption rate coefficient, and the breakthrough time were evaluated. Results showed that the fiber fabrics were almost intact after modification, with several micropores or slits distributed on external surface. The treatment of KOH activation at high temperature resulted in smaller diameter of fibers, the loss of nitrogen, and the increase of surface area and pore volume. The TEPA amination was an effective way to introduce nitrogen onto the surface of fibers, but its long chain structure could block the original micropores and further to decrease the available surface area and pore volume. It was observed that the modified Wheeler equation fitted the data better than the original one, and the new variable was depended on the adsorbent. The equilibrium adsorption capacity of carbon dioxide at a concentration of 15 % followed the order KOH-ACF ＞ ACF ＞ TEPA-ACF, which implied surface area and pore volume played the most important roles. In addition, the equilibrium adsorption amounts and breakthrough time decreased with increasing temperature, indicating the adsorption was an exothermic reaction.

並列關鍵字

Activated carbon fibers ； Carbon dioxide ； Surface modification ； Characterization ； Adsorption breakthrough curves