不同前處理對臺灣櫸修枝材化學性質及其活性碳孔隙特性之研究

本研究以未處理與經熱水、甲醇、乙醇、丙酮萃取後之臺灣櫸修枝材為原料，經500°C炭化後，再分別以750、800、850°C之水蒸汽活化製備活性碳。化學組成分結果顯示，未處理臺灣櫸修枝材之乙醇－甲苯抽出物、全纖維素、α－纖維素含量皆較4種處理者為高。不同前處理臺灣櫸修枝材經500°C炭化後，C元素含量介於80.90～86.80 wt.%。不同活化溫度製備之活性碳，其pH值皆偏鹼性，碳收率皆隨著活化溫度之提高而降低。在750、800、850°C等3種活化溫度下，未處理、熱水萃取、乙醇萃取、丙酮萃取處理之臺灣櫸修枝材活性碳BET比表面積皆隨著活化溫度的提高而增加；甲醇萃取處理則是隨著活化溫度之提高而降低。另外，由氮氣吸脫附等溫曲線結果得知，5種前處理臺灣櫸修枝材活性碳皆為Type I Va類型，具有等溫曲線Type I及Type II之特徵，屬於微－中孔碳，比表面積皆達到商業化之要求（＞500 m^2/g）。因此，將回收已萃取之臺灣櫸修枝材製備成活性碳，除了可減少林業廢棄物，亦可達到推動循環經濟再利用之目標。

關鍵字

臺灣櫸；修枝材；溶劑萃取；活性碳；孔隙特性

並列摘要

This study activated carbons prepared with untreated, hot water, methanol, ethanol and acetone extracted of Zelkova serrata pruning branches at c arbonization t emperature of 500 °C, and two-stage activated process at different temperatures (i.e., 750, 800 and 850°C) by steam. Based on the c hemical c omposition r esults, it in dicated th at th e u ntreated Z. serrata pruning bra nches h ad higher contents of alcohol-toluene extractives, holocellulose and α-cellulose than those from the four extracted o nes. The el emental c ontents of c arbon were between 80. 90~86.80 wt.% by different pretreatments at carbonization temperature of 500°C. The pH values of activated carbons prepared by different activation t emperatures w ere all r elatively alkaline, an d t he activated car bon yield w ere decreased with increasing activated temperature. Under the three different activation temperatures of 750, 800, and 850°C, the Brunauer-Emmett-Teller (BET) surface area of untreated, hot water, ethanol and acet one ex tracted Z. serrata pruning br anches i ncreased, but BE T surface a rea of methanol extracted o ne decreased with an i ncrease of the activation t emperature. In addition, t he ni trogen adsorption a nd de sorption i sotherms of a ctivated c arbon prepared fr om fi ve pre treatments of Z. serrata pruning branches were all Type IVa with the isotherm characteristics of Type I and Type II, indicating t hat m icro-mesopore wa s a major p ore s tructure. The B ET s urface ar ea o f act ivated carbons met the commercialization standard of (＞ 500 m^2/g). In this regard, recovering the extracted Z. serrata pruning bra nches to pre pare a ctivated c arbon c an reduce fore stry waste and a chieve the goal of recycling economy with renewable resources.

並列關鍵字

Zelkova serrata ； Pruning branches ； S olvents e xtracted ； A ctivated c arbon ； P ore characteristics

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