液相法製造程序對中孔洞沸石型吸附材特性及其丙酮吸附量影響之研究

Abstract

中孔洞沸石型吸附材因具有高比表面積及可調整孔洞大小之優勢，故為奈米科技重要研究範疇之一，但其價昂貴且目前為止應用於揮發性有機物之研究數量不若針對沸石之研究般廣泛。本研究以液相法製成中孔洞沸石，研究重點包括(1)討論室溫(RT)及高溫(HT)凝膠合成兩種不同合成程序(2)添加乙醇與否(3)改變界面活性劑與矽的莫耳比例，作為中孔洞沸石製成的操控變因。接著將製成之中孔洞沸石以熱重分析儀進行丙酮吸附試驗，並選出前述試驗中結果具代表性之的中孔洞沸石，進行反覆吸脫附試驗，以了解各項變因對丙酮吸附的影響，並與商業沸石進行比較。 HT法製成之吸附材雖比表面積較RT法低，且孔洞大小較RT法大，但具有均勻的孔洞分佈且結構性較好。RT法製成之吸附材其對丙酮之飽和吸附量均較HT法高。當界面活性劑與矽莫耳比例為0.3、添加乙醇情況下，RT法可得到最高的比表面積1334 m2/g，而當界面活性劑與矽莫耳比例為0.3、不添加乙醇情況下可得到最高的丙酮飽和吸附量132 mg/g。添加乙醇確可使製成之吸附材孔洞大小變小。而本研究中添加乙醇與否及改變界面活性劑與矽莫耳比例對丙酮飽和吸附量影響並無一定趨勢。在對丙酮反覆吸脫附的試驗中，其劣化程度為ZSM-5＞RT03＞HTE03>HT03，因此可能最佳的配方製成之吸附材為HT03。

The mesoporous adsorbent is an important subjest on nanotechnology because it has high specific surface area, and its pore size can be adjusted. But it’s expensive and therefore research on its application to air pollution control has been limmited. In this study mesoporous adsorbents are synthesized via liquid phase methods. The research topics include effects of (1) room temperature(RT) and hydrothermal(HT) synthesis (2) ethanol addition and (3) surfactant/silica molar ratio on the characteristic of mesoporous silica adsorbent and acetone adsorption. The acetone adsorption capacity was tested by thermogravimetric analysis(TGA). The adsorbents synthesized by HT method have lower specific surface area than that synthesized by RT method, but their pore distribution is uniform and obvious crystal array. The acetone adsorption capacity of adsorbents synthesized by RT method is higher than that by HT method. When surfactant/silica molar ratio is 0.3 with ethanol addition, the highest specific surface area of adsorbent synthesized at room temperature achieved at is 1334 m2/g, and when surfactant/silica molar ratio is 0.3 without ethanol addition, the highest acetone adsorption capacity of adsorbent synthesized at room temperature is achieved at 132 mg/g. Furthermore, the addition of ethanol reduces pore size of adsorbents. Addition of ethanol or not and change of surfactant/silica molar ratio have no especial relation to acetone adsorption capacity. Inferior quality of adsorbents damaged during repeated acetone adsorption-desorption test is in the sequence of ZSM-5＞RT03＞HTE03>HT03, so the synthesis method of HT03 may be the best prescription in this study.