以四氯化鋯為鋯源合成之短孔道SBA-15及其吸附相關研究

Abstract

介孔物質為孔徑在2至50 奈米之間的多孔性材料，並在分子的儲存、催化、吸附等有良好的研究成果。其中，SBA-15 因為其夠高的表面積、可調節的孔徑以及聚熱穩定性而成為熱門的研究材料之一。SBA-15 隨著製程的改變會展現不同的外型像是纖維狀、圓球狀、囊包狀或片板狀等。而近年來，片板狀的SBA-15 因為其短孔道而受到密切的注意，因此許多合成短孔道SBA-15的方式因而誕生。而在所有方法之中，以鋯為添加劑為最多人所使用的方法。 在絕大部分以鋯合成短孔道SBA-15的研究裡，都是以氯氧化鋯作為鋯源，因此在本實驗裡，嘗試著以氯化鋯作為另一種鋯來源合成片板狀短孔道之SBA-15介孔材料，並以比表面積分析儀、掃描式電子顯微鏡、穿透式電子顯微鏡等比較此材料與原製程(以氯氧化鋯為鋯源)在表面積、孔徑以及外型等性質。在結果中，可以發現兩者在這些性質上大似相近，因此可以得到陰離子的改變對於材料的合成並不會造成太大的影響，所以使用氯化鋯合成短孔道SBA-15 是可行的。 接著，氯化鋯合成之短孔道SBA-15在胺基化之後，則試著用於單寧酸的吸附。從吸附實驗中，可得知當溶液初始濃度為150 ppm時，平衡的吸附量為416.8 mg/g，較殼聚醣或多孔性黏土的效果好。此外，為了探討分子在孔道間的移動狀況，將胺基在不同製程下SBA-15上的負載量經由熱重分析得知後並進行討論，從結果中，可以看出短孔道中分子擴散的速率應較普通長孔道來的快，且以單位面積來說，短孔道對胺基的負載量也比長孔道來的高。

Mesoporous is a kind of material with pore diameter between 2 and 50 nanometers which is widely used in storage, catalytic reaction and adsorption. Among many kinds of mesoporous materials, SBA-15 is famous for its high surface area, tunable pore size and high heat stability. With different synthesis condition, different morphology of SBA-15 would be produced like fiber, sphere, vesicular or plate. Recently, SBA-15 with platelet structure is getting more and more popular because of its short channel. So there are more and more methods developed for production of short channel SBA-15, and in these methods, the widely used one is the addition of zirconium. In most of the research related to short channel SBA-15, zirconyl oxychloride is used as zirconium source. So, in this experiment, short channel SBA-15 was tried with another zirconium source, zirconium chloride. In order to check whether the product shows similar properties with the original one made by adding zirconyl oxychloride, BET, SEM and TEM was used to know the properties like surface area, pore size or morphology of these two products. From these data, we can see that the properties of these two products are similar, which means that the change of anion would not cause effect. So, production of short channel SBA-15 with zirconium chloride is feasible. And then, after modification of amine, the modified short channel SBA-15 was used for adsorption of tannic acid. And from the results, we can see that when the concentration of tannic acid before adsorption is 150 ppm, the equilibrium loading amount of tannic acid would be 416.8 mg/g, and it is higher than chitosan or clay as adsorbent. Besides, in order to figure out the molecular diffusion condition inside the channels, the amount of amine loaded on the surface was measured by thermal gravity analysis for discussion. From results, we can know that the diffusion rate of molecules inside short channel is faster than inside long channels, and also, higher loading capacity per unit surface area was also observed in platelet SBA-15.