- 學位論文
碳化聚丙烯腈與二氧化矽氣凝膠複合材料的製備與有毒物質吸脫附特性探討
Preparation of Carbonized Polyacrylonitrile and SiO2 Aerogel Composite Materials and Study on the Characteristics of Adsorption and Desorption over Toxic Materials
摘要
本研究使用實驗室自製之離子熔液(Ionic Licquid, IL) ,〔Bmim〕〔BF4〕當模板，以四乙氧基矽烷(Tetraethyl orthosilicate,Si(OC2H5)4, TEOS)前驅物，以溶膠凝膠法先製備出SiO2氣凝膠材料。再添加聚丙烯腈 (PAN)溶液及(DMAC)溶劑，於700℃高溫碳化，製備出「碳化聚丙烯腈與二氧化矽氣凝膠複 合材料(SiO2@C)」。 其次，利用SEM掃描式電子顯微鏡、TEM穿透式電子顯微鏡觀察表面形貌、EDS能量分散光譜儀鑑定元素比例、 TGA熱重分析儀及FT-IR傅立葉轉換紅外線光譜儀實施材料特性分析，再以BET孔洞及表面積分析儀，量測分析材料比表面積、氮氣(N2)脫吸附能量，探討此SiO2@C複合材料之性質。最後以親水性有毒化學物質甲酸(HCOOH)吸附實驗研析該SiO2@C複合材 料之吸附效能。 BET實驗結果顯示，碳化聚丙烯腈與二氧化矽氣凝膠複合材料(SiO2@C)之比表面積187.2m2/g 、孔體積4.81 cm3/g、平均孔徑10.3nm及氮氣(N2)吸附量314.7cm3/g，且其BET吸附脫附等溫線，在P／P0為0.6左右吸附與脫附曲線分裂，說明複合材料為兩端開孔結構；在低壓區的吸附量較少，當P／P0接近於1時，曲線與縱軸趨於平行；相對壓力越高，吸附量越多，表現出有孔充填，顯示其吸脫附效果佳，使用後吸附劑易再生。電子顯微鏡影像則顯示，所製備之SiO2@C複合材料，其內部為二氧化矽(SiO2)，外部為活性碳，具疏水、親油性吸附特性。此外，親水性有毒化學物質甲酸(HCOOH)吸附實驗結果顯示，SiO2@C對甲酸之吸附量約0.065mole/g，比市售活性碳有較良好之親水特性，提升約1倍之吸附效能。此兼具親水性與疏水性吸附特性，預期可作為「毒性化學物質偵測採樣」、「面具濾毒罐過濾、吸附」及「工業有毒化學物質廢水處理」等吸附介質相關材料運用。
並列摘要
In this study,the self-prepared room temperature ionic liquid, [Bmim][BF4] , was used as a template and TEOS as precursor to synthesize the SiO2 aerogel materials by the sol-gel method The SiO2 aerogel was then coated with a carbon layer to form a SiO2@C composite by calcination with , polyacrylonitrile (PAN)solutions and DMAC solvent at 700oC for carbonization. The morphology and elements ratio were examined by the SEM, TEM, EDS , FT-IR and TGA anaylses, and the BET surface area and the related parameters were obtained by the N2 adsorption/desorption measurement . Besides, the toxic hydrophilic formic acid was used as an example to investigate the efficiency adsorption for the as-prepared SiO2@C composites. It was found that the SiO2@C composites were successfully prepared with PAN and SiO2.the surface area, pore volume, average pore diameter and N2 adsorption volume was 187.2 m2/g , 4.81 cm3/g, 10.3nm and 314.7 cm3/g, respectively. Besides, The adsorption/desorption curves showed that the curves was type IV, indicating that the composite was basically mesoporous material. The results also indicates that the SiO2@C composite had better adsorption/desorption ability that the free active carbon, Besides,The SEM and TEM confirm that the inner part of the composite is SiO2, and the outer part iscarbon layer. Further more, the amount of the toxic hydrophilic formic acid absorbed in the SiO2@C composite measured by TGA was 0.065mole/g,which is two times higher that of the commercial active carbon. The results show that the SiO2@C composite is a potential material for application in low-concentration toxicants absorption, liquid and gas filtratio, as well as the handling of the toxic chemicals wastes handling.