以氫氟酸化學活化矽藻土

CNU IR > College of Sustainable Environment and Recreation > Dept. of Environmental Engineering and Science (including master's program) > Dissertations and Theses > Item 310902800/4522

Please use this identifier to cite or link to this item: https://ir.cnu.edu.tw/handle/310902800/4522

Title:	以氫氟酸化學活化矽藻土 Chemical Activation of Diatomaceous Earth by Hydrofluoric Acid
Authors:	賴智濰 Chih-Wei Lai
Contributors:	蔡文田嘉南藥理科技大學：環境工程與科學系碩士班
Keywords:	氫氟酸化學活化矽藻土 Characterization Hydrofluoric acid Chemical activation Diatomaceous earth
Date:	2005
Issue Date:	2008-10-20 15:38:53 (UTC+8)
Abstract:	本研究之目的乃利用氫氟酸做為含浸的活化劑，配合不同活化參數(濃度、時間、溫度)進行純矽藻土及廢矽藻土之化學活化。研究結果顯示純矽藻土化學活化之最佳條件為活化濃度2.5N、活化時間0.5 hr、活化溫度60℃、樣品重/活化液比為5/100的條件下，SBET可由3.81 m2/g上升至7.04 m2/g提升近2倍，孔洞體積也由0.0161cm3/g提升至0.0560cm3/g。廢矽藻土化學活化之最佳條件為活化濃度2.5N、活化時間0.5 hr、活化溫度25℃、樣品重/活化液比為5/100的條件下，SBET可由0.43m2/g上升至4.85m2/g提升了十倍，孔洞體積也由0.0036cm3/g提升至0.0430cm3/g。對活化後之產物做其物理/化學特性分析，包括表面積/孔洞體積、掃描式電子顯微鏡(SEM)、X光繞射(XRD)、傅利葉紅外線光譜(FTIR)及主要元素，顯示所得之產物從N2之等溫吸脫附分析大致為中-巨孔性結構(Type II及IV)。進一步以活化後最佳物性產物對環境賀爾蒙丙二酚A進行吸附實驗，並利用Langmuir及Freundlich等溫吸附模式進行迴歸，結果顯示此礦物性吸附劑對此屬疏水性環境有機化合物並沒有很高的吸附容量，主要係因靜電排斥作用力所致。 The objective of this study was to use hydrofluoric acid (HF) as etching agent for chemically activating fresh and spent diatomaceous earths under different activation parameters including impregnation concentration, holding time, temperature etc. The experimental results showed that the optimal activation conditions for fresh diatomaceous earth seemed to be at the concentration of HF 2.5 N, holding time of 0.5 hr, temperature of 60 ℃ and sample/solution weight ratio of 5/100. Under these conditions, the main physical properties of resulting product were BET surface area of 7.04 m2/g and total pore volume of 0.0560 cm3/g as compared to 3.81 m2/g and 0.0161 cm3/g of its precursor, respectively. Compared to the foregoing, the optimal activation conditions for spent diatomaceous earth seemed to be similar to those of fresh diatomaceous earth except temperature at 25 ℃. Under these conditions, the main physical properties of resulting product were BET surface area of 4.85 m2/g and total pore volume of 0.0430 cm3/g as compared to 0.43 m2/g and 0.0036 cm3/g of its precursor, respectively.The physical and chemical properties characterizations of some resulting products obtained in the chemical activation were further examined using the analyses of surface area/pore volume, scanning electron microscopy (SEM), X-ray diffraction (XRD), Fourier infrared spectroscopy (FTIR) and main elements. The analytical results showed that these samples are basically characteristic of types II and IV base on the nitrogen isotherm, indicating mesoporous-macroporous structure. Finally, the optimal porous product was used as a mineral adsorbent for environmental hormone bisphenol-A, showing that it has a poor adsorption capacity for the removal of this hydrophobic organic compound from the aqueous solution based on the fittings of Langmuir and Freundlich isotherms, mainly due to the electrostatic repulsion interaction between the adsorbent with negatively-charged surface and adsorbate with neutrally-polar structure.
Relation:	校內公開，校外永不公開
Appears in Collections:	[Dept. of Environmental Engineering and Science (including master's program)] Dissertations and Theses

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