本研究之目的是在探討微奈米碳球及鈦酸鹽奈米管之製備、鑑定及其在污染防治上之應用。研究重點在於建立合成參數和鑑定結果之關聯,及探討合成參數對實際應用上之影響。對微奈米碳球而言,使用不同的碳源、碳源濃度、合成溫度、反應時間及高溫碳化溫度以獲得具高比表面積、高孔隙體積、表面富含氧官能基及陽離子交換容量之微奈米碳球來作為吸附劑以去除酸及鹼性染料分子及重金屬離子。上述合成條件對微奈米碳球之顆粒大小、外觀及幾何形狀、微結構、表面化學特徵及孔洞結構之影響將由雷射粒徑分析儀、SEM、TEM、XRD、FTIR、界達電位分析儀及氮吸附曲線來鑑定。研究結果發現碳球產量隨碳源濃度、合成溫度及反應時間之增加而增加,且不同碳源製備所得之碳球產量是依下列順序遞增的:蔗糖 > 葡萄糖 > 木糖。在碳球型態及孔洞結構方面,所合成之碳球皆是實心而非中空的,而以木糖作為碳源時,所製備而得之微奈米碳球之球型最為明顯,且粒粒分明。另外,以蔗糖及木糖作為碳源所形成之微奈米碳球經熱處理後之結晶性較葡萄糖製備所得者為佳。隨著煅燒溫度之升高,微奈米碳球之比表面積及比孔隙體積亦隨之增加,但孔洞大小卻隨之變小,但過高之煅燒溫度,將會使得微奈米碳球產生燒結現象,進而使其比表面積大幅減少。使三種碳源製備之微奈米碳球之孔洞結構產生大幅變化之煅燒溫度皆在500oC,在後續之熱處理中,所能達到之最高比面積,則以葡萄糖碳源較高,約500m2/g,而蔗糖及木糖碳源則均大約在400m2/g。在表面化學特徵方面,熱處理可能會使碳球表面之某些親水性官能基消失(蔗糖例外),進而導致其疏水性增加。另外,不同煅燒溫度下之微奈米碳球之等電位點約在pH 3~4範圍內,當pH值大於4後,其表面電性皆呈負電。在染料吸附方面,由於微奈米碳球表面帶負電,因此對鹼性染料(帶正電)之吸附量略大於對酸性染料(帶負電)之吸附量。另外,由於微奈米碳球經鍛燒後,比表面積之增加主要是來自於微孔之增加所貢獻,因此大分子的染料不易進入微孔結構,造成吸附量未隨表面積之增加而增加。在銅離子吸附方面,不同碳源製備所得之微奈米碳球對銅離子之吸附量略有差異,並呈現下列順序:木糖 > 蔗糖 > 葡萄糖。另外銅離子之吸附量隨煅燒溫度之升高而增加。對鈦酸鹽奈米管而言,主要是在探討其孔洞結構及表面化學特徵對有機蒸氣吸附性質之影響。研究首先經由水熱合成法在反應溫度150oC及反應時間24小時下合成鈉鈦酸鹽奈米管,接著使用不同濃度之鹽酸溶液進行酸洗以獲得不同鈉含量之鈦酸鹽奈米管。針對上述合成步驟所得之鈦酸鹽奈米管,分別使用AA、SEM 及 TEM、XRD、氮吸脫附曲線及水蒸氣吸附曲線分別鑑定或分析樣品之鈉含量、表面型態、微結構、孔洞結構(表面積、孔隙體積及孔洞大小分佈)及表面極性隨酸洗濃度之變化情形。接著分別量測四種蒸發熱相近但極性及分子立體形狀具差異性之有機蒸汽:正己烷、甲苯、丁酮及環己烷在20及25oC之吸附平衡曲線,並將吸附平衡曲線和BET及GAB吸附模式作擬合及計算isosteric 吸附熱以探討有機蒸氣之吸附機制。研究結果發現當鈦酸鹽奈米管之鈉含量接近0 wt.%時(代表鈉離子幾乎完全被氫離子置換),則鈦酸鹽奈米管之管狀結構會被破壞;另外,假如鈦酸鹽奈米管之鈉離子未被氫離子完全取代,則隨著鈉含量之降低,鈦酸鹽奈米管將具有較高之比表面積及孔隙體積;而經由水蒸氣吸附曲線之分析可知各鈦酸鹽奈米管之SHI(疏水性)值介於-31至55%間,並依下列順序遞增:S-4 < S-5 < S-3
The objectives of this study are to examine the synthesis, characterization, and application of carbon micro/nanospheres and titanate nanotubes (TNTs). The results is emphasized on establishing the relationship between preparation conditions and product characterization as well as examining the effects of preparation conditions on the practical applications. For the first part, the carbon micro/nanospheres possessing high specific surface area, high pore volume, rich in oxygen-containing functional groups, and cation exchange capacity are synthesized with different carbon sources (xylose, glucose, and sucrose), concentrations (0.5, 1.0, 1.5M), controlled temperature (150~200oC), reaction time (2, 6, 12, 24, 48 h), and carbonized temperature (300~1100oC), from which the basic dyes and heavy metal ions can be removed by adsorption. Effects of preparation conditions on the revolution of microstructure and surface chemistry characteristics of carbon spheres are characterized with SEM, TEM, XRD, FTIR, zeta potential, and nitrogen isotherms. First, the adsorption capacities of a acid dye (Acid Red 1, AR1), a basic dye (Methylene Green, MG), and a heavy metal ion (Cu2+ ) on the carbon spheres at different pH values are measured to determine the best adsorbent. The potential application of carbon spheres for the adsorptive removal of dyes and heavy metal ions from wastewater is examined with the comparison of adsorption capacity of carbon spheres with that of other previously used adsorbents, such as activated carbon, montmorillonite, MCM-41, and titanate nanotubes. For TNTs, effects of both pore structure and surface chemical characteristics of TNTs on their adsorptive removal of organic vapors are investigated. TNT is prepared via a hydrothermal treatment of TiO2 powders in a 10 M NaOH solution at 150 oC for 24 h, and subsequently washed with HCl aqueous solution of different concentrations. Effects of acid washing process on microstructures and surface chemical characteristics of TNT are characterized with atomic absorption spectrometry, transmission electron microscopy, X-ray diffraction, nitrogen adsorption-desorption isotherms, and water vapor adsorption isotherms. For the adsorption experiments, gravimetric techniques are employed to determine the adsorption capacities of TNTs for four organic vapors with similar heats of vaporization (i.e. comparable heats of adsorption) but varying dipole moments and structures, including n-hexane, toluene, ketone, and cyclohexane, at isothermal conditions of 20 and 25 oC. The experimental data were correlated by well-known vapor phase models including BET and GAB models. Isosteric heats of adsorption were calculated and heat curves were established. Effects of the alteration of both microstructures and surface chemical characteristics of TNT, induced by acid washing process, on the organic vapor adsorption are discussed.