本研究利用水熱法在不同的操作條件(老化時間、攪拌速率、水熱溫度、填充壓力)下製備沸石,在組成份4.62Na2O:Al2O3:10SiO2:180H2O、水熱溫度100℃、水熱8小時、攪拌速率200 rpm、無填充壓力下合成P2型沸石,其比表面積超過400 m2/g,並對製成的產物進行物理、化學特性分析,且從N2等溫吸脫附分析得知產物大致為微孔性結構(TypeⅠ)。
將製備之吸附劑與商業化沸石對水中有機污染物進行動力吸附實驗,改變不同的動力吸附操作條件(吸附質起始濃度、吸附劑劑量、pH效應),探討各操作條件對吸附容量的影響。水中有機污染物丙二酚-A(BPA)在鹼性環境下吸附容量會降低,主要是因為BPA的pKa介於9.6~10.2之間,所以在鹼性環境下BPA會產生水解現象,以致吸附容量降低;而水中有機污染物甲烯藍在酸性環境下吸附容量會增加,主要是因為在低pH的情況下會造成本研究所製備之吸附劑產生酸蝕刻現象,導致所製備之吸附劑比表面積增加,所以吸附容量也相對提高。 The preparation of zeolite has been hydrothermally investigated under various process parameters (including aging time, agitation speed, hydrothermal temperature, and reaction pressure). It showed that the zeolite with Type P2 and BET surface area of over 400 m2/g can be obtained by using following synthesis conditions: feed composition ratio of 4.62 Na2O:Al2O3:10 SiO2:180 H2O, hydrothermal temperature of 100 ℃, aging time of 8 h, agitation speed of 200 rpm, and reaction pressure of 1 atm. The pore properties and chemical characterizations of synthesized zeolites have been carried out, indicating that these crystalline materials are Type I from their nitrogen adsorption/desorption isotherms, which are characteristic of microporous structures.
Under the investigations on liquid-phase adsorption kinetics of organic adsorbates (i.e., bisphenol-A, and methylene blue) with the effects of initial adsorbate concentration, initial solution pH and adsorbent dosage using the synthesized zeolite and commercial zeolite, the results exhibited the decrease in adsorption capacity of bisphenol-A at the alkaline conditions, mainly due to its hydrolysis at pH of about 10.0. On the other hand, the adsorption capacity of methylene blue increased with decreasing pH, especially in acidic conditions, because of the increase in surface area of synthesized zeolite as a result of etching effect.