| Summary: | 碩士 === 國立臺北科技大學 === 環境工程與管理研究所 === 104 === Forward osmosis (FO) has emerged as one of potential technologies to mitigate clean water and energy shortage. However, so far, the development of FO technology is still hindered by the unavailability of suitable draw solutions and the exploration of new draw solutes is vital for future FO applications. In the photolithography process of semiconductor or LCD (liquid crystal display) manufacturing, a large amount of developer is used and a large amount of developer wastewater is generated. The principal ingredient of the developer and its wastewater is toxic TMAH (tetramethyl ammonium hydroxide; (CH3)4NOH). This nitrogenous compound creates a problem wastewater. With the increasing use of TMAH in the semiconductor industry, however, the wastewater disposal problem is becoming serious, and the need for an efficient, inexpensive method of treating TMAH wastewater is becoming increasingly urgent. In this study, the performance of sodium acetate salt as draw solution in the FO process for dewatering TMAH was symmetrically investigated. Firstly, the effects of pH, cross-flow rate and draw solution concentration on the FO process were evaluated with deionized (DI) water as the feed solution. Next, simultaneous TMAH removal of FO was examined. The good solubility species of sodium acetate salt not only provided effective osmotic pressure to draw water from TMAH, but also reduced salt leakage significantly compared to traditional inorganic salts (NaCl). In addition, FO tests showed that using 1.0 M sodium acetate salt as draw solution for TMAH dewatering achieved a high water flux within the first hour and then water flux decreased sharply with the extension of experiment time. MD membranes were selected for draw solution recovery; a polytetrafluoroethylene membrane with a pore size of 0.45 μm was the most effective in achieving a high water flux (8.99 L/m2 h) and high salt rejection (approximately 100%) in a diluted CH3COONa draw solution.
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