薄膜蒸餾(membrane distillation, MD)為近來廣受重視的一種技術,其特色為具有低成本、可模組化、設備簡單且易於操作等多方面之優勢,常被廣泛應用於海水淡化、純水製備及廢水回收等。薄膜蒸餾原理乃是利用薄膜兩側的飽和蒸汽壓差為驅動力促使水蒸氣通過薄膜,進而達到分離的效果。本文將研究薄膜蒸餾法中的直接接觸薄膜蒸餾(DCMD)及真空式薄膜蒸餾(VMD)搭配市售之e-PTFE膜對於重金屬離子分離的效果。 本研究針對市售多種聚四氟乙烯薄膜(e-PTFE)以直接接觸薄膜蒸餾及真空式薄膜蒸餾針對廢水中常見有害重金屬離子進行分離,最後以Thermo iCAP Q ICP-MS及Perkin Elmer 7000DV ICP-OES進行檢測分析。進行分離之重金屬為錫(Tin)、銻(Antimony)、鉻(Chromium)、鎘(Cadmium),根據以下不同之操作條件進行討論:(一)薄膜孔隙尺寸、(二)重金屬濃度、(三) 熱流體進口溫度,進而得知在不同條件下所得到市售聚四氟乙烯薄膜(e-PTFE)的滲透液純水產率與重金屬離子的去除率。
Membrane distillation (MD) has been recently a widely valued technique, whose advantages include low cost, modularization, simplicity and easy operation. It has been extensively applied to seawater desalination, water purification and wastewater recycling. The principle of MD is to utilize the pressure difference of saturated vapor on both sides of the membrane as a driving force to make vapor pass the membrane to reach the effect of separation. This study will investigate the effect of tying in DCMC and VMD, two MD methods, with the e-PTFE membranes on the market on separation of heavy metals. This study applies DCMC and VMD to several e-PTFE membranes on the market to separate common hazardous heavy metals in the waste water. The results are analyzed by Thermo iCAP Q ICP-MS and Perkin Elmer 7000DV ICP-OES. The separated heavy metals are tin, antimony, chromium and cadmium. The discussions are based on the following operation conditions: (1) pore size of the membranes, (2) concentrations of heavy metals, and (3) entrance temperature of thermal fluid to see the yield of osmotic pure water and removal rate of heavy metals by the e-PTFE membranes on the market under different conditions.