在全球水資源日漸減少的情況下，廢水回收再利用及海水淡化技術應用也開始被重視。本研究利用自行製備之聚偏二氟乙烯中空纖維膜應用於薄膜蒸餾技術試驗，利用NaCl溶液及DI水作為進料端及滲透端，藉由電子顯微鏡(SEM)探討薄膜結構、孔洞大小、表面孔隙等，以直接接觸式薄膜蒸餾(DCMD)技術探討中空纖維膜對於滲透率及鹽阻率之影響。 中空纖維膜最佳鑄膜條件為20wt% PVDF、鑄膜液壓力3.5psi、芯液流速為16 mg/min，經試驗之後最佳通量為1.8 kg/m2hr，鹽阻率達99.95%。添加PEG20wt%之中空纖維膜後，其通量提高至2.31 kg/m2hr，鹽阻率維持於99.95%。 另外在長時間連續實驗操作試驗方面，20wt%聚偏二氟乙烯中空纖維膜膜組，經過14次循環實驗共168小時之連續操作，平均通量及鹽阻率為2.69 kg/m2h、99.93%，仍可維持一定的通量及鹽阻率，可證明此中空纖維膜組DCMD系統能長時間使用。 In the context of dwindling global water resources, waste water recycling and desalination technology is starting to pay attention. Membrane distillation (MD) is a non-isothermal membrane separation process applied for desalination of seawater. The driving force of the process is given by a partial vapor pressure difference commonly triggered by a temperature difference. Membrane structure, pore size, and surface porosity characterized by scanning electron microscopy (SEM). By conducting the batch DCMD process, the water flux and salt rejection for the prepared membrane were measured. The best hollow fiber condition casting solution was 20wt% PVDF with NMP, pressure of casting solution was 3.5 psi, flow rate of boil liquid were 16 mg/min. The permeate flux achieved 1.8 kg/m2 h and the rejection of NaCl maintained 99.95% with the above condition. Mix with soluble polymer polyethylene glycol (PEG) permeates flux up to 2.31kg/m2hr and with the same salt rejection. Furthermore, after 14 times continuously desalination experiment test which took 168 hours, average permeate flux keep at 2.69 kg/m2h with 99.93% salt rejection. PVDF hollow fiber membrane may be of great potential to be utilized in the DCMD process.
