近二十年來，半導體及光電產業在臺灣迅速地發展，也導致排放的廢水中含有各種 高濃度的含氮化合物。本計畫將針對光電產業所產生之高濃度含氨廢水，先利用真空薄 膜蒸餾系統將水中氨濃縮回收，剩餘的廢液以膜接觸技術處理，以達到放流水標準為目標。 首先以濕式紡絲法製備PVDF中空纖維膜，藉由延遲成膜法、改變製膜液、造孔劑 與沉澱槽之組成，製作出一系列不同皮層及孔隙結構之中空纖維膜。以SEM、DSC、 XRD、接觸角等對膜材物性及膜表面性質分析。設計並架設真空薄膜蒸餾測試系統以模 擬含氨廢液的濃縮，探討膜結構與操作條件對氨滲透率及濃縮效率的影響。 計畫第二年將以PVDF/NMP/PVA溶液進行中空纖維膜製備，進行中空纖維膜皮層結 構之最佳化，利用水為芯液，降低內表面相分離速率，增加內表面孔隙度，達到多孔性 PVDF中空纖維膜結構製備出最適合薄膜接觸技術之中空纖維膜，並製成管狀模組以薄膜接觸器去除水中氨氮效率與連續式測試，及其長期穩定性的影響。 計畫第三年將薄膜蒸餾與膜接觸複合技術針對實際工廠廢液作測試，探討其最佳操作條件及其相互影響因子，萃取液將使用光電廠之廢酸，探討各種廢酸(如廢硫酸、鹽 酸及磷酸)的萃取效率及其萃取飽和濃度。另外將中空纖維膜組放大並探討其效能。 The High-Tech Industries have been rapidly developing for the last two decades in Taiwan, which also result in high concentrations of various nitrogenous compounds in the wastewater. Although biological nitrification–denitrification methods have been used in reducing ammonia–nitrogen content in sewage effluent to an acceptable level, the effectiveness of this process is restricted by slow bioconversion and unfavorable environmental factors. It is necessarily to find an efficiency process of promoting the removal of ammonia from wastewater. Polyvinylidene fluoride (PVDF) membranes with asymmetric structures and good hydrophobicity will prepare by a phase-inversion method and have been applied to removal of ammonia from water by membrane contactor. Aqueous solution containing sulfuric acid was used as stripping solution to accelerate the removal of ammonia. This proposal plans for treatment of high concentration wastewater containing ammonia from the photoelectric industry. Use vacuum membrane distillation system concentration and recovery ammonia from solution. The remaining waste water treats by membrane contactor to achieve effluent standards. This research investigates the preparation and application in the vacuum membrane distillation of porous and hydrophobic PVDF membranes. PVDF hollow fiber membranes with different porous structures prepare by immersion-precipitation of a casting solution in coagulation baths composed of N-methyl pyrrolidinone(NMP) and water (nonsolvent). SEM, DSC, XRD, and Contact Angle analyzer use to characterize the membranes. A membrane module was prepared for ammonia concentrate stripping from wastewater will be setup. In addition, AGMD and VMD with tubular modules were also studied theoretically and experimentally. In the second year of the project, PVDF hollow fiber membrane spun via dry-wet spinning method to eliminate the outer dense skin layer by vapor induced phase separation. In addition, aqueous solvent solution is use as the bore liquid to increase inner surface porosity. So that it could achieve the objective of porous morphology design. In addition membrane tubular module was prepared for ammonia stripping from wastewater will be setup for studied theoretically and experimentally. The simulated wastewater, aqueous ammonium chloride solution to give a pH value of 8–12 is pump into the membrane contactor while the stripping solution, 0.05-0.2 M aqueous sulfuric acid solution was countercurrently fed into the other side of membrane contactor module. In the 3rd year, membrane distillation and membrane contactor hybrid system will be setup for the actual factory waste water tests. Experiment and study on system optimal operation conditions and influence factors. Waste acid (such as sulfuric acid, hydrochloric acid, and phosphoric acid) from the photoelectric plant as stripping solution will be used to study on acid stripping efficiencies and stripping saturation. In addition, scale up the hollow fiber membranes module and the effectiveness will investigate.
