用於水與有機溶劑分離之新型聚酮基複合摻合膜

Abstract

工業廢水中重金屬和奈米顆粒含量高得驚人，引發了全球對先進策略的關注，這些策略需要適應分離產業的多種應用。對於去除奈米級污染物和金屬離子，傳統處理方法效率有限，主要原因是分離材料的性能較差。在這方面，膜分離技術因其在製備、表面改質和孔徑控制方面的靈活性，成為一種極具吸引力的分離平台。然而，目前用於製備此類薄膜的聚合物通常存在機械強度差、可重複使用性差和易結垢等性能限制。因此，亟需尋找合適的聚合物候選材料和製備策略，以開發能實現永續水淨化技術的下一代薄膜系統。在本論文中，我們首先透過靜電紡絲法製備了一種最佳化的聚酮/尼龍-6共混奈米纖維膜，以利用其獨特的化學性質來實現更高的親水性（第四章）。由於尼龍-6以50:50的比例精確添加，PKN共混膜的純水通量比純PK薄膜增加了1.7倍。為了提高其重金屬截留性能，採用旋塗法，以3-氨丙基三乙氧基矽烷（APTES）對PKN(50:50)膜進行表面改質。 APTES表面改質後的PKN(50:50)薄膜對鉻、銀和鉛的截留率分別達87%、80%和100%，且具有良好的可重複使用性，性能未受影響。精確的共混比例和APTES表面改質使這些膜展現出優異的重金屬去除能力。第五章將重點放在PKN共混聚合物膜在水溶液中高效分離奈米顆粒的應用。將電紡PKN膜在不同溫度下進行熱壓延處理，以改善其理化性質。使用PKN膜對奈米顆粒的截留率達到了100%。 PKN膜的奈米顆粒截留能力經評估，截留率達100%。該膜在140℃、1.5 bar壓力下進行熱壓，通量為6000 Lmh/bar。此外，該膜在7小時內保持分離能力，通量下降幅度很小。這些研究結果透過GeoDICT模擬軟體進行驗證，並結合對所開發的PKN膜的機制理解。總之，本論文強調了PKN聚合物共混膜作為可持續高效分離重金屬和奈米顆粒的理想候選材料的重要性。這種能夠精確調控孔結構、具有高耐久性和可重複使用性的新一代膜平台，將在未來拓展分離產業的應用範圍。

The alarming levels of toxic heavy metals and nanoparticles in the industrial effluents have focused global attention on the need for advanced strategies that can be tailored to multiple applications in the separation industry. For the removal of nano-sized pollutants and metal ions, traditional treatment methods exhibit limited efficiency mainly due to the poor performance of the materials used in separation. In this regard, membrane-based separation offers an attractive separation platform technology due to the flexibility in fabrication, surface modification, and pore size control. However, the polymers currently available for fabricating such membranes often face limitations in performance due to poor mechanical strength, reusability issues, and severe fouling. Hence, there is a need to identify suitable polymer candidates and fabrication strategies to develop next-generation membrane systems that enable sustainable water purification technology. In this thesis, we first developed an optimised polyketone/nylon-6 blended nanofibrous membrane via the electrospinning method to exploit its unique chemical properties to achieve higher hydrophilicity (Chapter 4). The PKN blended membrane showed a 1.7-fold enhancement in the pure water flux compared to the pure PK membrane due to the precise addition of nylon-6 in the ratio of 50:50. To improve their heavy metal rejection behaviour, the PKN(50:50) membrane was surface-modified using 3-aminopropyltriethoxysilane (APTES) via the spin coating. The APTES surface-modified PKN(50:50) exhibited rejection rates of 87%, 80%, and 100% for Chromium, Silver, and Lead, respectively, with high reusability and no impact on their performance. The precise blending and APTES surface modification enabled these membranes to exhibit a superior heavy metal removal capacity. Chapter 5 focuses on investigating the PKN blended polymer membranes for efficient nanoparticle separation from aqueous systems. The electrospun PKN membranes were subjected to thermal calendaring at different temperatures to improve their physicochemical properties. A 100% efficiency in rejection was achieved in nanoparticle capturing by using the PKN membrane. The nanoparticle capturing ability of PKN was evaluated and found to achieve 100% rejection efficiency. This was observed in the membrane calendared at 140°C at 1.5 bar with 6000 Lmh/bar flux. In addition, the membrane showed 7 hours of separation capability with a marginal flux decline. These studies were performed and confirmed using GeoDICT simulation software, along with understanding the developed PKN membrane mechanistically. In summary, this thesis emphasises the significance of PKN polymer-blended membranes as a suitable candidate for sustainable high-performance separation of heavy metals and nanoparticles. Such next-generation membrane platforms, which enable precise tuning of the pore structure with high durability and reusability, will expand the scope of the separation industry in the future.