石墨烯量子點混合基質薄膜進行多尺度分子分離

Abstract

石墨烯量子點（Graphene Quantum Dots, GQDs）以其奈米尺度的尺寸、可調控的表面化學性質以及量子侷限效應，在多尺度分子分離的膜技術中帶來進步。雖然共價有機框架（COFs）、金屬有機框架（MOFs）和碳奈米管（CNTs）等材料在分離應用中顯示出潛力，但其實際應用面臨許多限制，例如合成過程複雜、生產成本高、機械結構脆弱以及易受污染影響。相比之下，基於石墨烯量子點的材料提供了一個可持續且多功能的替代方案，利用其簡單的電漿合成方法、科學的結構特性探討，以及在各種尺度上精細調控分子交互的能力。

在這項研究中，我們開發了結合氮摻雜石墨烯量子點（GQDs）的電漿工程膜，將其作為多功能的奈米填料。這些GQDs是通過綠色、大氣壓電漿技術合成，能夠精準控制孔結構、表面功能性以及分子間的交互作用。在奈米濾膜應用中，GQD膜表現達到了超高的水通量（289 L·m⁻²·h⁻¹·bar⁻¹）以及99.96%的染料阻絕率，這歸因於其優異的表面親水性和互聯的奈米通道。同時，GQD-無機複合材料在次奈米尺度的應用中展現出色的性能，對分子量相差200 Da的分子分離因子達到92.68。在氣體分離方面，GQD-Pebax混合基質膜實現了卓越的CO₂滲透率（415 Barrer）和CO₂/N₂選擇性（125），這得益於其形成了有利於CO₂擴散的埃米尺度通道。

透過解決多尺度分子分離的挑戰，薄膜技術為水純化、碳捕集和工業廢棄物處理等多樣化應用提供了量身定制的解決方案。小尺度分離（如氣體淨化和藥品精煉）依賴於分子專一性和精確的孔控設計，而大尺度分離（如大分子過濾和污染物去除）則受益於增強的機械穩定性和表面化學交互作用。這種多尺度框架不僅提高了分離效率，還擴展了膜的功能多樣性，為清潔能源、環境保護以及生物醫學技術之應用。

Graphene Quantum Dots (GQDs), with their nanoscale dimensions, tunable surface chemistry, and exceptional quantum effects, represent a transformative advancement in membrane technologies for multi-scale molecular separation. While existing materials, such as covalent organic frameworks (COFs), metal-organic frameworks (MOFs), and carbon nanotubes (CNTs), have demonstrated potential in separation applications, their practical implementation is hindered by several limitations, including complex synthesis procedures, high production costs, mechanical fragility, and susceptibility to fouling. In contrast, GQD-based matrices present a sustainable and versatile alternative, capitalizing on their facile plasma-based synthesis, robust structural attributes, and capacity to fine-tune molecular interactions across various scales. In this study, we developed plasma-engineered membranes incorporating nitrogen-doped GQDs as multifunctional nanofillers. Synthesized using a green, atmospheric-pressure microplasma process, GQDs offer precise control over pore architectures, surface functionality, and molecular interactions. At the nanofiltration scale, GQD membranes demonstrated exceptional performance, achieving ultrahigh water permeability (289 L·m⁻²·h⁻¹·bar⁻¹) and superior dye rejection (99.96%), attributed to enhanced hydrophilicity and interconnected nanochannels. Meanwhile, GQD-inorganic nanocomposites exhibited a remarkable separation factor of 92.68 for molecules differing by 200 Da in molecular weight, operating effectively at the sub-nanometer scale. For gas separation, GQD-Pebax mixed matrix membranes achieved exceptional CO₂ permeability (415 Barrer) and CO₂/N₂ selectivity (125), enabled by the creation of angstrom-level pathways favoring CO₂ diffusion. By addressing molecular separations across multiple scales, these membranes offer tailored solutions for diverse challenges in water purification, carbon capture, and industrial waste treatment. Small-scale separations, essential for applications such as gas purification and pharmaceutical refinement, rely on molecular specificity and precise pore control. Conversely, larger-scale separations, such as macromolecule filtration and pollutant removal, benefit from enhanced mechanical stability and surface chemical interactions. This multi-scale framework not only improves separation efficiency but also extends the functional versatility of membranes, paving the way for transformative applications in clean energy, environmental protection, and biomedical technologies.