Alebrahim Taliehsadat, Huang Liang, Welgama Heshali K, Esmaeili Narjes, Deng Erda, Cheng Shiwang, Acharya Durga, Doherty Cara M, Hill Anita J, Rumsey Clayton, Trebbin Martin, Cook Timothy R, Lin Haiqing
Department of Chemical and Biological Engineering, University at Buffalo, The State University of New York, Buffalo, New York 14260, United States.
School of Environmental Science & Engineering, Huazhong University of Science and Technology, Wuhan 430074, Hubei, China.
ACS Appl Mater Interfaces. 2024 Feb 28;16(8):11116-11124. doi: 10.1021/acsami.3c19631. Epub 2024 Feb 19.
Mixed matrix materials (MMMs) containing metal-organic framework (MOF) nanoparticles are attractive for membrane carbon capture. Particularly, adding <5 mass % MOFs in polymers dramatically increased gas permeability, far surpassing the Maxwell model's prediction. However, no sound mechanisms have been offered to explain this unusual low-loading phenomenon. Herein, we design an ideal series of MMMs containing polyethers (one of the leading polymers for CO/N separation) and discrete metal-organic polyhedra (MOPs) with cage sizes of 2-5 nm. Adding 3 mass % MOP-3 in a polyether increases the CO permeability by 100% from 510 to 1000 Barrer at 35 °C because of the increased gas diffusivity. No discernible changes in typical physical properties governing gas transport properties are detected, such as glass transition temperature, fractional free volume, -spacing, etc. We hypothesize that this behavior is attributed to fractal-like networks formed by highly porous MOPs, and for the first time, we validate this hypothesis using small-angle X-ray scattering analysis.
包含金属有机框架（MOF）纳米颗粒的混合基质材料（MMM）对于膜法碳捕集具有吸引力。特别地，在聚合物中添加<5质量%的MOF可显著提高气体渗透率，远远超过麦克斯韦模型的预测。然而，尚未有合理的机理解释这种不寻常的低负载现象。在此，我们设计了一系列理想的MMM，其包含聚醚（用于CO/N分离的主要聚合物之一）和笼尺寸为2 - 5纳米的离散金属有机多面体（MOP）。在聚醚中添加3质量%的MOP - 3，由于气体扩散率增加，在35℃时CO渗透率从510 Barrer提高到1000 Barrer，增幅达100%。在控制气体传输性质的典型物理性质方面未检测到明显变化，如玻璃化转变温度、自由体积分数、-间距等。我们假设这种行为归因于由高度多孔的MOP形成的类分形网络，并且我们首次使用小角X射线散射分析验证了这一假设。
