Feng Weilin, Li Fupeng, Li Jiaqi, Li Zhiyi, Xu Lu, Guo Hukang, Li Nanwen, Cao Xinzhong, Fang Chuanjie, Zhu Baoku, Zhu Liping
MOE Key Laboratory of Macromolecular Synthesis and Functionalization, Department of Polymer Science and Engineering, Zhejiang University, Hangzhou 310058, P.R. China.
MOE Engineering Research Center of Membrane and Water Treatment Technology, Zhejiang University, Hangzhou 310058, P.R. China.
Sci Adv. 2025 Sep 12;11(37):eady3674. doi: 10.1126/sciadv.ady3674.
Conventional fractionation of liquid hydrocarbons relies on energy-intensive distillation. While organic solvent reverse osmosis provides an energy-efficient alternative, the challenge lies in engineering membranes with accurately tailored molecular differentiation for complex hydrocarbons. Here, we develop diverse fluorinated polyimide membranes featuring programmable polymer chain architectures for efficient hydrocarbon separation. By stoichiometry-controlled polycondensation, the chain packing and microporosity of synthesized polyimides are finely regulated, verified by molecular simulations. The corresponding asymmetrical membranes with defect-free thin layers of 100 to 250 nanometers are prepared via solution casting and thermal annealing steps. Such programmed membranes enable tunable permselectivity for hydrocarbons with less than 40 carbon atoms. The fractionation of kerosene-paraffin mixture in toluene is demonstrated through a two-stage process containing the optimized membranes. The cascade process remarkably enriches the C-C hydrocarbons from 50% up to 97%. The demonstrated polyimide membranes with on-demand molecular discrimination capability provide a potential candidate for the membrane-based hydrocarbon fractionation.
液态烃的传统分馏依赖于能源密集型蒸馏。虽然有机溶剂反渗透提供了一种节能的替代方法，但挑战在于设计出对复杂烃类具有精确分子区分能力的膜。在此，我们开发了多种具有可编程聚合物链结构的氟化聚酰亚胺膜，用于高效烃类分离。通过化学计量控制的缩聚反应，合成聚酰亚胺的链堆积和微孔率得到精细调节，并经分子模拟验证。通过溶液浇铸和热退火步骤制备了相应的具有100至250纳米无缺陷薄层的不对称膜。这种可编程膜能够对碳原子数少于40的烃类实现可调的渗透选择性。通过包含优化膜的两阶段过程，展示了煤油 - 石蜡混合物在甲苯中的分馏。该级联过程显著地将C - C烃类从50%富集到97%。所展示的具有按需分子识别能力的聚酰亚胺膜为基于膜的烃类分馏提供了一个潜在候选方案。
