含油废水已成为日益严峻的生态和环境挑战。膜分离技术提供了一种基于尺寸抑制的有效策略，为分离油乳液提供了新的思路。与传统的聚合物分离材料相比，静电纺纳米纤维膜具有较小的直径和相互连接的孔隙，通过调控纺丝参数来赋予其独特的性能，从而使其成为低电阻液体过滤介质的首选材料。

近日，东北林业大学韩广萍教授、程万里教授和王栋副教授团队在期刊《Journal of Membrane Science》上，发表了最新研究成果“Hybrid membranes based on electrospun nanofiber modified with PDA for selective oil-in-water emulsion separation”。研究者通过静电纺丝技术制备出了由纤维素纳米晶体（CNC）和聚多巴胺（PDA）增强的水解聚丙烯腈（H-PAN）复合纳米纤维膜。水解赋予PAN纳米纤维丰富的羧基官能团，并与CNC中的羟基官能团形成氢键交联网络。此过程有助于保持膜的结构完整性并赋予其优异的抗溶胀性，这是CNC/PAN纤维膜所缺乏的。PDA修饰后，即使经过超声处理或均质化处理，PDA纳米颗粒仍能牢固地粘附在纳米纤维表面，显示出较高的表面粗糙度（Ra = 2.86 nm）。

此外，复合纤维膜的拉伸强度为4.19 MPa，孔径约为0.67 μm，其特殊的润湿性和孔隙结构可以在油水分离过程中捕获更多的水，形成油/水/固体界面，从而减少油滴与膜的接触，并有效阻止微小油滴逸出，使水迅速渗透。总体而言，CNC/H-PAN/PDA纤维膜具有较强的结构稳定性、特殊的润湿性、合适的孔隙结构，其表面PDA层有效促进了水包油乳液的分离，并支持乳液的长期循环过滤。

图1：（a-h）不同复合纳米纤维膜SEM形貌；（i）相应纤维膜的直径；CNC/H-PAN/PDA纤维膜的（j）光学微观形貌及（k）SEM-Mapping。

如图1所示，PAN、CNC/PAN和CNC/H-PAN纳米纤维表面光滑；CNC/H-PAN/PDA纳米纤维表面粗糙，PDA颗粒相互堆叠，形成微尺度的层状结构。为了验证PDA层状结构在纳米纤维表面的有效稳定性和膜的耐久性，采用物理（超声和均质化过程）和化学（盐酸，氢氧化钠浸泡）等手段对纳米纤维进行处理。结果表明，PDA层可以牢固地粘附在纳米纤维表面，并且膜的稳定性和耐久性较强。

图2：复合纤维膜的表面润湿性。

图2显示CNC/H-PAN/PDA纳米纤维膜在空气中对油和水均具有亲和力，水下则具有疏油性能，水下膜与油滴间的附着力较小。此外，与其他样品相比，水滴在与CNC/H-PAN/PDA膜接触后更容易从针头末端脱落，膜对水的亲和力最好。射流实验表明CNC/H-PAN/PDA纤维膜在水环境中对动态油（二氯乙烷、甲苯、正己烷、柴油）的排斥性更好，纤维膜具有优异的拒油性。

图3 CNC/H-PAN/PDA纤维膜乳液分离性能及示意图。

图3为CNC/H-PAN/PDA纤维膜对水包油乳液的分离通量、效率和循环稳定性。纤维膜对乳液循环分离20次后，膜通量可恢复到937 L m^-2 h^-1，甚至高于初始分离通量893 L m^-2 h^-1。此外，CNC/H-PAN/PDA膜可以有效防止微小油滴的逸出，让水在重力和毛细管吸力的作用下快速渗透。总体来说，PDA纳米团簇修饰的多级结构成功增强了纤维膜的水下疏油性、防污性和乳液分离性能。

论文链接：

https://doi.org/10.1016/j.memsci.2024.122610

人物简介：

韩广萍：东北林业大学教授。主要研究方向：生物质复合材料。主持国家自然科学基金、国家重点研发计划课题（任务）、黑龙江省重大科技攻关、国家林业局“948”项目等十余项。出版英文专著一部、参编国外教材一部、国内教材两部；发表论文130余篇，授权发明专利12件；编制林业行业标准两项。2022、2023年入选全球前2%顶尖科学家。

程万里，东北林业大学教授，主要研究方向：木材干燥理论与方法、木材高温热处理技术以及纤维素基功能性纳米纤维。主持国家自然科学基金6项、主持和参与其他科研项目等二十余项。发表学术专著一部，参编教材及学术著作五部；发表论文110余篇；授权发明专利18件。

王栋，东北林业大学副教授，主要研究方向：生物质复合材料，木质素、纤维素基功能性纳米纤维；生物制品、水凝胶传感器、水凝胶电解质。发表论文20余篇。

韩广萍教授代表性研究成果论文（近三年）

Haiying Yang, Xinhui Wang, Xuanyu Chen, Yonggui Wang, Dong Wang*, Wanli Cheng*, Guangping Han*. Hybrid membranes based on electrospun nanofiber modified with PDA for selective oil-in-water emulsion separation. Journal of Membrane Science, 2024, 122610. (IF: 9.5)

Xiuwen He, Tian Bai, Jiqing Lu, Yi Hu, Qingxiang Wang, Jie Yan, Hang Yao, Guangping Han*, Wanli Cheng*. High-strength, anisotropic bamboo hydrogel via in situ lignin modification for ion-selective transport and sensor. Chemical Engineering Journal, 2024, 481: 148416. (IF: 15.1)

Zhaoxuan Niu, Qingxiang Wang, Jiqing Lu, Yi Hu, Jiaqi Huang, Wei Zhao*, Yanju Liu*, Yunze Long*, Guangping Han*. Electrospun Cellulose Nanocrystals Reinforced Flexible Sensing Paper for Triboelectric Energy Harvesting and Dynamic Self-Powered Tactile Perception. Small, 2023, 2307810. (IF: 13.3)

Jiqing Lu, Tian Bai, Dong Wang, Haijiao Yu, Qingxiang Wang, Zhaoxuan Niu, Yi Hu, Xueying Liu, Guangping Han*, Wanli Cheng. Electrospun Polyacrylonitrile Membrane In Situ Modified with Cellulose Nanocrystal Anchoring TiO2 for Oily Wastewater Recovery. Advanced Fiber Materials, 2023. (IF: 16.1)

Yi Hu, Meilian Cao, Jianing Xu, Xueying Liu, Jiqing Lu, Jie Yan, Siqi Huan, Guangping Han*, Long Bai*, Wanli Cheng*, and Orlando J. Rojas*. Thermally insulating and electroactive cellular nanocellulose composite cryogels from hybrid nanofiber networks. Chemical Engineering Journal, 2023, 455: 140638. (IF: 15.1)

Dong Wang, Sameer Mhatre, Jingqian Chen, Xuetong Shi, Haiying Yang, Wanli Cheng, Yiying Yue*, Guangping Han*, Orlando J Rojas*. Composites based on electrospun fibers modified with cellulose nanocrystals and SiO2 for selective oil/water separation. Carbohydrate Polymers, 2023, 299: 120119. (IF: 11.2) 

Dong Wang, Haiying Yang, Qingxiang Wang, Yi Lu, Jie Yan, Wanli Cheng*, Orlando J. Rojas*, Guangping Han*. Composite membranes of polyacrylonitrile cross-linked with cellulose nanocrystals for emulsion separation and regeneration. Composites Part A: Applied Science and Manufacturing, 2022. 107300. (IF: 8.7)

Meilian Cao, Yi Hu, Wanli Cheng, Siqi Huan, Tian Bai, Zhaoxuan Niu, Yueyang Zhao, Guichu Yue, Yong Zhao*, and Guangping Han*. Lignin-based multi-scale cellular aerogels assembled from co-electrospun nanofibers for oil/water separation and energy storage. Chemical Engineering Journal, 2022, 436: 135233 （IF: 15.1)

Runzi Ding, Xiuwen He, Yi Hu, Jie Yan, Jiqing Lu, Sheldon Q. Shi, Guangping Han*, and Wanli Cheng. Uniform grafting of amino-functionalized multi-walled carbon nanotubes on the surface of oxidized bamboo fiber to enhance the interfacial strength with epoxy resin. Applied Surface Science, 2022, 603: 154480. (IF: 6.7)

Qingxiang Wang, Dong Wang, Wanli Cheng, Jiaqi Huang, Meilian Cao, Zhaoxuan Niu, YueYang Zhao, Yiying Yue*, and Guangping Han*. Spider-web-inspired membrane reinforced with sulfhydryl-functionalized cellulose nanocrystals for oil/water separation. Carbohydrate Polymers, 2022, 282: 119049 (IF: 11.2) 

Jie Yan, Tian Bai, Yiying Yue, Wanli Cheng, Long Bai, Dong Wang, Jiqing Lu, Cao Meilian , Sheldon Q. Shi, Siqi Huan*, Guangping Han*. Nanostructured superior oil-adsorbent nanofiber composites using one-step electrospinning of polyvinylidene fluoride/nanocellulose. Composites Science and Technology, 2022, 224, 109490 (IF: 9.1)

Jiqing Lu, Meilian Cao, Xiuwen He; Yi Hu, Long Bai, Siqi Huan, Guangping Han*, and Wanli Cheng*. Electrospun hierarchically channeled polyacrylonitrile nanofibrous membrane for wastewater recovery. Journal of Cleaner Production, 2022, 361, 132167 (IF: 11.1)

Zhaoxuan Niu, Wanli Cheng, Meilian Cao, Dong Wang, Qingxiang Wang, Jingquan Han, Yunze Long, and Guangping Han*. Recent advances in cellulose-based flexible triboelectric nanogenerators. Nano Energy, 2021, 87, 106175 （IF: 17.6）

Meilian Cao, Qingxiang Wang, Wanli Cheng, Siqi Huan, Yi Hu, Zhaoxuan Niu, Guangping Han*, Haitao Cheng*, and Ge Wang*. A novel strategy combining electrospraying and one-step carbonization for the preparation of ultralight honeycomb-like multilayered carbon from biomass-derived lignin. Carbon, 2021, 179, 68-79 (IF: 9.4)

Tian Bai, Dong Wang, Jie Yan, Wanli Cheng, Haitao Cheng, Sheldon Q. Shi, Ge Wang, and Guangping Han*. Wetting mechanism and interfacial bonding performance of bamboo fiber reinforced epoxy resin composites. Composites Science and Technology, 2021, 213, 108951 (IF: 9.1)

Meilian Cao, Dong Wang, Jiqing Lu, Wanli Cheng, Guangping Han*, and Jianbo Zhou. Electrospun porous carbon nanofibers@SnOx nanocomposites for high-performance supercapacitors: Microstructures and electrochemical properties. Composites Part A: Applied Science and Manufacturing, 2021, 143, 106278 (IF: 8.7)

Dong Wang, Junjiao Zang, Qingxiang Wang, Wanli Cheng, Guangping Han*, Siqi Huan*. Hierarchical composite membrane with multiscale roughness structures for water-in-oil emulsion separation. Applied Surface Science, 2021, 566, 150666. (IF: 6.7)