Regarding emulsion separation using porous materials, two keypoints, i.e. proper average pore size and wettability, should be carefully considered. Herein, three-dimensional (3D) superhydrophilic polyvinyl alcohol-formaldehyde (PVA-PVF) sponges with tunable pore size are successfully prepared through crosslinking reaction of polyvinyl alcohol (PVA) in the polyvinyl alcohol-formaldehyde (PVF) network under acidic condition. The introduction of PVA containing chitosan, diatomite and sodium alginate can effectively decrease the average pore size of PVF from approximately 75 μm to 23 μm along with a few hundred nanometers pore channels, while maintaining porosity above 73.4%. These PVA-PVF composite sponges with hierachical pore structure are applied to separate various surfactant­stabilized oil-in-water emulsions solely by gravity. The separation efficiency can reach up to 97.40% with a high water flux of 2.40 × 10⁴ L m⁻² h⁻¹ bar⁻¹. Meanwhile, the separation efficiency of different charged PVA-PVF composite sponges (i.e. PVA-CS-PVF, PVA-Si-PVF, PVA-SA-PVF) for oil-in-water emulsions stabilized by different types of surfactants, including anionic, nonionic, and cationic surfactants, is also evaluated. Definitely, the PVA-PVF composite sponges with outstanding hydrophilic, excellent stability, simple preparation method can be regarded as a new candidate of emulsion separation material in practical applications.

关于使用多孔材料进行乳液分离，应仔细考虑两个关键点，即适当的平均孔径和润湿性。在此，通过聚乙烯醇（PVA）在聚乙烯醇-甲醛（PVF）网络中在酸性条件下的交联反应，成功制备了具有可调孔径的三维（3D）超亲水聚乙烯醇-甲醛（PVA-PVF）海绵。含有壳聚糖、硅藻土和海藻酸钠的 PVA 的引入可以有效地将 PVF 的平均孔径从大约 75 μm 降低到 23 μm，并具有数百纳米的孔道，同时保持孔隙率在 73.4% 以上。这些具有分级孔结构的 PVA-PVF 复合海绵用于仅通过重力分离各种表面活性剂稳定的水包油乳液。⁴  L m ^-2  h ^-1  bar ^-1。同时，不同带电PVA-PVF复合海绵（即PVA-CS-PVF、PVA-Si-PVF、PVA-SA-PVF）对不同类型表面活性剂稳定的水包油乳液的分离效率，包括阴离子、还评估了非离子和阳离子表面活性剂。毋庸置疑，亲水性优异、稳定性好、制备方法简单的PVA-PVF复合海绵可作为实际应用中乳化分离材料的新候选。