In Situ Redox Strategy to Fabricate Superhydrophobic Sponges for Efficient Oil–Water Separation

In this work, a superhydrophobic MnO2@AF-MWCNTs@PDMS@Melamine sponge (S-MMP@MS) with highly efficient oil–water separation was prepared. MnO2 nanoparticles were loaded onto melamine sponges through the in situ redox reaction between AF-MWCNTs and KMnO4. To further enhance the hydrophobic properties of the modified sponges, a nontoxic polydimethylsiloxane (PDMS) glue layer was fixed on the sponges by dip-coating. The S-MMP@MS demonstrated excellent superhydrophobicity (with a water contact angle of 156.8°), a high adsorption capacity (54.3–136.7 g/g), and excellent recyclability (50 times of the adsorption–extrusion cycle). In addition to immiscible oil–water mixtures, the modified sponges can separate water-in-oil emulsions and oil-in-water emulsions with equal effectiveness (the separation rate exceeded 99.0%). Furthermore, the modified sponges can maintain stable superhydrophobicity in simulated complex marine environments, including acidic environments, alkaline environments, corrosive conditions, different temperatures, and mechanical compression. The superhydrophobic melamine sponges are expected to be a potential material for oil spill treatment due to their excellent oil–water separation efficiency, reusability, environmental suitability, and mechanical stability.

本研究制备了一种具备高效油水分离性能的超疏水二氧化锰@氨基化多壁碳纳米管@聚二甲基硅氧烷@三聚氰胺海绵（S-MMP@MS）。通过氨基化多壁碳纳米管（AF-MWCNTs）与高锰酸钾（KMnO4）之间的原位氧化还原反应，将二氧化锰纳米颗粒负载至三聚氰胺海绵基底。为进一步提升改性海绵的疏水性能，通过浸涂法将无毒聚二甲基硅氧烷（PDMS）胶层固定于海绵表面。该S-MMP@MS展现出优异的超疏水性能（水接触角达156.8°）、较高的吸附容量（54.3~136.7 g/g）以及出色的循环复用性（可完成50次吸附-挤出循环）。除可分离互不相溶的油水混合物外，该改性海绵对油包水型乳液及水包油型乳液均具备同等高效的分离效果，分离率均超过99.0%。此外，该改性海绵在模拟复杂海洋环境中可保持稳定的超疏水性能，涵盖酸性环境、碱性环境、腐蚀工况、不同温度条件以及机械压缩作用。鉴于其优异的油水分离效率、可复用性、环境适配性及机械稳定性，这类超疏水三聚氰胺海绵有望成为溢油处理的潜在候选材料。