The increasing release of oily wastewater from both household and industrial activities has led to a significant environmental challenge. Among the various methods for treating oil-water mixtures, membranes with specialized wettability characteristics have emerged as one of the most effective and cost-efficient approaches. In this field, reducing the thickness of membranes is a key strategy to lessen resistance to mass transfer. This paper describes the creation of a super-hydrophobic, submicron-thin (945 nm) and even transparent (79.99% relative transparency at 600 nm wavelength) composite membrane for oil/water separation. This was achieved by depositing polydivinylbenzene (PDVB) onto ∼170 nm ultrathin freestanding polyethylene (PE) membranes to form hierarchical rough textures. Based on the super-hydrophobicity and high roughness, PE/PDVB composite membrane is enabled to separate oil from water in both mixtures and emulsions of immiscible oil/water. Moreover, PE/PDVB demonstrated a separation efficiency exceeding 99.91% for various water-in-oil emulsions. Impressively, this efficiency could be sustained above 99.87% even after 30 cycles of separation involving surfactant-stabilized isooctane/water emulsions. This performance robustness persisted against various chemical environments such as acidic, alkaline, and saline conditions over prolonged periods. To our knowledge, PE/PDVB is currently the thinnest oil/water purification membrane available, combining both an active layer and support. This work also highlights the practicality of using an ultra-thin support layer for efficient oil/water separation. This work may be at use for membrane scientists who are developing ultra-thin membrane materials and processes for future applications.

中文翻译：

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亚微米超薄PE/PDVB复合膜实现高效油水分离

家庭和工业活动中含油废水的排放量不断增加，给环境带来了严峻的挑战。在处理油水混合物的各种方法中，具有特殊润湿特性的膜已成为最有效和最具成本效益的方法之一。在这一领域，减少膜的厚度是减少传质阻力的关键策略。本文描述了用于油/水分离的超疏水、亚微米薄（945 nm）甚至透明（600 nm 波长相对透明度为 79.99%）复合膜的创建。这是通过将聚二乙烯基苯（PDVB）沉积到〜170 nm超薄独立聚乙烯（PE）膜上以形成分层粗糙纹理来实现的。基于超疏水性和高粗糙度，PE/PDVB复合膜能够在不相溶的油/水混合物和乳液中分离油水。此外，PE/PDVB 对各种油包水乳液的分离效率超过 99.91%。令人印象深刻的是，即使在使用表面活性剂稳定的异辛烷/水乳液进行 30 个分离循环后，这种效率仍可维持在 99.87% 以上。这种性能稳健性能够在各种化学环境（例如酸性、碱性和盐水条件）下长期持续存在。据我们所知，PE/PDVB 是目前最薄的油/水净化膜，结合了活性层和支撑层。这项工作还强调了使用超薄支撑层进行高效油/水分离的实用性。这项工作可能可供正在开发超薄膜材料和工艺以供未来应用的膜科学家使用。