For a fixed porous framework, developing an efficient composite material with selective removal of oil and water from an oil–water mixture is of significance but challenging because of the effect of its decreased pore size and porosity and single wettability. Herein, a Janus fabric via a general strategy of surface hydrophobization, oxidation treatment, and chemical bath deposition is constructed. The obtained composite fabric consists of a hydrophilic Co(CO₃)_0.5OH·0.11H₂O nanoneedle/cotton fiber side and a hydrophobic cotton fiber side, which endows it with a unidirectional water transportation capability and exhibits an effective separation for both light and heavy oil–water mixtures under gravity. Especially using the water wetted composite fabric as a separation cell, the built-in lyophobic layer originating from fluid passed through the nonwetting region of wetted fabric decreases the unfavorable contact between lyophobic interface and separated liquid, and the permeation flux is enhanced by 214.5% for water and by 112.5% for oil, respectively, compared to that in the pristine fabric, whereas it has no effect on the separation efficiency of a heavy oil–water mixture. Meanwhile, the Janus composite fabric exhibits an excellent oil–water separation stability and durability and is easily recycled for long-term use. The facile Janus material synthesis strategy is available on various substrates including melamine sponge, Ni foam, cellulose paper, and other nanosheet arrays on cotton fabric. Thus, this work provides a route to develop multifunctional materials for potential application in quick oily wastewater remediation.

中文翻译：

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用于油水分离的Co（CO ₃）_0.5 OH·0.11H ₂ O纳米酮合成Janus复合织物的一般原位沉积策略

对于固定的多孔骨架，开发一种有效的复合材料并从油水混合物中选择性去除油和水具有重要意义，但由于其减小的孔径和孔隙率以及单次润湿性的影响而具有挑战性。在此，通过表面疏水化，氧化处理和化学浴沉积的一般策略来构造Janus织物。所得的复合织物由亲水性Co（CO ₃）_0.5 OH·0.11H _2组成纳米针/棉纤维一面和疏水棉纤维一面，使其具有单向水传输能力，并且在重力作用下对轻质和重质油水混合物均具有有效的分离能力。尤其是使用湿润的复合织物作为分离单元时，内置的疏液层起源于通过湿润织物的非湿润区域的流体，从而减少了疏液界面与分离液之间的不利接触，渗透通量提高了214.5％。与原始织物相比，水和油分别减少了112.5％，而对重油-水混合物的分离效率没有影响。与此同时，Janus复合织物具有出色的油水分离稳定性和耐用性，并且易于回收再长期使用。简便的Janus材料合成策略可用于多种基材，包括三聚氰胺海绵，镍泡沫，纤维素纸和棉织物上的其他纳米片阵列。因此，这项工作提供了开发多功能材料的途径，可用于快速含油废水的修复。