Copper surfaces decorated with micro- and nanostructures can be applied to self-cleaning superhydrophobic surfaces, energy devices and pollution remediation. Wet chemical etching is the classical strategy to grow micro- and nanostructures on copper surfaces. However, such processes usually produce hazardous chemical waste. Here, we present a one-step, eco-friendly and solvent-less alternative to conventional wet chemical methods. Our method involves the use of volatile compounds released from yolk and egg white of boiled chicken eggs as green oxidants for the growth of micro- and nanostructures on the copper surface. After treatment with egg components, copper substrates were modified with stearic acid to make them superhydrophobic. Stearic acid-coated substrates had a contact angle of about 150°, thus confirming their superhydrophobicity. Similar to copper sheets, superhydrophobic copper meshes were also prepared and used for the selective removal of oil from oil/water mixture. Results show that our method produces a wide range of shapes including hollow and solid spheres, nanoflakes, nanoneedles and dome shapes. We found that H₂S, the major volatile compound emitted by eggs, is mainly responsible for the growth of microstructures. Therefore, our method can be used both to capture H₂S and to design specific surfaces. The mesh exhibited excellent separation efficiency, more than 95% for the organic solvents. A key advantage of our method is that it can be performed also using waste and expired eggs.

中文翻译：

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用于油/水分离的超疏水铜表面的环保制备

装饰有微结构和纳米结构的铜表面可用于自清洁超疏水表面，能源设备和污染修复。湿法化学蚀刻是在铜表面上生长微结构和纳米结构的经典策略。但是，这样的过程通常会产生危险的化学废料。在这里，我们提出了一种传统的湿化学方法的一步，环保且无溶剂的替代方法。我们的方法涉及使用从煮鸡蛋的蛋黄和蛋清中释放的挥发性化合物作为绿色氧化剂，以在铜表面上生长微结构和纳米结构。用鸡蛋成分处理后，铜基板用硬脂酸改性，使其具有超疏水性。涂有硬脂酸的基材的接触角约为150°，因此证实了它们的超疏水性。类似于铜板，还制备了超疏水性铜网，并将其用于从油/水混合物中选择性去除油。结果表明，我们的方法可产生多种形状，包括空心球和实心球，纳米薄片，纳米针和圆顶形状。我们发现H₂ S是鸡蛋释放的主要挥发性化合物，主要负责微观结构的生长。因此，我们的方法可用于捕获H ₂ S和设计特定表面。筛网表现出出色的分离效率，有机溶剂的分离效率超过95％。我们方法的主要优势在于，它也可以使用废鸡蛋和过期鸡蛋来进行。