The interaction of biofilms with metallic surfaces produces two biologically induced degradation processes of materials: microbial induced corrosion and bioleaching. Both phenomena affect most metallic materials, but in the case of noble metals such as gold, which is inert to corrosion, metallophilic bacteria can cause its direct or in direct dissolution. When this process is controlled, it can be used for hydrometallurgical applications, such as the recovery of precious metals from electronic waste. However, the presence of unwanted bioleaching-producing bacteria can be detrimental to metallic materials in specific environments. In this work, we propose the use of single-layer graphene as a protective coating to reduce Au bioleaching by Cupriavidus metallidurans, a strain adapted to metal contaminated environments and capable of dissolving Au. By means of Scanning Tunneling Microscopy, we demonstrate that graphene coatings are an effective barrier to prevent the complex interactions responsible for Au dissolution. This behavior can be understood in terms of graphene pore size, which creates an impermeable barrier that prevents the pass of Au-complexing ligands produced by C.metallidurans through graphene coating. In addition, changes in surface energy and electrostatic interaction are presumably reducing bacterial adhesion to graphene-coated Au surfaces. Our findings provide a novel approach to reduce the deterioration of metallic materials in devices in environments where biofilms have been found to cause unwanted bioleaching.

中文翻译：

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石墨烯涂层作为防止细菌介导的金溶解的有效屏障

生物膜与金属表面的相互作用产生了两种生物诱导的材料降解过程：微生物诱导的腐蚀和生物浸出。这两种现象都会影响大多数金属材料，但是对于对腐蚀呈惰性的贵金属（如金），嗜金属细菌会导致其直接或直接溶解。控制此过程后，可用于湿法冶金应用，例如从电子废物中回收贵金属。但是，有害的生物浸出产生细菌的存在可能对特定环境中的金属材料有害。在这项工作中，我们建议使用单层石墨烯作为保护性涂层，以减少金属铜脲类化合物对金的生物浸出，一种适应金属污染环境并能够溶解金的菌株。通过扫描隧道显微镜，我们证明了石墨烯涂层是防止造成Au溶解的复杂相互作用的有效屏障。此行为可以在石墨烯的孔径，这产生一个不可渗透的阻挡而言可以理解的是防止所产生的Au-络合配体的通C. metallidurans通过石墨烯涂层。此外，表面能和静电相互作用的变化可能会减少细菌对石墨烯涂层Au表面的粘附。我们的发现提供了一种新颖的方法，可以减少在发现生物膜导致有害生物浸出的环境中设备中金属材料的劣化。