Plasma-Made Graphene Nanostructures with Molecularly Dispersed F and Na Sites for Solar Desalination of Oil-Contaminated Seawater with Complete In-Water and In-Air Oil Rejection
Plasma-Made Graphene Nanostructures with Molecularly Dispersed F and Na Sites for Solar Desalination of Oil-Contaminated Seawater with Complete In-Water and In-Air Oil Rejection
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DOI：
10.1021/acsami.0c07921
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发表时间：
2020-08-26
影响因子：
9.5
通讯作者：
Fisher, Timothy S.
中科院分区：
文献类型：
--
作者：
Wu, Shenghao;Gong, Biyao;Fisher, Timothy S.
利用界面蒸发的太阳能脱盐是解决全球水资源短缺的一个有前途的解决方案。真实世界的原料（例如，天然海水和受污染的水）包括油污染问题，从而迫切需要提供抗油污能力的脱盐系统;然而，制备拒油同时吸水的表面仍然具有挑战性。这项工作展示了在等离子体制造的垂直取向的石墨烯纳米片上分子分散功能性F和Na位点以实现在空气和水中疏油、亲水表面的概念。石墨烯结构呈现高的空气中（138度）和水中（145度）油接触角，同时具有高的水亲和力（0度）。这种表面润湿性通过分散在石墨烯表面上的分子的疏油、疏水-CFx和亲水-COONa基团;固体表面张力的低分散（0.439 mJ m（-2））和高极性（95.199 mJ m（-2））组分;以及石墨烯边缘产生的增加的表面粗糙度来实现。石墨烯纳米结构通过毛细管作用将水向上泵送，但从表面排斥油，从而导致完全的水中和空气中的油排斥以及用于太阳能脱盐的通用抗油污能力。因此，无论原料是纯水还是油污染的水（例如，漂浮在水面上的油的混合物，水包油乳液），从而在几天内有效地产生清洁水。这种出色的性能归因于普遍的（在水中和空气中）疏油润湿性，以及纳米陷阱贡献的高光吸收率，鳍状纳米结构增强的快速界面传热，以及尖锐的石墨烯边缘实现的加速蒸发。
Solar desalination that exploits interfacial evaporation represents a promising solution to global water scarcity. Real-world feedstocks (e.g., natural seawater and contaminated water) include oil contamination issues, raising a compelling need for desalination systems that offer anti-oil-fouling capability; however, it is still challenging to prepare oil-repellent and meanwhile water-attracting surfaces. This work demonstrates a concept of molecularly dispersing functional F and Na sites on plasma-made vertically oriented graphene nanosheets to achieve an in-air and in-water oleophobic, hydrophilic surface. The graphene architecture presents high in-air (138 degrees) and in-water (145 degrees) oil contact angles, with simultaneously high water affinity (0 degrees). Such surface wettability is enabled by oleophobic, hydrophobic -CFx, and hydrophilic -COONa groups of the molecules that disperse on graphene surfaces; low-dispersion (0.439 mJ m(-2)) and high-polarity (95.199 mJ m(-2)) components of the solid surface tension; and increased surface roughness produced by graphene edges. The graphene nanostructures pump water upward by capillary action but repel oil from the surface, leading to complete in-water and in-air oil rejection and universal anti-oil-fouling capability for solar desalination. Consequently, stable solar-vapor energy efficiency of more than 85% is achieved regardless of whether the feedstock is pure or oil-contaminated water (e.g., a mixture of oil floating on water, an oil-in-water emulsion), resulting in the efficient production of clean water over several days. This outstanding performance is attributed to the universal (both in-water and in-air) oleophobic wettability, together with high light absorptance contributed by nanotraps, fast interfacial heat transfer enhanced by finlike nanostructures, and accelerated evaporation enabled by sharp graphene edges.