ZIF-8 induced growth of blade-like Zn nanosheets on carbon fiber cloth for high-performance separation of oil-in-water emulsion

Abstract With the increase in environmental protection requirements, the oil in the wastewater from offshore oil wells or industries has to be removed with high-precision before discharge. However, the oil-in-water emulsion with high stability is intractable, which makes the oil removal a great challenge. Herein, we designed a novel approach to fabricate carbon fiber cloth with cutting effect that can separate oil-in-water emulsion efficiently. Carbon fibers were firstly modified by ZIF-8 nanoparticles through a hydrothermal method, which induced an ultrafast growth of vertical zinc blades during subsequent electrodeposition (100 s). The blade-like Zn nanosheets on carbon fiber cloth (B-Zn/CFs) were assembled into a superhydrophilic/underwater superoleophobic hierarchical structure, which have the capability of rupturing oil-in-water emulsion via unique cutting effect of the zinc blades. High separation efficiency of 99.72% with exceptional emulsion flux of 962.95 L m −2  h −1  bar −1 , and remaining above 98.53% after 10 cycles were achieved over the composite materials. In addition, the underwater superoleophobic property of B-Zn/CFs persisted even after ultrasonic treatment and salt solution immersion. It is demonstrated that the composite materials show excellent recyclability, mechanical stability and environmental stability during oil/water separation. This work provides a new pathway to design functional materials for high-precision oil removal from wastewater. Graphical abstract