| In recent years,with the frequent occurrence of crude oil spill accidents,as well as large amount of oily wastewater discharged from factories,oily wastewater affects the ecological environment and people's daily life,Thus,oil cleanup has become an urgent yet challenging task.The separation process of membrane is a non-phase change of physical function,low energy consumption and simple design of separation device,high selectivity etc.The choice of membrane material determines the effect of oil-water separation,The material with super-hydrophobic and super-oleophilic material has attracted much attention because of its special interface properties for oil and water.Here,we report a facile and environmental-friendly approach to fabricate superhydrophobic porous membranes for oil-water separation by 3D printing of ordered mesh structure.Porous membranes with special wettability such as superhydrophobicity-superoleophilicity,which repel water on their surface but allow oil to flow through the membrane pores,were proposed to be important candidates for oil-water separation.However,these traditional treatment methods often suffer from complex process,its application is restricted.So it is very important to find new environmentally friendly materials that can efficiently separate oil and water.In this paper,we report a facile and environmental-friendly approach to fabricate superhydrophobic porous membranes for oil-water separation.The fabrication of porous membranes not only has good wettability and mechanical stability,but also can be used in the separation of oil-water mixtures.Although superhydrophobic porous membrane is considered as a very promising candidate for oil-water separation,its fabrication methods often involve complicated treatments to build a coating with micro-nano feature on the porous mesh(called "coating on mesh structure"),which lead to weak mechanical stability of superhydrophobic surfaces and the formation of inhomogeneous membrane pores.Herein,we report a facile and environmental-friendly 3D printing approach to fabricate the superhydrophobic membranes with ordered porous structure for oil-water separation using hydrophobic nano-silica filled polydimethylsiloxane(PDMS)ink.The addition of nano-silica can improve the mechanical strength of the ink and thus ensures the formation of desired topographical structures without collapsing during 3D printing.Through adjusting the geometrical parameters,a superhydrophobic PDMS membrane is obtained,which mainly depends on the roughness at sub-millimetre scale.More importantly,3D printing approach integrates the superhydrophobic surface into the porous framework and results in a mechanically durable superhydrophobic membrane,which successfully avoids the weak interface adhesion issue from the traditional "coating on mesh structure".Besides,the pore size of the printed membrane can be easily adjusted by computer program to optimize both liquid flux and separation efficiency of the membranes.The maximum oil-water separation efficiency(above 99%)can be achieved for the printed porous membrane with the pore size of 0.37 mm,which also exhibits a high flux of?23700 L/m~2·h.The special wettability membrane can also separate water and oil mixtures with different acidity and basicity,and the separation efficiency is more than 85%.The test results above show that:we independently developed,designed and fabricated superhydrophobic membrane can not only gets rid of the complexity of the preparation process,but also has the advantages of convenient preparation and rapid production;and the mechanical stability and oil-water separation efficiency of the printed membrane are high,the purpose of the research is to solve practical problems about the oily wastewater pollution,especially for oil spill pollution problem,which is of great significance. |
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