The Performance Of Extreme Wettability Cement-Coated Meshes And Their Experiment Research For Oil/Water Separation

The large amount of oily industrial wastewater emissions and the frequent occurrence of oil spills not only aggravate the situation of water scarcity but also threaten the survival of aquatic organisms.Therefore,how to solve the problem of oil pollution in water effectively has become a hot issue in modern society.Materials with extreme wettablility have attracted increasing attention for oil/water separation due to the different interface effects of oil and water.However,most of the addressed filtration materials are technically sophisticated,high cost,low durability or inclined to involve corrosive or toxic chemicals.In this work,basing on the superhydrophilicity and the micro-nanoscale particles of the ordinary portland cement(PO 42.5),we fabricated superhydrophilic and under water superoleophobic cement-coated meshes and superhydrophobic-superoleophilic cement-coated meshes by dip-coating method and applied them in the separation of oil/water mixture.The main contents and results are as follows:(1)The fabrication processes of these two cement-coated meshes were studied.The extreme wettability,the morphologies and chemical composition of these two cement-coated meshes were analyzed.The durability and the stability of these two cement-coated meshes were explored.The results show that these two cement-coated meshes fabricated by dip-coating method both have great extreme wettability,durability and stability.The water droplet can spread rapidly and completely on the surface of the superhydrophilic cement-coated meshes.And the contact angles of different oils on the surface are all above 152°.The surface is ultralow oil adhesion under water.The contact angle and the sliding angle of water droplets on the superhydrophobic-superoleophilic cement-coated mesh are 154° and 6° respectively.These two cement-coated meshes can stain great extreme wettability after being bent at least for 20 times or stored for 120 h.(2)The superhydrophilic cement-coated mesh was applied in the filtration of oil/water mixture.The separation ability for oils with different kinematic viscosities,the recyclability and the ability for the separation of oil/water mixtures containing hot water,salt,and alkali were tested.The separation properties of the meshes with different ? ware explored.The results show that the superhydrophilic cement-coated mesh has excellent separation efficiencies and purities for oils with different kinematic viscosities.The mesh can be used for oil/water separation at least for 30 cycles.The mesh can separate the mixtures containing hot water,salt,and alkali.The meshes with different ? have different water flux and oil invasion pressure during the separation process.(3)The superhydrophobic-superoleophilic cement-coated mesh was used for oil/water separation.The method for the separation of light oil/water mixture using this mesh was studied.The separation ability for oils with different kinematic viscosities and the recyclability were tested.The results show that the superhydrophobic-superoleophilic cement-coated mesh can not only be used for the separation of heavy oil/water mixtures but also can be used for the collection of light oil.The mesh has excellent separation efficiencies and purities for oils with different kinematic viscosities.The mesh can be used for oil/water separation at least for 20 cycles with great separation efficiency.