The Study On Preparation Of Several Superhydrophobic Materials And Properties For Oil/Water Separation

With the rapid development of industry,the industrial oily wastewater and oil spill accidents have caused serious environmental pollution,so oil/water separation becomes an urgent issue in modern chemical industry and environmental protection.Because oil/water separation is an interfacial challenge,using special wettability to fabricate novel materials is an effective and facile way.Among them,"removing oil"material with superhydrophobic/superoleophilic is a focus of research in recent years.Using varieties of preparation methods and technology,scientists have prepared a large number of superhydrophobic oil-water separation materials for water restoration.However,due to complicated processes of prepration,sophisticated equipment,high price or toxicity of raw materials and weak superhydrophobic stability at high temperature and corrosive environment,most superhydrophobic/superoleophilic materials are limitted in practical application of oil-water separation in complex environment.This paper prepared several of oil-water separation materials with superhydrophobicity/superlipophilicity by facile methods,taking the commercial availability stainless steel mesh and polyurethane sponge as substrates and the candle soot?CS?,silica?SiO₂?,zinc oxide?ZnO?as main raw materials.In addition,its characteristics of surface wettability and performance of oil-water separation were also studied and the mechanism involved in oil/water separation was simply explained.The main research contents and conclusions are as follows:1.The overlap coated superhydrophobic mesh was prepared by depositing CS NPs and hydrophobic SiO₂ NPs on the stainless steel mesh sequentially.The CS-SiO₂coated meshe can selectively separate a series oils and water mixtures with high separation efficiency larger than 98%.In addition,the separation efficiency of the overlap coated mesh could still reach up to 98%after 55-time oil/water separation.More importantly,the prepared overlap coated meshes exhibited excellent environmental stability to corrosive liquids and hot water?about 92°C?,so it could be used to separate mixtures of oil and hot water,strong acid?1 M HCl?,strong alkali?1M NaOH?,salt?1 M Na Cl?solutions.2.The superhydrophobic sponge was fabricated by dip-coating candle soot and SiO₂ nanoparticles on polyurethane?SiO₂-CS-PU?sponge.The coated sponge exhibited high absorption capacity for oils and organic solvents and the separation efficiency of oil/water mixtures is higher than 99.00%.In addition,the superhydrophobic sponge could still maintain good superhydrophobicity in hot water,acid,alkali,salt solutions.It is worth noting that the SiO₂-CS-PU sponge could selectively absorb oils from hot water and ice/water mixture and it even could remove oils from the suspensions of oils in corrosive solutions at magnetic stirring.Lastly,the superhydrophobic sponge connected with a vacuum system could remove oil from water,quickly and continuously.3.Superhydrophobic ZnO coated meshes with different water adhesion were prepared by a facile spray-coating process.In the process,we simply change the mass percentages of hydrophobic ZnO NPs in the hydrophobic/hydrophilic ZnO mixtures to tune the surface chemical composition without changing the surface morphology.Studies have shown that the water adhesion of the superhydrophobic meshes has nearly no effect on the oil/water separation efficiency.However,it has a little effect on the water intrusion pressure and oil flux.In addition,combining with the wettability models,we explicated the schematic that superhydrophobic ZnO coated meshes with different water adhesion has nearly same oil/water separation property.