Research On Surface Modification Of Foamed Iron And Its Application In Oil-water Separatio

In recent years,with the progress and development of the industrial society,the demand for fossil energy has been increasing,and the oily waste water produced during industrial production processes such as petroleum extraction and transportation,mining,and textiles has also increased.The genera methods of separating oil-water mixtures mainly include gravity separation,centrifugal separation,flotation,biological methods and other technologies.However,these separation methods have relatively low efficiency,high operating costs,and easy to cause secondary pollution.Therefore,it is urgent to further develop a low,environmentally friendly,recyclable oil-water separation material,and a simple and feasible oil-water separation method.In this paper,three-dimensional(3D)porous hydrophobic-superoleophilic materials,superhydrophobic-superoleophilic materials and thermal-responsive 3D porous material were fabricated with Fe foam by dip coating method and one-pot solvothermal method according to the wetting theory of solid surface.And these materials were explored their actual applications in oil-water separation.The main research works are as follows:(1)The surface of the Fe foam was modified with a layer of dodecyl mercaptan by a simple dip coating method,and the surface of the obtained sample showed hydrophobicity and superoleophilicity.The water contact angle of the obtained material was 145.0°,and the oil contact angle was 0°.The obtained materials were characterized by scanning electron microscope(SEM),infrared absorption spectroscopy(FTIR),and contact angle tester.Excellent oil-water separation performance were observed.It could separate a variety of oil-water mixtures and the separation efficiencies were up to 99.9%,and it displayed excellent recycling performance.Even after 45 cycles,the separation efficiency was still over 98.8%.In addition,the material shown good mechanical stability.The contact angle of water on the surface remained above 140.30 even after 50 times of abrasive wears.And it had excellent chemical stability,which could separate the mixture of acid,alkaline,salt solution and oil,and the separation efficiency could reach 99.8%.The as-prepared materials with magnetically responsive could be used to remotely control oil-water separation.Then,combining the as-prepared materials with a pump could achieve continuous oil-water mixture separation.(2)A layer of hydrophobic polymer was modified on Fe foam by one-pot solvothermal method,and a superhydrophobic-superoleophilic porous material was successfully prepared.The water contact angle of the as-prepared material was 153.4°,and the contact angle of oil was 0°.The as-prepared materials were characterized by SEM and FTIR.The material shown great recycling performance,which separation efficiency remained above 99.8%even after 70 cycles.In addition,the material displayed good mechanical stability,its surface contact angle was still above 141.8° after 50 wears.At the same time,the material shown good weather resistance,which could maintain superhydrophobicity after 14 days of exposuring to humid air(humidity is 90%),and could separate the mixture of corrosive solution and oil with high efficiency(99.7%).With the help of a pump,not only the mixture of light oil and water could be continuously separated,but also the mixture of heavy oil and water could be continuously separated.(3)A layer of temperature-sensitive polymer was modified on the surface of the Fe foam by a simple solvothermal method,and the surface of the obtained sample shown switchable wettability.When the temperature was 10℃,the sample surface displayed hydrophilicity and the water contact angle of the as-fabricated material was 0°.When the temperature was 35℃,the sample surface displayed hydrophobicity and the water contact angle of the as-fabricated material was 135.2°.The materials were characterized by SEM and FTIR.The prepared sample could realize the reversible conversion of surface wettability under the stimulation of temperature.The material performed temperature-sensitive and could separate oil-water separation without external force drive.When the system temperature was 10℃,the water quickly passed through the foam,but the hexane did not.When the system temperature was 35℃,the hexane passed through the foam,but the water did not.It was found that the wettability of the as-prepared Fe foams could switch reversibly between hydrophilicity and hydrophobicity according to their temperature response.This material could efficiently and quickly separate a variety of oil-water mixtures.Its flux to water could reach 15.5×104 L m-2 h-1,and its flux to oil could reach 18.1×104 L m-2 h-1,and its separation efficiency was up to 91.8%.Through the above research,it was found that the material with special wettability prepared by using Fe foam as the base material can efficiently and quickly separate the oil-water mixture,and the preparation method was simple and easy to realize industrial production.