Fabrication And Oil-water Separation Applications Of Superhydrophobic And Superoleophilic 3D Porous Materials

Since entering industrialization,human demand for fossil fuels has increased year by year,and with it comes the problem of pollution of various petrochemical products.Both the oil spill and the discharge of untreated industrial organic solvents will cause serious pollution to the ecological environment.How to effectively separate oil from water has become one of the problems that need to be solved.Materials with special wettability,especially hydrophobic and lipophilic materials,are a class of materials with great research and application potential in the current oil-water separation application field.The development and use of such materials will generate inestimable value for the future effective separation of oil from oil-water mixtures and the reuse of oil resources.In this study,a three-dimensional porous melamine sponge was used as the base material,and graphene oxide composite methylchlorosilane and polydimethylsiloxane composite methylchlorosilane were used as modifying agents and combined with the substrate.Two different super-hydrophobic super-lipophilic sponge materials and related properties were studied in detail.The specific work content is as follows:(1)First,we used modified Hummers to prepare an excellent graphene oxide(GO).After immersing the melamine sponge in the GO solution,three different chlorosilanes were used to impregnate the GO coated sponge.Different chlorosilane-modified sponges have completely different surface morphologies,which are in the form of "points,lines,and planes".The experiment selects methyl trichlorosilane(MTS),which can produce a three-dimensional "plane" structure modifier on the sponge surface,as the most Excellent hydrophobic modification reagent.As the MTS concentration gradually increases from a lower level(0.006%),the hydrophobic properties of the material also gradually increase.When the MTS concentration reaches 0.1%,a micronano rough structure with a "jellyfish" shape is formed on the surface of the melamine sponge.The contact angle of the sample to water reached about 155 °,and a GO @ MTS @ MS material with good hydrophobic properties was successfully prepared.(2)In order to solve the problem that the surface coating of GO @ MTS melamine sponge is easy to come off,we introduced PDMS with adhesive effect into the preparation of hydrophobic sponge.When the number of PDMS immersion reached 2 times,the immersion concentration reached 2%(m / m),a strong PDMS buffer layer will be generated on the surface of the sponge skeleton,which effectively prevents the shedding of polysiloxane powder generated by MTS hydrolysis and enhances the stability of the hydrophobic coating on the surface of the material,while also maintaining the material Hydrophobic property,successfully prepared a PDMS @ MTS @ MS material with more excellent stability.(3)For GO @ MTS @ MS material,its adsorption capacity for oils and organic solvents can reach 50-100 times its own weight.The adsorption capacity is positively correlated with the density and viscosity of organic matter.After introducing a gear pump to construct a simple oil-water separation system,the material achieves the effect of in-situ oil-water separation.Because the melamine sponge itself has fire resistance,the modified hydrophobic melamine sponge can be used for short-term use in the recovery of combustion oil products,and has important application potential for fuel recovery.By simulating the recovery of LNAPL in groundwater,it is shown that GO @ MTS melamine sponge has good practical application ability.(4)For the PDMS @ MTS @ MS material,due to its increased stability,the sponge can maintain a stable oil absorption flux and high selective adsorption during the continuous oil absorption process through the oil-water separation system for up to 100 hours.At the same time,PDMS @ MTS modified melamine sponge was immersed in acidic and alkaline aqueous solution for a week,and still showed super-hydrophobicity,which shows that P2 sponge has good acid and alkali resistance.The super-hydrophobic PDMS @ MTS melamine sponge increases the density due to the addition of PDMS,and its oil absorption rate is 44-97 times its own weight.These results indicate that the super-hydrophobic super-lipophilic PDMS@MTS sponge has stable oil-water separation performance.Experiments show that the hydrophobic material prepared with melamine sponge as the base material has many excellent characteristics,such as good hydrophobicity,elasticity and stability.We apply the prepared two hydrophobic materials to oil-water separation,and combine gear pump or self-priming pump to construct a simple oilwater separation system,which can realize in-situ efficient separation of oil-containing wastewater and recovery and reuse of oil products.All in all,the two super-hydrophobic sponges prepared in this paper demonstrate the important theoretical research significance and practical application value of hydrophobic lipophilic materials.