Preparation Of PDMS-modified Sponges And Evaluation Of Their Hydrophobic Properties

The problem of environmental pollution caused by marine transportation and the leakage of offshore drilling platforms become more and more serious.How to deal with the marine oil spill accident is one of the hot issues in the field of petroleum engineering.The preparation of hydrophobic materials is an effective way to solve this problem.The materials currently used in marine oil spill accidents have certain shortcomings,such as low separation efficiency,poor recyclability,and possible secondary pollution.Therefore,the researchers conducted in-depth research on the modification of carbon sponge and melamine sponge.Three kinds of carbon sponges were prepared by atmospheric pressure,belt pressure method and Pickering emulsion method,GA was modified with polydimethylsiloxane(PDMS)to prepare hydrophobic and lipophilic carbon sponges.The carbon sponge prepared under normal pressure is named A-1,the carbon sponge prepared by PDMS modified atmospheric pressure is named A-2.The carbon sponge prepared under pressure is named B-1,and the carbon sponge prepared by PDMS modification under pressure is named B-2.The carbon sponge prepared by Pickering method was named GA,the carbon sponge prepared by PDMS modified Pickering method was named PDMS/GA.Melamine Sponge(hereinafter referred to as MS)was modified by PDMS to obtain a hydrophobic sponge named PDMS@MS.After the self-polymerization reaction of dopamine hydrochloride,the nano Fe₃O₄ particles were successfully grafted to obtain a sponge named Fe₃O₄/MS.After modification by PDMS,the sponge was named Fe₃O₄/MS.The superhydrophobic magnetic melamine sponge was obtained and named PDMS@Fe₃O₄/MS.The main work is as follows:Carbon sponge was prepared by 95?hydrothermal method and 180?Pickering emulsion method,and then modified by PDMS to prepare carbon sponge by different methods.X-ray diffractometer(XRD),infrared spectrum(FT-IR),scanning electron microscope(SEM),thermogravimetric(TG)and contact angle(oil,water)were analyzed.The surface contact angle of sponge A-1,A-2,B-1,B-2,GA and PDMS/GA are 71.9,115.7°,81.2°,126.4°,81.3°and 134.4°.Kerosene and n-hexane and other oils have good adsorption performance,and the adsorption capacity can still reach about 10 g/g after five cycles.Using melamine sponge as the substrate,modified with nano Fe₃O₄ and PDMS,superhydrophobic melamine sponge(PDMS@MS and PDMS@Fe₃O₄/MS)were obtained,and XRD,FT-IR,SEM,and contact angle were analyzed.The contact angle of PDMS@MS to water is 128.5°,that of PDMS@Fe₃O₄/MS is 150.9°,the contact angle to oil of both sponges is 0°.The adsorption capacity of PDMS@MS for various oils such as corn oil was greater than 14.54 g/g.At the same time,the adsorption capacity for various oils is still at least 12.30 g/g.After 20 operations,PDMS@Fe₃O₄/MS can still absorb up to 8.34 g/g.The experimental results show that the hydrophobic modification of carbon sponge and melamine sponge by PDMS can be applied to the treatment of marine oil spill accidents.Experiments show that the modification of melamine sponge by PDMS and nano Fe₃O₄ can not only obtain magnetic properties,but also enable the sponge to obtain the selective adsorption performance of oil products,increase the oil absorption rate and the hydrophobic ability of the sponge.In oil-water separation,the mechanism of the whole separation process is based on the Young-Laplace equation,which increases the contact angle by reducing the surface energy of the solid by grafting hydrophobic groups.Using carbon sponge and melamine sponge as base materials,the original sponge was modified from hydrophilic to hydrophobic by grafting silicon-containing hydrophobic groups on its surface through PDMS.This paper provides a new research direction for the preparation of hydrophobic material modification methods for marine oil spill accidents.