Study On The Preparation Of Superhydrophobic Melamine Sponge And Its Oil-water Separation Performance

The environmental pollution and harm caused by oil leakage and organic chemical reagent leakage are very serious.Due to its large specific surface area and fast oil absorption,the sponge is an important material for oil cleaning and has great potential in the separation of oil-water mixture.The melamine sponge has the characteristics of simple production process,low cost,good mechanical and flame retardant properties,and can meet the requirements of economical and mechanical properties of oil cleaning.In this paper,the melamine sponge was hydrophobically modified by the infiltration method and the original growth method and self-assembly method to obtain superhydrophobic sponge with good oil-water separation performance.The specific research contents and achievements are as follows:(1)The melamine sponge was successively immersed in nano SiO2 n-hexane dispersion solution and polydimethylsiloxane n-hexane solution for hydrophobic modification.The optimum conditions of modification were determined by orthogonal tests of silica species,concentration of soaking solution and soaking time.The study found that when the silicon source for nano SiO2,nano SiO2 n-hexane dispersed solution concentration of 3 wt%,the modification time for 20 min,the contact Angle is 140° melamine sponge,to n-hexane,gasoline,peanut oil,kerosene,and carbon tetrachloride adsorption capacity for the weight of 41,44,77,82,and 95 times;After 20 times of repeated oil absorption and oil displacement,the oil absorption ability of the material decreased to 80%of the initial oil absorption.The modified melamine sponge has good hydrophobicity and high oil absorption ability.(2)Hydrophobic modification of melamine sponge by in-situ growth method of cetyltrimethyloxysilane combined with nano-silica,modification process conditions,hydrophobic properties of sponge,oil-water separation performance and thermal stability,etc.The study found that when the in-situ growth reaction temperature was 35?,the reaction time was 3h,the silane concentration was 2 wt%,the modification temperature was 75?,and the reaction time was 2 h,and the contact angle reached 152°.The absorption masses of n-hexane,gasoline,peanut oil,kerosene,and carbon tetrachloride were 42,52,85,100,and 105 times their own weights,respectively.After repeated use for 20 times,the oil absorption capacity still maintained 97%of the initial oil absorption capacity.The results of scanning electron microscopy and mechanical properties test show that the modification process does not affect the foam cell structure and mechanical strength.The sponge still has excellent resilience and oil absorption capacity,and the material has good thermal stability and acid resistance.Alkali properties and excellent flame retardant properties.(3)The self-assembly of silanization of the amine group on the surface of the melamine sponge was selected by using dodecyltrichlorosilane to obtain superhydrophobic properties of the sponge.The solvent used for silanization,the concentration of dodecyltrichlorosilane and the reaction time were orthogonally tested and the optimum reaction conditions were determined.The results showed that the solvent was toluene,the concentration was 0.5 wt%,and the reaction time was 10 min,the contact angle of the melamine foam reached 152°.The adsorption amounts of n-hexane,gasoline,peanut oil,kerosene,and carbon tetrachloride were 53,62,98,121,and 163 times their own weights,respectively.The oil absorption capacity has not decreased significantly after repeated use for 50 times.Simulated filtration experiments show that the material can continuously separate the oil-water mixture.And the material has higher thermal stability,acid and alkali resistance and excellent flame retardant properties.Through the above studies,it was found that three different modification methods can significantly improve the hydrophobic properties of melamine sponge and achieve oil-water separation.In comparison,the dodecyltrichlorosilane self-assembly method has a simple modification process,a short cycle and a good effect.The modified melamine sponge has good oil-water separation performance,thermal stability and acid and alkali resistance,and provides an effective application potential for oil pollution control and cleaning as well as oil-water separation in other fields.At the same time,it also provides important reference for the development of other superhydrophobic materials.