Surface Construction And Emulsified Water Separation Of Coalescence-Separation Dual-Stage Filter Material

The presence of surfactants and other additives in diesel oil can reduce the size of water droplets and improve their stability,especially for emulsified water whose particle size is less than 20?m,at present,the oil-water separating filter material used for industry has not been able to separate it efficiently.In this paper,a kind of coalescence-separation dual-stage filter material for emulsified water separation is constructed on the basis of fiber-glass filter material.Firstly,acrylic copolymers with amphiphilic molecular segments are designed,prepared and applied to glass-fiber substrate to form coalescent filter material with demulsification and coalescence function of emulsified water.Then superhydrophobic and superoleophilic structure is constructed on the surface of the glass-fiber filter material to form separation filter material for intercepting and separating the water droplets which are from demulsification and coalescence process.Finally,coalescence material and separation material are combined to form coalescence-separation dual-stage filter material to separate emulsified water in diesel oil efficiently.The main research work are as follows:Amphiphilic functional monomer polyethylene glycol methacrylate?PEGMA?was prepared by esterification reaction between methacrylic acid and polyethylene glycol.The effects of reaction time,reaction temperature,water absorbent dosage,amount of catalyst and inhibitor on esterification rate were investigated.The results show that the optimum reaction conditions are as follows:the molar ratio of MAA to PEG is 1:1,The reaction temperature is120?,the reaction time is 6 h,the water absorbent dosage is 13.00wt%,the amount of catalyst is 3.00wt%,and the amount of inhibitor is 0.30wt%,and the purity of the product is up to 90.67wt%.The results of IR,NMR,GPC indicate that we prepared the target product PEGMA successfully.Then,acrylic copolymers containing amphiphilic segments are prepared by free radical copolymerization of PEGMA with MAA,MMA,BA and HEMA,The effects of PEGMA copolymerization activity,reaction time,initiator content,PEGMA content and monomer adding process on free radical copolymerization were studied.The results show that the theoretical solid content of the reaction system is 20.00wt%,the PEGMA content is within35.81wt%,the amount of initiator is 1.2wt%,and the reaction time is 5h,the best reaction process is two-steps dropping reaction.The prepared copolymer containing PEGMA was applied onto glass-fiber filter material to construct coalescent filter material,and compared with original glass-fiber filter material and filter material treated with pure acrylic copolymer,the demulsification and coalescence effect of emulsified water of filter material was demonstrated and studied.The results show that the filter material containing PEGMA copolymer has excellent coalescence performance.The average diameter of water droplets increases from 10?m to 200?m after emulsified water going through coalescence materials containing PEGMA.Superhydrophobic and superoleophilic glass-fiber filter material is prepared by in-situ sol-gel method using methyl triethoxy silane?MTES?as precursor.We studied the effects of reaction time,precursor concentration,acid-base environment and high temperature environment on the surface properties of filter materials,otherwise the strength,thermal stability and wettability of prepared filter materials under high temperature and acid-base environment are also characterized.The results show that hydrophobic/oleophilic-CH₃ group and rough special structure are prepared on the surface of glass fibers after MTES hydrolysis and condensation,which endow the glass-fiber with superhydrophobic and superoleophilic properties.Finally,we combine coalescence material and separation material to form coalescence-separation dual-stage filters,and test the separation efficiency of emulsified water in diesel oil.The results show that coalescence-separation dual-stage filter material has excellent separation efficiency of emulsfied water in diesel oil,the separation efficiency is up to 97.58%.The coalescence-separation dual-stage filter material has good chemical stability and can be recycled in diesel oil,it shows a wide application prospect in the field of emulsified water separation.