Study On Hydrophilic Modification Of PVDF Membrane In Printing And Dyeing Wastewater Treatment

The main pollutant of textile printing and dyeing industry is printing and dyeing wastewater,its composition is more complex.High pollutant concentration and large sewage discharge are its main characteristics.The difficult treatment of dyeing wastewater is decolorization and mineralization of dye wastewater.In recent years,with the rapid development of textile printing and dyeing industry,but also brings a problem:printing and dyeing wastewater treatment,it is more and more difficult to deal with it.In recent years,our country has gradually paid more attention to the environment,so the environmental protection requirements have higher requirements,emission indicators have also been improved,which requires our printing and dyeing wastewater treatment is more and more high.This has also attracted the attention of our researchers and enterprises.Pvdf membrane used in printing and dyeing wastewater was studied in this paper.Polyvinylidene fluoride(PVDF)is a polymer with good mechanical strength,high chemical stability and easy film formation,and it is used to prepare ultrafiltration or microfiltration membranes.However,PVDF has strong hydrophobicity,so when the membrane is in the treatment of aqueous solution,it is easy to appear the phenomenon of high permeability resistance to water and protein adsorption pollution resulting in a sharp decline in permeability.In this regard,we can improve the membrane flux,reduce membrane pollution and prolong the service life of PVDF membrane by hydrophilic modification.This thesise selected Zn-X zeolite blend of methods of physical modification of PVDF membranes,Before the experiment,the 4.46g Zn(N03)2 solid was first dissolved in 150ml distilled water,and the Na-X molecular sieve lOg was added to the above solution.The mixture was fully stirred to make it mix evenly,and 5h was continuously stirred at 60 degree constant temperature water bath.Solids were obtained,80 drying,grinding,Zn-X molecular sieve ion exchange.Then it is called 4G molecular sieve Zn-X,dissolving with 46m L distilled water and stirring 2H at 75 C at constant temperature water bath.Among them,respectively,adding a certain amount of cationic surfactant(C19H42BrN)and anionic surfactant(C17H35COONa),amphoteric surfactant(C5H11N02),filtration,drying,modified Zn-X.The surface of the modified Zn-X will have a large number of non polar groups with hydrophobicity,which leads to the slowing down of the sedimentation rate in the non polar solution to improve the hydrophilic polymer membrane surface to improve the membrane flux and reduce membrane fouling and prolong membrane life.By studying the different solvents,different PVDF concentrations and different Zn-X zeolite addition on the final material obtained blend films and the contact angle of water flux performance.The results showed that,irrespective of DMF or DMAC as the solvent,the resulting water flux of blend membranes than pure water flux of PVDF membrane has increased;on the product further confirmed that the contact angle test,after the modified zeolite,PVDF hydrophilic membrane was significantly enhanced,such as hydrophilic blend membranes increased the amount of zeolite added further enhanced.