| With the continuous development of technology and science,many process es inevitably produce a large amount of waste water.Water pollution and shortage of water resources have been the most serious social problem,therefore,separation membranes with high separation performance,high permeability and anti-fouling properties are very important to resolve these problems.According to the actual requirements and combined with the advantages of poly(vinylidene fluoride)(PVDF),hydrophilic modification of PVDF membrane was achieved through the in situ polymerization method of hydrophilic ionic liquid in the PVDF solution.The main researches are as follows:1.Poly(vinylidene fluoride)composite film with 1-butyl-3-vinylimidazolium bromide(ILs)as hydrophilic modifier and methyl methacrylate(MMA)as compatibilizer were prepared by the immersion precipitation process.Fourier transform infrared spectrometer(FTIR)results show that ILs and MMA are introduced into PVDF matrix successfully and ILs promotes the formation of β crystal.Scanning electron photomicrographs indicate that PVDF is miscible with MMA-co-ILs copolymer and no phase separation takes place.Water contact angle results show that the hydrophilicity of PVDF is enhanced significantly by ILs.The modified PVDF composite films display high pure water flux and bovine serum albumin(BSA)rejection,which shows excellent application prospect in water separation films.2.In this part,MMA-co-ILs copolymer modified PVDF films with 20wt% ILs were prepared.The influence of DMAc content on the properties of the composite films was studied.The DMAc content affected cortex,hole diameter and surface properties.Scanning electron microscope(SEM)and porosity r esults showed the porosity and pure water flux increased with the increase of DMAc content.The antifouling properties results indicated that t he composite membrane showed very strong adsorption with the negatively charged pollutant.The results indicated that the composite films were hydrophilic and positively charged.3.Poly(vinyl pyrrolidone)(PVP)was used as pore-forming additive of the films.The effect of PVP concentration on the properties of composite films was investigated.The results indicated that,with the increase of PVP content,the porosity and water flux increased.Dye stuff separation experiments showed that the rejection ratio of orange G decreased with the increase of pore size. |
