Modification And Properties Of Polymer Separation Membranes Based On Mussel Bionic Materials

Polymeric polymer membrane has received great attention and widely used in various fields such as chemical industry,food,medicine,and environment.Its development was limited due to its properties and humanity's requirements.The hydrophobic property and low surface energy are unbeneficed to the separation of water-soluble fluids resulting in the natural organic matter and microbial easily adhere to the surface of the film,causing surface contamination,a decrease in flux and the service life.In order to further optimize the performance of the polymer membrane,it is necessary to improve the hydrophilicity and raise the penetration resistance,and cooperate with the modified material or modifier to enhance antifouling performance,thereby improving the current situation.In this study,functional modification of polymer separation membrane materials based on mussel-like biomass materials,polyvinylidene fluoride(PVDF)and polysulfone(PSF)were used as matrix and modificated by the substitution of two-dimensional nanomaterials,the grafting of hydrophilic molecules and the co-deposition of mussel biomimetic biomass.From internal to surface modification is carried out to explore the effect on the performance of the separation membrane.The main results are as follows:(1)The PVDF/GO blend membrane was prepared by solvent-induced phase separation method.Polyfunctional graphene oxide was used as the active site,the hydrophilic molecule amino polyethylene glycol(PEG-NH2)was grafted.The hydrophilicity of M1-g-PEG was improved and WCA decreased to 59.9°,water flux recovery(FRR)increased to 90.2%,and total pollution rate(Rt)decreased to 20.7%.The antifouling performance was improved and the service life would be extended.(2)Grapheme oxide was modified by dopamine and lysine,and uniformly dispersed in a PVDF casting solution to construct the membrane with a nano water channel of uniform size.The water contact angle of the PVDF membrane was decreased from 118.4° to 76.3°.The water flux increased by one order of magnitude,was from 99.7 to 713.6 L m-2 h-1 at 1 bar,and rejection rate of bovine serum albumin reached 95.2%,breaking the trade-off relationship between water flux and solute rejection.At the same time,PVDF /(GO-PDA-LYS-0.5%)membrane has good antiadhere and excellent antibacterial properties against Escherichia coli.(3)Based on the surface modification method of mussel biomimetic biomass,using the characteristics of self-polymerization and adhesion of dopamine/catechol.Two co-deposition of dopamine and sodium polystyrenesulfonate,catechol and L-lysine were used to modify the membrane.The formed layer enhanced hydrophilicity and the rejection of the two proteins of bovine serum albumin and lysozyme were as high as 100%.The deposited layer also had a large number of functional groups with amount of positive and negative charges acting as electrostatic repulsion and sterilization and the antifouling performance was significantly increased.