Effects Of Fillers On The Structure And Properties Of Polyethersulfone (PES) Membranes And Optimization

Nowadays,with the rapid development of China's economics,water pollution become more and more seriously.The mainly materials are polythersulfone(PES)which have been prepared for ultrafiltration,microfiltration,gas separation,blood osmosis membranes et al,because PES materials have excellent physical properties,chemical stability,resistance to oxidation and chlorine.However,the membranes which the unitary raw materitals of PES were prepared have some defects in hydrophilicity,strength,lifetime and other properties.Therefore,the membranes are generally modified by blending with additives to improve their properties.In this paper,the influences of different additives including Polyethylene glycol/Polyvinylpyrrolidone(PEG/PVP),Polyurethane(PU),PU/PVP,Cellulose/lithium chloride(LiCl)were studied on the properties of PES membranes,for instance,Water Flux,Contact Angle,Pore Size,Rejection,Pollution Index,Moisture Content and the practical application.In this paper,PES ultrafiltration membranes were prepared by adding PEG.The impacts of PEG with different molecular weights and contents on the properties of PES membranes were investigated.The results showed: The hydrophilicity of membrane was improved significantly by the additive of PEG.With the increase of molecular weight of PEG,the contact angle decreased firstly and then increased,but the water flux was opposite.Under the same molecular weight of PEG,the increase of contents caused that the contact angle decreased before steadied and the water flux increased firstly then decreased.The performance of PES membranes got the high peak when the molecular weight of PEG was 6000 and the content of PEG was 4%.The distribution of surface pore of PES membrane was uniform and the structure of membrane showed a continuous finger-like hole in Cross-section;the turbidity of wastewater reached the national standard of drinking water after treatment.PES ultrafiltration membranes were prepared by adding PU.The effects of different contents of PU with 5w% PVP were studied on the properties of PES membranes.The results showed: the strength of the PES membrane had been greatly improved by the adding of PU.However,with the content of PU increased,the membrane's strength increased steady and the ratio of membrane-forming property decreased continuously.Contact angle,pollution index and strength of the PES membrane decreased.Water flux,water content and average pore diameter of the PES membrane increased.Color and turbidity of the water which filtered by the PES membrane were accorded with the national standard.In this paper,it also studied that the different contents of cellulose had impact on the properties of PES membranes.The results showed: a little cellulose would have a great influence on the structure of membrane.With the increase of cellulose,the pore size of the membrane surface was transformed to nonuniformity,and the structure of cross-section was changed obviously.The contact angle decreased primarily and then increased abruptly;the water flux increased firstly and then decreased abruptly.