Synthesis Of Mixed Charged Copolymer And Comparison The Performance Of Their Blended Membranes

Polysulfone(PSf)has the advantages of good thermal stability,high mechanical strength,resistance to chemical corrosion.but at the same time,the commercial polysulfone material membrane was hydrophobic and prone to fouling,resulting in membrane flux declined,energy consumption increased.furthermore,the application of polysulfone membrane was restricted in water treatment and biological materials.To diminish the fouling of polysulfone ultrafiltration membrane,this experiment synthesis the mixed charged copolymer with hydrophobic segment and counter charge segment by 2,2'-azobisisobutyronitrile initiated solution polymerization,which was PSt-DMC-AA(polystyrene-methacryloxyethyltrimethyl ammonium chloride-acrylic acid).then the molar ration of hydrophobic moity and hydrophilic moity was varied.St:DMC:AA feed ratios were 7.5:1:1,7:1:1,6.5:1:1 and 6:1:1.The composition and thermal stability of copolymer were characterized by FT-IR and thermogravimetric analysis.The TGA results showed that mixed charged polymer ionic monomers comprise the overall polymer content of 25%and 27%.Then using the above copolymer as additive,the blended membranes were fabricated through immersion precipitation phase inversion method.The performance of membranes were characterized by cross-section morphology,contact angel measurement,water flux and antifouling property,the results revealed that the blended membrane were improved to hydrophilicity and water flux.Membrane characterizations revealed that copolymers had significant effect on membrane formation,such as roughing the membrane surface and both increasing of porosity and pore size.Contact angle and filtration experiments of the blended membrane were measured and found the hydrophilicity as well as anti-fouling properties were significantly enhanced,especially for PSF/PS7D1A1 membrane,their irreversible fouling almost declined to zero.When the amount of PS7D1A1 was 10%,the blended membranes could accept the best antifouling performance.The first flux recovery ration was 100%,the second flux recovery ration was 96%.When the amount of PS7D1A1 was 15%,the water flux of blended membranes could accept the largest,2which was 232 L.m-2.h-1.Furthermore,the increased of flux did not sacrifice membrane rejection rate,the blended membranes rejection rate for BSA solution remained at more than 98%.The above results showed that the novel blended polysulfone ultrafiltration membrane of high-throughput,hydrophilicity and resistance to fouling can be prepared with the introduction of mixed charged polymers.