高背压条件下超滤膜运行特性研究

Study on ultrafiltration membrane operation characteristics under high back pressure

采用死端过滤方式进行试验,考察了背压(超滤膜出水端的压力)对再生纤维素(RC)超滤膜运行特性的影响,包括膜通量、膜过滤阻力、膜的截留性能及膜微观结构.研究结果表明:背压对RC膜纯水通量的影响较小.施加背压会引起背压阻力(除膜固有阻力外额外的过滤阻力),与过滤时间和背压有关,占总过滤阻力的比例较小.RC膜在不同背压条件下(0.00,0.02,0.05,0.10,0.15 MPa)压缩10 h与压缩30 min相比,对卵清蛋白的截留率分别提高了10.51%,14.02%,17.99%,18.99%和20.01%.扫描电镜(SEM)结果表明施加背压导致表面膜孔数量减少及背面支撑层压缩.接触角(CA)、傅里叶红外光谱(FT-IR)和拉曼光谱(Raman)等数据表明施加背压不会引起膜面亲疏水性、官能团和化学键的强度等其他微观结构的显著变化.

The influence of back pressure(pressure at the outlet of the ultrafiltration membrane) on the operating characteristics of regenerated cellulose(RC) ultrafiltration membranes was investigated by dead-end filtration,including membrane flux, membrane filtration resistance, membrane interception performance and membrane microstructure.Research results show that back pressure less effects membrane pure flux.Back pressure application would cause back pressure resistance(additional filtration resistance besides membrane intrinsic resistance),which is relative to back pressure and filtration time,and accounts for a small proportion of total filtration resistance.The retention to ovalbumin is increased by 10.51%,14.02%,17.99%,18.99% and 20.01% at 0.00,0.02,0.05,0.10 and 0.15 MPa back pressures for compressing 10 h compared with that for 30 min.Scanning electron microscopy(SEM) pictures show that the surface pore numbers decrease and the backing layer is compressed by exerting back pressure.The data of contact angle(CA),Fourier transform infrared spectroscopy(FT-IR) and Raman spectroscopy indicate that back pressure application would not cause significant changes in other microstructures such as hydrophobicity,functional groups and bond strength.