摘要
The membrane pore size and operating condition effects on the filtration flux, membrane fouling and solute rejections in cross-flow microfiltration of BSA/dextran binary suspension are studied. Two flat sheet microfiltration membranes with mean pore sizes of 0.1 and 0.025 μm are used as filter media in these experiments. The filtration flux increases with increasing cross-flow velocity and filtration pressure because of less membrane fouling or higher filtration driving force. The filtration resistance caused by membrane fouling is much higher than that caused by concentration polarization or virgin membrane. This impact is more significant under higher transmembrane pressures. The membrane fouling extent due to dextran adsorption is expressed as pore size reduction and fouled layer depth, which can be estimated theoretically based on hydrodynamic models. The dextran rejection decreases with increasing Reynolds number in the membrane pores and approaches constant when the Reynolds number exceeds a critical value. This is attributed to the increase in wall shear stress and molecular deformation in the membrane pores. A higher cross-flow velocity results in higher dextran rejection because of the sweeping effect occurring on the membrane surface. The BSA rejection under various operating conditions can be reasonably explained by the membrane sieving effect. The BSA rejection decreases linearly with increasing pore size in the fouled membrane with no obvious cross-flow velocity effect on BSA rejection found. The effects of the dextran concentration and Reynolds number in the membrane pores on the dextran adsorption layer thickness are also discussed.
摘要译文
在BSA /葡聚糖二进制悬浮横流微滤的过滤通量，膜污染和溶质排斥的膜孔径和运行状态的影响进行了研究。为0.1和0.025的平均孔径大小的两个平片微滤膜该过滤通量增加而增加，因为较少膜污染或更高的过滤驱动力交叉流速度和过滤压力。引起的膜污染的过滤阻力比引起的浓差极化或处女膜高得多。这种影响是在较高的跨膜压力更显著。膜污染是由于葡聚糖吸附程度上表现为收缩毛孔产品并造成对手犯规层深度，理论上可基于流体动力学模型来估计。随着在膜孔雷诺数葡聚糖排斥减小，当雷诺数超过临界值接近恒定。这是由于在膜孔中的增加的壁剪切应力和分子变形。较高的横流速度的结果，因为在膜表面发生的清扫效果高葡聚糖排斥。各种操作条件下的BSA的排斥可通过该膜的筛分效果进行合理的解释。的BSA的排斥随孔径在结垢膜对BSA排斥没有明显的交叉流速度效应发现线性减小。还讨论的葡聚糖浓度和雷诺数在对葡聚糖吸附层厚度的膜孔的效果。
Kuo-Jen Hwang; Pan-Yu Sz. Effect of membrane pore size on the performance of cross-flow microfiltration of BSA/dextran mixtures[J]. Journal of Membrane Science, 2011,378(1-2): 272–279