Boyd R F, Zydney A L
Department of Chemical Engineering, University of Delaware, Newark, Delaware 19716, USA.
Biotechnol Bioeng. 1998 Aug 20;59(4):451-60.
Protein fouling can significantly alter both the flux and retention characteristics of ultrafiltration membranes. There has, however, been considerable controversy over the nature of this fouling layer. In this study, hydraulic permeability and dextran sieving data were obtained both before and after albumin adsorption and/or filtration using polyethersulfone ultrafiltration membranes. The dextran molecular weight distributions were analyzed by gel permeation chromatography to evaluate the sieving characteristics over a broad range of solute size. Protein fouling caused a significant reduction in the dextran sieving coefficients, with very different effects seen for the diffusive and convective contributions to dextran transport. The changes in dextran sieving coefficients and diffusive permeabilities were analyzed using a two-layer membrane model in which a distinct protein layer is assumed to form on the upstream surface of the membrane. The data suggest that the protein layer formed during filtration was more tightly packed than that formed by simple static adsorption. Hydrodynamic calculations indicated that the pore size of the protein layer remained relatively constant throughout the adsorption or filtration, but the thickness of this layer increased with increasing exposure time. These results provide important insights into the nature of protein fouling during ultrafiltration and its effects on membrane transport.
蛋白质污染会显著改变超滤膜的通量和截留特性。然而，关于这种污染层的性质一直存在相当大的争议。在本研究中，使用聚醚砜超滤膜，在白蛋白吸附和/或过滤前后获取了水力渗透率和葡聚糖筛分数据。通过凝胶渗透色谱分析葡聚糖分子量分布，以评估在广泛溶质尺寸范围内的筛分特性。蛋白质污染导致葡聚糖筛分系数显著降低，对于葡聚糖传输的扩散和对流贡献观察到非常不同的影响。使用双层膜模型分析葡聚糖筛分系数和扩散渗透率的变化，其中假设在膜的上游表面形成一个独特的蛋白质层。数据表明，过滤过程中形成的蛋白质层比简单静态吸附形成的蛋白质层堆积更紧密。流体动力学计算表明，蛋白质层的孔径在整个吸附或过滤过程中保持相对恒定，但该层的厚度随着暴露时间的增加而增加。这些结果为超滤过程中蛋白质污染的性质及其对膜传输的影响提供了重要见解。
