Optimization of fabrication conditions of high-efficiency ultrafiltration membranes using methods of uniform design and regression analysis

In this work, an experimental design with 18 represented treatment-points was used to study the influences of one qualitative and three quantitative variables of the fabrication conditions of membranes on the membrane performances. The uniform design (UD) method was used to select 18 represented treatment points from the experimental domain studied. The pure flux and the retention abilities of each of the four protein references, namely the egg white lysozyme (15 kDa), egg white albumin (45 kDa), bovine serum albumin (67 kDa) and bovine gamma -globulin (150 kDa), of duplicate membranes prepared at each of the selected 18 experimental points were determined. The data collected from each of the selected 18 experimental points were then regressed with the studied casting conditions by using the SAS software. An acceptable regression equation was obtained in most cases studied. Several high-efficiency ultrafiltration membranes for separating the 150- and 67-kDa molecules, 67- and 35-kDa molecules and 45- and 15-kDa molecules were successfully prepared by following the predictions given by using the statistical analyses. (C) 2000 Elsevier Science B.V. All rights reserved.