Protein and Lactose Separation by Modified Ultrafiltration Membrane using Layer by Layer Technique

Layer-by-Layer (LbL) is a method which can be used for nanoscale coating and surface functionalization of a material. LbL technique mainly uses the electrostatic attracting between charged materials (polyelectrolytes, nanoparticles, etc.) and an oppositely charged surface. In this study, protein separation (BSA) from lactose solution was carried out using the LbL self-assembly method, which was used to produce a polyelectrolyte (PE) nanofiltration membrane. The impact of number of dual layers of PE and pH of solution on the retention of BSA and lactose was systematically investigated. For separation experiments, the BSA and lactose were used as a model protein and disaccharide sugars, respectively. Maximum retentions of 10.7% lactose and 100% BSA were achieved by the PE nanofiltration membrane with six bilayers at pH 6.5. Moreover, whey was used for the real filtration application, and the retention of fat, protein, and lactose were 100%, 98%, and 15%, respectively. The results showed that the separation of protein and lactose from the mixed solution could be achieved by PE nanofiltration membrane using the LbL method.