Electrospun nylon 6/zinc doped hydroxyapatite membrane for protein separation: Mechanism of fouling and blocking model

Development of composite nanofibrous membrane via electrospinning a polymer with ceramic nanoparticles (NPs) for application in protein separation systems is explored during this study. Positively charged zinc doped hydroxyapatite (xZH) NPs were prepared in three different compositions via chemical precipitation method. Herein, we created a positively charged surface containing nanoparticles on electrospun Nylon-6 nanofibers (NFs) to improve the separation and selectivity properties for adsorption of negatively charged protein, namely bovine serum albumin (BSA). The decline in permeate flux was analyzed using the framework of classical blocking models and fitting, demonstrated that the transition of fouling mechanisms was dominated during the filtration process. The standard blocking model provided the best fit of the experimental results during the mid-filtration period. The membrane decorated by NPs containing 4 at.% zinc cations not only provided maximum BSA separation but also capable of separating higher amounts of BSA molecules (even after 1 h filtration) than the pure Nylon membrane. Protein separation was achieved through this membrane with the incorporation of NPs that had high zeta potential (+ 5.9 ± 0.2 mV) and lower particle area (22,155 nm2). The developed membrane has great potential to act as a high efficiency membrane for capturing BSA.