Electrospun PET Membranes: Optimization and Performance Assessment for Dairy Protein Filtration

This study presents the development, optimization, and application of electrospun polyethylene terephthalate (PET) membranes for protein separation in dairy processing. Using an I-optimal experimental design, electrospinning parameters (i.e., voltage, flow rate, and tip-to-collector distance) were systematically optimized to produce membranes with uniform fiber diameters. The optimized membrane, fabricated at 25 kV, 7 mL/h, and 14.95 cm, exhibited a thickness of 340 μm and favorable mechanical properties, including a Young’s modulus of 15.65 MPa and elongation at break of 211.83%. Water permeability tests confirmed high intrinsic permeability and low hydraulic resistance of the electrospun PET membrane. Filtration trials using whey protein and sodium caseinate solutions demonstrated a pronounced flux decline, with trends varying according to protein type and concentration. Notably, sodium caseinate exhibited greater retention and fouling tendencies than whey protein, highlighting the membrane’s potential for protein fractionation. Hermia model fitting applied to low-concentration protein data revealed complete pore blocking for sodium caseinate and standard blocking for whey protein. These findings demonstrate the viability of electrospun PET membranes as cost-effective and sustainable alternatives for dairy protein separation, with tunable properties suitable for further scale-up and functionalization.