Unveiling a high-performance composite membrane for bioethanol dehydration: Optimizing fiber diameter of MXene-incorporated PVA nanofibers via response surface methodology

Efficient bioethanol purification is crucial for advancing biofuels. This study introduces a novel pervaporation membrane for bioethanol dehydration, incorporating MXene-reinforced polyvinyl alcohol (PVA) nanofibers. MXene, a two-dimensional nanomaterial, was synthesized and characterized using X-ray diffraction (XRD), Raman spectroscopy, and Fourier transform infrared spectroscopy (FTIR), confirming successful etching of the precursor MAX phase. Field emission scanning electron microscopy (FE-SEM) verified its morphology. PVA nanofibers were fabricated via electrospinning, enhancing membrane properties by increasing surface area. A response surface methodology was employed to optimize nanofiber diameter, identifying optimal conditions: a nozzle distance of 16.5 cm, voltage of 26 kV, MXene concentration of 2.99.wt%, and a flow rate of 0.9 mL/h, yielding a minimum fiber diameter of 171 nm. Characterization via energy dispersive X-ray analysis (EDS), Brunauer-Emmett-Teller (BET) analysis, and mechanical testing confirmed the desirable structural, hydrophilic, and mechanical properties of the nanofibers. Cross-linking further enhanced performance, resulting in a permeate flux of 86.24 g/m²h and a separation factor of 467.19 for 90 %.wt ethanol dehydration at 30 °C—representing improvements of 46.12 % and 60.32 %, respectively, over pristine PVA membranes. This work emphasizes the importance of optimizing nanofiber diameter for developing high-performance pervaporation membranes for bioethanol purification.