Development of Advanced PVDF-HFP Membranes Incorporating Natural and Synthetic Additives for Enhanced Desalination Performance in DCMD Applications

This research addresses the needs of Petro Techna Co., an industrial joint venture operating globally in oil and gas plants, focusing on managing hot saltwater separated from crude oil. The study aimed to develop a durable and cost-effective membrane for Direct Contact Membrane Distillation (DCMD) to reduce sodium chloride (NaCl) concentrations from several hundred thousand ppm to less than 100 ppm. Electrospinning was chosen as the fabrication method due to its ability to produce highly porous and flexible membranes suitable for incorporating diverse materials. A novel aspect of this research was the use of cinnamon powder as a superhydrophobic additive in membrane desalination. Cinnamon contains cinnamaldehyde, eugenol, and linalool, which enhance hydrophobicity and anti-wetting properties. Membranes were initially fabricated using polypropylene (PP), polyvinylidene fluoride-co-hexafluoropropylene (PVDF-HFP), and polytetrafluoroethylene (PTFE). PVDF-HFP was selected as the base polymer for further modifications based on its superior durability. Additives such as cinnamon powder, reduced graphene oxide (heat-treated and untreated), and silane-treated SiO₂ and TiO₂ were incorporated into the membranes to evaluate their synergistic effects. Advanced characterization techniques and desalination performance tests were conducted using a 100 g/L NaCl solution in the DCMD setup. The results revealed that membranes incorporating cinnamon powder exhibited 1.7 times greater longevity compared to other additives. Furthermore, PVDF-HFP membranes combining cinnamon powder, rGO, and SiO₂ demonstrated improved compatibility and the highest longevity (89 hours), highlighting the potential of these materials for advanced membrane desalination applications.