Mechanically improved superhydrophobic nanofibrous polystyrene/high-impact polystyrene membranes for promising membrane distillation application

Robust membranes for commercial applications of membrane distillation (MD) are nearly the Achilles ankle of the process. Despite from high hydrophobicity requirements of the MD membranes, they must have enough mechanical and thermal stabilities. In this regard, flexible, superhydrophobic, and high-productive nanofibrous membranes were fabricated using mixed dope solutions made of polystyrene (PS) and high-impact PS (HIPS) through the electroblowing process. Although the PS nanofibers can be designed to have hierarchically rough surfaces to show superhydrophobicity, the inherent brittleness of this polymer still remains a big issue for practical application for a longer period of time. Upon adding HIPS into the PS-containing dope solution, the rigid PS membrane turned into a more flexible one with improved elongation at break from 5.83% to 14.89%. Also, excellent direct contact membrane distillation performance was achieved using high saline (up to 150 g/L) and 0.1 mM sodium dodecyl sulfate/35 g/L NaCl feed solutions during 96 and 24 h, respectively. Superhydrophobicity (>160 degrees) and high LEP value (up to 173.2 kPa) gifted membranes with outstanding wetting resistance. Our proposed procedure can pave the route for the facile fabrication of robust MD membranes using cost-effective materials and a high-throughput fabrication process.

Automated summary

The development of robust membranes for commercial membrane distillation applications is crucial due to the high hydrophobicity requirements. By adding high-impact PS into the PS dope solution, flexible and superhydrophobic nanofibrous membranes with improved mechanical properties were successfully fabricated. The membranes showed excellent wetting resistance and high membrane distillation performance, suggesting a promising route for cost-effective and high-throughput fabrication of MD membranes.