Regeneration of superhydrophobic TiO₂ electrospun membranes in seawater desalination by water flushing in membrane distillation

Herein, we fabricate nanofiber membranes by electrospinning with poly (vinylidene fluoride-co-hexafluoropropene) and then coated with TiO₂ nanoparticles using electrospraying (hereafter E-TiO₂), to demonstrate a simple way for membrane regeneration during real seawater desalination by membrane distillation (MD). Coupled with a ferrate pretreatment followed by dissolved air floatation (F-DAF), MD achieved enhanced fouling control and membrane regeneration. In this present study, we report the characteristics of the fabricated membrane, effects of pretreatment, membrane performance, and fouling mitigation for 5-day real seawater desalination. Compared with a commercial PVDF membrane, E-TiO₂ membrane had increased anti-fouling and anti-wetting properties that could efficiently be recovered by simple physical water flushing. Fouled fabricated membranes showed recoverable super-hydrophobicity after 30 mins of simple water flushing (contract angle recovered from 131.4° ± 2.2° to 151.3° ± 1.2°). Additionally, in-situ ferrate generated from NaOCl and Fe(III) reduced the algal organic matter (AOM) in seawater and subsequently reduced membrane fouling. Membrane distillation coupled with F-DAF system has proven its potential to be applied in long-term seawater desalination by controlling AOM and membrane fouling mitigation and has shown its high performance as a facile technology.