A novel omniphobic polychlorotrifluoroethylene (PCTFE) membrane incorporating fluorinated silica nanoparticles with superior performance and outstanding resistance to wetting and fouling was prepared, characterized and applied for mem-brane distillation process. A three-step approach was used to prepare the membrane, which has a re-entrant structure and low surface energy. This was achieved through the incorporation of fluorinated SiO2 and a positively charged surface modified with 3-aminopropyl-triethoxysilane (APTES). Various super-hydrophobic membranes were also prepared by different SiO2 concentrations (1–7 wt.%) through the phase inversion method. The membranes\\\\\\\' wetting and fouling resistance were assessed using contact-angle measurements, sliding angle, and direct contact membrane distillation (DCMD) tests. The membrane\\\\\\\'s structural features were confirmed via scanning electron microscopy (SEM), atomic force microscopy (AFM), and attenuated total reflection Fourier transform infrared (ATR-FTIR), while porosity and liquid entry pressure (LEP) were also measured. Transmission electron microscopy (TEM) provided insights into the morphology of the fluorinated silica. The anti-fouling characteristics of prepared membranes were also assessed using humic acid and CaCl2 as fouling agents, along with different surfactants to analyze the performance of membranes in membrane distillation (MD). Results indicated that the pure water flux (PWF) increased from 37.25 ± 1.02 kg/m 2h for the neat membrane to 47.25 ± 0.98 kg/m2h for the omniphobic variant, also surpassing the commercial sample (34.48 ± 1.35 kg/m2h). The water flux decreased from 47.25 ± 0.98 to 43.88 ± 0.85 kg/m2h for NaCl containing solution (35,000 ppm). The omniphobic PCTFE membrane exhibited outstanding resistance to wetting and fouling, achieving a flux rate more than 40 ± 0.35 kg/m2h and rejection rate surpassing 98%.

Keywords