Desalination, Vol.428, 255-263, 2018
Omniphobic membranes for direct contact membrane distillation: Effective deposition of zinc oxide nanoparticles
An omniphobic membrane was fabricated for membrane distillation (MD) by effectively depositing ZnO nano particles on a hydrophilic glass fiber (GF) membrane using a chemical bath deposition method to create hierarchical re-entrant structures, followed by surface fluorination and the addition of a polymer coating to lower the surface energy of the membrane. The omniphobic membranes possessed a particulate membrane morphology and an extremely high fluorine concentration on the surface. The omniphobicity of the fabricated membrane was indicated by the contact angles for water and ethanol, which were as high as 152.8 +/- 1.1 degrees and 110.3 1.9 degrees, respectively. Compared to hydrophobic GF membranes without deposited ZnO nanoparticles, the omniphobic membrane revealed a higher wetting resistance to low surface tension feed solutions in direct membrane distillation (DCMD) experiments. The water flux was stably maintained in a 0.3 mM sodium dodecyl sulfate (SDS) solution (60 degrees Cl M NaCl) with salt rejection rate higher than 99.99%. The results suggest that the omniphobic membrane exhibited not only superior wetting resistance to low surface tension liquids but also promise for desalinating low surface tension wastewaters.
Keywords:Omniphobic membrane;Direct contact membrane distillation;Chemical bath deposition;Zinc oxide nanoparticle