Abstract:
The paper describes desalination by membrane distillation (MD) using ion-track membranes.
Poly(ethylene terephthalate) (PET) ion-track membranes were hydrophobized by the immobilization
of hydrophobic vinyl-silica nanoparticles (Si NPs). Si NPs were synthesized by the sol-gel method,
and the addition of the surfactant led to the formation of NPs with average size of 40 nm. The thermal
initiator fixed to the surface of membranes allowed attachment of triethoxyvinyl silane Si NPs
at the membrane surface. To further increase hydrophobicity, ethoxy groups were fluorinated.
The morphology and chemical structure of prepared membranes were characterized by SEM, FTIR,
XPS spectroscopy, and a gas permeability test. Hydrophobic properties were evaluated by contact
angle (CA) and liquid entry pressure (LEP) measurements. Membranes with CA 125–143◦ were
tested in direct contact membrane distillation (DCMD) of 30 g/L saline solution. Membranes showed
water fluxes from 2.2 to 15.4 kg/(m2
·h) with salt rejection values of 93–99%.
