Graft Polymerization of Octadecyl Acrylate on PET Track-Etched Membranes for Direct Contact Membrane Distillation

Water purification is a critical environmental and social issue of our era. The contamination of water sources by industrial waste, agricultural chemicals, household debris, and plastic pollution significantly degrades the quality of available freshwater. This poses substantial threats to human health and ecosystems. While water is plentiful on Earth, only a limited amount is freshwater that people can safely consume. Population growth, urbanization, and climate change are further exacerbating this scarcity, especially in arid regions. This study examines the membrane distillation process employing ion-track membranes. Hydrophobic poly(ethylene terephthalate) ion-track membranes with increased pore diameters were synthesized via UV-induced graft polymerization of octadecyl acrylate on the membrane surface. Hydrophobic properties were assessed through water contact angle measurements. Fourier transform infrared spectroscopy analyzed functional groups while scanning electron microscopy examined surface morphology. The hydrophobic membranes were subsequently evaluated for desalination performance using direct contact membrane distillation method with saline solutions of varying concentrations. The effect of pore size and feed salt concentration on permeate flux and salt rejection efficiency was systematically examined. Membranes with a contact angle of 95±3° were tested in saline solutions with concentrations from 7.5 to 30 g/L.