Superhydrophobic nanoparticle-coated PVDF–HFP membranes with enhanced flux, anti-fouling and anti-wetting performance for direct contact membrane distillation-based desalination

Abstract

Water is one of the most precious natural resources of the planet. Global water demand is expected to increase by 20–30% in near future, mainly due to the increase of industrial activities and domestic use. In this context, up to now, many water treatment technologies have been proposed to address water scarcity. Among them, processes based on membrane technology such as membrane distillation (MD) have received significant scientific and technological attention. In the present work, innovative nanocomposite polymeric membranes were developed, aiming to enhance the performance in relation to the state of the art membranes for desalination using direct contact membrane distillation (DCMD). To this aim, the development of porous poly(vinylidene fluoride-co-hexafluoropropylene) (PVDF–HFP) membranes and their modification by introducing a top layer of superhydrophobic fluorinated silicon nanoparticles on their surface was thoroughly studied. The developed membranes were characterized by a variety of techniques such as SEM, contact angle and liquid entry pressure (LEP). The superhydrophobic nanoparticle-coated membranes compared to pristine PVDF–HFP membranes, have improved fouling resistance properties, increased permeability and wetting resistance against various low surface tension organic compounds. The results indicate that the nanocomposite membranes exhibit improved overall performance aiming to tackle critical issues of membrane distillation process.