A critical review on recent polymeric and nano-enhanced membranes for reverse osmosis

In this paper, current and recent advances in polymeric and nano-enhanced membrane development for reverse osmosis have been reported in terms of membrane performance and fouling. Graphene, zeolites, carbon nanotubes, silica, silver, and titanium dioxide are the predominantly tested nanoparticles in current and recent investigations. Membranes from graphene, zeolites, and carbon nanotubes have all been shown to enhance membrane water permeability. Silica has been observed to exhibit high affinity for water and improve the hydrophilicity of RO membranes. Silver and titanium dioxide have strong antimicrobial properties and can be included in RO membranes to reduce biofouling. However, the use of nanomembranes for commercial and industrial RO applications is still under development as their scalability is still a challenge. Polymeric membranes, such as cellulose acetate and polyamide, and their integration with other polymers or nanoparticles have also been presented in this paper. Overall, the choice of membrane materials for future RO processes would depend largely on the required permselectivity and the targeted foulants. However, membrane performance and antifouling features would have to be taken into consideration for sustainability of the type of RO membrane desired for a specific application.