Combined organic–inorganic fouling of forward osmosis hollow fiber membranes

This research focused on combined organic–inorganic fouling and cleaning studies of forward osmosis (FO) membranes. Various organic/inorganic model foulants such as sodium alginate, bovine serum albumin (BSA) and silica nanoparticles were applied to polyamide-polyethersulfone FO hollow fiber membranes fabricated in our laboratory. In order to understand all possible interactions, experiments were performed with a single foulant as well as combinations of foulants. Experimental results suggested that the degree of FO membrane fouling could be promoted by synergistic effect of organic foulants, the presence of divalent cations, low cross-flow velocity and high permeation drag force. The water flux of fouled FO hollow fibers could be fully restored by simple physical cleaning. It was also found that hydrodynamic regime played an important role in combined organic–inorganic fouling of FO membranes.

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► Combined organic–inorganic fouling of FO hollow fiber membranes was studied.
► Synergistic effect between BSA and alginate was observed during the filtration.
► Strong interactions between SiO2 and BSA did not seem to affect the water flux.
► The water flux of fouled hollow fibers could be fully restored by surface flushing.