Amorphous SiO2 NP-Incorporated Poly(vinylidene fluoride) Electrospun Nanofiber Membrane for High Flux Forward Osmosis Desalination.

Abstract

Novel amorphous silica nanoparticle-incorporated poly(vinylidine fluoride) electrospun nanofiber mats are introduced as effective membranes for forward osmosis desalination technology. The influence of the inorganic nanoparticle content on water flux and salt rejection was investigated by preparing electrospun membranes with 0, 0.5, 1, 2, and 5 wt % SiO2 nanoparticles. A laboratory-scale forward osmosis cell was utilized to validate the performance of the introduced membranes using fresh water as a feed and different brines as draw solution (0.5, 1, 1.5, and 2 M NaCl). The results indicated that the membrane embedding 0.5 wt % displays constant salt rejection of 99.7% and water flux of 83 L m(-2) h(-1) with 2 M NaCl draw solution. Moreover, this formulation displayed the lowest structural parameter (S = 29.7 μm), which represents approximately 69% reduction compared to the pristine membrane. Moreover, this study emphasizes the capability of the electrospinning process in synthesizing effective membranes as the observed water flux and average salt rejection of the pristine poly(vinylidine fluoride) membrane was 32 L m(-2) h(-1) (at 2 M NaCl draw solution) and 99%, respectively. On the other hand, increasing the inorganic nanoparticles to 5 wt % showed negative influence on the salt rejection as the observed salt flux was 1651 mol m(-2) h(-1). Besides the aforementioned distinct performance, studies of the mechanical properties, porosity, and wettability concluded that the introduced membranes are effective for forward osmosis desalination technology.