Earlier research on seawater desalination using FO process was generally concerned with the
choice of draw solution and flux recovery. However, fouling propensity of seawater on the
FO membrane, the necessity for any seawater pretreatment prior to passage through the FO
membrane and boron rejection by the FO membrane have not been studied in detail. Lately,
Jin et al. (2011) investigated boron passage through the FO membrane in two membrane
orientation modes, namely the dense layer facing the feed solution and the dense layer facing
the draw solution. Under simulated test conditions, artificial seawater (i.e., 0.5M NaCl) was
tested at batch scale with the addition of boron solution. Boron rejection was better for dense
layer facing the feed solution mode due to effective and efficient rejection of boron.
Furthermore, it was reported that the boron rejection increased with increasing membrane
water flux.
Nevertheless, there is a necessity to use actual seawater and run it in continuous mode to
investigate the boron flux and hence its rejection by the FO membrane. Fouling due to
seawater exacerbates the plant throughput, thus affecting the water production efficiency. As
far as RO process is concerned, fouling in seawater desalination is basically due to particulate
matter, organic compounds, and biological growth (Magara et al., 2000). Therefore, research
is necessary in membrane fouling, boron rejection by the FO membrane, impact of
pretreatment of seawater using the MF membrane and overall recovery of the system for
seawater desalination. Tapping the osmotic gradient energy of the highly concentrated
sodium sulphate as a draw solution in the FO process, seawater was desalinated at laboratory
scale in this study. Studies on flux performance, fouling and boron rejection of the FO
membrane were carried out.
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