Regeneration efficacy of sodium chloride and sucrose binary draw solutions using hollow fine fibre reverse osmosis membrane

Abstract: In this study, the regeneration performance of sodium chloride and sucrose draw solutions using a forward osmosis (FO) membrane was experimentally investigated in a FO–RO system. This efficiency was examined in terms of water flux (J_w), water recovery percentage (R%) and specific energy consumption (SEC) using a commercial RO membrane. Two sodium chloride feed solution concentrations of 9.3 g/l (osmotic pressure (OP) = 7.31 bars) and 17.9 g/l (osmotic pressure (OP) = 14.05 bars), as well as two sucrose feed solution concentrations of 150 g/l (OP = 11.21 bars) and 200 g/l (OP = 15.13 bars) were tested separately. At each experiment, feed solution is pumped to the RO membrane at different applied feed pressure values, while the flow rate and temperature of the solutions were kept constant throughout the experiments. The experimental results indicated that: water flux and water recovery percentage for sodium chloride and sucrose feed solutions in general are increased with rise in the RO feed pressure applied. Also, the SEC for sodium chloride and sucrose feed solutions decreased as the RO feed applied pressure was raised. The findings exhibit that the hollow fine fibre HR3155P RO membrane is more reliable for the regeneration of sodium chloride draw solution than sucrose draw solution. Moreover, the RO technique is not reliable to use in the regeneration of sucrose draw solution in a FO–RO system.