(480a) Polybenzimidazole (Pbi) Nanofiltration Hollow Fiber Membranes Applied in Forward Osmosis Process

Recently, forward osmosis (FO) has drawn much attention from researchers and its applications have been developed in various fields, such as wastewater treatment, pharmaceutical and juice concentration, seawater desalinating, even in the power generation and the potable water reuse in space. By employing the osmotic pressure as a driving force, forward osmosis can operate without high hydraulic pressures which are necessary in the reverse osmosis process. As the barrier between the draw solution and the feed solution to transport water and reject solutes, membrane plays an important role on the realization of forward osmosis. However, almost all available membranes used in the forward osmosis are dense semi-permeable membranes coming from reverse osmosis industry. For the first time, the potential of polybenzimidazole (PBI) nanofiltration (NF) hollow fiber membrane used in forward osmosis has been investigated. PBI NF membrane was chosen as candidate because of its unique nanofiltration characteristics, robust mechanical strength and excellent chemical stability. The mean effective pore radius of the fabricated PBI NF hollow fiber membrane is 0.32 nm. The MgCl2 solutions with different concentrations and other different salt solutions were employed as draw solutions to test the water permeation flux through the PBI membrane during forward osmosis. High water permeation flux and excellent salt selectivity were achieved by using the PBI NF membrane which has a narrow pore size distribution. Effects of membrane morphology, operation conditions and flowing orientations of the two feed streams within the membrane module on water transport performance have been also investigated. It is concluded that PBI nanofiltration membrane is a promising candidate utilized in forward osmosis.