Organic fouling in the membrane support is one of the major causes for the flux decline and low efficiency in the pressure retarded osmosis (PRO) process for osmotic power generation, especially when the fouling is complicated by inorganic salt ions. A facile method to fabricate antifouling hollow fiber membranes was demonstrated in this study, which employed the readily available poly(vinyl alcohol) (PVA) as the modification agent. The poly(ether sulfone) (PES) support for the thin film composite (TFC) membranes was first coated by polydopamine (PDA) and then coated with PVA with the aid of glutaraldehyde (GA). PDA was found to detach from the support in the first 2 h and gradually stabilized at pH 2, verifying its applicability for PRO processes. In addition, the existence of a PVA layer was confirmed by X-ray photoelectron spectroscopy. It is important to note that by controlling the reaction conditions, the water flux and salt reverse flux in the PRO process were not sacrificed, proving that the modification can well maintain the porous structure of the support. The modified membranes showed significantly improved fouling resistance to not only alginate but also complex alginate-calcium solutions. The water flux remained ∼80% instead of ∼64% in the latter case. Moreover, much of the fouling was converted from irreversible to reversible, which helped enhance the efficiency of physical cleaning to ∼90%, and hence improved the sustainability of the PRO process.
Bibliographical noteFunding Information:
This research was funded by the Singapore National Research Foundation under its Competitive Research Program for the project entitled, ?Advanced FO Membranes and Membrane Systems for Wastewater Treatment, Water Reuse and Seawater Desalination? (Grant R-279-000-336-281) and was also supported by the Singapore National Research Foundation under its Environmental & Water Technologies Strategic Research Programme and administered by the Environment & Water Industry Programme Office (EWI) of the PUB under the project entitled ?Membrane development for osmotic power generation, Part 1. Materials development and membrane fabrication? (1102-IRIS-11-01) and NUS Grant R-279-000-381-279. The authors also thank Wan Chunfeng for his help.
- Osmotic power
- Poly(vinyl alcohol)
- Pressure retarded osmosis
ASJC Scopus subject areas
- General Chemistry
- Environmental Chemistry
- General Chemical Engineering
- Renewable Energy, Sustainability and the Environment