Forward osmosis (FO) for desalination or wastewater reclamation is receiving remarkable attention due to its low energy consumption and simple operation compared to reverse osmosis. In addition, the process of pressure-retarded osmosis (PRO) has been highlighted for its ability to harvest renewable and emissions-free energy from plentiful ubiquitous resources, namely seawater. However, development of a high performance membrane for FO and PRO processes is still a challenge.<br/>Here, we propose a novel thin film nanocomposite (TFN) membrane with vertically-embedded carbon nanotubes (CNT) in the active layer and support layer to maximize membrane permeability without significantly sacrificing selectivity. For the first time, a spray-assisted electromagnetic field alignment technique was applied to vertically embed CNT in the active layer of the TFN membrane (M. Son and H. Choi et al, 2016). After vertically embedding the CNT and chemical etching of the active layer, water flux was increased over 300% (40 LMH). Meanwhile, the increased reverse salt flux was mild. The developed TFN membrane thus showed even higher water flux and lower reverse salt flux when compared to recently-provided commercial FO membrane. In addition, TFN with CNT positioning in support layer was also successfully synthesized and tested in a combination of seawater desalination and wastewater reclamation process and PRO process.<br/>The thin film nanofiber composite (TNC) membrane for FO and PRO processes was also developed to overcome the inherent limitations noted with the use of a conventional polymer-based membrane. This TNC membrane exhibited slightly improved water flux from 14.46 to 18.24 LMH with increased reverse salt flux from 6.18 to 7.58 gMH compared to the TFN membrane in FO process. The developed TNC membrane for the PRO process showed improved maximum power density, since it maintained water flux as operating pressure increased. Therefore, a high performance TNC membrane with an excellently tuned fiber properties was successfully synthesized and proposed in this study as a novel membrane for use in FO and PRO processes.<br/>

Thin film nanocomposite membranes for forward osmosis and pressure retarded osmosis

253rd National Meeting (2017)

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