Electro-Forward Osmosis

Type
Article

Authors
Son, Moon
Kim, Taeyoung
Yang, Wulin
Gorski, Christopher A.
Logan, Bruce

KAUST Grant Number
OSR-2017-CPF-2907-02

Date
2019-06-18

Abstract
The impact of ion migration induced by an electrical field on water flux in a forward osmosis (FO) process was examined using a thin-film composite (TFC) membrane, held between two cation exchange membranes. An applied fixed current of 100 mA (1.7 mA cm-2) was sustained by the proton flux through the TFC-BW membrane using a feed of 34 mM NaCl, and a 257 mM NaCl draw solution. Protons generated at the anode were transported through the cation exchange membrane and into the draw solution, lowering the pH of the draw solution. Additional proton transport through the TFC-BW membrane also lowered the pH of the feed solution. The localized accumulation of the protons on the draw side of the TFC-BW membrane resulted in high concentration polarization modulus of 1.41 × 105, which enhanced the water flux into the draw solution (5.56 LMH at 100 mA), compared to the control (1.10 LMH with no current). These results using this electro-forward osmosis (EFO) process demonstrated that enhanced water flux into the draw solution could be achieved using ion accumulation induced by an electrical field. The EFO system could be used for FO applications where a limited use of draw solute is necessary.

Citation
Son, M., Kim, T., Yang, W., Gorski, C. A., & Logan, B. E. (2019). Electro-Forward Osmosis. Environmental Science & Technology, 53(14), 8352–8361. doi:10.1021/acs.est.9b01481

Acknowledgements
We thank Dr. Manish Kumar and Mr. Woochul Song at Pennsylvania State University for the loan of the dead-end filtration test device. This research was supported by the King Abdullah University of Science and Technology (KAUST) (OSR-2017-CPF-2907-02) and Pennsylvania State University.

Publisher
American Chemical Society (ACS)

Journal
Environmental Science & Technology

DOI
10.1021/acs.est.9b01481

Additional Links
https://pubs.acs.org/doi/10.1021/acs.est.9b01481

Permanent link to this record