Microalgae dewatering based on forward osmosis employing proton exchange membrane

- Electrically-facilitated forward osmosis was established for microalgae dewatering.
- Proton exchange membrane was employed for the suggested forward osmosis module.
- Dewatering flux and final biomass concentration was significantly increased.
- Chlorophyll was successfully removed from the dewatered biomass.
- Both microalgae dewatering and chlorophyll removal were achieved simultaneously.

In this study, electrically-facilitated forward osmosis (FO) employing proton exchange membrane (PEM) was established for the purpose of microalgae dewatering. An increase in water flux was observed when an external voltage was applied to the FO equipped with the PEM; as expected, the trend became more dramatic with both concentration of draw solution and applied voltage raised. With this FO used for microalgae dewatering, 247% of increase in flux and 86% in final biomass concentration were observed. In addition to the effect on flux improvement, the electrically-facilitated FO exhibited the ability to remove chlorophyll from the dewatered biomass, down to 0.021 ± 0015 mg/g cell. All these suggest that the newly suggested electrically-facilitated FO, one particularly employed PEM, can indeed offer a workable way of dewatering of microalgae; it appeared to be so because it can also remove the ever-problematic chlorophyll from extracted lipids in a simultaneous fashion.