Microalgae dewatering based on forward osmosis employing proton exchange membrane

Area of Science:

• Biotechnology
• Chemical Engineering
• Environmental Science

Background:

• Microalgae are a promising source for biofuels and bioproducts.
• Efficient dewatering is crucial for cost-effective microalgae processing.
• Current dewatering methods face challenges with energy consumption and purity.

Purpose of the Study:

• To develop and evaluate an electrically-facilitated forward osmosis (FO) system for microalgae dewatering.
• To investigate the impact of applied voltage and draw solution concentration on water flux.
• To assess the system's capability for chlorophyll removal during dewatering.

Main Methods:

• Implementation of forward osmosis (FO) using a proton exchange membrane (PEM).
• Application of an external electrical voltage to the FO system.
• Variations in draw solution concentration and applied voltage were tested.
• Measurement of water flux, biomass concentration, and chlorophyll content.

Main Results:

• A significant increase in water flux was observed with the application of external voltage.
• Flux improvement was more pronounced at higher draw solution concentrations and applied voltages.
• A 247% increase in flux and 86% increase in final biomass concentration were achieved.
• Chlorophyll content in the dewatered biomass was reduced to 0.021±0.015 mg/g cell.

Conclusions:

• Electrically-facilitated FO with PEM offers an effective method for microalgae dewatering.
• The system enhances dewatering efficiency and biomass concentration.
• Simultaneous chlorophyll removal simplifies downstream lipid extraction processes.
• This technology presents a viable solution for industrial microalgae processing.