Carbon dioxide delivery and resulting biomass separation in microalgae cultivation using triethanolamine

ABSTRACT

This study investigates a novel use of triethanolamine (TEA), a well-known carbon dioxide (CO₂) – capturing chemical, to simultaneously deliver CO₂ and separate microalgae biomass from the growth media in microalgae cultivation processes. For this purpose, the growth and nutrient utilization rates of Chlorella sp., were monitored at different concentrations of TEA saturated with 15% of CO₂ in a gas mixture. In addition, the total inorganic carbon content in the growth media was followed in order to estimate the CO₂ delivery rates. The highest growth and nutrient utilization rates occurred at 20 and 30 mM TEA concentrations, which results in 2.5-fold increase in biomass production rate at these TEA concentrations. More than 85% of the produced biomass was successfully separated from the medium by flotation facilitated by the release of oxygen and CO₂ gases to the air from the oversaturated growth media, as well as the surfactant characteristics of TEA.

KEYWORDS:

• Triethanolamine
• carbon dioxide
• microalgae
• harvesting
• flotation

Disclosure statement

No potential conflict of interest was reported by the author(s).

Novelty statement

Novelty of the present work includes the following items: (1) using TEA after saturating with 15% CO₂ to supply CO₂ for microalgal biomass production and (2) biomass separation by flotation facilitated by the release of oxygen and CO₂ gases to the air from the oversaturated growth media, as well as the surfactant characteristics of TEA.

Additional information

Funding

This study was funded by Gebze Technical University [grant no: 2017-A105-55] and partially supported by The Scientific and Technological Research Council of Turkey (TUBITAK) [grant no: 109Y296].