CO2 - Nanobubbels

CO2 nanobubbles
Capturing CO₂
Capturing CO₂ in water using nanobubbles is a much more effective method than flushing water with CO₂ gas

injecting CO₂ gas

Injection of CO2 gas (flow 1 L/min, normopressure, room temperature), generates bubbles that rise rapidly to the surface. This method has limited transfer efficiency, although the natural solubility of CO2 in water is much higher than of O2.

CO₂ nanobubble generator
With the nanobubble generator (CO2-flow 1 L/min, normopressure), transfer efficiency is much higher, only a small number of tiny bubbles escape to the surface. In fact, transfer of CO2 to water is even more efficient than transfer of O2: approx. 94%.
Verification of CO₂ capture

Limewater test
Samples of CO2-nanobubbles, at different circulation times in the nanobubble generator (1 L/min CO2, 50 L water), were mixed with a dilute aqueous solution of calcium hydroxide ("limewater") resulting in precipitation of calcium carbonate.
Acidification
A fraction of CO₂ that dissolves in water reacts to form carbonic acid, H₂CO₃. Carbonic acid is unstable and rapidly dissociates to form hydrogen ions and bicarbonate- and carbonate ions. Dissolving CO₂ in water therefore results in acidification.
pH measurements
^{_{pH measurements during capture of CO2 (flow 1 L/min) by circulation in our nanobubble generator (50 L tapwater, temperature 20.3-26.3oC). Starting pH of tapwater is 8. Increasing accumulation of CO2 results in lowered pH (acidification).}}

Estimation of dissolved CO2
^{_{Since the alkalinity of our tapwater is known (KH 7,97 mEq/L), the concentration of free dissolved CO2 in water during circulation in the nanobubble generator can be estimated from the pH, using the equation CO2=KH/2.8*10^(7.90-pH).}}
Persistent CO₂ concentration

Open vessel
After dissolving CO₂ in water using nanobubbles, the pH rises and DCO₂ decreases gradually in 3 weeks.
This indicates that CO₂ nanobubbles remain in the water for a long time, longer than O_2.
(O₂ disappears in 1 week).
Closed vessel
In closed bottles pH and DCO2 remain low and high, respectively, for a very long time.
Removal of CO₂

After adding fytoplankton to the CO₂-nanobubble water, pH rises rapidly and CO₂ is removed within 2 days. The microalgae use the CO2 to produce carbon-rich lipids.
Our CO₂ nanobubble generators

Transfer efficiency of our systems for CO₂ is approx. 94%
Other gases

CO2 nanobubbles

Capturing CO2

injecting CO2 gas

Injection of CO2 gas (flow 1 L/min, normopressure, room temperature), generates bubbles that rise rapidly to the surface. This method has limited transfer efficiency, although the natural solubility of CO2 in water is much higher than of O2.

CO2 nanobubble generator

With the nanobubble generator (CO2-flow 1 L/min, normopressure), transfer efficiency is much higher, only a small number of tiny bubbles escape to the surface. In fact, transfer of CO2 to water is even more efficient than transfer of O2: approx. 94%.

Verification of CO2 capture

Limewater test

Samples of CO2-nanobubbles, at different circulation times in the nanobubble generator (1 L/min CO2, 50 L water), were mixed with a dilute aqueous solution of calcium hydroxide ("limewater") resulting in precipitation of calcium carbonate.

Acidification

A fraction of CO2 that dissolves in water reacts to form carbonic acid, H2CO3. Carbonic acid is unstable and rapidly dissociates to form hydrogen ions and bicarbonate- and carbonate ions. Dissolving CO2 in water therefore results in acidification.

pH measurements

pH measurements during capture of CO2 (flow 1 L/min) by circulation in our nanobubble generator (50 L tapwater, temperature 20.3-26.3oC). Starting pH of tapwater is 8. Increasing accumulation of CO2 results in lowered pH (acidification).

Estimation of dissolved CO2

Since the alkalinity of our tapwater is known (KH 7,97 mEq/L), the concentration of free dissolved CO2 in water during circulation in the nanobubble generator can be estimated from the pH, using the equation CO2=KH/2.8*10^(7.90-pH).

Persistent CO2 concentration

Open vessel

After dissolving CO2 in water using nanobubbles, the pH rises and DCO2 decreases gradually in 3 weeks.This indicates that CO2 nanobubbles remain in the water for a long time, longer than O2.(O2 disappears in 1 week).

​Closed vessel

In closed bottles pH and DCO2 remain low and high, respectively, for a very long time.

Removal of CO2

After adding fytoplankton to the CO2-nanobubble water, pH rises rapidly and CO2 is removed within 2 days. The microalgae use the CO2 to produce carbon-rich lipids.

Our CO2 nanobubble generators

Transfer efficiency of our systems for CO2 is approx. 94%

Other gases

Capturing CO₂

injecting CO₂ gas

CO₂ nanobubble generator

Verification of CO₂ capture

A fraction of CO₂ that dissolves in water reacts to form carbonic acid, H₂CO₃. Carbonic acid is unstable and rapidly dissociates to form hydrogen ions and bicarbonate- and carbonate ions. Dissolving CO₂ in water therefore results in acidification.

^{_{pH measurements during capture of CO2 (flow 1 L/min) by circulation in our nanobubble generator (50 L tapwater, temperature 20.3-26.3oC). Starting pH of tapwater is 8. Increasing accumulation of CO2 results in lowered pH (acidification).}}

^{_{Since the alkalinity of our tapwater is known (KH 7,97 mEq/L), the concentration of free dissolved CO2 in water during circulation in the nanobubble generator can be estimated from the pH, using the equation CO2=KH/2.8*10^(7.90-pH).}}

Persistent CO₂ concentration

After dissolving CO₂ in water using nanobubbles, the pH rises and DCO₂ decreases gradually in 3 weeks.
This indicates that CO₂ nanobubbles remain in the water for a long time, longer than O_2.
(O₂ disappears in 1 week).

Closed vessel

Removal of CO₂

After adding fytoplankton to the CO₂-nanobubble water, pH rises rapidly and CO₂ is removed within 2 days. The microalgae use the CO2 to produce carbon-rich lipids.

Our CO₂ nanobubble generators

Transfer efficiency of our systems for CO₂ is approx. 94%