TWS, playing around and manipulating dissolved gas saturation, supersaturation and concentration using Chemistry Laws is fun and often profitable too.
Henry, a chemist of long ago, had an idea like supersaturating a can of Dr. Pepper with gas to make it effervescent when opened. How much gas is really possible to dissolve into water and force into solution? What are the limitations and so on? His hypothesis, over time proved always true and correct. His idea eventually solidified and a Chemistry Gas Law was born. A law as true, stable and reliable as Newton’s Laws of Gravity.
Here’s how the basic chemistry of dissolved gas solubility works (manipulating gas tension in the water) - Henry’s Gas Law applied:
The gas tension (individual gas pressure) is what makes gas molecules move from point A to point B… drives the gas molecule from the gas phase into solution or dissolves the gas into the water. The greater the tension the more gas dissolved into the water.
Conditions: Air (20% oxygen/80% nitrogen), fresh water, stable water temperature, 0.0 solute, sea level barometric pressure (760 mm/hg). If you know the % of the gas , and we do, know the barometric pressure and the solute concentrate, here’s the math.
Barometric pressure X % of gas = gas tension or pressure at sea level
2. Pure 100% Oxygen O2 the element is only 1 gas
760 mm/hg X 1.0 = 760 mm/hg gas tension
400% more O2 gas dissolves in water in normal environmental conditions using 100% pure O2 vs. using air (aeration) that contains only 20% oxygen in the mixture of gases.
Tremendous amounts of Nitrogen dissolve into water when air is dissolved – 608 mm/hg nitrogen (that’s aeration). But, dissolving a lot of Nitrogen gas in res water is really not the point of oxygenation if and when minimal safe “oxygenation is the whole point.”
When manipulating dissolved oxygen is the point, the difference between using air and using O2 becomes clear, at least it does to me. When dissolving air into water, the % O2 gas in air is the limiting factor. The DO is controlled by water temperature; dissolved solute concentrations and barometric pressure, but the limiting factor of dissolved oxygen is always the % of oxygen gas being dissolved.
Cheers
J
Henry, a chemist of long ago, had an idea like supersaturating a can of Dr. Pepper with gas to make it effervescent when opened. How much gas is really possible to dissolve into water and force into solution? What are the limitations and so on? His hypothesis, over time proved always true and correct. His idea eventually solidified and a Chemistry Gas Law was born. A law as true, stable and reliable as Newton’s Laws of Gravity.
Here’s how the basic chemistry of dissolved gas solubility works (manipulating gas tension in the water) - Henry’s Gas Law applied:
The gas tension (individual gas pressure) is what makes gas molecules move from point A to point B… drives the gas molecule from the gas phase into solution or dissolves the gas into the water. The greater the tension the more gas dissolved into the water.
Conditions: Air (20% oxygen/80% nitrogen), fresh water, stable water temperature, 0.0 solute, sea level barometric pressure (760 mm/hg). If you know the % of the gas , and we do, know the barometric pressure and the solute concentrate, here’s the math.
Barometric pressure X % of gas = gas tension or pressure at sea level
- Air contains only 2 major gases 20% Oxygen and 80% Nitrogen
- Air contains 80% Nitrogen
2. Pure 100% Oxygen O2 the element is only 1 gas
760 mm/hg X 1.0 = 760 mm/hg gas tension
400% more O2 gas dissolves in water in normal environmental conditions using 100% pure O2 vs. using air (aeration) that contains only 20% oxygen in the mixture of gases.
Tremendous amounts of Nitrogen dissolve into water when air is dissolved – 608 mm/hg nitrogen (that’s aeration). But, dissolving a lot of Nitrogen gas in res water is really not the point of oxygenation if and when minimal safe “oxygenation is the whole point.”
When manipulating dissolved oxygen is the point, the difference between using air and using O2 becomes clear, at least it does to me. When dissolving air into water, the % O2 gas in air is the limiting factor. The DO is controlled by water temperature; dissolved solute concentrations and barometric pressure, but the limiting factor of dissolved oxygen is always the % of oxygen gas being dissolved.
Cheers
J
