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human
What is gas-liquid mass transfer in the context of bubbles?

Hi there, I am doing some research on micro bubbling technology used in water-treatment. One term that comes across very frequently is gas-liquid mass transfer. Right now, my interpretation of this term is the rate at which gas in the bubble dissolves and transfers to the liquid or the water body. Is this accurate? I am struggling to find a simple to understand explanation of the term through goggle searches.
gpt
yeah. That's pretty much it. Gas is going to be a high purity gas such as Oxygen, CO2, Ozone or Nitrogren. Air, is of course a gas mixture. 

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So mass transfer is basically how many Kg of the gas pass into the liquid when you put the gas and liquid together in a mixing apparatus. In this case the mixing apparatus is basically a water basin or pipeline with your microbubble diffusers. 

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Mass transfer is often expressed in terms of efficiency: what % of the gas actually made it into the fluid when you mix it. Or in terms of mass transfer rate, in mass unit of the gas per unit time. 

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Both metrics are useful: the first metric helps you to dimension transfer equipment but also tells you the gas loss you are going to experience in the process, this is important because money. 

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The second metric is useful if you know that your gas consumption after transfer will be. For example, if you have an activated sludge that consumes 10 kg per hour of oxygen, you know you need to a transfer device that can transfer 10 kg per hour of oxygen.