How do people get pure gases? (e.g, a helium tank for balloons)
In: Physics
Helium is a special case. Basically all the helium we use is extracted along side natural gas and separated out using [Fractional Distillation](https://en.wikipedia.org/wiki/Fractional_distillation) to separate the helium from the other components of natural gas
Less rare gasses like Nitrogen and Oxygen can be gathered from the atmosphere using either membranes or adsorption.
For the membrane approach you use a specially crafted membrane and ram air through it, the gas you want will scoot through the membrane while the others won’t and it gives you a decently pure supply.
For adsorption, you take a material which grabs onto the gas you want and load a chamber up with it. Pressurize the chamber with normal air for a bit and you’re desired gas will get stuck the the adsorbent like a sponge, then you dump the air and reseal the chamber, the adsorbent will give up the gas and you can suck the gas out of there and put it in a pressurized chamber. You can repeat this to get whatever purity of the gas you need (99.9995% nitrogen is made this way)
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