can helium be filtered from common air?

Answer 1

No, here's why.

Helium is usually produced as a byproduct of natural gas processing. Natural gas contains methane and other hydrocarbons, which are the principal sources of heat energy when natural gas is burned. Most natural gas deposits also contain smaller quantities of nitrogen, water vapor, carbon dioxide, helium, and other non-combustible materials, which lower the potential heat energy of the gas. In order to produce natural gas with an acceptable level of heat energy, these impurities must be removed. This process is called upgrading.

There are several methods used to upgrade natural gas. When the gas contains more than about 0.4% helium by volume, a cryogenic distillation method is often used in order to recover the helium content. Once the helium has been separated from the natural gas, it undergoes further refining to bring it to 99.99+% purity for commercial use.

Crude helium must be further purified to remove most of the other materials. This is usually a multi-stage process involving several different separation methods depending on the purity of the crude helium and the intended application of the final product.

The crude helium is first cooled to about -315° F (-193° C). At this temperature, most of the nitrogen and methane condense into a liquid and are drained off. The remaining gas mixture is now about 90% pure helium.
Air is added to the gas mixture to provide oxygen. The gas is warmed in a preheater and then it passes over a catalyst, which causes most of the hydrogen in the mixture to react with the oxygen in the air and form water vapor. The gas is then cooled, and the water vapor condenses and is drained off.
The gas mixture enters a pressure swing adsorption (PSA) unit consisting of several adsorption vessels operating in parallel. Within each vessel are thousands of particles filled with tiny pores. As the gas mixture passes through these particles under pressure, certain gases are trapped within the particle pores. The pressure is then decreased and the flow of gas is reversed to purge the trapped gases. This cycle is repeated after a few seconds or few minutes, depending on the size of the vessels and the concentration of gases. This method removes most of the remaining water vapor, nitrogen, and methane from the gas mixture. The helium is now about 99.99% pure.

Dr. H

Answer 2

Yes. The process is called distillation, where compressed air is refrigerated to it's liquid state at cryogenic temperatures. Different elements have different boiling or vaporization temperatures and as the temperature rises, the lighter molecules evaporate first, leaving the heavier molecules behind. Helium is one of the lightest gases, so it would be one of the first to 'gas off', after the hydrogen and before the oxygen.
Because He is so rare in 'normal air', liquid natural gas (LNG) is commonly used as a source for He, but the principle of controlling the evaporation rate and temperature is the same.

Answer 3

There's none in the atmosphere. We first found it on the sun with a new spectrum and then we started finding gas wells with about 1% an unknown gas in the Great Planes and it was identified as helium.

Answer 4

There isn't much helium in common air.

Helium is usually distilled from natural gas which has 5-10% He.

Answer 5

Helium indeed can be distilled from liquefied air, but there materials which can bound He from gas mixtures...

Answer 6

My guess would be no - or it would be extremely difficult. You can see how helium leaks out of a baloon after a couple days.