08/05/2021
Various ways to prepare Oxygen-
• Oxygen Concentrators- Working on Pressure Swing Adsorption (PSA) technique, Oxygen concentrators are a simple way to produce oxygen from air. In the process, air is passed over an adsorbent at high pressure. The selection of adsorbent for the process is based on its tendency to adsorb N2 majorly and O2 insignificantly or not at all. In general, a zeolite with a pore size small enough to adsorb N2 and large enough to let oxygen gas pass through; is chosen. At high pressure, most of the N2 of air sample is adsorbed and left-over air with high concentration of O2 is collected in cylinders. After on, the pressure is reduced so as to make N2 desorbed. N2 is released in air and zeolite is re-ready for use. Most of the now-running oxygen generating industries are based on this technique. A beautiful illustration is here-
https://youtu.be/LxaoBoOAFAk
• Fractional distillation of air- In this process, natural air is compressed to high pressure resulting in heating of it. then the compressed hot air is passed through an expansion chamber where it gets cooled due to expansion and as a result of which CO2 gas separates from air as dry ice. The left air is allowed to expand more and sudden due to which it liquifies. Now the liquid air is subjected to fractional distillation. N2 and Ar gets out of the mixture due to their higher boiling points than oxygen. Oxygen is left in distillation column and is collected in cylinders after further purifications. A beautiful illustration is here-
https://youtu.be/OMF8np_gs7Q
The first way, which is the most used way to prepare oxygen for all kind of purposes uses Zeolites as an adsorbent making zeolites extremely useful. Zeolites are silicon-aluminum based minerals ocurring naturally and being prepared artificially as well. They have fine pores originating from chemical arrangement of atoms present in it. These pores have capacity to adsorb selective molecules and ions and inert gases making zeolites useful in water purification, oxygen separation from air, pollutant separation from air and water, various kind of catalysis etc. 😊
In this Science (Chemistry) video in Hindi for class 9 we explained how to obtain different gases from air. Air consists of different gases like nitrogen, ox...