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Physisorption in Gas Phase Filtration
When we talk about air filtration in critical environments, HEPA and ULPA filters often take the spotlight — but gaseous contaminants require a different kind of solution. Beyond chemisorption, there’s also physisorption. These terms can sound intimidating, but they don’t have to be. Let’s break it down in a way that makes the whole picture clear.
What is Physisorption?
Physisorption is the adhesion of gas molecules onto the surface of a solid medium due to weak physical interactions (van der Waals forces). Unlike chemisorption, there is no chemical reaction involved. The process is reversible where molecules can be released back into the air under certain conditions, such as increased temperature or pressure.
In HVAC gas phase filtration, physisorption occurs on activated carbon, a material with a vast network of pores and an exceptionally large surface area. This structure makes it ideal for trapping gases through physical attraction.
How Physisorption Works in Air Filtration
- Air passes through the filter media — typically activated carbon.
- Gas molecules adsorp into the pores of the carbon.
- Van der Waals forces bind the molecules onto the internal surfaces of the pores.
This physical adhesion holds the gases in place, effectively reducing their concentration in the air stream.
Related: 4 Corrosive Air Contaminants Threatening Data Center Operations
Applications of Physisorption in HVAC Systems
- Commercial Buildings: Removes odours and VOCs from furniture, paints, adhesives, and cleaning agents, improving indoor comfort.
- Airports and Transportation Hubs: Controls fuel and exhaust fumes for better passenger experience.
- Museums and Archives: Protects sensitive artifacts from harmful organic vapours.
- Healthcare Environments: Mitigates odours and chemical fumes, creating a safer, more pleasant environment.
Final Thoughts
Chemisorption and physisorption are two key gas phase filtration processes in the HVAC industry, each working differently but serving the same purpose: keeping air cleaner and environments safer for people and equipment alike. By working with trusted industrial professionals and selecting the right filtration solution for your facility, you can protect sensitive equipment, reduce costly maintenance, and keep operations running efficiently.
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Read More: Choosing An Air Filter Manufacturer Right For Your Industry
