Home air purifier filter carbon evaluation - R&D project case study report

J. Hern, S. Basta*, Molecular Products Ltd, UK

A leading home air purifier manufacturer requested evaluation of the carbon used in its multigas filter, with the objective of identifying opportunities for increased performance efficiency and capacity. The filter - 40 x 40 x 2 cm dimensions, of paperboard frame/honeycomb construction containing granular 4 x 8 US mesh particle size activated carbon, is specified as “3.5 lbs. of granular activated carbon (GAC) that is treated to remove all gases. Expected life is 12 months.”

The filter was reported to contain chemically impregnated activated carbon for multiple gas removal capability. Based on the filter manufacturer claims of “treated to remove all gases”, and Molecular Products’ prior home air purification gas filtration projects, Molecular Products selected three test gases representing three different classes of gas types as follows:

  1. Cyclohexane (as a benchmark for organic vapors)
  2. Nitrogen dioxide (as a benchmark for acidic gases)
  3. Formaldehyde

Each gas type above is recognized as commonly in either outdoor urban air pollution (smog) or indoor air pollution (cooking, odors, off gassing from construction materials, etc.). Formaldehyde is of interest for meeting Chinese home air purifier filter ratings as defined in standard GB/T 18801.

Gas removal capability was done by testing tubes of packed beds against a challenge concentration of each separate gas under known conditions.

Carbon from the filter was compared to three standard Molecular Products carbon types in 4x8 US mesh particle size, consisting of the following:

  1. Chemsorb 1000 4x8 US Mesh (organic vapor activated carbon)
  2. Chemsorb 1505 4x8 US Mesh (impregnated activated carbon intended for formaldehyde gas removal)
  3. Chemsorb 3520 4x8 US Mesh (impregnated activated carbon intended for multiple gas removal)

All Chemsorb carbon types were built on 60 CTC activity, coconut shell-based activated carbons. Chemsorb carbons were tested under identical conditions to the filter carbon for each gas type. The results of the Leading Brand Filter testing demonstrated...

Session: G3 - Adsorption
Day: 13 March 2018
Time: 16:45 - 18:00 h

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