Indoor
air pollution is a complicated problem involving a mix of
many diverse contaminants that can negatively affect human health
at elevated concentrations. Volatile organic compounds (VOCs) are
some of the more toxic chemicals detected in indoor air. We evaluated
the performance of materials commonly found in commercial air purifiers
(activated carbon and zeolite clay) and a novel organosilica for their
ability to remove VOCs from indoor air. Data from batch sorption experiments
with toluene and benzene were modeled using Freundlich, Langmuir,
and Temkin isotherm fitting techniques to quantify important sorption
parameters. A new experimental technique was developed for conducting in situ gas chromatography measurements of batch sorption
experiments in 20 mL glass vials that allowed for direct gas measurement
after sorption without any further sample processing. Samples were
analyzed for the VOC concentration remaining in the vial using gas
chromatography with a flame ionization detector (GC-FID). The maximum
adsorption capacity of activated carbon for toluene and benzene was
46.9 and 55.5 mg/kg, respectively, according to Langmuir adsorption
isotherm fits. The adsorption capacities of organosilica for toluene
and benzene were 3.49 and 2.05 mg/kg, respectively. Zeolite yielded
minimal adsorption capacity compared with the two other sorbents.
Projections from the experimental sorbent capacities indicate that
under normal operating conditions (10 m3 with four air
changes per hour and 200 cubic feet per minute), an air purifier filter
could remove 30 ppb of VOCs for up to 690 days.