Adsorption of chlorinated hydrocarbons on silica gel

Thesis/Dissertation · Thu Jan 01 04:00:00 EST 1987

OSTI ID:5675121

Kuo, S L

A survey of indoor air pollutants was conducted in this study. A gravimetrical adsorption apparatus was designed and used to study the adsorption and diffusion of chlorinated hydrocarbons in silica gel. A new theoretical heterogeneous isotherm, using local Jovanovic isotherm and a Morse-type probability density function, was developed and tested. The new adsorption isotherm as well as the Langmuir and the BET models were then used to correlate the experimental adsorption data for the six chlorinated hydrocarbons investigated in this study. The diffusion coefficients of six chlorinated hydrocarbons in spherical silica gel beads were also investigated using the same gravimetrical adsorption apparatus. Results suggested that silica gel can be effectively used to both dehumidify and remove pollutants. A comparison of the new model with other heterogeneous isotherm equations showed that the new model gives a more accurate and yet simpler description of adsorption behavior on heterogeneous adsorbents. The new isotherm equation also correlated the experimental data extremely well. The Langmuir model provided better correlations for the isotherm data for the heavier adsorbates than for lighter ones, while the BET model provided good correlations for the isotherm data only up to 35% saturation pressure for each adsorbate. Diffusion studies of the chlorinated hydrocarbons in spherical silica gel beads showed that the diffusion rate controlling step was surface diffusion while the effects of gas and Knudsen diffusions were found to be less significant. Surface diffusion coefficients were found to be within an order of magnitude of the liquid phase diffusion coefficients, which suggests that surface diffusion exhibits liquid-like characteristics for multilayer coverage of the solids.

• Research Organization: Oklahoma State Univ., Stillwater, OK (USA)
• OSTI ID: 5675121
• Country of Publication: United States
• Language: English

Related Subjects

500200* -- Environment
Atmospheric-- Chemicals Monitoring & Transport-- (-1989)
54 ENVIRONMENTAL SCIENCES
ADSORBENTS
ADSORPTION
AIR POLLUTION
AIR POLLUTION CONTROL
CONTROL
CORRELATIONS
DEHUMIDIFICATION
DESIGN
DIFFUSION
EQUATIONS
HYDROCARBONS
INDOOR AIR POLLUTION
ISOTHERMS
MATHEMATICAL MODELS
MEASURING INSTRUMENTS
ORGANIC CHLORINE COMPOUNDS
ORGANIC COMPOUNDS
ORGANIC HALOGEN COMPOUNDS
POLLUTION
POLLUTION CONTROL
SILICA GEL
SORPTION
SORPTIVE PROPERTIES
SURFACE PROPERTIES