Keywords: porous media, heat conduction, thermal conductivity, incineration, thermal desorption, contaminated sand, wet porous media, contaminant removal, dry sand, wet sand, infrared heating, temperature, moisture, heat transfer, mass transfer, environment, environmental pollution, waste management, environmental management, soil contamination
Contaminant removal from dry and wet sands by thermal desorption
Infrared heating was used to determine the effects of temperature and moisture on the removal of selected organic compounds from contaminated sand matrices. Quartz sand was used as a chemically inert surrogate for soil to isolate the heat transfer and mass transfer effects without any chemical contribution from soil. The selected organic contaminants were 3-nitrobenzene sulphonic acid, sodium salt (NBSS) and naphthalene (NAPH). The results of the weight loss data and concentration analyses of the contaminants in the sand showed that at similar concentrations and operating temperatures, a short period of time was required for NAPH, compared to the time required for NBSS, for achieving the same removal level. Temperature profiles in dry quartz sand were determined experimentally and predicted by a one-dimensional conduction model with variable thermal conductivity. The results from the wet sand experiments indicate that the presence of small moisture content can help the removal process by providing an additional convective heat transfer mechanism.