Toluene sorption by granular activated carbon and its use in cold regions permeable reactive barrier: Fixed bed studies

Sorption characteristics of toluene on a granular activated carbon (GAC) derived from coconut shell have been investigated at 4 and 20 °C to facilitate the development of a permeable reactive barrier (PRB) to treat oil-contaminated surface and sub-surface waters in cold regions. A one-dimensional solute transfer model describing quantitatively the equilibrium and kinetics of sorption of toluene on GAC fixed-bed reveals that breakthrough and saturation capacities reduce with increased water flow rates. The GAC sorption capacity in a fixed bed is between 30 and 60% of the capacity determined in equivalent batch system. Fixed-bed performance is also significantly reduced at low temperature, with breakthrough and saturation capacities at 4 °C between 20 and 30% less than the values at 20 °C. The detrimental effect of low temperature on fixed bed performance will have significant implications for the PRB design to treat contaminated waters in cold regions and should be considered at planning stage.