Adsorption characteristics of perchloroethylene in natural sandy materials with low organic carbon content

Laboratory batch tests were conducted to investigate the sorption isotherms and sorption kinetics of the chlorinated hydrocarbon perchloroethylene (PCE) in five natural sandy materials with an organic carbon content (f (oc)) in the range 0.080-0.540%. The amended non-linear dual-mode model can describe the sorption isotherms in materials with f (oc) in the range 0.080-0.090%. For a sample with a much higher f (oc) of 0.54%, the absorption isotherm was found to fit a linear model. These results may indicate that organic carbon is not the main factor influencing the sorption isotherm. The sorption kinetics of PCE in samples with f (oc) in the range 0.080-0.090% are not first-order and are different from those observed in the samples with higher f (oc). The sorption process in the materials with lower f (oc) involves fast sorption, fast desorption and an equilibrium stage. The results may imply that the factors affecting sorption kinetics of PCE in low f (oc) media are pore filling and capillary condensation rather than organic carbon content.