In this study, the importance of individual soil mineral constituents on non-ionic surfactant sorption is evaluated by employing scanning electron microscopy (SEM) equipped with energy-dispersive X-ray analysis (EDAX) to observe microchemical surface composition of model soil colloids and relate surface microchemical composition to the sorption behavior of a non-ionic surfactant, Polyethylene Glyco Mono-p-nonylphenyl Ether (A 9 PE 1 0 ), on selected model soil colloids. This information is critical to understanding the fate and transport of this class of contaminants in subsurface. Results obtained from this study indicate that a correlation between the atomic ratio of Si:(Al+Fe) on soil mineral surface and A 9 PE 1 0 sorption capacity exist, where those soil with larger value of Si:(Al+Fe) ratio exhibit higher sorption capacity. This allows us to predict that the non-ionic surfactant sorption capacity for soil decrease with progressively increasing states of soil maturity.