A Comparison of Competitive Adsorption Kinetics Between Iron, Copper, and Nickel Using Soil-Based Media

Abstract

Treating urban stormwater runoff requires the removal of several pollutants including heavymetals. Soil-based media are applied as a filter material to treat stormwater runoff. Adsorption is a common pollutant removal mechanism utilized by soil-based media. Competitive adsorption can influence removing co-existing metals from stormwater runoff. To determine the influence of competitive metal adsorption on soil-based media, the concentrations of iron, copper, and nickel in single metal and ternary metal systems were monitored over a week-long period. The changing concentrations were fit to a kinetic adsorption model. The model parameters and the experimental concentrations were compared between the two systems to determine the influence of competitive adsorption. The study found that the rate of adsorption and quantity of metal adsorbed is different between the single metal and ternary metal systems. Thus, competitive adsorption occurs between iron, copper, and nickel. The results indicate changes in adsorption mechanisms and the number of compatible adsorption sites as the limiting factors. This study may contribute to treatment planning and media selection for stormwater runoff.