Relationship between chemical components of surface coatings and the maximum adsorption of Cd and Pb by surface coatings developed in natural waters

Adsorption of Cd and Pb to components of surface coatings developed in five natural waters (Jilin Province, China) was carried out. The result indicates that the content of Fe oxides on surface coatings is much higher than that of Mn oxides. Langmuir isotherm is more suitable to describe the adsorption of Cd and Pb onto surface coatings. The maximum adsorption of Pb and Cd to surface coatings is directly proportional to the contents of Mn oxides and Fe oxides on surface coatings with significant correlation (n = 5, alpha =0.01), respectively, and to the content of aluminum oxides with significant correlation (n=5, alpha =0.05), highlighting the relative importance of metal oxide fraction for Pb and Cd adsorption to the surface coatings developed in the five natural waters. The result agrees with that previously obtained by selective extraction technique for the relative importance of Fe and Mn oxides and organic materials in controlling Cd and Pb adsorption to surface coatings developed in Cayuga Lake(New York, USA).