Adsorption Characteristics of Cadmium, Lead and Mercury in Different Sized Soils

Three kinds of soil samples with different texture were sieved into nature fraction, sandsized fraction and silt and claysized fraction. Adsorption characteristics of these three different sized fractions of three different soils for Cd, Pb and Hg were studied. The results showed that adsorption capacity of Cd and Pb by silt and claysized fraction was higher than that by two other fractions. However, adsorption capacity of Hg showed opposite result to Cd and Pb, which was far higher by sand fraction than that by nature and silt and clayfraction. And the adsorption for Cd, Pb and Hg by three kinds of soils with three different sizes showed the similar characteristics. Furthermore, the Langmuir equation was proved to be the best description for Cd adsorption by different soils, the Henry equation was suitable for the description of Pb adsorption by different soils and the Freundlich equation could better fit the experimental data of Hg adsorption by three different soils.