Abstract:Adsorptions of Cu2+ and Zn2+ by three typical variable charge soils and four typical constant charge soils di-f ferent in pH and in accompanying ion, Na+, Zn2+ or Cu2+ were determined, respectively. The results showed that adsorption of Cu2+ and Zn2+ by the soils could be described by the Langmiur equation C/(Xm) = 1/Kb+C/b both in the single ion and coexisting ions systems. The adsorption of Cu2+ or Zn2+ increased with pH and reached a plateau value when the pH value was 5. The affinity in adsorption of Cu2+ was greater than that of Zn2+. The mechanism of adsorption Cu2+ and Zn2+ was closely related to chemical composition and surface properties of the soils. The relative contribution of specific adsorption to the adsorption of Cu2+ and Zn2+ by the variable charge soils was greater than that by the constant charge soils.