摘要
Studies were carried out by using electrophoretic method on the effects of the specific adsorption of the anions,such as SO4^2-,PO4^3-,and F^- ions,the cations,such as Ca^2+,Mn^2+,Zn^2+,and Cu^2+,ions,and the anions and cations coexisting,such as Zn^2+ and SO4^2= ions,on electrokinetic properties of the red soils as typical variable charge soils in China concerning variation in the specific ion species and concentrations,with an emphasis on the interaction between soil colloid surfaces and the ions in soil solutions.The results showed that the adsorption of specific ions led to a very pronounced decrease in zeta potentials of the soil colloids and a shift of the IEPs to lower values for specific anions,and an obvious increase in zeta potentials of the soil colloids and a shift of the IEPs to higher values for specific cations.Under circumstances of the specific anions and cations coexisting,for instance,Zn^2+ and SO4^2- ions,the zeta potentials changed with values higher than the value for SO4^2- alone and lower than that for Zn^2+ alone,and the IEP was between that for Zn^2+ and that for SO4^2-.The adsorption of Zn^2+ and Cu^2+ ions resulted in a reversal of the zeta potentials,and appearance of two IEPs for Zn^2+ and no IEP for Cu^2+,exhibiting interesting special effects of these kinds of metal ions.The higher the concentrations of the ions,the greater the change of the electrokinetic properties.
Studies were carried out by using electrophoretic method on the effects of the specific adsorption of the anions, such as SO42-, PO43-, and F~ ions , the cations, such as Ca2+, Mn2+, Zn2+ and Cu2+, ions , and the anions and cations coexisting, such as Zn2+ and SO42- ions , on electrokinetic properties of the red soils as typical variable charge soils in China concerning variation in the specific ion species and concentrations , with an emphasis on the interaction between soil colloid surfaces and the ions in soil solutions. The results showed that the adsorption of specific ions led to a very pronounced decrease in zeta potentials of the soil colloids and a shift of the IEPs to lower values for specific anions, and an obvious increase in zeta potentials of the soil colloids and a shift of the IEPs to higher values for specific cations. Under circumstances of the specific anions and cations coexisting, for instance, Zn2+ and SO42- ions, the zeta potentials changed with values higher than the value for SO42- alone and lower than that for Zn2+alone, and the IEP was between that for Zn2+and that for SO42-. The adsorption of Zn2+ and Cu2+ ions resulted in a reversal of the zeta potentials , and appearance of two IEPs for Zn2+ and no IEP for Cu2+, exhibiting interesting special effects of these kinds of metal ions . The higher the concentrations of the ions, the greater the change of the electrokinetic properties.
