| Research on colloid transport behavior in saturated porous media is a hot topic in the field of environment.On the one hand,it's contribute to predict pollutant migration behavior to prevent outbreaks of water-borne diseases.On the other hand,it's also can be used in the field of contaminated sites environmental restoration,by adding the colloidal reagent.In this paper,we through the soil column experiment and breakthrough curves to study the migration behavior of the colloid.Experiment consists of two parts,the first part by comparing the colloid transport in two kinds of glass beads to explore the influence of surface chemical heterogeneity,the second part compares the attachment/detachment behaviors of colloids under different pH environment.And the paper expounds the relationship between the chemical heterogeneity and pH at last.In addition,a extended DLVO approach was employed to calculate the interaction between colloids and glass beads for each group,this will help to understand from the aspects of mechanism.Results show that chemical heterogeneity can enhance the colloid adsorption ability in primary minimum under both favorable and unfavorable conditions,and the difference more obvious under unfavorable conditions.Under unfavorable conditions,colloid adsorption becomes difficult with pH increased.High p H environment can make colloids detachment from impurities surface and primary minimum,and the quantity increased with the p H increased.When solution pH increased to 10 or higher,the influence of chemical heterogeneity to the absorption process can be ignored.But some attached colloids due to chemical impurities can't release in full through increasing p H.The number of attached colloids depend on both the final environment and the adsorption process.The paper can improve our understanding to the role of chemical impurities and pH in the process of colloid transport,and provide the experimental basis for the future research. |
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