Hydrodynamic Behavior of Colloidal Suspension as a Carrier of Hazardous Substances

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Hazardous substances of low water solubility, e.g. heavy metal and dioxin, can migrate in the water forming complexes with soil colloids such as clay and humic substances. Therefore, hydrodynamic behavior of soil colloids with potential of contaminant carrier is crucial when the system of monitoring, the scheme of assessment and the criteria of environment are considered. The present study is performed focusing this aspect placing an emphasis on the fact that hydrodynamic behavior of colloid is critically controlled by the stability of colloid Obtained results can be summarized as follows:1)The increase of excluded volume due to the formation of floc structure was turned out to be important for the description of rheological properties which are critically related to the transportation problem. This effect was experimentally verified for the kinetics of flocculation in the shear field, capillary viscometry and bridging flocculation with polyelectrolytes.2)Set-up of column experiment was established as a model system of colloid transport in the ground water. The presence of a functional form of the filtering of colloidal material against flocculation and dispersion of colloid particles and the scale of pore in the column was verified. This can be the basis for the further analysis of hydrodynamic properties of colloidal particles in relation to the rate theory of coagulation in the flow field.3)The role of organic substances such as humic substances are critical when considering the formation of complex of heavy metal on the clay surface. This is also important in the analysis of flocculation. However, very little is know about this aspect, which is the motivation of further study.