Dynamics of colloid transport and deposition in heterogeneous granular porous media

The effect of zeta potential on the initial rate of colloid deposition through chemically heterogeneous porous media is investigated in the first part of the dissertation. The transport behavior of negatively charged silica colloids is examined under chemically heterogeneous conditions commonly encountered in the subsurface by packing columns with various ratios of clean and chemically modified sand grains. It is concluded that the key factor controlling the deposition kinetics of colloidal particles in patchwise heterogeneous subsurface porous media, such as iron oxide-coated sand aquifers, is the fraction mineral grain surfaces coated with iron oxide.; In the second part, the deposition dynamics of colloidal particles is investigated focusing on the effect of particle size, flow velocity, solution ionic strength, and the interrelation between these parameters. The maximum attainable surface coverages (jamming limits) were determined from the colloid breakthrough curves for the various physicochemical conditions. Greater extent of blocking was observed for larger particles, higher flow rates, and lower ionic strengths. This observation is attributed to the so-called "shadow effect", whereby the local excluded area around deposited particles increases due to a shadow zone down gradient of the deposited particles.; In the third part, a general form of the dynamic blocking function in the framework of a virial expansion theory was used to model particle blocking dynamics during deposition in granular porous media. From the experimental breakthrough data, the virial coefficients up to the second order were found using a non-linear curve-fitting technique with the initial deposition rate determined from the experimental breakthrough curves. Hydrodynamic interactions and the range and magnitude of double layer interactions were found to be correlated with the virial coefficients of the dynamic blocking function. It has been demonstrated that the general form of the dynamic blocking function based on RSA mechanics must incorporate of colloidal and hydrodynamic interactions to properly characterize deposition dynamics of colloids in granular porous media under the influence of ionic strength, particle size, and flow velocity.