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Kinetics of localized adsorption of charged colloid particles on homogeneous solidlliquid interfaces was analyzed. Limiting analytical equations were formulated for the maximum surface concentration e ,, the blocking parameterB(O), and adsorption kinetics in terms of the lateral interaction parameter h* depending on the ionic strength of the colloid suspension. In the general case particle adsorption kinetics proceeding according to the random sequential adsorption (RSA) mechanism was simulated numerically by using the Monte Carlo method. The theoretical predictions were experimentally tested by applying the direct observation method based on the stagnation point flow cell. Monodisperse suspensions of negatively charged latex particles of micrometer size range were used with freshly cleaved mica sheets as the adsorbing surfaces. The theoretical predictions were quantitatively confirmed showing that the RSA model describes well the kinetics of localized adsorption of interacting colloid particles especially for higher flow intensity. The widely used Langmuir model was found inappropriate for colloid particle adsorption from liquid phases.

Prediction of bacterial deposition rates onto substrates in natural aquatic systems is quite challenging because of the inherent complexity of such systems. In this study, we compare experimental deposition kinetics of nonmotile bacteria (Pseudomonas aeruginosa) on an alginate-coated substrate in a radial stagnation point flow (RSPF) system to predictions based on DLVO theory. The "softness" of the surface layer of the bacteria and alginate-coated substrate was considered in the calculations of their electrokinetic surface properties, and the relevance of both the classical zeta potential and the outer surface potential as surrogates for surface potential was investigated. Independent of the used electrical potentials, we showed that significant discrepancies exist between theory and experiments. Analysis of microscopic images in the RSPF system has demonstrated, for the first time, that irreversible deposition of particles or cells entrapped in the secondary energy minimum can occur on the alginate layer, despite the hydrodynamic forces resulting from the radial flow in the RSPF system. It is suggested that polymeric structures associated with the surface of the particle/cell and the alginate-coated substrate are responsible for the transition between the secondary minimum and primary energy well. This mode of deposition is likely to be important in the deposition of microorganisms in complex aquatic systems.