Kinetics of Colloid Particle Adsorption at Heterogeneous Surfaces

Abstract

Adsorption kinetics of negatively charged polystyrene latex particles (average size 1.38 μm) over a heterogeneous surface was studied experimentally. The substrate of a controlled heterogeneity was produced by covering natural mica sheets by smaller (average size 0.55 μm) positively charged latex particles. The direct microscope observation method combined with the impinging jet technique was used to determine particle adsorption kinetics. The initial flux of particles (the slope of the kinetic curves in the limit of short adsorption time) was determined quantitatively as a function of the coverage of smaller particles. It was demonstrated that the initial flux attains the limiting values for the smaller particle (heterogeneity) coverage as small as a few percent. The experimental results were interpreted in terms of the generalized random sequential adsorption model by considering the coupling between the bulk and surface transfer steps. A good agreement was found which seems to confirm the validity of the theoretical model for predicting particle adsorption at heterogeneous surfaces.

Deposition of colloid particles at heterogeneous and patterned surfaces

“…As demonstrated in Ref. [93], a significant deposition of particles was observed for negative values of the averaged zeta potential of the surface, i.e., of the same sign as adsorbing particles. This was so because the electrical doublelayer thickness was much smaller than the site dimensions; therefore, a considerable part of the site charge remained available for adsorbing particles.…”

“…The heterogeneity hypothesis is further supported by the measurements of particle deposition on sites formed by preadsorption of oppositely charged latex on mica [93], for particle size ratio 2.9. The averaged zeta potential of mica as a function of site coverage was measured by the streaming potential method, analogously as in the present case.…”

Deposition of Silver Nanoparticles in Geochemically Heterogeneous Porous Media: Predicting Affinity from Surface Composition Analysis

“…The kinetics of particle deposition onto heterogeneous surface has been investigated both theoretically and experimentally (Vaidyanathan and Tien 1991;Johnson, Sun et al 1996;Adamczyk, Siwek et al 2001;Adamczyk,Weronski et al 2002;Elimelech, Chen et al 2003;Adamczyk, Jaszcz et al 2005;Nazemifard, Masliyah et al 2006). Using an inverse procedure of parameter estimation, Song and Elimelech were able to identify the characteristic parameters for the surface charge heterogeneity from experimental results based on either the patch---wise model or the random distribution model.…”

Colloid Particle Adsorption at Random Site (Heterogeneous) Surfaces

“…2 has been confirmed in experiments involving polystyrene latex particles adsorbing at sites produced from smaller sized particles preadsorbed at mica (26).…”

“…The validity of the simulations and Eq. [7] has been confirmed in model experiments involving polystyrene latex particles adsorbing at oppositely charged sites attached to mica (26).…”