Relation between Aggregation Kinetics and the Structure of Kaolinite Aggregates

Abstract

Dynamic and static light scattering were applied to the determination of the stability ratio and fractal dimension of kaolinite (KGa-2) at different kaolinite or/and electrolyte concentrations at pH 9.5. Dynamic light scattering was used to measure the kinetics of early stage aggregation to determine the stability ratio, W, as well as the cluster sizes which determine the fractal regime. Static light scattering was used to measure the fractal dimension, D(f). Results show that the two classes of "universality" (Lin et al. Nature 1989, 339, 360) characterizing the diffusion- and reaction-limited regimes of cluster-cluster aggregation do apply to colloidal kaolinite as limit cases when W approximately 1 or W > 100, respectively. In the intermediate regime where 5 < W < 100, the growth of the aggregate radius showed a power-law behavior similar to diffusion-limited cluster aggregation. For the intermediate aggregation regime, a scaling relation between fractal dimension and stability ratio, reflecting a continuous increase in particle packing density in the aggregate as the sticking probability of particles was reduced, was demonstrated.

Arginine controls heat‐induced cluster–cluster aggregation of lysozyme at around the isoelectric point

“…In this case, the morphology of the aggregation is more compact structure, because a large number of cluster-cluster collisions are needed before a bond between proteins is formed. [38][39][40] In fact, the addition of Arg resulted in the formation of denser aggregates than those in the absence of solution additives (see Figure 4). It is worth mentioning that a-crystallin 33,35,37 and GroEL 53 change the regime of protein aggregation from DLCA to RLCA.…”

Effects of ageing conditions and block copolymer concentration on the stability and micellization of P123-Ti4+ sols prepared by the templating method

“…-sol was 205. Previous workers have already reported the relationship between stability ratio, W, and aggregation kinetics [40][41][42]. In this respect, two well-defined regimes of fractal aggregation were proposed.…”

“…A stability ratio less than unity indicates aggregation faster than that due to diffusion alone and aggregation is driven by electrostatic attraction superimposed on diffusion [40]. However, a stability ratio of unity and W [ 100 imply the presence of DLCA and RLCA regimes, respectively [40]. Based on the calculated magnitude of W for our synthesized LC-Ti 4?…”

“…However, in RLCA, a substantial repulsive force is maintained between particles, so the existence of a nearly zero aggregation probability is likely and particles may collide many times before sticking to each other [43]. A stability ratio less than unity indicates aggregation faster than that due to diffusion alone and aggregation is driven by electrostatic attraction superimposed on diffusion [40]. However, a stability ratio of unity and W [ 100 imply the presence of DLCA and RLCA regimes, respectively [40].…”

Effect of aluminum speciation and pH on in-line coagulation/diatomite microfiltration process: Correlations between aggregate characteristics and membrane fouling

“…Recently, small-angle laser light scattering (SALLS) using Masterizer 2000 has been extensively employed in fractal dimension determination in various systems, such as kaolin, latex, and aluminum suspension [23][24][25]. During the SALLS, a laser light beam with the wavelength of 632.8 nm was passed through the suspension, which was then scattered by the sample.…”