Aggregation in the Presence of Inorganic Electrolytes

The aggregate fractal dimension dp is a function of size distribution of constituting particles, solids concentration, temperature, pH, ionic strength and polymer concentration [14, 33-35]. Computer simulation has been applied extensively [36] to study both DLA and RLA and predict aggregate structure by manipulating simulation parameters such as the random walk size [37, 38]. 

RLA occurs when repulsive forces are stronger than attractive forces. In addition to the electrical double layer force, under certain conditions of pH and electrolyte concentration, a thin hydration layer develops around the particle surface and results in short-range hydration repulsion, which could cause a reduction in collision efficiency between particles and leads to slow aggregation kinetics [44, 45]. Based on empirical models derived from force-distance measurements using atomic force microscopy, Runkana et al. [24] derived the following expression for hydration 

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