Turbulent Aggregation of Titania in Water

Area of Science:

• Materials Science
• Physical Chemistry
• Fluid Dynamics

Background:

• Understanding particle aggregation is crucial for controlling material properties.
• Titanium dioxide (TiO2) is a widely used material whose aggregation behavior impacts its applications.
• In situ monitoring allows for real-time observation of dynamic processes like aggregation.

Purpose of the Study:

• To apply and compare two in situ particle sizing methods for studying titanium dioxide aggregation.
• To investigate the influence of stirring rate and solid volume fraction on aggregation dynamics.
• To interpret aggregation phenomena using a model that includes aggregate morphology, optical properties, and hydrodynamic interactions.

Main Methods:

• Utilized turbidity measurements for diluted titanium dioxide suspensions (solid volume fraction < 10(-4)).
• Employed backscattered light analysis for highly concentrated titanium dioxide suspensions.
• Performed in situ measurements to track aggregation from initiation to the observed steady state.

Main Results:

• Demonstrated the applicability of both turbidity and backscattered light analysis for in situ particle sizing in different concentration regimes.
• Quantified the effects of stirring rate and solid volume fraction on the kinetics and extent of titanium dioxide aggregation.
• Observed a consistent final steady state in the aggregation process under various conditions.

Conclusions:

• In situ particle sizing methods provide valuable insights into the dynamic process of titanium dioxide aggregation.
• Aggregation dynamics are complex, influenced by hydrodynamic forces, particle concentration, and aggregate properties.
• A comprehensive model incorporating aggregate morphology and interactions is essential for understanding the observed aggregation behavior.