Uncovering the mechanism of ultrasonic cavitation-induced deagglomeration of 7-ADCA agglomerates.

Although ultrasound-mediated deagglomeration is an efficient and environmentally friendly technique, its underlying mechanism is not yet fully understood. This study systematically investigates the unique agglomeration behavior of 7-ADCA crystals and the deagglomeration mechanisms under ultrasonication. 7-ADCA crystals exhibit a strong face-specific agglomeration tendency, attaching on the main crystal face because of the stable configuration with low energy. Ultrasonic treatment effectively disrupts agglomerated structures, significantly reducing the mean particle size and improving the uniformity of the particle size distribution (PSD). Kinetic modeling based on the Kapur function demonstrates that larger agglomerates, due to their greater specific surface area and more structural defects known as Griffith cracks, are more susceptible to cavitation effects and consequently exhibit substantially higher breakage rates. Mechanistic analysis confirms that shock waves generated from cavitation bubble collapse serve as the primary cause of agglomerate structural breakage by the combination of fracture and abrasion mechanisms.