Crystallization by acoustic and hydrodynamic cavitation: Mechanisms and process scalability

Research on crystallization processes induced by alternative technologies such as acoustic and hydrodynamic cavitation has been gaining popularity over the past few decades. Despite most studies being focused on laboratory scale experiments, the application of these technologies at larger scales has also been explored, bringing the field one step closer to industrial scale. This review article offers a critical discussion on the studies published in the last decade (2014-2024) related to crystallization induced by acoustic and hydrodynamic cavitation, with a special focus on scale-up applications. Parameters such as underlying mechanisms, operation modes (batch, continuous flow or flow-through), reactor configurations and operational conditions are covered, as well as major challenges and future trends. It was observed that the use of cavitation was associated with smaller crystal sizes, as well as higher process yields. Furthermore, continuous flow and flow-through processes were the most popular for both acoustic and hydrodynamic cavitation applications. No scale-up studies have been reported using hydrodynamic cavitation, despite its advantages over ultrasound reactors, and there is a lack in mechanistic studies for this technology. Furthermore, very few studies present all the essential information regarding process parameters and reactor configuration, which can hinder progress in further studies. However, the research topic of scale-up crystallization induced by acoustic and hydrodynamic cavitation has a high potential for further developments.