Sustainable bubble-mediated dynamic triphasic antisolvent crystallization for magnesium sulfate nano-micron particles: Precise size and morphology control

Abstract

Particle ultrafine processing is an effective strategy for enhancing the physical and chemical properties of materials. However, traditional antisolvent crystallization for ultrafine particle preparation often faces the challenge of uneven particle size distribution. To address this issue, a new method, Bubble-Mediated Dynamic Triphasic Antisolvent Crystallization (BDTAC), is proposed in this study. This method uses a vacuum pump to drive atomized droplets into an antisolvent body, where rapid solvent exchange and crystallization occur at the dynamic interface of ascending bubbles. By adjusting droplet inlet size, vacuum pump flow rate, and precipitation time, BDTAC achieves precise control of magnesium sulfate particles at the nano- and micron-scales, while synergistic antisolvent screening and ultrasonic treatment permit thin flake morphology. The products exhibit USP-compliant free-flowing properties (θ_r < 35°). Importantly, all processed materials retain the crystal structure of magnesium sulfate hexahydrate, a promising heat storage material. Compared to conventional methods, BDTAC enhances product quality through an energy-efficient, environmentally friendly process that operates under ambient conditions and uses reusable solvents, providing a sustainable route for efficient ultrafine particle preparation.