Optimization and Performance Evaluation of Ultrasound-Assisted Cooling Crystallization of Oxalic Acid via Response Surface Methodology

Abstract

This study aimed to optimize the operating parameters for ultrasound-assisted cooling crystallization of oxalic acid dihydrate using response surface methodology based on a Box-Behnken design. Saturation temperature, agitation speed, and sonication time were selected as key variables. Fifteen experiments were conducted, resulting in a second-order mathematical model that correlates crystallization yield and induction time with these parameters, enabling effective process control. The maximum crystallization yield of 94.59% was achieved at 55 °C, 300 rpm, and 10 min of sonication, with the shortest induction time of 15 s. A comparative analysis between conventional and ultrasound-assisted crystallization demonstrated the superior efficiency of the ultrasound-based method. Overall, the technique proved to be highly effective, resulting in increased yield, reduced induction time, and the formation of uniform crystals with improved morphology.