双频复合超声强化无水葡萄糖溶液结晶成核研究

溶液结晶技术在许多领域有着广泛的应用,其中结晶成核是溶液结晶的关键环节。以无水α-葡萄糖为研究对象,采用双频复合超声(25 k Hz+40 k Hz)强化糖液结晶成核,研究了溶液浓度、超声功率和作用时间对成核速率的影响,对单频和双频作用的晶核形态进行了对比,并采用碘化钾溶液中碘的释放量研究超声空化产额。研究结果表明:在同等条件下,双频复合超声降低了溶液成核的初始浓度,提高了成核速率,同时得到粒度均匀的晶核;双频复合超声的空化产额远高于单频25 k Hz超声和单频40 k Hz超声的空化产额,双频复合超声具有协同作用。双频复合超声强化溶液成核是一种快速、高效、节能的方法。

Nucleation of anhydrous-glucose solution crystallization enhanced by dual frequency ultrasonic irradiation

Solution crystallization technology is widely used in many fields and its crucial aspect is nucleation. Dual frequency ultrasonic irradiation (25 kHz+40 kHz) is proposed to enhance the nucleation of anhydrous glucose solution. The effects of the concentration of the solution, the ultrasonic power and ultrasonic processing time on the nucleation rate are studied. The crystal size under the dual frequency ultrasonic irradiation is analyzed by comparison with the single frequency ultrasonic irradiation. And the iodine released from potassium iodide is determined to assess the cavitation yields of dual and single frequency ultrasound. The results show that the dual frequency ultrasound could, under the same condition, reduce the initial concentration of the nucleation of anhydrous glucose solution, increase the nucleation rate and achieve the crystal nucleus, which has regular morphology and uniform particle size distribution by comparison with no ultrasound and with single frequency ultrasound. The results of absorbency experiments indicate that the cavitation yields, i.e. the iodine content, of dual frequency ultrasound is more than that of a single 25 kHz or 40kHz ultrasound, that is to say, a significant synergetic effect of dual frequency ultrasound exists. Consequently, nucleation under the dual frequency ultrasonic irradiation is a rapid, high-effective and energy-saving method.