Choi Jongbok, Lee Hyeonjae, Son Younggyu
Department of Environmental Engineering, Kumoh National Institute of Technology, Gumi 39177, Republic of Korea; School of Civil, Environmental, and Architectural Engineering, Korea University, Seoul 02841, Republic of Korea.
Department of Environmental Engineering, Kumoh National Institute of Technology, Gumi 39177, Republic of Korea; R&D Center, Changmyoung Industry Co., Yangju 11426, Republic of Korea.
Ultrason Sonochem. 2021 Jan;70:105334. doi: 10.1016/j.ultsonch.2020.105334. Epub 2020 Sep 2.
The effects of air sparging (0-16 L min) and mechanical mixing (0-400 rpm) on enhancing the sonochemical degradation of rhodamine B (RhB) was investigated using a 28 kHz sonoreactor. The degradation of RhB followed pseudo first-order kinetics, where sparging or mixing induced a large sonochemical enhancement. The kinetic constant varied in three stages (gradually increased → increased exponentially → decreased slightly) as the rate of sparging or mixing increased, where the stages were similar for both processes. The highest sonochemical activity was obtained with sparging at 8 L min or mixing at 200 rpm, where the standing wave field was significantly deformed by sparging and mixing, respectively. The cavitational oxidation activity was concentrated at the bottom of the sonicator when higher sparging or mixing rates were employed. Therefore, the large enhancement in the sonochemical oxidation was attributed mainly to the direct disturbance of the ultrasound transmission and the resulting change in the cavitation-active zone in this study. The effect of the position of air sparging and mixing was investigated. The indirect inhibition of the ultrasound transmission resulted in less enhancement of the sonochemical activity. Moreover, the effect of various sparging gases including air, N, O, Ar, CO, and an Ar/O (8:2) mixture was compared, where all gases except CO induced an enhancement in the sonochemical activity, irrespective of the concentration of dissolved oxygen. The highest activity was obtained with the Ar/O (8:2) mixture. Therefore, it was revealed that the sonochemical oxidation activity could be further enhanced by applying gas sparging using the optimal gas.
使用28kHz的声化学反应器研究了鼓泡曝气（0 - 16L/min）和机械搅拌（0 - 400rpm）对增强罗丹明B（RhB）声化学降解的影响。RhB的降解遵循准一级动力学，鼓泡曝气或搅拌均能显著增强声化学降解效果。随着鼓泡曝气或搅拌速率的增加，动力学常数呈三个阶段变化（逐渐增加→指数增加→略有下降），两个过程的阶段相似。鼓泡曝气速率为8L/min或搅拌速率为200rpm时，声化学活性最高，此时驻波场分别因鼓泡曝气和搅拌而发生显著变形。当采用较高的鼓泡曝气或搅拌速率时，空化氧化活性集中在超声换能器底部。因此，在本研究中，声化学氧化的显著增强主要归因于超声传播的直接干扰以及由此导致的空化活性区的变化。研究了鼓泡曝气和搅拌位置的影响。超声传播的间接抑制导致声化学活性增强较少。此外，比较了包括空气、N₂、O₂、Ar、CO₂以及Ar/O₂（8:2）混合气等各种鼓泡气体的影响，除CO₂外，所有气体均能增强声化学活性，且与溶解氧浓度无关。使用Ar/O₂（8:2）混合气时活性最高。因此，研究表明通过使用最佳气体进行鼓泡曝气可进一步增强声化学氧化活性。
