The effect of preparation time and aeration rate on the properties of bulk micro-nanobubble water using hydrodynamic cavitation

• Published in: Ultrasonics sonochemistry Vol. 84; p. 105965
• Main Authors: Zhou, Shaoqi, Nazari, Sabereh, Hassanzadeh, Ahmad, Bu, Xiangning, Ni, Chao, Peng, Yaoli, Xie, Guangyuan, He, Yaqun
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier B.V 01.03.2022; Elsevier
• Subjects: Aeration rate; Bubble concentration and size; Bulk microbubbles (BMBs); Bulk nanobubbles (BNBs); Dissolved oxygen (DO) content; Preparation time; Short Communication; Bulk nanobubbles (BNBs); Dissolved oxygen (DO) content; Bubble concentration and size; Aeration rate; Bulk microbubbles (BMBs); Preparation time
• ISSN: 1350-4177; 1873-2828; 1873-2828
• DOI: 10.1016/j.ultsonch.2022.105965

•Bulk micro-nanobubble solutions were prepared using a fine-bubble generator under different preparation times and aeration rates.•The dissolved oxygen contents of bulk micro-nanobubble water under different conditions were evaluated.•The bubble concentrations and sizes in bulk micro-nanobubble water under different conditions were evaluated.•The relationship between the dissolved oxygen concentration and the cavitation behaviors of bubbles was discussed. Fundamental research on bulk micro-nanobubbles (BMNBs) has grown rapidly due to the demand for their industrial applications and potential role in interfacial sciences. This work focuses on examining properties of such bubbles, including the number, concentration, zeta potential, and surface tension in water. For this purpose, BMNBs were generated by the hydrodynamic cavitation (HC) mechanism. Distilled water and air in the experiments were the liquid and gas phases, respectively. The characterization of bulk microbubbles (BMBs) and bulk nanobubbles (BNBs) were performed through focused beam reflectance measurement (FBRM) and nanoparticle tracking analysis (NTA) techniques, respectively. Zeta potential and surface tension of aqueous solutions were measured at different time and aeration rates. The results showed that aeration rate and preparation time had an important role in the properties of BNBs (concentration, bubble size, and surface charge) and BMBs (number, and bubble size). The instability of BMBs led to the rapid changes in the dissolved oxygen (DO) content in the water. The number of BMBs decreased when preparation time and aeration rate increased, but their size remained constant. By enhancing the preparation time and aeration rate, the concentration of BNBs improved first and then reduced. Additionally, the surface tension of an aqueous solution containing BNBs was significantly lower than that of pure water.