Generation, Properties and Applications of Oxygen Nanobubbles in Aeration

Nanobubbles (NBs) in water exhibit many appealing characteristics, such as a long residence time of bubbles in water due to their low buoyancy and stability against coalesces, collapse or burst. Long retention times in water potentially enhance chemical reactions and mass transfer in processes such as ozonation or aeration. In addition, gaseous NBs may increase the solubility of the gas species (e.g., ozone, oxygen or other gases) that may have low solubility in water or other liquids. Therefore, NBs hold promise in green and sustainable engineering applications in diverse fields (e.g., water/wastewater treatment, food processing, medical applications, and agriculture).

This presentation will give an overview of the common generation processes of NBs and their respective principles. Particularly, we will focus on the membrane-bubbling process that our group has been studying since 2016 and demonstrated advantages such as the ability to continuously generate a nanobubble water flow with tunable bubble sizes and compositions. The governing factors such as the membrane pore size, surface hydrophobicity, injection gas pressure on the produced bubble sizes and concentrations in water will be discussed. Then, the colloidal properties of nanobubbles such as stability, dissolution and aeration behavior in water have been examined and will be introduced. These properties are important for many applications of NBs such as chemical reactions and environmental remediation.

Wen Zhang is a professor of Newark College of Engineering in the Department of Civil and Environmental Engineering at New Jersey Institute of Technology. Dr. Zhang's research focuses on colloidal interfaces and processes that are crucial for environmental and chemical engineering applications.