Effect and application of micro- and nanobubbles in water purification

Abstract

Objective and methods The importance of water purification has increased due to the availability of several pollutants, such as chemicals, toxic metals, gases, and biological contaminants in the water. Commercial wastewater and domestic wastewater have commonly been treated using biological approaches. However, these approaches have limitations, such as high energy costs, low efficiency, requirement of trained staff, expensive chemicals, and multistep processing. Therefore, to overcome these challenges, the development of advanced technologies is increasingly in demand. Micro- and nanobubbles with advantages such as small size, large specific surface area, long residence time in the water, high mass transfer power, high zeta interface potential, and the capacity to produce hydroxyl radicals are considerably significant. Results and conclusions In this study, we discuss the current applications of micro- and nanobubbles using traditional and advanced techniques, such as flotation, aeration, and ozonation, which are capable of eliminating contaminants and color, water disinfection, and the oxidation of organic pollutants. Bubble technology has emerged as a potential platform for the successful extraction of harmful contaminants from water using these techniques.