A Critical Review of Nanobubble Flotation for Seawater Treatment Process

The growth in public demand for clean water is increasing due to the development of the population, triggering the decline in clean water resources. Seawater provides an unrestricted, consistent supply of high-quantity water from the water cycle. It is a solution to the public issue of limited clean water, which can be processed with desalination technology to get fresh and clean water. Seawater desalination removes salt and other impurities from seawater to produce fresh, potable water. Furthermore, to produce freshwater using nanobubbles, seawater desalination and nanobubble flotation are interconnected through their roles in the water treatment and purification process. It is necessary to modify the nanobubble flotation, which has unique properties (minimal nano gas), to separate the salt ions and suspended solids from water to get freshwater. This paper has reviewed the water treatment that was conducted for the nanobubble flotation, especially ion flotation, which is a formation of positively buoyant bubble particles that agglomerate mixed with a recycling stream to saturate with air or carbon dioxide at high pressure to generate nanobubbles. This review investigates effective and efficient nanobubble flotation for the water treatment process in the seawater desalination issue to get pure water. The review highlights the mechanism of NB flotation that can effectively separate the dissolved ions and suspended solids in the flotation column, which contains seawater with different salt concentrations. This review focuses on ion flotation and investigates three mechanisms in the flotation process, which consist of collisions, attachment, and detachment. This process can enhance the flotation performance in the flotation separation process. As a result, it has produced fresh, potable water.