Micro nano bubble technology refers to the rapid dispersion of gas in water in the state of micron or nano bubble. Generally, bubbles with a diameter of 1-50μm are micro bubbles, and those with diameters less than 1μm are nano bubbles, which are collectively referred to as micro nano bubbles. Compared with ordinary large bubbles, micro-nano bubbles have unique physical and chemical properties, such as large specific surface area, long time in water, high gas-liquid mass transfer rate, high interface points, and the ability to spontaneously generate free radicals.
The characteristics of micro nano bubbles have applications in many fields, such as aquaculture, groundwater remediation, wastewater treatment, air flotation, and seed soaking. The micro nano bubbles have small particle size, large specific surface area and strong gas dissolving ability, which can greatly improve the reaction speed between gas and liquid. Using the characteristics of micro nano bubbles, the dissolved oxygen in water can be rapidly increased by using air or oxygen as the gas source, which has potential practical application value in the field of soilless culture as well as oxygen enrichment.
Based on the characteristics of micro nano bubbles for rapid oxygen increasing and dissolved oxygen, the micro nano bubble generator was combined with hydroponic facilities. By improving the oxygen environment in the rhizosphere of hydroponic crops, the growth and function of hydroponic crops can be promoted, so as to reduce the root rot caused by insufficient oxygen supply. The aeration and oxygenation of micro-nano bubbles can effectively promote the growth as well as development of the root system of hydroponic lettuce. The development of the root system enables the hydroponic lettuce to absorb more various nutrients in the nutrient solution, thereby promoting the growth of the above ground of the hydroponic lettuce.