What is micro-nano bubbles?
Micro-nano bubbles refer to bubbles with diameters ranging from tens of micrometers to hundreds of nanometers when they form. These bubbles, which lie between microbubbles and nanobubbles, possess unique physical and chemical properties not found in conventional bubbles.
How are micro nanobubbles generated?
The Xinozone micro-nano bubble generator operates on the principle of achieving a high degree of dissolution and mixing between gas and liquid. It employs a dynamic high-speed shearing device to finely break down the bubbles within the gas-liquid mixture. Due to the powerful shear force generated by these components, the bubbles can be fragmented to sizes ranging from tens of nanometers to several micrometers, ultimately forming a milky-white micro-nano bubble solution.
This method allows the Xinozone generator to simultaneously accomplish gas-liquid mixing and microbubble generation, featuring enhanced gas-liquid processing capabilities.
CHARACTERISTICS OF MICRO-NANO BUBBLES
large specific surface area
In other words, when the total volume remains constant (V unchanged), the total surface area of the bubbles is inversely proportional to the diameter of a single bubble.
According to the theoretical formula, compared to bubbles with a diameter of 1 millimeter, bubbles with a diameter of 10 micrometers have a specific surface area that is theoretically 100 times larger under the same volume.
This means the contact area between air and water increases by a factor of 100, thereby theoretically enhancing the reaction rates by the same 100-fold magnitude.
Self compression – dissolution
According to the Young-Laplace equation:
P=2γ/r
where ( P ) represents the pressure difference, ( γ ) represents the surface tension coefficient, and ( r ) represents the bubble radius.
For bubbles with a diameter greater than or equal to 0.1 mm, the additional pressure they experience is negligible. However, bubbles with a diameter of 10 μm are subjected to an additional pressure of approximately 0.3 atmospheres, and when the bubble diameter decreases to 1 μm, the pressure can reach up to 3 atmospheres.
The dissolution of micro-nano bubbles in water is a process in which the bubbles gradually shrink. As the bubble size decreases, the pressure it experiences increases significantly, thereby accelerating the dissolution rate of the gas and ultimately causing the bubble to completely dissolve in water. Theoretically, the pressure on the bubble as it approaches disappearance tends toward infinity.
With a negatively charged surface
Plain water mainly consists of water molecules and a small number of H⁺ and OH⁻ ions produced by ionization. The gas-liquid interface formed by bubbles in water tends to attract H⁺ and OH⁻ ions. Usually, cations leave the interface more easily than anions, making the interface negatively charged. This charged surface then attracts oppositely charged ions (especially higher-valence ions) from the water, forming a stable electrical double layer.
The surface charge of microbubbles is often characterized by the zeta potential, which is a key factor determining their adsorption ability.
When micro-nano bubbles shrink in water, the charged ions accumulate rapidly at the tiny interface, leading to a sharp increase in the zeta potential. Right before the bubbles collapse, the zeta potential at the interface can reach an extremely high peak value.
Generate a large amount of free radicals
At the moment when micro-nano bubbles burst, the sudden disappearance of the gas-liquid interface leads to the rapid release of chemical energy stored in the highly concentrated ions accumulated at the interface. This process can stimulate the generation of a large number of hydroxyl radicals.
With their extremely high redox potential, these hydroxyl radicals produce powerful oxidation effects, enabling the degradation of pollutants that are difficult to oxidize under normal conditions—such as phenol—in water, thereby achieving water purification.
High gas dissolution rate
At the heart of micro-nano bubble technology for water ecosystem restoration is addressing insufficient dissolved oxygen levels.
By deploying micro-nano bubble aerators to perform large-scale oxygenation, the dissolved oxygen content in water is significantly increased.
This activates indigenous microbial communities and creates favorable conditions for aerobic microorganisms to thrive.
Utilizing the metabolic processes of these microorganisms, pollutants in the water are rapidly degraded or transformed, leading to a noticeable reduction in key indicators such as COD, BOD, suspended solids, and ammonia nitrogen within a short timeframe.
As a result, water clarity improves markedly, allowing the aquatic environment to regain its natural self-purification capacity and functional integrity. This approach helps maintain the stable balance of water ecosystems and ensures long-term self-sustaining purification.
