When we think of bodies of water, such as the oceans, they seem so vast to the human eye. Even just thinking about solutions to balance out dissolved oxygen levels, water pollution, and micro-plastic content can feel daunting, but what if I told you that we have created an innovation for our rivers and streams that is invisible to the naked eye? Meet the nanobubble- a gaseous bubble that can be applied in areas from treating microbial injuries all the way to removing toxic algal blooms.
What exactly is a nanobubble and how is it made?
Nanobubbles are gaseous bubbles that are typically less than 200 nm in diameter that lack buoyancy - which allows them to be suspended in liquid for days, weeks, or even months. Typically, these "super bubbles" are made through a process called hydrodynamic cavitation and although the name is a mouthful, the process itself is used due to its simplicity compared to alternative methods.
Hydrodynamic cavitation is the "mechanical rotation of a fluid" (with usually oxygen or hydrogen gas in the liquid stream) in at an increasing velocity in narrow, constricted tubes. The acceleration of the liquid through the tubes will cause a drastic decrease in static pressure, leading to gas filled cavities that take shape in the form of bubbles within the remaining liquid in the tubes(this specific action is called "cavitation"). However, as the liquid exits the constricting tube to the outside environment, the pressure will build up once again, causing those same cavities to collapse. It might seem like this process is ineffective at first, but after multiple cycles of creating and collapsing the cavities, hydrodynamic cavitation will lead to smaller and smaller bubbles produced- until they become naked to the human eye (200nm)!
How can they aid so many STEM innovations?
Nanobubbles' simplicity and flexibility to several conditions allows it to be used in several applications such as:
Enhancing Plant Growth: According to an article by Virginia Tech, nanobubbles help provide "high amount of accessible oxygen" that can even withstand water since they're hydrophobic after being produced. This allows plants to experience less oxygen stress in dense and waterlogged environments and conditions.
Removing Biofilm From Pipes: Since biofilm is made up of several bacterial and fungal microorganisms, they attach to a pipe's inner surface with a sticky, glue-like bond. This hydrophobic adherence can block pipes, harbor germs to impact drinking water, and also accelerate corrosion of the pipes. However, the nanobubbles can attach to the biofilm and decrease surface tension among the microorganisms.Once they burst, they release a high amount of energy generating hydroxyl and oxygen radicals which can inactivate bacteria.
Protein Extraction: Protein is the process of isolating certain proteins from cells or tissues to further analyze in research and industrial use, however it is difficult to remove such microscopic organelles from different biological materials. Nanobubbles can aid in this effort by having a large surface area for proteins to stick onto, enhancing buoyancy and therefore separation.
My Take
Nanobubbles help make large-scale change feel possible in multiple industries. By quietly improving oxygen levels, disrupting biofilms, and helping with processes like protein extraction and wastewater treatment, they offer a way to support healthier rivers, farms, and industries without relying solely on chemicals or massive infrastructure. In terms of cost, nanobubble production is initially more costly than traditional aeration methods, but it has shown to be cost-effective over time.
To me, their most inspiring quality is that they work “behind the scenes”: invisible to the naked eye, yet capable of influencing entire aquatic environments over time. As this technology becomes more affordable and better understood, it could become a key tool in how future engineers, scientists, and communities restore polluted waters and protect aquatic life, one tiny bubble at a time.
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