History of devices to generate hydroxyl radicals contained in water
Background
The origin of hydroxyl radicals contained in water
It all began in 1997. Working on a project of the former Ministry of International Trade and Industry on purification of air in living environments, Panasonic researchers became interested in a technology for generating hydroxyl radicals contained in water. They wondered if tiny water particles could provide a new way to clean air. And in 2001, a team of just two researchers set to work.
This was entirely new technology, and it presented significant challenges. The team needed to develop verification methods and evaluation techniques from the ground up, and the electrical discharge phenomenon at the core of the process was difficult to control. The work continued without results for some time, and at one point the research was nearly abandoned. However, the research director at the time decided to persevere, saying, "Let's keep at it for one more year!" Panasonic devotion to technology saved the project. And finally, in 2003, the team succeeded in creating nano-sized water particles that purify the air. The technology of hydroxyl radicals contained in water was born.
The ongoing challenge of improving air quality
Work to advance the technology of hydroxyl radicals contained in water continues today. One key focus is the verification of effects in inhibiting harmful impacts on the human body of pathogenic microorganisms (bacteria, mould, and viruses) and allergens, and the breaking down of PM 2.5 particles.
For example, in 2009, with the help of an independent testing organisation, Panasonic demonstrated the effect of hydroxyl radicals contained in water against bird flu and new strains of influenza. And in 2012, in collaboration with an independent testing organisation in Germany, we conducted virus clearance testing that showed the effectiveness of the technology against the four types of viruses (with and without envelope, DNA type and RNA type). Based on this we announced that hydroxyl radicals contained in water can be expected to have an inhibitory effect on new, unknown viruses. While it had already seemed clear that the activity of hydroxyl radicals contained in water could be expected to inhibit the activity of viruses, this verification was a highly significant milestone.
Another key focus of our ongoing research is efforts to increase the effect of hydroxyl radicals contained in water by increasing the concentration of radicals generated. Working to address the growing risks associated with air quality the world faces today, Panasonic is pressing forward with its research into more advanced devices.
The need for air quality improvement knows no borders. Panasonic will continue to pursue the potential of hydroxyl radicals contained in water, applying technology to enhance air quality and contribute to the health and quality of life of people worldwide.
Timeline
Research into purification of air in living environments begins
Development of technology of hydroxyl radicals contained in water begins
Trial production of prototype to generate hydroxyl radicals contained in water and testing begin
Completion of device to generate hydroxyl radicals contained in water [480] (water refill type)
Completion of device to generate hydroxyl radicals contained in water [480] (Peltier type)
Development of next-generation highly reactive device to generate hydroxyl radicals contained in water begins
Inhibitory effect on viruses and bacteria and reduction of pesticide residues verified
Inhibitory effect on adhering and airborne Staphylococcus aureus and bacteriophage Φχ174 viruses verified
Inhibitory effect on swine-origin influenza virus verified
Denaturing of proteins in pollens found year around verified
Completion of a smaller device that generates more hydroxyl radicals (4th-generation Peltier type)
Inhibitory effect on mould verified
Inhibitory effect on viruses verified by virus clearance test
Inhibitory effect on pet-related allergens, bacteria, mould, and viruses verified
Decomposition of PM 2.5 components and inhibition of growth of mould attached to Yellow Sand verified
Device to generate hydroxyl radicals contained in water [4800] completed
Inhibitory effect on all “View 39” inhalation-type allergens that are the main cause of allergic conditions verified
Verification of inhibitory effect on novel coronavirus (SARS-CoV-2)
> Press release
What are hydroxyl radicals contained in water [4800] (nano-sized electrostatic atomized water particles)?
In 2016, Panasonic enhanced the discharge component of the hydroxyl radicals contained in water [480] device (generates 480 billion hydroxyl radicals per second*¹), succeeding in creating a hydroxyl radicals contained in water [4800] device (generates 4.8 trillion hydroxyl radicals per second*²) that produces 10 times*³ the hydroxyl radicals with an unchanged ozone generation level.
|
|
Hydroxyl radicals contained in water [480] |
Hydroxyl radicals contained in water [4800] |
|
|---|---|---|---|
|
Ion |
Illustration |
 |
 |
|
Method |
Discharge system |
Electrostatic atomization (corona discharge) |
Electrostatic atomization (multi-leader discharge) |
|
Condensation method |
Peltier method |
||
|
Basic features |
Electric charge |
Minus |
|
|
Size |
5 to 20 nm |
||
|
Hydroxyl radicals |
480 billion/second |
4.8 trillion/second |
|
|
Ion lifespan |
About 600 seconds |
||
|
Water content |
About 1,000 times |
||
|
Characteristics |
Mild acidity |
||
|
Generating principle |
 A generator for hydroxyl radicals contained in water [480] cools and condenses water from the air. A high voltage is applied to the collected water to generate hydroxyl radicals contained in water. |
 In the generator for hydroxyl radicals contained in water [480], radicals are discharged in a radial dispersion. On the other hand, the generator for hydroxyl radicals contained in water [4800] generates a broad plasma region by discharging at one point, generating 10 times*³ as many hydroxyl radicals. |
|
|
Discharge condition |
 |
 |
|
*¹ Generator for hydroxyl radicals contained in water [480] measured by ESR method in September 2010. (Panasonic research)
*² Generator for hydroxyl radicals contained in water [4800] measured by ESR method in September 2016. (Panasonic research)
*³ Comparison between generator for hydroxyl radicals contained in water—480 billion particles per second—and generator for hydroxyl radicals contained in water—4.8 trillion particles per second. Measurement by ESR method. (Panasonic research)