Do not exclude or kill, correctly understand the sterilization and disinfection artifact-deep ultraviolet LED

The Spring Festival of the Year of the Rat in 2020 is doomed to be the most memorable Spring Festival for the people of the country due to the raging of the new coronavirus. As of March 1, more than 80,000 people have been diagnosed with new coronavirus pneumonia (COVID-19) and more than 2,900 people have died. The new crown epidemic has made "disinfection" a high-frequency vocabulary, and 75% concentration of alcohol, 84 disinfectant, and no-clean hand sanitizer have been mentioned again and again.

 

In the "New Coronavirus Infected Pneumonia Diagnosis and Treatment Program (Trial Version 5)" issued by the National Health and Health Commission, "the virus is sensitive to ultraviolet rays and heat", and ultraviolet sterilization and disinfection have become a current hot spot. In the past, ultraviolet sterilization and disinfection were often only used as sterilization and disinfection methods in special scenes such as hospitals. Consumers are still relatively new to ultraviolet sterilization and disinfection.

 

So, how does ultraviolet light kill bacteria and viruses? What are the characteristics of ultraviolet sterilization? What precautions? Why is the deep ultraviolet LED called sterilization artifact? What is the layout of this industry in various countries? This article will unveil the mystery of deep ultraviolet LED for readers.


1. The principle of ultraviolet sterilization


Many articles have been carried out on ultraviolet sterilization recently, and here are three points to reiterate:


First, ultraviolet rays are divided according to wavelengths, which can be divided into UVA long-wave ultraviolet (wavelength range 315-400 nm), UVB medium-wave ultraviolet (wavelength range 280-315 nm), UVC short-wave ultraviolet (wavelength range 200-280 nm) and VUV vacuum Ultraviolet (wavelength range 10-200 nm). Among them, UVA long-wave ultraviolet is often called near ultraviolet, and UVC short-wave ultraviolet is often called deep ultraviolet.

 

Second, ultraviolet light is a mutagen. Under a specific wavelength range (mainly UVC) and a sufficiently high dose, ultraviolet light can cause abnormal formation of adjacent pyrimidine molecules in DNA or RNA in microbial cells such as bacteria and viruses. Chemical bonds hinder the replication of DNA or RNA, causing microbial cell death. The deep ultraviolet LED achieves the effect of sterilization and disinfection by emitting deep ultraviolet rays of UVC wavelength.

 

Third, researchers from the Chinese Center for Disease Control and Prevention found that SARS virus could be killed by irradiating coronavirus with deep ultraviolet light with an intensity greater than 90uW/cm2 for 60 minutes. The new coronavirus is similar to the SARS virus and belongs to the single-stranded positive-strand RNA virus. Therefore, theoretically and scientifically and rationally using ultraviolet light can effectively kill the new coronavirus.


Second, the characteristics of ultraviolet sterilization


Ultraviolet sterilization and disinfection mainly have the following characteristics:


(1) High sterilization and disinfection efficiency: The US Food and Drug Administration's Health Evaluation and Research Center research shows that under the ultraviolet light source with a characteristic wavelength of 254nm and a radiation intensity of 4016uW/cm2, the SARS virus kill rate can reach 99.99 after 6 minutes %. Compared with the heat sterilization that takes 45 minutes at 75 degrees Celsius to kill the SARS virus, the efficiency of ultraviolet sterilization and disinfection is much higher.


(2) Broad-spectrum sterilization: Since ultraviolet rays directly affect the DNA and RNA of bacteria and viruses, ultraviolet sterilization has the highest broad-spectrum among all current sterilization and disinfection methods, and can be applied to almost all bacteria and viruses. Efficient killing.


(3) No secondary pollution: The commonly used sodium hypochlorite disinfectant is harmful to the environment and will cause water pollution. The free chlorine released by it may cause poisoning. In contrast, ultraviolet light can cause bacteria and viruses to die directly, and no other chemical pollutants are produced. But pay attention to avoid using ultraviolet rays with a wavelength less than 243nm to generate ozone.


3. Advantages of UV LED


At present, there are two main types of ultraviolet light sources for sterilization and disinfection: traditional mercury lamps and deep ultraviolet LEDs. Compared with many shortcomings of traditional mercury lamps, deep ultraviolet LED has obvious policy advantages and technical advantages.


Disadvantages of traditional mercury lamps:


(1) The appearance is bulky, large in size, and equipped with high voltage electricity.

(2) It takes a long time to start up and cannot be used immediately.

(3) Fragile, short service life, up to 90% of service life is consumed in frequent switching phases.

(4) Highly toxic, which will cause mercury leakage after rupture, pollute the environment, and seriously endanger human health.


The policy advantage of DUV LED: The United Nations Minamata Convention signed by 128 countries around the world has officially entered into force in China in August 2017. The treaty clearly states that countries will ban the production and import and export of various mercury-containing products from 2020 The lamp will be prohibited from production and sale. The Chinese government has promulgated a series of policy documents such as the “List of Strictly Restricted Toxic Chemicals in China” and the “List of Priority Controlled Chemicals (First Batch)”, which set clear requirements for mercury control. As a traditional mercury manufacturing and mercury pollution country, the Chinese government actively implements the requirements of the Minamata Convention. Although ultraviolet mercury lamps used for curing and sterilization are not under the main control this year, in the long run, just as LEDs in the general lighting field replace traditional light sources, it is an inevitable trend. As green and environmentally friendly new ultraviolet solid-state light sources, deep ultraviolet LEDs , Will be the only alternative to the traditional ultraviolet light source-mercury lamp. With the entry into force of the "Minamata Convention" and the continuous advancement of DUV LED's own technology, DUV LED will usher in the rapid growth of its industrial scale.


Technical advantages of deep ultraviolet LEDs: Among the various sterilization and disinfection methods, only deep ultraviolet LEDs have energy saving, ready to use, space saving, maintenance-free, non-toxic and harmless, long life, no irritating odor, etc. Excellent characteristics. Compared with other sterilization and disinfection methods, DUV LED has obvious technical advantages.