Views: 0 Author: Site Editor Publish Time: 2022-07-27 Origin: Site
With the spread of COVID-19 around the world, various protective measures and disinfection technologies have attracted much attention. Medical alcohol, disinfectant, ultraviolet radiation, etc. are all products and means to prevent and control the spread of the new coronavirus. Compared with chemical disinfection technology, what is the performance and safety of UV radiation disinfection technology? With the continuous development of ultraviolet LED (UV LED) technology, is there any difference in disinfection performance and application scenarios between ultraviolet solid-state light sources and ultraviolet mercury lamps? What are the difficulties and pain points that need to be solved urgently in the advancement of UV LED in the application field? The above problems are closely related to the follow-up development of UV LED. This article will analyze these aspects for your reference.
Ultraviolet disinfection technology
Ultraviolet light is between the visible light band and X-ray. According to the wavelength, ultraviolet light can be subdivided into near ultraviolet (UVA: 320-400 nm), medium ultraviolet (UVB: 280-320 nm), deep ultraviolet (UVC: 200-280 nm) ) and vacuum ultraviolet (VUV: 10-200 nm) [1, 2]. Among them, the UVC band has the highest ultraviolet energy, but due to its shortest wavelength, it is absorbed in the atmosphere, resulting in serious attenuation. The near-Earth solar spectrum almost does not contain ultraviolet light in this band, also known as the "solar blind" ultraviolet band.
The inactivation mechanism of ultraviolet light on microorganisms is not complicated. It mainly uses the absorption of ultraviolet light by the nucleic acid of microorganisms, destroys its nucleic acid function, and stops the reproduction of microorganisms, thereby realizing disinfection and purification. It should be pointed out that not the entire ultraviolet band has the inactivation function for microorganisms. Among them, only the ultraviolet rays located in the range of 240-260 nm in the UVC band are easily absorbed by bacteria and effectively act on the DNA of bacteria, interfering with their normal replication. Causes the death of bacteria , while UVA and UVB are outside the range of microbial absorption peaks, so the sterilization efficiency is very low, and they belong to the ultraviolet part that is ineffective for disinfection.
There are no chemicals involved in the UV disinfection process and no disinfection by-products are produced. The data shows that under the condition of UVC irradiation intensity of 30 mW/cm2, nearly 100% inactivation of most bacteria can be achieved within 1 s. Therefore, UV disinfection technology is a physical disinfection method, which has the advantages of broad-spectrum, high efficiency, fast and convenient, environmentally friendly, harmless, simple and practical, and easy to operate.
The application of ultraviolet light in the field of disinfection has a long history. As early as the 19th century, the research of Downes and Blunt mentioned that ultraviolet light has the effect of disinfection and sterilization. The Danish scientist Finsen then applied ultraviolet light to the field of medical health, and in 1903 he was awarded the Nobel Prize in Physiology or Medicine. The above shows that ultraviolet disinfection and sterilization technology has long been recognized and applied by humans. It is mentioned in the "New Coronavirus Pneumonia Prevention and Control Plan" that the new coronavirus is sensitive to ultraviolet light and heat. Therefore, in the prevention and control of the epidemic, in addition to chemical disinfection technologies such as medical alcohol and chlorine-containing disinfectants, ultraviolet disinfection technology, which is one of the physical disinfection methods, is also recognized by relevant institutions.
At present, the application scenarios of ultraviolet disinfection technology are mainly in specific places such as factories and hospitals, and are not popular in families. In addition to the influence of objective factors such as the volume of UV disinfection equipment, concerns about photobiological safety are also an important reason for affecting and limiting the application of such products. This concern is mainly due to the potential damage to the human eye and skin caused by UV radiation. It should be pointed out that under the premise of ensuring a safe dose, ultraviolet rays are difficult to cause damage to human skin, and are also beneficial to human health under certain conditions. For example, ultraviolet radiation in sunlight can promote the production of vitamin D in the human body. Therefore, Infants and young children are encouraged to get adequate sun exposure, but excessive exposure to the sun can cause darkening of the skin and even burns. To sum up, we believe that in actual use, it is necessary to combine the characteristics of UV light sources and product descriptions, and use UV disinfection technology in a scientific and standardized manner. Under the premise of complying with the safe dose, the UV disinfection method is feasible and beneficial. In addition, with the advantages of small size, easy integration, and fast switching of solid-state light sources, combined with mature sensing technology and control technology, it can effectively avoid potential safety hazards caused by improper use of ultraviolet rays. Therefore, under the premise of ensuring safety and reliability, UV disinfection technology can be fully utilized to serve human beings.
