Author: Site Editor Publish Time: 11-11-2025 Origin: Site
Microbial contamination poses a major threat to public health. Ultraviolet disinfection, particularly in the UVC band (200–280 nm), achieves rapid microbial inactivation by damaging DNA/RNA and is recognized as a highly efficient physical disinfection method. Traditional low-pressure mercury lamps have long dominated the market, but their mercury content raises environmental concerns. With advances in semiconductor technology, UVC-LEDs are emerging with advantages such as mercury-free operation and extended lifespan. This article systematically compares the principles and performance of both technologies, referencing research from PubMed and other databases.
1.1 Traditional UVC Disinfection: Low-Pressure Mercury LampThe core principle of low-pressure mercury lamps relies on gas discharge exciting mercury atoms to emit light. A quartz tube is filled with mercury vapor and inert gas; when energized, electron collisions excite mercury atoms, causing electrons to transition from the ground state to higher energy levels. Upon returning to the ground state, they emit 253.7 nm UVC light. This wavelength is close to the UVC sterilization peak (~265 nm), with radiant efficiency reaching 30–40%. Additionally, 185 nm light can be produced to generate ozone.
Technical Features:
Advantages: Mature technology, low cost, high optical power, strong monochromaticity.
Disadvantages: Mercury-related environmental risks, warm-up time required, lifespan of ~8,000–10,000 hours, bulky size, temperature sensitivity.
1.2 Emerging UVC Disinfection: UVC-LED
UVC-LEDs operate on the principle of electron-hole recombination in a semiconductor PN junction. Primarily using AlGaN materials, under forward bias, electrons are injected into the P-region and recombine with holes, releasing photons. The wavelength is tuned via material composition, typically 255–280 nm. The energy relationship follows E=hcλE = \frac{hc}{\lambda}E=λhc.
Technical Features:
Advantages: Mercury-free, instant-on, lifespan of 10,000–50,000 hours, compact size, shock-resistant, tunable wavelength.
Disadvantages: Wall-plug efficiency (WPE) currently ~5–10%, higher cost, requires efficient heat dissipation.
| Comparison Dimension | Traditional Low-Pressure Mercury Lamp | UVC-LED | Analysis & Conclusion |
|---|---|---|---|
| Sterilization Principle | Gas discharge, atomic energy level transition | Semiconductor PN junction, electron-hole recombination | Fundamental differences make LEDs more environmentally friendly and flexible. |
| Core Wavelength | Fixed at 253.7 nm | Tunable (e.g., 265–280 nm) | LEDs can be optimized for specific pathogens, such as SARS-CoV-2. |
| Start-Up Time | Seconds to minutes | Nanosecond-level instant | LEDs support pulse control for energy savings. |
| Physical Characteristics | Fragile glass, contains mercury, large volume | Solid-state, mercury-free, micro-sized | LEDs ideal for portable applications. |
| Energy Efficiency & Heat Dissipation | 30–40% | <10% (recently >10%) | LED efficiency improving, but heat management remains critical. |
| Lifespan | 8,000–10,000 hours | >10,000 hours (up to 50,000 hours) | LEDs offer significant advantages with proper thermal management. |
| Cost | Low | High, but declining rapidly | LED costs trending downward; market CAGR projected >30% from 2023–2032. |
Studies show UVC-LEDs achieve equivalent or superior inactivation doses for microbes like E. coli in water disinfection compared to mercury lamps, especially against spores.
Low-pressure mercury lamps are suited for high-power scenarios, such as municipal water treatment and large-scale air disinfection. UVC-LEDs are gaining traction in portable devices, medical instruments, and dynamic disinfection applications—e.g., sterilization boxes, robots, and air conditioning antimicrobial modules. In the future, UVC-LEDs will surpass mercury lamps by achieving >10% WPE and lower costs, aligning with global environmental treaties.
UVC-LEDs and low-pressure mercury lamps differ fundamentally: solid-state emission versus gas discharge, resulting in advantages for LEDs in environmental impact, flexibility, and lifespan. Currently, mercury lamps dominate large-scale applications, but UVC-LED advancements signal their rise to lead the future disinfection market with greener, smarter solutions.
