Application of Ozone Decomposition Catalysts in UV Disinfection Equipment

UV disinfection technology, with its advantages of high efficiency and no chemical residues, has been widely used in water treatment, air purification, medical device sterilization, and other fields. However, during the operation of UV lamps (especially vacuum ultraviolet lamps with a wavelength of 185 nm), oxygen (O₂) in the air is ionized to generate ozone (O₃). Although ozone itself has strong oxidizing properties and can assist in sterilization, when its concentration exceeds 0.1 ppm, it can harm the human respiratory system and easily react with organic compounds to form secondary pollutants. Therefore, how to quickly decompose residual ozone after disinfection has become a key technical challenge in the design of UV disinfection equipment. The application of ozone decomposition catalysts provides an efficient and environmentally friendly solution to this problem.

 

1. Working Principle of Ozone Decomposition Catalysts

The core function of ozone decomposition catalysts is to convert ozone (O₃) into oxygen (O₂) through catalytic action. The reaction mechanism can be summarized as:

2O₃ → 3O₂

This reaction occurs at an extremely low rate under natural conditions, but catalysts significantly reduce the activation energy by providing active sites, thereby accelerating the decomposition process.

 

Catalytic Reaction Mechanism

 

Adsorption-Activation-Dissociation: Ozone molecules adsorb onto the catalyst surface (e.g., metal oxides), are activated through electron transfer, and then the O-O bond breaks, generating oxygen atoms (O) and oxygen molecules (O₂).

 

Oxygen Atom Recombination: Free oxygen atoms combine with another ozone molecule to further generate O₂, completing the chain reaction.

 

Catalyst Material Selection

Common catalysts include:

 

Transition Metal Oxides: Such as manganese dioxide (MnO₂), copper oxide (CuO), and cobalt tetroxide (Co₃O₄), which are cost-effective and highly stable.

 

Noble Metal-Loaded Catalysts: Such as platinum (Pt) and palladium (Pd) supported on alumina (Al₂O₃) or activated carbon, which have higher activity but are more expensive.

 

Composite Catalysts: Enhanced by doping rare earth elements (e.g., Ce, La) or constructing porous structures to increase surface area and moisture resistance.

 

Environmental Factors

 

Temperature: The optimal operating temperature is typically 20~80°C; excessively high temperatures may cause catalyst sintering and deactivation.

 

Humidity: High humidity may clog catalyst pores, requiring hydrophobic modification techniques.

 

Ozone Concentration: Catalysts must adapt to a wide concentration range of 0.1~10 ppm to ensure dynamic response capability.

 

2. Integrated Application of Ozone Decomposition Catalysts in UV Disinfectors

The ozone issue in UV disinfectors mainly occurs in two scenarios: exhaust emissions in water treatment and air circulation ducts in air purification equipment. The application of catalysts requires targeted design based on specific scenarios.

 

Water Treatment UV Disinfection Systems

 

Integration Location: Install catalytic modules at the exhaust port of the UV lamp reaction chamber to decompose residual ozone before emission.

 

Module Design: Use honeycomb ceramic carriers loaded with MnO₂, with low airflow resistance (pressure drop < 50 Pa), suitable for large-flow treatment (e.g., municipal wastewater treatment plants).

 

Case Study: After installing the catalyst, a wastewater treatment device reduced the outlet ozone concentration from 5 ppm to below 0.05 ppm, complying with the GB14554-93 "Emission Standard for Odor Pollutants."

 

Air Purification UV Disinfectors

 

Catalytic Layer in Circulation Ducts: Arrange catalyst-coated metal mesh around UV lamps to decompose ozone in real-time, preventing indoor accumulation.

 

Smart Control: Use ozone sensors to link with fans, dynamically adjusting the catalytic module's operating state (e.g., increasing airflow to enhance decomposition efficiency at high concentrations).

 

Household Device Example: A brand of air disinfection machine using Pt/Al₂O₃ catalyst achieved 99% ozone removal at 30 m³/h airflow, with a service life exceeding 5 years.

 

Medical Equipment Sterilization Devices

 

Compact Catalytic Unit: Use nanofiber-loaded Co₃O₄, with a volume only 1/3 of traditional catalysts, suitable for integration into small sterilization chambers.

 

High-Temperature Adaptability: Use cordierite honeycomb ceramic substrates to maintain activity in 120°C steam sterilization environments.

 

3. Technical Advantages and Challenges

Core Advantages

 

High Efficiency: Catalytic decomposition rates can be 10⁴~10⁶ times faster than natural conditions, achieving 90% ozone conversion within 5 seconds.

 

Environmental Friendliness: No secondary pollution; compared to activated carbon adsorption, no periodic replacement of consumables is required.

 

Cost-Effectiveness: Catalyst lifespan typically reaches 3~5 years, with lower overall costs than plasma decomposition and other technologies.

 

Technical Challenges and Solutions

 

Humidity Sensitivity: Improve moisture resistance through SiO₂ hydrophobic coatings or molecular sieve composite structures.

 

Poor Low-Temperature Activity: Introduce noble metals (e.g., 0.5% Pt) to reduce the ignition temperature from 80°C to room temperature.

 

Catalyst Poisoning: Optimize carrier structures (e.g., mesoporous TiO₂) to reduce deactivation caused by organic adsorption.

 

The integration of ozone decomposition catalysts with UV disinfection technology not only addresses the hidden risks of ozone pollution but also promotes the development of disinfection equipment toward higher efficiency, safety, and intelligence. With breakthroughs in new materials and integration technologies, future catalysts will demonstrate greater potential in more complex working conditions (e.g., high-humidity medical environments, ultra-low ozone concentration control), providing core support for the widespread adoption of green disinfection technologies.