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UV-based Advanced Oxidation Processes

Ozone treatment is an established and continuously evolving abatement method of various pollutants in air & water treatment alike. Additionally, its usage as a germicidal agent is also one of its main applications. The secret lies in its high oxidative potential, where the target pollutants or microorganisms are converted into CO2 and H2O by the means of advanced intermediate steps in which the compounds are continuously oxidized and converted until termination. Ozonetech has great experience in optimizing these types of systems with high efficiency in both air and water applications.

UV technology for air treatment

Another technology that has been established for similar applications areas with very promising results, is the UV technology. Utilizing lamps emitting light in the UV range is a conventional method for disinfection purposes due to the subsequent absorption and destruction of microorganisms’ genetic material, commonly used in hospital applications.

More recently, it has been shown to also have potential in the reduction of industrial pollutants e.g. Volatile Organic Compounds (VOCs) and odors as a stand-alone treatment through its photolysis reactions.

However, its greatest potential lies in the combination of UV with ozone, as the UV light can both generate and destroy ozone, naturally occuring in the lifecycle of ozone in the atmosphere, depending on the wavelength.

The generated oxygen singlet (O) is highly reactive that can react with various pollutants similarly to ozone, in highly effective oxidation reactions. However, the main phenomenon of interest, is the oxygen singlet reaction with ambient humidity that generates hydroxyl radicals (OH∙). This radical acts on the same and an even larger variety of pollutants and odors compared to ozone, due to its edge in oxidation potential (EOP, see table below). Furthermore, as the hydroxyl radicals have a substantially quicker reaction time than ozone, the required contact time and therefore the size of the treatment can be reduced.

The combination of ozone and UV generates hydroxyl radicals and is therefore an AOP (Advanced Oxidation Process).

AOP can consist of a catalyst instead of UV light, please see our AOP system for water treatment RENA Vitro for more information.

Oxidizing Agent

EOP (V)

Hydroxyl Radical (OH∙)

2.80

Oxygen singlet (O)

2.42

Ozone (O3)

2.07

Hydrogen peroxide (H2O2)

1.78

Hypochlorite

1.49

Chlorine (Cl)

1.36

Chlorine dioxide (ClO2)

1.27

Oxygen (O2)

1.23

 

Due to UV technology’s high potential and various application areas, and most importantly, its high compatibility with existing ozone treatment methods, Ozonetech has developed a modular UV solution (UV-C Air 515) for air applications in order to enable additional tools for ensuring an optimal solution depending on the needs of the customer.

Advanced Oxidation Processes: Applied

The difference in the oxidation potential and reactivity between the already strong ozone-molecule (2.07 eV) and the hydroxyl-radical (2.80 eV) allows for significant increases in reaction speeds (therefore lowered footprint of treatment) and efficiency for certain compounds that are difficult to oxidize. One example is the oxidation of the common volatile organic compound: acetaldehyde. Comparing the efficiency of ozone treatment, UV treatment and UV-based AOP at realistic conditions show that ozone treatment yield approximately double the conversion of UV and AOP further doubles the conversion of ozone treatment.

Comparison of efficiency: O3, UV and AOP

To further investigate the efficiency and applicability of the different technologies for removal of acetaldehyde (VOCs), rigorious in-house tests with control of temperature, moisture and air flows have been made to generate the following results.

In-depth analysis: O3, UV & AOP

The results above show the apparent synergistic effect between ozone and UV-technology when it comes to the abatement of organic pollutants. Our RENA Pro Ozone Systems can be seamlessly combined with UV-technology such as the modular UV-C Air 515

Do not hesistate to contact us regarding Tailored pilot projects for air treatment to take the first step in achieving the optimal air treatment solution for your application!

Ozone tech