The irradiation of contaminated air with ultraviolet (UV) light can cause a significant reduction in certain pollutants. Harbauer has shown in several pilot tests and projects that UV oxidation is an economical alternative for the removal of vinyl chloride. Until now, this critical pollutant could only be treated by means of thermal-catalytic exhaust gas purification.
In addition to vinyl chloride, other volatile organic compounds (VOCs) and odor contamination can also be removed by UV oxidation. The technology can be used as a pure photolytic stage or in combination with a catalyst.
The basic principle of pollutant treatment by means of UV oxidation is the irradiation of the contaminated gas with high-energy UV light, as a result of which a physico-chemical chain reaction is initiated.
The initiated reactions depend on the energy content of the light used, which in turn depends directly on the emitted wavelengths λ.
Depending on the radiation source used and the treated substance mixture, various reactions are triggered, a distinction is made between direct and indirect photolysis. The most important reactions of the photolyses are listed below.
Indirect photolysis of oxygen and water with the formation of reactive oxidizing agents
Photolysis of O2 go to O3
O2 + Hʋ < 240 nm → 2 O●
O2 + O● → O3
Photolysis of water molecules to hydroyl radicals
O3 + H2O + Hʋ → O2 + Houses2O2
H2O2 + Hʋ → 2OH●
Direct photolysis of organic pollutants with formation of reactive organic radicals
R-R + Hʋ → R● + R●
Ultimately, the pollutants are split and broken down by a combination of the reactions shown. With sufficient duration and intensity of irradiation, complete mineralization of harmful substances in carbon dioxide, water and inorganic acids is achieved.
Depending on the pollutant mixture, UV oxidation can offer a more economical alternative to conventional cleaning methods. Advantages result from a significantly lower energy requirement and a simple process control with little technical effort.
Harbauer has already tested UV oxidation for the degradation of various pollutants and has successfully used it in practice. Further applications in the field of exhaust air purification are handled by our subsidiary uviblox implemented.