Usage of Isotopic Labeling and Transient Conditions as Methods to Understand the Reaction Mechanisms Related to Catalytic Oxidation of Volatile Organic Compounds

Catalytic oxidation has proven to be an efficient and environmentally sound technology in the abatement of volatile organic compounds (VOCs). It is especially suitable for the abatement of solvent emissions originating from different coating processes. However, a really successful application of catalytic oxidation to more difficult emissions, such as to VOCs containing chlorine and sulfur, requires more detailed information on kinetics and mechanisms of these catalytic reactions (oxidation, deactivation, regeneration).

Application of an energy-efficient reverse-flow process to catalytic oxidation of VOCs has been commercialized about 10 years ago. Transient operation of the process has not only certain advantages on the catalysts' performance, but it also creates a challenging research task, since the existing phenomena are not completely understood. In addition, selectivity of the catalytic oxidation of S- and Cl-containing compounds is very important, because unwanted corrosive and/or toxic by-products should be avoided.

Isotopic labeling technique, which uses 18O2 isotopes, gives significant information on oxygen mobility and reaction mechanisms on the catalytic surface. The combination of transient experiments, isotopic labeling and modeling can be used to create an overall picture and deeper understanding of phenomena involved. This information can be further utilized in the development of more selective and active catalysts. The catalysts will also be characterized by surface science methods: chemisorption, physisorption, electron microscopy, X-ray diffraction etc. when needed.

This research aims
(1) to prepare novel sample catalysts by conventional (impregnation) and non-conventional (redox) methods,
(2) to study catalysts activity in the oxidation of Cl- and S-containing VOCs at steady and unsteady states,
(3) to reveal the surface oxidation mechanisms and oxygen mobility of the most active catalysts,
(4) to obtain information about the catalyst deactivation in the oxidation of Cl- and S- containing volatile organic compounds and
(5) to improve the catalysts composition to achieve high performance in the above mentioned applications.

Researchers: D.Sc.(Tech.) Satu Ojala

Advisors: Prof. Riitta Keiski (University of Oulu), Prof. Daniel Duprez (University of Poitiers), Prof. Tapio Salmi (Åbo Akademi University ), Prof. Arvaidas Galdikas (University of Kaunas)