Environmental catalysis

Dry reforming of methane:

Biogas is a mixture containing mainly carbon dioxide and methane that is produced by microorganisms during the anaerobic decomposition of organic matter.
Methane and carbon dioxide can be catalytically converted by means of dry reforming process into synthesis gas (a mixture of carbon monoxide and hydrogen), which exhibits about 25 % higher heating value than biogas. In addition, it allows further separation of the two components to produce high purity hydrogen. The main challenge of the heterogeneously catalyzed dry reforming of methane is an intense accumulation of carbon on the catalyst surface (depending on the catalytic material, operating temperature and methane to carbon dioxide ratio in the feed), which in addition to its deactivation ultimately leads to clogging of the reactor unit and termination of the process. In the Laboratory for Environmental Sciences and Engineering we develop advanced nanocrystalline bimetallic catalysts based on transition metals with additional functionality, namely the ability to promptly oxidize the deposited carbon and consequently to significantly prolong the catalyst service life.

Catalytic wet air oxidation (CWAO):

The presence of pesticides, pharmaceuticals, hormones, endocrine disruptors (EDCs) as well as personal care products in the outflow of water treatment plants, rivers, drinking water and groundwater increases the concern of the international community and consequently intensifies activities in this field. Biological treatment processes do not always give satisfactory results, because many organic pollutants are either toxic or persistant and therefore not suitable for biological degradation. Therefore, advanced oxidation processes (AOPs), based on chemical oxidation, represent the only option for the elimination of liquid-dissolved organic pollutants, such as pesticides and endocrine disruptors. This group of treatment techniques also includes the process of catalytic wet-air oxidation (CWAO), which is based on the oxidation of organically polluted aqueous solutions and primarily involves the participation of hydroxyl radicals and energy (i.e. heat) in the oxidation reaction steps, leading ultimately to the degradation of pollutants. Complete mineralization of dissolved organic pollutants in water samples can be achieved by conducting the CWAO process in a bubble-column or trickle-bed reactor at high pressures and temperatures. In the Laboratory for Environmental Sciences and Engineering we develop new and economically more efficient catalysts based on titania, the effectiveness of which for the removal of priority organic pollutants from model solutions and real effluents is investigated in a three-phase trickle-bed reactor.