In this work, 3% Ru-Al2O3 and 2% Rh-CeO2 catalysts were synthesized and testedfor CH4-CO2 reforming activity using either CO2-rich or CO2-lean model biogas feed. Low carbon deposition was observed on both catalysts, which negligibly influenced catalytic activity. Catalyst deactivation during temperature programmed reaction was observed only with Ru-Al2O3, which was caused by metallic cluster sintering. Both catalysts exhibited good stability during the 70 h exposure to undiluted equimolar CH4/CO2 gas stream at 750 °C. By varying residence time in the reactor during CH4-CO2 reforming, very similar quantities of H2 were consumed for water formation. Reverse water-gas shift (RWGS) reaction occurred to a very similar extent either with low or high WHSV values over both catalysts, revealing that product gas mixture contained near RWGS equilibrium composition, confirming the dominance of WGS reaction and showing that shortening the contact time would actually decrease the H2/CO ratio in the syngas produced by CH4-CO2 reforming, as long as RWGS is quasi equilibrated. H2/CO molar ratio in the produced syngas can be increased either by operating at higher temperatures, or by using a feed stream with CH4/CO2 ratio well above 1.
COBISS.SI-ID: 4844826
This paper presents an exhaustive literature review and discussion of data on the effect of nanoparticulate TiO2 on different test organisms with the aim to identify the characteristics of the nanoparticles that have most biological significance. The nanotoxicity data from a number of studies fail to reveal the characteristics actually responsible for their biological reactivity because reported nanotoxicity studies rarely carry information on the physicochemical characteristics of the nanoparticles tested. This work served as a preliminary step in setting up experimental system to test the potential nanotoxicity on different test organisms. The information gained based on this data analysis will serve as a basis for reliable and quality experimental data.
COBISS.SI-ID: 6536057
The aim of our work was to compare Fenton's oxidation with existing biological SBR employed for treatment of the leachate, generated in local municipal landfill. Efficiencies of both procedures were monitored by chemical analyses and by acute toxicity studies with Vibrio fischeri and measurement of inhibition of oxygen consumption by activated sludge. Leachate was very toxic and toxicity was not significantly reduced in existing biological treatment plant. Fenton's oxidation, accomplished at different molar ratios of reagents (M(Fe2+)/M(H2O2) was 1/1; 1/3.3; 1/6.6 and 1/13.3) and various temperatures (20–45 C), assured good removal of organic compounds (80% as COD) as well as other pollutants and slightly reduced toxicity. Furthermore, additional oxidation experiments confirmed, that Fenton's oxidation is not appropriate for polishing already treated leachate in SBR.
COBISS.SI-ID: 34925829