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2 Polish Journal of Chemical Technology

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Application of catalysts in the treatment of selected waste chloroorganic compounds

Żarczyński A., Zaborowski M., Paryjczak T., Gorzka Z., Kaźmierczak M.

Polish Journal of Chemical Technology

2007

Vol. 9, nr 2

61-64

Tetrachloromethane (TCM) and 1,1,2,2-tetrachloroethane (TChE) were oxidized in the temperature range from 300 to 600°C and at contact time of 0.36 s. The following catalysts were applied during the process: the granular one - platinum (0.12%) at the TiO2-SiO2 carrier, platinum ZChO-80 (0.15%) at γ-Al2O3 carrier, palladium (1%) at γ-Al2O3 carrier and monolithic platinum-rhodium catalyst (Pt - 0.09% and Rh - 0.04%) at the cordierite carrier. The substrates were oxidized in the presence of the above mentioned catalysts with various efficiencies depending on the molecular structure and the type of the catalyst. Palladium contact appeared to be the most active among the others. In the presence of this catalyst, total oxidation of TCM and TChE proceeded at the temperature of 425 and 500°C, respectively. The content of PCDD/Fs in gaseous products obtained during the oxidation of both substrates, was significantly lower than the admissible value of the toxicity equivalent (0.1 ng TEQ/m3).

Dioxins in the process of 1,1,2,2-tetrachloroethane oxidation with the application of monolithic catalysts

Żarczyński A., Gorzka Z., Paryjczak T., Kaźmierczak M., Szczepaniak B.

Polish Journal of Chemical Technology

2005

Vol. 7, nr 2

100-104

The activity of three monolithic catalysts with ceramic constitution were investigated in the process of 1,1,2,2-tetrachloroethane oxidation (TChE). One of the catalysts contained rhodium and platinum at the intermediate layer with gamma-Al2O3. The second one contained platinum at ZrO2 and the third one - platinum at TiO2. The gaseous and liquid products of the reaction were analysed in order to determine the contents of polychlorinated dibenzo-p-dioxins and dibenzofuranes (PCDD/Fs). The process temperature was ranging from 400 to 700°C. The contact time was 0.36 s. The total oxidation of TChE was found to be achieved at the temperature of 550°C with the application of the monolithic platinum-rhodium catalyst or at higher temperatures with the application of other catalysts. The presence of the most toxic congener of PCDD/Fs, i.e. 2,3,7,8-TCDD, was not observed in the reaction products. Only the single less toxic congeners at the concentrations significantly lower than 0.1 ngTEQ/m^3 (the admissible value in Poland and other EU countries) were determined in the combustion gases. If zirconium catalyst was applied in the process, then no presence of PCDD/Fs congeners was found in the combustion gases.