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Activated Carbon as a Support of Catalysts for the Removal of Nitrogen Oxides

Białas Anna, Szlendak Joanna, Czosnek Cezary, Motak Monika

Mineralogia

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2020

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Vol. 51, iss. 1

9--16

EN

Activated carbon was oxidised with concentrated nitric acid and impregnated with urea to form nitrogen-containing groups. Such a support was impregnated with cobalt, copper or silver nitrates to obtain catalysts for the selective catalytic reduction of nitrogen oxides with ammonia. Infrared spectra confirmed the formation of carboxylic and other organic oxygen-containing groups during oxidation. Nitrogen-containing species resulted from urea thermal decomposition. The metal-containing samples were hydrophilic. Cobalt and copper were present in the samples as small Co3O4 and CuO crystallites, while silver occurred in the form of large metallic crystallites, as seen from the X-ray diffraction patterns. Low temperature N2 sorption revealed that all samples were microporous solids, and the chemical and thermal treatment did not change their textural properties. The copper admixture caused the highest NO conversion, but worsened the selectivity and thermal stability of functionalised carbon support.

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Selective catalytic reduction of NO with ammoniaat low temperature over Cu-promotedand N-modified activated carbon

Saad Marwa, Białas Anna, Grzywacz Przemysław, Czosnek Cezary, Samojeden Bogdan, Motak Monika

Chemical and Process Engineering

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2020

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Vol. 41, nr 1

59–-67

EN

Catalytic properties of activated carbons oxidized, treated with N-compounds, and promoted withcopper were studied in selective catalytic reduction NOXby ammonia (NH3-SCR). The modificationof the catalysts consisted of a series of steps (pre-oxidation of activated carbon, impregnation with urea,impregnation with copper). The physicochemical properties of the obtained samples were determinedusing X-ray diffraction, FT-IR spectroscopy, and low-temperature N2sorption. The modification withcopper improved the catalytic activity and stability of the catalysts. All the functionalized carbon dopedwith copper reached more than 90% of NO conversion and CO2did not exceed 240 ppm at 220◦C.The sample doped with 5 wt.% Cu had the maximum NO conversion of 98% at 300◦C. The maximum N2O concentration detected for the same sample was only 55 ppm, which confirmed its selectivity.

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Tlenkowe katalizatory cerowo-miedziowe naniesione na węgiel do niskotemperaturowego usuwania NOx ze stacjonarnych źródeł emisji

Saad Marwa, Białas Anna, Czosnek Cezary, Motak Monika

Przemysł Chemiczny

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2019

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T. 98, nr 4

546--550

PL

Zbadano aktywność katalityczną i stabilność termiczną aktywowanego węgla (utlenionego, funkcjonalizowanego azotem, dotowanego miedzią i cerem) w selektywnej redukcji tlenku azotu(II) amoniakiem. Tlenkowy katalizator cerowy naniesiony na węgiel był aktywny i zapewniał 90-proc. przereagowanie NO. Był stabilny termicznie i wytwarzał tylko nieznaczne ilości N₂O. Mały dodatek miedzi (1%) nie polepszył aktywności katalizatora, obniżył jego stabilność termiczną i zwiększył stężenie powstającego N₂O. Promowanie cerem katalizatorów o wyższej zawartości miedzi powodowało pogorszenie stabilności termicznej w porównaniu z preparatami zawierającymi jedynie miedź.

EN

Activated C was promoted with Cu₂O and CeO₂ and used as catalyst for redn. of NO to N₂ with NH₃. The Ce-contg. catalysts were more active at 140-300°C than the Cu-contg. ones and attained almost total NO conversion.