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Chmielarz L.,Jagiellonian University | Rutkowska M.,Jagiellonian University | Jablonska M.,Jagiellonian University | Wegrzyn A.,Jagiellonian University | And 4 more authors.
Applied Clay Science | Year: 2014

Vermiculites treated with solutions of HNO3, HCl and H2SO4 were tested in the role of catalysts for high-temperature decomposition of N2O to N2 and O2. Acid treatment of clay mineral resulted in a partial leaching of components of its octahedral sheets, which were partially deposited on the surface of vermiculite. Such modification of the clay samples significantly increased their specific surface area and porosity as well as influenced their surface acidity. Acid treatment of vermiculites activated them in the process of high-temperature N2O decomposition, however activation effect depended on type of acid used as well as duration of acid modification. © 2014 Elsevier B.V. Source

Chmielarz L.,Jagiellonian University | Kowalczyk A.,Jagiellonian University | Michalik M.,Jagiellonian University | Dudek B.,Jagiellonian University | And 2 more authors.
Applied Clay Science | Year: 2010

Vermiculite and phlogopite were reacted with nitric acid under controlled conditions. The products were characterized by the composition (XRF), structure (XRD, FTIR, UV-vis-DRS), texture (BET); morphology (SEM) and surface acidity (NH3-TPD). Acid-activation increased the specific surface area and porosity and led to partial leaching of iron, aluminium and magnesium from the octahedral sheets. The acid-activated vermiculites and phlogopites were active and selective catalysts of the DeNOx process (4 NO+4 NH3+O2=4N2+6H2O). The best catalytic results were obtained for vermiculite activated with nitric acid (0.8M) at 95°C for 24h. The modified phlogopites were less active. The best catalytic results were also obtained after reaction with HNO3 for 24h. © 2010 Elsevier B.V. Source

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