The reactivity of products of thermal interaction between ammonium meta-vanadate and potassium sulfite as catalysts for oxidation of sulfur dioxide Original Research Article

The study deals with the catalytic activity of the reaction products of interaction of ammonium meta-vanadate with potassium sulfite at different temperatures, as catalysts used for oxidation of sulfur dioxide. The catalysts prepared were characterized by means of X-ray diffraction patterns, electronic absorption and infrared spectra as well as chemical analysis. The results of X-ray diffraction patterns revealed that the prepared catalysts are composed of a mixture of compounds, e.g. K2O, K2SO4, V2O5·3H2O, K3VO4, ammonium and potassium polyvanadates ((NH4)4V6O17·14H2O, K2V8O21, K4V2O7·2H2O), ammonium and potassium bronzes ((NH4)2V12O29, K0.33V2O5, K2V18O45), potassium dioxovanadium sulfate (KVO2SO4·3H2O), vanadyl sulfate (VOSO4·H2O), and ammonium vanadic sulfate (NH4V(SO4)2). The reactions that lead to formation of these compounds were suggested and discussed. The catalytic activity was found to depend not only on the presence of catalytically active vanadium compounds but also on the content of pyrosulfate in the catalyst. The catalytic activity was found to increase with increasing of the content of sulfate in the catalyst which in turn transformed to pyrosulfate during the process of catalytic reaction. The catalytic activity of the prepared catalysts showed good results compared with the reference catalyst produced by Monsanto Enviro-Chem Systems, Inc., USA, performing the test of activity in a semi-pilot plant applying the known industrial conditions.