abstracts - Институт катализа им. Г.К. Борескова

OP-II-10KINETICS OF AQUEOUS NITRATE SOLUTIONS HYDROGENATIONOVER Rh/Al 2 O 3 AND Rh-Cu/Al 2 O 3 CATALYSTSKarski S., Witońska I., Gołuchowska J.Institute of General and Ecological Chemistry, Technical University of Lodz,ul. Żeromskiego 116, 90-924 Łódź, PolandE-mail: karski@mail.p.lodz.plNitrates(V) are among the most widespread pollutants of underground and surfacewaters. One of the main and difficult to eliminate dangers to the cleanliness of water isconnected with agriculture (overuse of fertilizers and plant protection substantes inagricultured regions, introduction of industrial waste such as silage into the environment)country and city areas without a sewer system and also air pollution. Moreover, waters aregreatly contaminated by plants producing nitrogen compounds, storehouses, sewage treatmentplants and transport. For these reasons the fact that the content of nitrates(V) in groundwaterused to produce drinking water has increased in the last few years is alarming.Nitrate ions (NO - 3 ) are not directly toxic but they could be transformed to harmful nitriteions (NO - 2 ) in the human body. It has been reported that nitrite ions cause a blue babysyndrome and are a precursor to carcinogenic nitrosoamine [1]. The European Communityallows up to 50 mg/dm 3 of nitrates(V) in drinking water. World Health Organization (WHO)recommends 25mg NO - 3 /dm 3 as an acceptable level for drinking water.Removal of nitrates from drinking water is an important and constantly developing fieldof studies. Biological and physicochemical methods allow effective removal of nitrates buthave several economical and ecological disadvantages. Therefore, an increasing attention isbeing focused on catalytic denitrification using solid catalysts as an alternative technology[2, 3]. Advantages of this technology include rapid treatment, safety and economical benefits.The catalytic hydrogenation of NO - 3 in water involved the use of noble metal catalysts [4-22].Among these metals, palladium has proved to be the most active and selective for thisreaction. Rhodium catalysts are less selective towards N 2 in this process than Pd catalysts.The activity and selectivity can be improved by an addition of a second metal of groups 11,12, 13 and 14.Mostly copper, tin, indium and zinc were used as a promoting second metal [4-22].Although there have been published a lot of papers connected with studies of activity andselectivity toward nitrogen formation the changes in the catalytic behaviour as a function of204