Nitrates Abatment With Pd,In Alumina Supported Catalysts. Continuous Down Flow Reactor Studies.

GUSTAVO MENDOW1, F. ALBANA MARCHESINI1, CARLOS QUERINI1 AND EDUARDO MIRO

San Francisco, USA

Congreso; National American Meeting; 2009

The nitrates are proven to be harmful to the human health especially to pregnant women and neonates. The main sources of water contamination with nitrates are from the over use of fertilizers in agriculture, waste effluents from industries and the ground water contamination with septic tanks. Increasing attention has lately been paid to a novel technology, still in its development stages: catalytic denitrification which employs solid bimetallic catalysts. In this catalytic process, nitrates are reduced to nitrogen using hydrogen; however, undesirable products as nitrite and ammonium are also formed [1]. The possible mechanism for the catalytic reduction is through the combination of active sites in the bimetallic catalyst where the nitrate is reduced to nitrite over the bimetallic particle, and then the nitrite produced is reduced over the noble metal particle to nitrogen or ammonium depending on site selectivity and environmental conditions [2]. Nitrate reduction produces hydroxide ions, and the local accumulation of these could produce a loss of selectivity and activity [3]. In this study, the stability of P-In catalysts supported on alumina is studied in a flow reactor. Different alternatives for pH control are presented.