Nitrates Abatement in Water With Cu, in And Co-promoted Pd Catalysts

MARCHESINI, C. NEYERTZ, C. A. QUERINI, E. E. MIRÓ

Rio de Janerio, Brasil

Congreso; ENPROMER 2005; 2005

One of the most important contamination problems of water is the presence of high concentrations of nitrites and nitrates in aquifers, due to their strong toxicity. Among the emergent technologies for the abatement of nitrates and nitrites, the catalytic reduction of these species to N2 is a promising alternative. In the present work we study the effect of different promoters on the activity and selectivity of Pd-based catalysts for the above said reaction using H2 as reducing agent. The Pd-Cu, Pd-Co and Pd-In catalysts were supported on alumina by wet impregnation in orden to obtain a Pd:Metal atomic ratio of 2:1. The samples were characterized by TPR, DRX and H2 chemisorption. TPR results indicate a strong interaction between both metal species for the three catalysts used in this work. The catalytic activity was evaluated in a batch reactor in a H2 saturated solution, at room temperature, atmospheric pressure and a constant pH value of 5. The results obtained show that the activity and selectivity order is: Pd-Cu > Pd-In >> Pd-Co. While for Cu and In promoters the catalytic reduction was selective towards nitrogen, appreciable amounts of ammonium were produced when Co was the second metal.