Reducción catalítica de nitrato y nitrito

HERNÁN OLIVERO; ADRIAN L. BONIVARDI; MARA A. VOLPE; DANIEL DAMIANI

Santa Fe, Argentina

Congreso; XIV Congreso Argentino de Catálisis; 2005

The elimination of NO3- y NO2- from an aqueous solution with Pd/SiO2, Pd-Ga/SiO2, Pd/ZnO and Pt/ZnO catalysts is studied in the present work. The reaction is carried out in a Batch reactor at room temperature and 1 atm of H2. The variation of pOH is taken as a measurement of the reaction evolution. The activity and selectivity are measured and compared for the different samples. For the reduction of nitrite, the Pd-Ga/SiO2 catalyst is, initially, more active than the monometallic one, while the selectivity towards ammonia is the same for both samples. The disadvantage of the Ga promoted sample is that gallium is extracted from the solid . For the reduction of nitrate, Pd/SiO2 catalyst is inactive. For the same reaction the Pd-Ga/SiO2 is initially much more active than Pd/ZnO, however for long reaction time the higher conversión levels are achieved for the Pd/ZnO than for the Ga promoted sample. Both samples, Pd-Ga/SiO2 and Pd/ZnO , present the same value for the selectivity towards ammonia (10-11%). The Pt/ZnO catalysts presents a quite high conversion of nitrate, though the production of ammonia is too high (20%).