INCAPE   05401
INSTITUTO DE INVESTIGACIONES EN CATALISIS Y PETROQUIMICA "ING. JOSE MIGUEL PARERA"
Unidad Ejecutora - UE
congresos y reuniones científicas
Título:
Nitrite elimination by Pd-based catalysts using Formic Acid as a sustainable hydrogen source
Autor/es:
BELTRAME, T. F; BERNARDES, A. M.; ZOPPAS, F. M.; MIRÓ, E. E.; ALBORNOZ, L. L.; MARCHESINI, F. A.
Lugar:
Dresden
Reunión:
Conferencia; 5th Green and Sustainable Chemistry Conference; 2020
Resumen:
In recent years, the contamination with nitrogen compounds of drinking water is increasingly due the poor disposal of animal waste and excessive consumption of fertilizer. Nitrates and Nitrites present in water produce serious problems for human health. Acceptable limits for Nitrate, Nitrite, and Ammonium in drinking water were set by the World Health Organization in 50 ppm, 3 ppm and 0.5 ppm respectively [1]. The past few years have seen diverse technologies for nitrates and nitrites elimination, such as reverse osmosis, electrodialysis, ion exchange, catalytic abatement, biodenitrification, among them for nitrite case the catalytic reduction, result attractive due to easy accessibility, low investment costs, needless additional treatment and so on. In catalytic technology, it is used a noble metal composed catalyst, like Pd, supported on different massive oxides. H2(g) is used as reducing agent for promoting the nitrite reduction to gaseous nitrogen. In this sense, Formic acid (FA) has been considered as a way to storage H2(g), and it could be used as a reducing agent for nitrite reduction [2]. . In addition, formic acid is a product resulting from the acid hydrolysis of cellulosic biomass [3] and therefore, it is interesting applying a green chemistry standpoint take advantage of this product. To the best of our knowledge, there are no studies of catalytic removal of nitrite using formic acid as a reducing agent. Since this agent is suitable for the removal of nitrate, the study of this agent in nitrite removal deserves attention. The objective of this study was to investigate the behavior of Formic Acid as a hydrogen source in the catalytic elimination of nitrite (100 N-ppm) present in drinking or waste water.Pd catalysts supported on alpha-alumina, silica, and ZSM-5 zeolite in a mixture of Si:Al30, were synthesized by wet impregnation and evaluated for nitrite removal in a batch reactor. Palladium chloride (PdCl2) was used as a precursor. The results obtained show that in presence of FA and without catalyst, the nitrite was 80% oxidized to nitrate. This reaction follows a chemical equilibrium between these two compounds [4]. In all tests, nitrate formation occurred. However, it was found that using catalysts, the formation of nitrate is lower, in comparison with its formation without catalyst. The catalyst which shows the best selectivity in same conversion (95%) to N2 was that one supported in alumina (55%). The nitrate selectivities obtained in the same conversion (95%) are: 80%, 55%, 45% and 65% for formic acid, PdSi:Al30, alpha-Al2O3, PdSiO2 respectively. Also, in the same order, the ammonium selectivities obtained in the same conversion (95%) are: 0%, 0.9%, 0% and 0%, respectively. Therefore alpha-Al2O3 promotes a better selectivity to gaseous compounds, being the most promising support among those evaluated for this reaction. The use of FA shows a promising result, which must be optimized for its future use in catalytic nitrogen removal processes.