HYBRID PROCESS FOR NITRATES ELIMINATION IN WATER

C. NEYERTZ; C. A. QUERINI; G. MENDOW; B. SÁNCHEZ

Puerto Vallarta - Evento virtual

Congreso; XXVII Congreso Iberoamericano de Catálisis; 2020

Groundwater contamination with nitrates is a worldwide problem that needs a solution, because thesecompounds are harmful to health. There are several technologies to reduce the nitrate content in water tovalues accepted by the W.H.O. (50 mg L-1). Among them, one of the most advantageous is the catalyticreduction. This paper proposes the use of a combined process, using ion exchange resins that contain Pd andSn as catalysts. First, nitrates are retained at the resin exchange sites, and then reduced over the metal sites ina regeneration stage. The most active and selective catalyst was Pd 2% -Sn 0.5%, reaching conversions of97%, with 66% selectivity to N2, when the regeneration was performed in H2 flow at room temperature andatmospheric pressure. This catalyst was also remarkably stable, maintaining conversions close to 90% in 28successive cycles. The variables involved in the regeneration process were investigated. The addition of CO2to the H2 stream did not improve either the conversion or the selectivity. The increase in temperatureaccelerated the process, but favored the catalyst deactivation.