Heterogeneous Catalytic and Photocatalytic Nitrate Abatement in Drinking Water Using Agpt and Pdsn Supported on Titania Nanocatalysts. Éliminitation du Nitrate dans l'eau Potable par Catalyse Hétèrogène et Photocatalyse au Moyen de Nanocatalyseurs AgPt et PdSn Supportés Sur Oxyde de Titane

Identifier:  TDX:2636

Handle: https://hdl.handle.net/20.500.11797/TDX2636

Authors:  Antolín Pozueta, Ana María

Abstract:
Denitration of water towards N2 gas and H2O has been investigated by catalytic and photocatalytic processes in presence/absence of hydrogen as reducing agent. The catalysts used were: monometallic catalysts (Ag/P25, Pt/P25); physical mixture of both monometallics (Ag/P25 + Pt/P25); and bimetallic catalysts (Ag-Pt(Pt-Ag)/P25 and Pd-Sn/P25). These catalysts were supported on Titania P25 with the aim of testing their versatility in both catalytic and photocatalytic processes to accomplish the EU Normative for N-compounds in drinking water (50 mg/L NO3-, 0.5 mg/L NO2-, 0.3 mg/L NH4+). The effect of the metal loading (Ag,Pt), Pt precursor (H2PtCl6∙6H2O; K2PtCl6), impregnation order (Ag-Pt,Pt-Ag), and morphology (Pd-Sn spherical NPs and nanorods (NRs)) were examined through various characterization techniques(XRD, N2- physisorption, TEM, DRUV-Vis, XPS, H2-TPR y H2- Chimisorption). Good N2 selectivity (76%) in the catalytic process was achieved with the Ag(2)/P25+Pt(4)/P25(H) mixture but with ca. 13% NO2- yield. Bimetallic catalysts show versatility being active in both processes. The selectivity to nitrogen for NRs was higher (51%) than that for spherical NPs (32%). Pt(4)-Ag(2)/P25(K) presented the highest selectivity to N2 (80%). Further studies are still needed to decrease NO2- and NH4+ yields.