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Title: Novel catalytic and mechanistic studies on wastewater denitrification with hydrogen
Authors: Theologidis, Christodoulos 
Olympiou, Georgios 
Savva, Petros G. 
Pantelidou, Nantia 
Constantinou, Barbara 
Chatziiona, Vasiliki 
Valanidou, Lilian 
Piskopianou, Charoula 
Costa, Costas 
Keywords: Active species;Catalytic denitrification;DRIFTS;Mechanistic studies;SSITKA
Category: Other Agricultural Sciences
Field: Agricultural Sciences
Issue Date: 1-Jan-2014
Publisher: IWA Publishing
Source: Water Science and Technology Volume 69, Issue 3, 2014, Pages 680-686
Abstract: The present work reports up-to-date information regarding the reaction mechanism of the catalytic hydrogenation of nitrates in water media. In the present mechanistic study, an attempt is made, for the first time, to elucidate the crucial role of several catalysts and reaction parameters in the mechanism of the NO3-/H2 reaction. Steady-state isotopic transient kinetic analysis (SSITKA) experiments coupled with ex situ diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) were performed on supported Pd-Cu catalysts for the NO3-/H2 and NO3-/H2/O2 reactions. The latter experiments revealed that the formation and surface coverage of various adsorbed active intermediate N-species on the support or Pd/Cu metal surface is significantly favored in the presence of TiO2 in the support mixture and in the presence of oxygen in the reaction's gaseous feed stream. The differences in the reactivity of these adsorbed N-species, found in the present work, adequately explain the large effect of the chemical composition of the support and the gas feed composition on catalyst behaviour (activity and selectivity). The present study leads to solid mechanistic evidence concerning the presence of a hydrogen spillover process from the metal to the support. Moreover, this study shows that Cu clusters are active sites for the reduction of nitrates to nitrites.
Description: Presented at: IWA Regional Conference on Waste and Wastewater Management, Science and Technology, 2013, Limassol, Cyprus, 26-28 June
ISSN: 02731223
DOI: 10.2166/wst.2013.781
Rights: © IWA Publishing 2014.
Type: Article
Appears in Collections:Άρθρα/Articles

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