Développement d’un capteur électrochimique pour la détection des nitrates dans les eaux naturelles

– Shérif Abed, CNRS, Toulouse –

Résumé :

The environmental impact of nitrates (NO₃^–) in natural waters depends directly its concentration. Indeed, nitrates are essential to ecosystems, used by plants and phytoplankton to grow via photosynthesis. Availability of nitrates then limits primary production. However, an excessive discharge of nitrate leads to severe pollutions of coastal and continental waters via eutrophication process. In order to monitor nitrate concentration and meet the needs of high spatial and temporal resolution data, in situ, autonomous sensors, adaptable on different types of platforms and under water vehicles are the key. So far, the sensors available for in situ nitrates monitoring are not providing satisfactory performances in terms of sensitivity, selectivity and portability. This work is part of the NESS: Nitrate Electrochemical SenSor project, which proposes the use of electrochemical methods for the measurement of nitrate concentrations in natural waters without prior treatment of the sample. The design of new working electrode materials is necessary in order to achieve the sensitivity levels required. For this purpose, two strategies are studied: (i) the conception of bimetallic electrodes by copper electrodeposition on different metallic substrates, (ii) the electrochemical surface treatment of a massive copper electrode. The performances of all formed electrodes are evaluated by detecting nitrates in natural and synthetic water matrices using square wave voltammetry.

Membres du jury :

• Laurent Bouffier (Rapporteur) : Chargé de recherche CNRS, Institut des Sciences Moléculaires, Bordeaux
• Florence Geneste (Rapporteure) : Directrice de recherche CNRS, Institut des Sciences Chimiques, Rennes
• Pierre Chamelot (Examinateur) : Professeur, Laboratoire de Génie Chimique, Université de Toulouse III
• Pierre Gros (Examinateur) : Professeur, Laboratoire de Génie Chimique, Université de Toulouse III
• Mary-Lou Tercier Waeber (Examinatrice) : Ingénieure de recherche, Université de Genève, Suisse
• Carole Barus (Co-directrice de thèse) : Ingénieure de recherche CNRS, Laboratoire de Génie Chimique, Toulouse
• Laurent Massot (Directeur de thèse) : Maître de conférence, Laboratoire de Génie Chimique, Université de Toulouse III
• Arnaud David (Invité) : Ingénieur Recherche et Développement, nke Instrumentation, Hennebont