摘要
Nitrate from the application of nitrogen-based fertilizers in intensive agriculture is a notorious waste product, though it lacks cost-effective solutions for its removal from potential drinking water resources. Catalytic reduction appears to be a promising technique for converting nitrates to benign nitrogen gas. Mesoporous silica SBA-15 is a frequently used catalyst support that has large surface areas and highly ordered nanopores. In this work, mesoporous silica SBA-15 bimetallic catalysts for nitrate reduction were investigated. The catalyst was optimized for the selection of promoter metal (Sn and Cu), noble metal (Pd and Pt) and loading ratios of these metals at different temperatures and reduction conditions. The catalysts prepared were characterized by FT-IR, N2 physisorption, XRD, SEM, and ICP. All catalysts showed the presence of cylindrical mesoporous channels and uniform pore structures that remained even after metals loading. In the presence of a CO<sub>2</sub> buffer, the catalysts 4Pd-1Cu/SBA-15 and 1Pt-1Cu/SBA-15 reduced at 100?C under H2 and 1Pd-1Cu/SBA-15 reduced at 200°C under H2 demonstrated very high nitrate conversion. Furthermore, the forementioned Pd catalysts had higher N2 selectivity (88% - 87%) compared to Pt catalyst (80%). Nitrate conversion by the 4Pd-1Cu/SBA-15 catalyst was significantly decreased to 81% in the absence of CO<sub>2</sub>.
Nitrate from the application of nitrogen-based fertilizers in intensive agriculture is a notorious waste product, though it lacks cost-effective solutions for its removal from potential drinking water resources. Catalytic reduction appears to be a promising technique for converting nitrates to benign nitrogen gas. Mesoporous silica SBA-15 is a frequently used catalyst support that has large surface areas and highly ordered nanopores. In this work, mesoporous silica SBA-15 bimetallic catalysts for nitrate reduction were investigated. The catalyst was optimized for the selection of promoter metal (Sn and Cu), noble metal (Pd and Pt) and loading ratios of these metals at different temperatures and reduction conditions. The catalysts prepared were characterized by FT-IR, N2 physisorption, XRD, SEM, and ICP. All catalysts showed the presence of cylindrical mesoporous channels and uniform pore structures that remained even after metals loading. In the presence of a CO<sub>2</sub> buffer, the catalysts 4Pd-1Cu/SBA-15 and 1Pt-1Cu/SBA-15 reduced at 100?C under H2 and 1Pd-1Cu/SBA-15 reduced at 200°C under H2 demonstrated very high nitrate conversion. Furthermore, the forementioned Pd catalysts had higher N2 selectivity (88% - 87%) compared to Pt catalyst (80%). Nitrate conversion by the 4Pd-1Cu/SBA-15 catalyst was significantly decreased to 81% in the absence of CO<sub>2</sub>.
作者
Mouhamad Rachini
Mira Jaafar
Nabil Tabaja
Sami Tlais
Rasha Hamdan
Fatima Al Ali
Ola Haidar
Ali Jaber
Mohammad Kassem
Eugene Bychkov
Lucette Tidahy
Renaud Cousin
Dorothée Dewaele
Tayssir Hamieh
Joumana Toufaily
Mouhamad Rachini;Mira Jaafar;Nabil Tabaja;Sami Tlais;Rasha Hamdan;Fatima Al Ali;Ola Haidar;Ali Jaber;Mohammad Kassem;Eugene Bychkov;Lucette Tidahy;Renaud Cousin;Dorothée Dewaele;Tayssir Hamieh;Joumana Toufaily(Laboratory of Materials, Catalysis, Environment and Analytical Methods (MCEMA), EDST, FS, Lebanese University, Hariri Campus, Hadath, Lebanon;Université du Littoral Cô,te d’Opale (ULCO), LPCA, EA 4493, F-59140 Dunkerque, France;Laboratory of Applied Studies for Sustainable Development and Renewable Energy (LEADDER), EDST, Lebanese University, Hariri Campus, Hadath, Lebanon;College of Engineering and Technology, American University of the Middle East, Kuwait, Kuwait;Department of Chemistry, American University of Beirut, Riad El-Solh, Beirut, Lebanon;Laboratoire de Recherche et Développement des Médicaments et des Produits Naturels RDMPN, Faculty of Pharmacy, Lebanese University, Hariri Campus, Hadath, Lebanon;Université du Littoral Cô,te d’Opale, UCEIV, Unité de Chimie Environnementale et Interactions sur le Vivant, EA 4492, SFR Condorcet FR CNRS 3417, Dunkerque, France;Centre Commun de Mesures, Université du Littoral Cô,te d’Opale, Dunkerque, France;Faculty of Science and Engineering, Maastricht University, Maastricht, The Netherlands)
