Use of Rh (III)-Heteropolymolybdate as Potential Catalysts for the Removal of Nitrates in Human Drinking Water: Synthesis, Characterisation and Catalytic Performance
The investigation and development of technologies to remediate water contaminated with NO3− are constantly increasing. An economically and potentially effective alternative is based on the catalytic hydrogenation of NO3− to N2. With this objective, bimetallic RhMo6 catalysts based on Anderson-type heteropolyanion (RhMo6O24H6)3− were prepared and characteri3ed in order to obtain well-defined bimetallic catalyst. The catalysts were supported on Al2O3 with different textural properties and on silica. The heteropolyanion-support interaction was analysed by temperature-programmed reduction (TPR) and X-ray photoelectron spectroscopy (XPS). The differences obtained in activity and selectivity to the different products can be assigned to the different interaction between the RhMo6 Anderson phase and the supports. The RhMo6/G, (G: γ-Al2O3) system showed the best catalytic performance. This catalyst exhibited the lowest reduction temperature of Rh and Mo in the TPR assay and a Rh/Mo surface ratio similar to that of the original phase, as observed by XPS analysis. These studies allowed us to verify a synergic effect between Rh and Mo, through which Mo reducibility was promoted by the presence of the noble metal. The catalytic activity was favoured by the active sites generated from the Anderson phase. This fact was confirmed by comparing the activity of RhMo6/G with that corresponding to a conventional catalyst prepared through successive impregnation of both Rh (III) and Mo (VI) salts.
KeywordsNitrate Water pollution Well-defined catalysts Anderson phase Hydrogenation Synergic effect
We are grateful to Mrs. Graciela Valle, Eng. Edgardo Soto, Lic. Mariela Theiller, Dra. Laura Barbelli and Eng. Hernán Bideberripe for their contribution and technical support.
This study received financial support from the following institutions: CONICET (PIP 0276 and 0003), ANPCyT (PICT 0409) and UNLP (Subsidio Jóvenes Investigadores, Subsidio de Viajes) and Projects I172, X633 y X700; and CICPBA (Project 832/14).
- Barrett, E. P., Joyner, L. G., & Halenda, P. P. (1951). The determination of pore volume and area distributions in porous substances. I. Computations from nitrogen isotherms. Journal of the American Ceramic Society, 73, 373–380.Google Scholar
- Bertolini, G. R., Cabello, C. I., Muñoz, M., Casella, M., Gazzoli, D., Pettiti, I., & Ferraris, G. (2013). Catalysts based on Rh (III)-hexamolybdate/γ-Al2O3 and their application in the selective hydrogenation of cinnamaldehyde to hydrocinnamaldehyde. Journal of Molecular Catalysis A: Chemical, 366, 109–115. https://doi.org/10.1016/j.molcata.2012.09.013.CrossRefGoogle Scholar
- Bertolini, G. R., Vetere, V., Gallo, M. A., Muñoz, M., Casella, M. L., Gambaro, L., & Cabello, C. I. (2016). Composites based on modified clay assembled Rh (III)–heteropolymolybdates as catalysts in the liquid-phase hydrogenation of cinnamaldehyde. Comptes Rendus Chimie, 19(10), 1174–1183. https://doi.org/10.1016/j.crci.2015.09.015.CrossRefGoogle Scholar
- Bouras, O. (2003). Doctoral thesis, Université de Limoges, Faculté de Sciences et Techniques, Francia cap. 2.Google Scholar
- Brunauer S, Emmett PH, Teller E (BET) method. (1985). In J. R. Anderson & K. C. Pratt (Eds.), Introduction to characterization and testing of catalysts. Australia: Academic Press.Google Scholar
- Cabello, C. I., Botto, I. L., & Thomas, H. J. (2000). Anderson type heteropolyoxomolybdates in catalysis: 1. (NH4)3[CoMo6O24H6]·7H2O/γ-Al2O3 as alternative of Co-Mo/γ-Al2O3 hydrotreating catalysts. Applied Catalysis A: General, 197, 79–86. https://doi.org/10.1016/S0926-860X(99)00535-9.CrossRefGoogle Scholar
- Citak, S., & Sonmez, S. (2010). Effects of conventional and organic fertilization on spinach (Spinacea oleracea L.) growth, yield, vitamin C and nitrate concentration during two successive seasons. Scientia Horticulturae, 126, 415–420. https://doi.org/10.1016/j.scienta.2010.08.010.CrossRefGoogle Scholar
- Ding, Y., Sun, W., Yang, W., & Li, Q. (2017). Formic acid as the in-situ hydrogen source for catalytic reduction of nitrate in water by PdAg alloy nanoparticles supported on amine-functionalized SiO2. Applied Catalysis B: Environmental, 203, 372–380. https://doi.org/10.1016/j.apcatb.2016.10.048.CrossRefGoogle Scholar
- Gitzen, W. H. (Ed.). (1970). Alumina as a ceramic material (1st. ed.). Wiley-American Ceramic Society. https://doi.org/10.17226/9575.
- Gurvitsch, L. (1914). Physicochemical attractive force. Russian Journal of Physical Chemistry, 47, 805–812.Google Scholar
- Haber, F., Le Rossignol R. (1910). Production of ammonium, US Patent 971501.Google Scholar
- Harkins, W. D., & Jura, G. (1994). Surfaces of solids. XIII. A vapor adsorption method for the determination of the area of a solid without the assumption of a molecular area, and the areas occupied by nitrogen and other molecules on the surface of a solid. Journal of the American Ceramic Society, 66, 1366–1376.Google Scholar
- Jaworski, M. A., Vetere, V., Bideberripe, H. P., Siri, G., & Casella, M. L. (2013). Structural aspects of PtSn/γ-Al2O3 catalysts prepared through surface-controlled reactions: behavior in the water denitrification reaction. Applied Catalysis A: General, 453, 227–234. https://doi.org/10.1016/j.apcata.2012.12.034.CrossRefGoogle Scholar
- Marchesini, F. A., Irusta, S., Querini, C., & Miró, E. (2008). Nitrate hydrogenation over Pt, In/Al2O3 and Pt, In/SiO2. Effect of aqueous media and catalyst surface properties upon the catalytic activity. Catalysis Communications, 9, 1021–1026. https://doi.org/10.1016/j.catcom.2007.09.037.CrossRefGoogle Scholar
- Marchesini, F. A., Gutierrez, L. B., Querini, C. A., & Miró, E. E. (2010). Pt,In and Pd, In catalysts for the hydrogenation of nitrates and nitrites in water. FTIR characterization and reaction studies. Chemical Engineering Journal, 159, 203–211. https://doi.org/10.1016/j.cej.2010.02.056.CrossRefGoogle Scholar
- Pettiti, I., Botto, I. L., Cabello, C. I., Colonna, S., Faticanti, M., Minelli, G., Porta, P., & Thomas, H. J. (2001). Anderson-type heteropolyoxomolybdates in catalysis: 2. EXAFS study on γ-Al2O3-supported Mo, Co and Ni sulfided phases as HDS catalysts. Applied Catalysis A: General, 220, 113–121. https://doi.org/10.1016/S0926-860X(01)00707-4.CrossRefGoogle Scholar
- Soares, O., Órfão, J., Ruiz-Martínez, J., Silvestre-Albero, J., Sepúlveda-Escribano, A., & Pereira, M. F. R. (2010). Pd–Cu/AC and Pt–Cu/AC catalysts for nitrate reduction with hydrogen: Influence of calcination and reduction temperatures. Chemical Engineering Journal, 165, 78–88.CrossRefGoogle Scholar
- Thommes, M., Kaneko, K., Neimark, A. V., Olivier, J. P., Rodríguez-Reinoso, F., Rouquerol, J., & Sing, K. S. W. (2015). Physisorption of gases, with special reference to the evaluation of surface area and pore size distribution (IUPAC Technical Report). Pure and Applied Chemistry, 87(9–10), 1051.Google Scholar
- Wagner, C. D., Davis, L. E., Zeller, M. V., Taylor, J. A., Raymond, R. H., & Gale, L. H. (1981). Empirical atomic sensitivity factors for quantitative analysis by electron spectroscopy for chemical analysis. Surface and Interface Analysis, 3, 211–225. https://doi.org/10.1002/sia.740030506.CrossRefGoogle Scholar
- Zhao, J., & Chen, Q. (2003). Study on enhancement in gibbsite precipitation of Bayer process under 33 kHz ultrasound. Journal of Materials Science and Technology, 19, 607–610.Google Scholar
- Zoppas, F. M., Marchesini, F. A., Devard, A., Bernardes, A. M., & Miró, E. E. (2016). Controlled deposition of Pd and In on carbon fibers by sequential electroless plating for the catalytic reduction of nitrate in water. Catalysis Communications, 78, 59–63. https://doi.org/10.1016/j.catcom.2016.02.012.CrossRefGoogle Scholar