Ion-exchanged geopolymer for photocatalytic degradation of a volatile organic compound

In thepresentworkitisshownhowgeopolymerscanbeusedtocontrolindoorandoutdoorair pollution byphotolysisof2-ButanoneasaVolatileOrganicCompound(VOC).Anionexchange procedurewasfollowedtoincorporateTiO2 into ageopolymer(IEG),anddifferent2-Butanone concentrations wereusedinabatchreactorunderdryandhumidconditions.Variationon 2-Butanone concentrationwasfollowedbygaschromatography.ALangmuir Hinshelwood modelwas used todeterminethedisappearancerateofreactantattheinitialstageofthereaction.Gasca-Tirado, J.; Manzano-Ramirez, A.; Vazquez-Landaverde, PA.; Herrera-Diaz, EI.; Rodriguez-Ugarte, ME.; Rubio-Avalos, JC.; Amigó Borrás, V.... (2014). Ion-exchanged geopolymer for photocatalytic degradation of a volatile organic compound. Materials Letters. 134:222-224. doi:10.1016/j.matlet.2014.07.090S22222413

Highly porous mullite ceramics from engineered alkali activated suspensions

Air may be easily incorporated by vigorous mechanical stirring, with the help of surfactants, of activated geopolymer-yielding suspensions. The cellular structure is stabilized by the viscosity increase caused by curing reactions, configuring an inorganic gel casting. The present paper is aimed at extending this approach to mullite foams, obtained by the thermal treatment of engineered alkali activated suspensions. Green foams were first obtained by gel casting of a suspension for Na-geopolymer enriched with reactive -Al2O3 powders. Sodium was later extracted by ionic exchange with ammonium salts. In particular, the removal of Na+ ions was achieved by immersion in ammonium nitrate solution overnight, with retention of the cellular structure. Finally, the ion-exchanged foams were successfully converted into pure mullite foams by application of a firing treatment at 1300 degrees C, for 1hour. Preliminary results concerning the extension of the concept to mullite three-dimensional scaffolds are presented as well

Ion Exchange in Geopolymers

Geopolymers have been widely used for construction and building materials. Nevertheless, some other applications have been found from their ability to be ion exchanged. An example is the encapsulation of heavy metals, but some others involve the ion exchange of the aluminosilicate structure to form photoactive particles or to link copper ions. In this chapter, we summarize some of the properties which make aluminosilicate inorganic polymer (geopolymers) ion exchangeable: the synthesized temperature, its effect over their porosity and their stoichiometric nature. Also, the effects of ion exchanging a geopolymer with an NH4+Cl, (NH4)2TiO2(C2O4)2 and (CH3)4N+Br are presented. The geopolymer was characterized by FT-IR, XRD, BET and MAS NMR, showing how a 100% of replacement was achieved for NH4+Cl. On the contrary, the efficiency was reduced in (NH4)2TiO2(C2O4)2 and (CH3)4N+Br, effect ascribed to the fact of the molecular size that did not allow the counterions to reach the aluminum atoms in the geopolymer. Finally, the procedure followed to ion exchange a metakaolinite-based geopolymer is described, and the potential applications related are presented

Modelación numérica hidrodinámico-hidrológica en zonas de inundación con presencia de infraestructura

Se presenta la modelación numérica computacional de la hidrodinámica superficial e hidrológica de la zona de estudio donde se pretende construir infraestructura para la exploración de hidrocarburos en las márgenes del río Grijalva, México; para ello se muestra el análisis de la información meteorológica, determinando los valores de intensidad de precipitación, temperaturas, evaporación y una estimación de los gastos, correspondiente al año 2014; las zonas de inundación se estimaron con el uso de programas desarrollados en Fortran y Matlab, que resuelven las ecuaciones de Navier-Stokes-Reynolds para flujos a superficie libre y la intensidad de precipitación con la distribución de Gumbel, con parámetros estimados mediante el método de Momentos Ponderados con Probabilidad (MPP), con los cuales, mediante una malla numérica de la topografía, en conjunto con los valores meteorológicos, como condiciones iniciales y forzantes, se determina la magnitud de la inundación del área de estudio, así como la obtención de gastos, velocidades y el funcionamiento hidráulico de las obras de mitigación propuestas para preservar el balance hidrológico del sistema

A new geopolymeric binder from hydrated-carbonated cement

This paper evaluates the use of hydrated Portland cement as the raw material in the production of geopolymers. The silicon and aluminium oxides needed for the geopolymerization process were produced by the carbonation of hydrated Portland cement, which transforms CSH and CAH (Portland cement hydrates) into silica and alumina gels. Hydrated-carbonated Portland cement was alkali activated with a NaOH/waterglass solution. Pastes and mortars were prepared, and micro-structural and mechanical properties were analyzed. It has been noted that geopolymers are mechanically stable and yield compressive strength higher than 10 MPa when mortars are cured at 65 °C for 3 days. The results have shown that there are interesting possibilities for re-using the cement-rich fraction of construction and demolition waste. Alkaline activation of hydrated-carbonated Portland cement could be considered a low CO 2-emission binder. © 2012 Elsevier B.V. All rights reserved.Paya Bernabeu, JJ.; Borrachero Rosado, MV.; Monzó Balbuena, JM.; Soriano Martinez, L.; Mitsuuchi Tashima, M. (2012). A new geopolymeric binder from hydrated-carbonated cement. Materials Letters. 74:223-225. doi:10.1016/j.matlet.2012.01.132S2232257

New geopolymeric binder based on fluid catalytic cracking catalyst residue (FCC)

This paper provides information about the synthesis and mechanical properties of geopolymers based on fluid catalytic cracking catalyst residue (FCC). FCC was alkali activated with solutions containing different SiO 2/Na 2O ratios. The microstructure and mechanical properties were analysed by using several instrumental techniques. FCC geopolymers are mechanically stable, yielding compressive strength about 68 MPa when mortars are cured at 65°C during 3 days. The results confirm the viability of producing geopolymers based on FCC. © 2012 Elsevier B.V. All rights reserved.We acknowledge the Ministerio de Ciencia e Innovacion (MICINN) of the Spanish Government and FEDER funds (MAT-2011-19934 project) and the PROPG-UNESP "Universidade Estadual Paulista Julio de Mesquita Filho", Brazil.Mitsuuchi Tashima, M.; Akasaki, JL.; Castaldelli, V.; Soriano Martínez, L.; Monzó Balbuena, JM.; Paya Bernabeu, JJ.; Borrachero Rosado, MV. (2012). New geopolymeric binder based on fluid catalytic cracking catalyst residue (FCC). Materials Letters. 80:50-52. https://doi.org/10.1016/j.matlet.2012.04.051S50528

Incorporation of photoactive TiO2 in an aluminosilicate inorganic polymer by ion exchange

In the present paper, it is described a procedure to ion exchange in an aluminosilicate inorganic polymer (geopolymer) in order to incorporate photoactive TiO 2. Metakaolin base geopolymers synthesized at 40 and 90 °C were chosen to be ion-exchanged with a solutions of (NH 4) 2 TiO (C 2O 4) 2-H 2O with and without previous treatment with NH 4Cl. The final geopolymers were characterized by SEM, FT-IR, Raman, XRD, BET, UV/Vis spectroscopy and fluorescence. It was confirmed that ion-exchange method incorporated anatase TiO 2 particles inside the geopolymer, affecting the geopolymers bond vibration modes of the AlO 4-SiO 4 framework. The observed blue shift in the UV/Vis spectra, suggest that those TiO 2 nanoparticles grew inside the micropores of the geopolymer producing quantum size effects. The photoactivity of such particles was determined by means of photoluminescent spectra and bleaching of methylene blue (MB), which confirms the potential applications of ion-exchanged geopolymers (IEGs) for photocatalytic purposes. © 2011 Elsevier Inc. All rights reserved.J.R. Gasca-Tirado wants to thank CONACYT for scholarship and to A. Galindo-Sifuentes, M.A. Hernandez-Landaverde, J.E. Urbina-Alvarez, F. Rodriguez-Melgarejo, A. Mauricio-Sanchez, J.L. Ojeda-Elizarraras, M.S. Garcia-Guillen, C. Vazquez-Ramos and G. Fonseca-Hernandez for their kind technical assistance.Gasca-Tirado, JR.; Manzano Ramirez, A.; Villaseñor-Mora, C.; Muñiz-Villarreal, MS.; Zaldivar-Cadena, AA.; Rubio-Ávalos, JC.; Amigó Borrás, V.... (2012). Incorporation of photoactive TiO2 in an aluminosilicate inorganic polymer by ion exchange. Microporous and Mesoporous Materials. 153:282-287. doi:10.1016/j.micromeso.2011.11.026S28228715