Characterization of Porous Solids II, Proceedings of the IUPAC Symposium (COPS 11), 1991
Summary Mercury porosimetric studies were carried out on Ancient Egyptian mortars extracted from ... more Summary Mercury porosimetric studies were carried out on Ancient Egyptian mortars extracted from the Sphinx body core and North side chest as well as from the Khafra Valley temple. Such studies were complemented by the application of X-ray diffraction and simultaneous thermogravimetric and differential thermal analysis. The results obtained suggest that Ancient Egyptian mortars are characterized by two sets of pores within the gypsum matrix. The larger pores (of width 1-15μm) appear to be located between the CaSO 4 granules, whereas the smaller pores (of width
Abstract This research describes the design of green oxidation catalysts capable of cleaning toxi... more Abstract This research describes the design of green oxidation catalysts capable of cleaning toxic gaseous effluents using low cost rice production sub-products, iron oxide chosen as the active phase due to its low toxicity and price (ca. 4 orders of magnitude less than noble metals normally utilised in oxidation reactions) and a low cost abundant clay with excellent rheological properties to facilitate the conformation of the catalysts. These catalysts have activities similar to others which often are based on synthetic and/or expensive and hazardous materials. The use of agro-industrial sub-products lowers the production costs, improves the catalytic performance, leading to a sustainable cycle in which waste materials from an industry are used as renewable raw materials for the same or others. Although addition of palladium (taken as an example of an efficient noble metal for catalytic oxidations) to the best iron containing catalyst, improves the oxidation of toluene decreasing energy costs, there are evidences that its presence in particulates and aerosols produced on use, can cause health problems.
2011 World Congress on Sustainable Technologies (WCST)
The use of agricultural industrial wastes to obtain value added products is an issue of utmost im... more The use of agricultural industrial wastes to obtain value added products is an issue of utmost importance today, since solutions to problems of environmental pollution are crucial in order to achieve a sustainable development. In this respect the contribution of the so called “Renewable Raw Materials” from agricultural wastes can be a promising starting point. Further, given their provenance, these materials can be also considered as “Ecomaterials”. This issue is now considered as one of the main scientific goals at an international level, given their benign environmental impact Using waste materials avoids the expense of other often non-renewable materials, among many other benefits, with groups which are working in this philosophy called “cradle to grave” under which industries may be able to turn waste into useful materials for themselves or others, thus closing a cycle with obvious benefits. The renewable raw materials developed in our group are value added materials prepared from agricultural industrial wastes, avoiding the use of toxic substances to the environment, as well as achieving maximum economy and reduction of energy expenditure. Some of the processes developed are: immobilization of enzymes for biocatalytic processes, design of scaffolds for tissue engineering, conversion of liquid renewable raw materials into fine chemical intermediates avoiding the use of petroleum derivatives and catalysts for environmental protection.
Studies in Surface Science and Catalysis - STUD SURF SCI CATAL, 1995
In this work the merits of the use of a natural fibrous mineral, sepiolite, as a binder to produc... more In this work the merits of the use of a natural fibrous mineral, sepiolite, as a binder to produce titania based monoliths of high mechanical strength and abrasion resistance is discussed. The monoliths of square channels were conformed with an initial 7.5 channels cm−2 and 1 mm wall thickness. The textural characterization was made by mercury intrusion porosimetry (MIP), nitrogen adsorption/desorption (BET), and X-ray diffraction (XRD). The mechanical resistance, dimensional changes and weight losses at each stage of heat treatment were also determined. The thermal expansion coefficients (TEC) of the monoliths were determined between 200° and 400°C, since in practice the usual working temperature of DENOX catalysts lies between 250°–350°C.
... b Instituto de Materiales de Madrid, CSIC, c/Sor Juana In6s de la Cruz 3, 28049 Madrid, Spain... more ... b Instituto de Materiales de Madrid, CSIC, c/Sor Juana In6s de la Cruz 3, 28049 Madrid, Spain. ... [10] M. Yates, J. Blanco, MA Martin-Luengo and MP Martin, Stud. Surf. Sci.Cat., 144 (2002) 569. [11 ] S. Brunauer, PH Emmett and E. Teller, J. Amer. Chem. Soc., 60 (1938) 309. ...
Titania in its anatase form has been shown to have a high photocatalytic activity for the degrada... more Titania in its anatase form has been shown to have a high photocatalytic activity for the degradation of volatile organic compounds at low temperature. This property is especially important when these compounds contain chlorine where catalytic oxidation or conventional combustion at higher temperatures can lead to the formation of highly toxic dioxins and furans. In systems with large volumes of gas to be treated the conformation of titania as open channelled monoliths, extrudates or sheets can ease the handling characteristics and improve the abrasion resistance. However, it is practically impossible to extrude titania without the inclusion of agglomerating agents. In this study bentonite, a natural silicate, was chosen as the agglomerating agent in order to conform the incorporated type ceramic bodies. A series of titania/bentonite materials ranging from 0 to 80% titania by weight were prepared. The inclusion of bentonite was found to increase the total specific surface area, abrasion resistance and mechanical strength of the monoliths, although causing a reduction in the total pore volume. The relationship between the surface coverage and the composition was determined by measuring the zero point charge as photocatalytic activity is a surface phenomenon since the photons can only penetrate the first 2 μm. Key words: Titania, bentonite, composite materials, photocatalysts.
ABSTRACT Highly ordered rod-like polymeric monoliths with large-pores have been successfully synt... more ABSTRACT Highly ordered rod-like polymeric monoliths with large-pores have been successfully synthesized using ionic liquids (ILs) IL-1 (1-Butyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide [BMIM][NTf2]) and IL-2 (1-octyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide [OMIM][NTf2]) as alternative porogenic solvents. The presence of ILs can not only promote the formation of a highly ordered macroporous structure, control the morphology of the polymer and control the chemical composition of surfaces for monoliths prepared from DVB. In this regard, post-functionalization of the monoliths can be easily achieved using the functional monomers introduced in the polymerization process or the unreacted vinyl groups present in the polymeric matrix. This control has allowed the preparation of monolithic Supported Ionic Liquid-like Phases (m-SILLPs) with excellent morphological properties. These m-SILLPs have been studied as supports for large biomolecules. Bioadsorption studies show that the adsorbed amount of protein reaches values as high as 150-200 mg of protein per gram of support.
ABSTRACT Pd-zirconia-based monolithic catalysts were prepared with various commercial zirconia ra... more ABSTRACT Pd-zirconia-based monolithic catalysts were prepared with various commercial zirconia raw materials and a natural magnesium silicate binder, sepiolite, for the selective catalytic reduction (SCR) of NO with CH4 in oxygen excess. The different textural properties, metastable tetragonal zirconia phase stability, surface acidity, Pd dispersion and catalytic properties of these monoliths were compared to select the most suitable structured catalyst for NOx control in natural gas-fired power plants. The influence of operating temperature in the two reactions, NO reduction and CH4 combustion, with the monolithic catalysts was determined. A 0.4wt.% Pd-zirconia catalyst, manufactured from a sulphated zirconium hydroxide raw material, was selected as the most appropriate in the reaction under study, reaching a maximum NO conversion at 400°C.
... catalyst with a platinum content of 0.20 wt.% was also prepared by incipient wetness impregna... more ... catalyst with a platinum content of 0.20 wt.% was also prepared by incipient wetness impregnation ... equation assuming a non-intersecting cylindrical pore model was used to calculate the pore ... over supported Pt catalysts was carried out at a gas hourly space velocity (GHSV) of ...
Monolithic catalysts based on Rh/TiO2–sepiolite were developed and tested in the decomposition of... more Monolithic catalysts based on Rh/TiO2–sepiolite were developed and tested in the decomposition of N2O traces. Several effects such as the presence of NO, O2 and NO+O2 in the gas mixture, the catalysts pre-treatment and the metal loading were evaluated. The system was extremely sensitive to the amount of rhodium, passing through a maximum in the catalytic activity at a Rh
Resumen es: Las propiedades texturales y estructurales de los soportes de alumina estan relaciona... more Resumen es: Las propiedades texturales y estructurales de los soportes de alumina estan relacionadas con las diferentes fases cristalinas que las constituyen, pero e...
Textural and structural properties of alumina supports are related to the d ifferent crystalline ... more Textural and structural properties of alumina supports are related to the d ifferent crystalline phases that form, but these are very important in synthesizing catalysts that operate in extreme ly hostile media, as in environmental catalytic processes. The catalyst support is an important part of the cata lyst as it provides the active phase of mechanical strength (which is essential when operating with high flows) and thermal (ideal when operating at high temperatures.) We study the modification of textural and structural propertie s of a sponge, � alumina ceramic by adding layers of alumina and evaluating changes by gravimetric techniques, optical and electronic microscopy, besides the textural properties of these supports porous media were evaluated using the BET equation, porosimetry
Characterization of Porous Solids II, Proceedings of the IUPAC Symposium (COPS 11), 1991
Summary Mercury porosimetric studies were carried out on Ancient Egyptian mortars extracted from ... more Summary Mercury porosimetric studies were carried out on Ancient Egyptian mortars extracted from the Sphinx body core and North side chest as well as from the Khafra Valley temple. Such studies were complemented by the application of X-ray diffraction and simultaneous thermogravimetric and differential thermal analysis. The results obtained suggest that Ancient Egyptian mortars are characterized by two sets of pores within the gypsum matrix. The larger pores (of width 1-15μm) appear to be located between the CaSO 4 granules, whereas the smaller pores (of width
Abstract This research describes the design of green oxidation catalysts capable of cleaning toxi... more Abstract This research describes the design of green oxidation catalysts capable of cleaning toxic gaseous effluents using low cost rice production sub-products, iron oxide chosen as the active phase due to its low toxicity and price (ca. 4 orders of magnitude less than noble metals normally utilised in oxidation reactions) and a low cost abundant clay with excellent rheological properties to facilitate the conformation of the catalysts. These catalysts have activities similar to others which often are based on synthetic and/or expensive and hazardous materials. The use of agro-industrial sub-products lowers the production costs, improves the catalytic performance, leading to a sustainable cycle in which waste materials from an industry are used as renewable raw materials for the same or others. Although addition of palladium (taken as an example of an efficient noble metal for catalytic oxidations) to the best iron containing catalyst, improves the oxidation of toluene decreasing energy costs, there are evidences that its presence in particulates and aerosols produced on use, can cause health problems.
2011 World Congress on Sustainable Technologies (WCST)
The use of agricultural industrial wastes to obtain value added products is an issue of utmost im... more The use of agricultural industrial wastes to obtain value added products is an issue of utmost importance today, since solutions to problems of environmental pollution are crucial in order to achieve a sustainable development. In this respect the contribution of the so called “Renewable Raw Materials” from agricultural wastes can be a promising starting point. Further, given their provenance, these materials can be also considered as “Ecomaterials”. This issue is now considered as one of the main scientific goals at an international level, given their benign environmental impact Using waste materials avoids the expense of other often non-renewable materials, among many other benefits, with groups which are working in this philosophy called “cradle to grave” under which industries may be able to turn waste into useful materials for themselves or others, thus closing a cycle with obvious benefits. The renewable raw materials developed in our group are value added materials prepared from agricultural industrial wastes, avoiding the use of toxic substances to the environment, as well as achieving maximum economy and reduction of energy expenditure. Some of the processes developed are: immobilization of enzymes for biocatalytic processes, design of scaffolds for tissue engineering, conversion of liquid renewable raw materials into fine chemical intermediates avoiding the use of petroleum derivatives and catalysts for environmental protection.
Studies in Surface Science and Catalysis - STUD SURF SCI CATAL, 1995
In this work the merits of the use of a natural fibrous mineral, sepiolite, as a binder to produc... more In this work the merits of the use of a natural fibrous mineral, sepiolite, as a binder to produce titania based monoliths of high mechanical strength and abrasion resistance is discussed. The monoliths of square channels were conformed with an initial 7.5 channels cm−2 and 1 mm wall thickness. The textural characterization was made by mercury intrusion porosimetry (MIP), nitrogen adsorption/desorption (BET), and X-ray diffraction (XRD). The mechanical resistance, dimensional changes and weight losses at each stage of heat treatment were also determined. The thermal expansion coefficients (TEC) of the monoliths were determined between 200° and 400°C, since in practice the usual working temperature of DENOX catalysts lies between 250°–350°C.
... b Instituto de Materiales de Madrid, CSIC, c/Sor Juana In6s de la Cruz 3, 28049 Madrid, Spain... more ... b Instituto de Materiales de Madrid, CSIC, c/Sor Juana In6s de la Cruz 3, 28049 Madrid, Spain. ... [10] M. Yates, J. Blanco, MA Martin-Luengo and MP Martin, Stud. Surf. Sci.Cat., 144 (2002) 569. [11 ] S. Brunauer, PH Emmett and E. Teller, J. Amer. Chem. Soc., 60 (1938) 309. ...
Titania in its anatase form has been shown to have a high photocatalytic activity for the degrada... more Titania in its anatase form has been shown to have a high photocatalytic activity for the degradation of volatile organic compounds at low temperature. This property is especially important when these compounds contain chlorine where catalytic oxidation or conventional combustion at higher temperatures can lead to the formation of highly toxic dioxins and furans. In systems with large volumes of gas to be treated the conformation of titania as open channelled monoliths, extrudates or sheets can ease the handling characteristics and improve the abrasion resistance. However, it is practically impossible to extrude titania without the inclusion of agglomerating agents. In this study bentonite, a natural silicate, was chosen as the agglomerating agent in order to conform the incorporated type ceramic bodies. A series of titania/bentonite materials ranging from 0 to 80% titania by weight were prepared. The inclusion of bentonite was found to increase the total specific surface area, abrasion resistance and mechanical strength of the monoliths, although causing a reduction in the total pore volume. The relationship between the surface coverage and the composition was determined by measuring the zero point charge as photocatalytic activity is a surface phenomenon since the photons can only penetrate the first 2 μm. Key words: Titania, bentonite, composite materials, photocatalysts.
ABSTRACT Highly ordered rod-like polymeric monoliths with large-pores have been successfully synt... more ABSTRACT Highly ordered rod-like polymeric monoliths with large-pores have been successfully synthesized using ionic liquids (ILs) IL-1 (1-Butyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide [BMIM][NTf2]) and IL-2 (1-octyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide [OMIM][NTf2]) as alternative porogenic solvents. The presence of ILs can not only promote the formation of a highly ordered macroporous structure, control the morphology of the polymer and control the chemical composition of surfaces for monoliths prepared from DVB. In this regard, post-functionalization of the monoliths can be easily achieved using the functional monomers introduced in the polymerization process or the unreacted vinyl groups present in the polymeric matrix. This control has allowed the preparation of monolithic Supported Ionic Liquid-like Phases (m-SILLPs) with excellent morphological properties. These m-SILLPs have been studied as supports for large biomolecules. Bioadsorption studies show that the adsorbed amount of protein reaches values as high as 150-200 mg of protein per gram of support.
ABSTRACT Pd-zirconia-based monolithic catalysts were prepared with various commercial zirconia ra... more ABSTRACT Pd-zirconia-based monolithic catalysts were prepared with various commercial zirconia raw materials and a natural magnesium silicate binder, sepiolite, for the selective catalytic reduction (SCR) of NO with CH4 in oxygen excess. The different textural properties, metastable tetragonal zirconia phase stability, surface acidity, Pd dispersion and catalytic properties of these monoliths were compared to select the most suitable structured catalyst for NOx control in natural gas-fired power plants. The influence of operating temperature in the two reactions, NO reduction and CH4 combustion, with the monolithic catalysts was determined. A 0.4wt.% Pd-zirconia catalyst, manufactured from a sulphated zirconium hydroxide raw material, was selected as the most appropriate in the reaction under study, reaching a maximum NO conversion at 400°C.
... catalyst with a platinum content of 0.20 wt.% was also prepared by incipient wetness impregna... more ... catalyst with a platinum content of 0.20 wt.% was also prepared by incipient wetness impregnation ... equation assuming a non-intersecting cylindrical pore model was used to calculate the pore ... over supported Pt catalysts was carried out at a gas hourly space velocity (GHSV) of ...
Monolithic catalysts based on Rh/TiO2–sepiolite were developed and tested in the decomposition of... more Monolithic catalysts based on Rh/TiO2–sepiolite were developed and tested in the decomposition of N2O traces. Several effects such as the presence of NO, O2 and NO+O2 in the gas mixture, the catalysts pre-treatment and the metal loading were evaluated. The system was extremely sensitive to the amount of rhodium, passing through a maximum in the catalytic activity at a Rh
Resumen es: Las propiedades texturales y estructurales de los soportes de alumina estan relaciona... more Resumen es: Las propiedades texturales y estructurales de los soportes de alumina estan relacionadas con las diferentes fases cristalinas que las constituyen, pero e...
Textural and structural properties of alumina supports are related to the d ifferent crystalline ... more Textural and structural properties of alumina supports are related to the d ifferent crystalline phases that form, but these are very important in synthesizing catalysts that operate in extreme ly hostile media, as in environmental catalytic processes. The catalyst support is an important part of the cata lyst as it provides the active phase of mechanical strength (which is essential when operating with high flows) and thermal (ideal when operating at high temperatures.) We study the modification of textural and structural propertie s of a sponge, � alumina ceramic by adding layers of alumina and evaluating changes by gravimetric techniques, optical and electronic microscopy, besides the textural properties of these supports porous media were evaluated using the BET equation, porosimetry
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