Mortar and concrete play an important role in the engineered barrier system of the near field nuc... more Mortar and concrete play an important role in the engineered barrier system of the near field nuclear waste repositories. In these systems, problems appear within the course of time, when the water of the rock formation takes contact with concrete, being this an alkaline ion source that causes a series of physicochemical transformations in other components of the system and diminishes the confinement capacity of radionucleids. The final objective of this work is to improve concrete characteristics of permeability, durability and resistance through carbonation process using SCCO2 as a reagent. First, the reaction of calcium ions with supercritical carbon dioxide in aqueous media was studied. After a deep understanding of the carbonation reaction, several cement types were carbonated at supercritical conditions. The in situ precipitation of calcite between the fibers of cellulose paper is also presented.
h i g h l i g h t s scCO 2 was used to precipitate micro and nanoparticles of CaCO 3 for CO 2 cap... more h i g h l i g h t s scCO 2 was used to precipitate micro and nanoparticles of CaCO 3 for CO 2 capture. At 750°C, microcalcite showed a residual conversion value of 0.65 after 25 cycles. At 900°C, the residual conversion of microcalcite doubled the value of limestone. Micrometric CaCO 3 held higher CO 2 absorption than tight agglomerated nanoparticles. g r a p h i c a l a b s t r a c t Conversion values obtained in the carbonation/calcination cycles, for the synthesised PSCCa(OH) 2 and PSCCaO and SEM images of the carbonated samples taken at cycles 0, 5 and 13.
... Anhydrous Supercritical Carbon Dioxide Method for the Controlled Silanization of Inorganic Na... more ... Anhydrous Supercritical Carbon Dioxide Method for the Controlled Silanization of Inorganic Nanoparticles** By Eva Loste, Julio Fraile, María A. Fanovich, Geert F. Woerlee, and Concepción Domingo* ... [17] C. Domingo, J. García-Carmona, J. Llibre, R. Rodríguez-Clemente, Adv. ...
Porous, stable and functional MOF polymer hybrids can be prepared by the in situ polymerization o... more Porous, stable and functional MOF polymer hybrids can be prepared by the in situ polymerization of otherwise unstable soft crystals.
Materials that combine flexibility and open metal sites are crucial for myriad applications. In t... more Materials that combine flexibility and open metal sites are crucial for myriad applications. In this article, we report a 2D coordination polymer (CP) assembled from CuII ions and a flexible meta-carborane-based linker [Cu2(L1)2(Solv)2]•xSolv (1-DMA, 1-DMF, and 1-MeOH; L1: 1,7-di(4-carboxyphenyl)-1,7-dicarba-closo-dodecaborane). 1-DMF undergoes an unusual example of reversible phase transition on solvent treatment (i.e., MeOH and CH2Cl2). Solvent exchange, followed by thermal activation provided a new porous phase that exhibits an estimated Brunauer-Emmett-Teller (BET) surface area of 301 m2 g−1 and is capable of a CO2 uptake of 41 cm3 g−1. The transformation is reversible and 1-DMF is reformed on addition of DMF to the porous phase. We provide evidence for the reversible process being the result of the formation/cleavage of weak but attractive B–H∙∙∙Cu interactions by a combination of single-crystal (SCXRD), powder (PXRD) X-ray diffraction, Raman spectroscopy, and DFT calculations.
Chemistry (Weinheim an der Bergstrasse, Germany), Jan 8, 2018
The supercritical carbon dioxide synthesis of non-reduced graphene oxide (GO) aerogels from dispe... more The supercritical carbon dioxide synthesis of non-reduced graphene oxide (GO) aerogels from dispersions of GO in ethanol is here reported as a low-cost, efficient and environmentally friendly process. The preparation is carried out at the mild conditions of 333 K and 20 MPa. The high aspect ratio of the used GO sheets (ca. 30 µm lateral dimensions) allowed the preparation of aerogel monoliths by simultaneous scCO2 gelation and drying. Solid state characterization results indicate that a thermally stable mesoporous non-reduced GO aerogel was obtained by using the supercritical procedure, keeping the GO sheets most of the surface oxygenated groups, thus, facilitating further functionalization. Moreover, the monoliths have a very low density, high specific surface area and excellent mechanical integrity, characteristics which rivals with that of most light-weight reduced graphene aerogels reported in the literature.
ABSTRACT A simple modification of a combustion method has been used for the production of ultrapo... more ABSTRACT A simple modification of a combustion method has been used for the production of ultraporous metals in air. Nitrates of different metallic elements were reacted with glycine as a reducing fuel. The glycine to nitrate ratio can be simply used to control the formation of oxides or, in the case of fuel-rich mixtures, the formation of metals such as Ni, Co, Cu or Ag. Furthermore, the metallic monoliths obtained present a remarkable porosity of fractal nature (from macro to nano scales) with pores ranging from many microns down to at least 5 nm. This exceedingly simple approach shows the way for the design and synthesis of complex porous microstructures of metals for the wide variety of applications where interface optimization is crucial.
In this work, the authors studied the influence of citric acid, sucrose, calcium lignosulfonate, ... more In this work, the authors studied the influence of citric acid, sucrose, calcium lignosulfonate, sodium dodecyl sulfate, polyethylene glycol and triethanolamine (1 wt.%) as well as of CaSO 4 Á1/2H 2 O and aerosol OT (0.5 wt.%) on the morphology and aggregation of calcite precipitated by carbonation of slaked lime. It was found that the three first additives modify the precipitation mechanism yielding elongated agglomerates similar to those known as chain-like, precursors of colloidal nanometric calcite. The other additives used do not modify the mechanism and yield scalenohedral calcite of submicrometric/micrometric size, similar to that obtained in the absence of additives. These results are explained in terms of the effect of these additives on the dissolution rate of Ca(OH) 2 and their inhibitory effect in the chain-like to colloidal calcite transformation. Concerning the aggregation phenomena, sucrose and citric acid act aggregating the primary chain-like particles. Lignosulfonate aggregates on the whole size range. The other additives showed a small dispersing effect. D
The formation of powdered calcite from slurries containing a calcium source and carbon dioxide (i... more The formation of powdered calcite from slurries containing a calcium source and carbon dioxide (industrial carbonation route) is a complex process of considerable importance nowadays. In the absence of additives, the rhombohedral morphology can be obtained in precipitation processes by using solution routes, but rarely by the industrial method where the most common morphology of precipitated calcite is the scalenohedral one. In this work, the conditions and mechanisms for producing calcite particles with various shapes and sizes have been investigated in a reaction between aqueous calcium hydroxide and compressed carbon dioxide (compressed vapour, liquid or supercritical). Influence of pressure, temperature and reaction time were analyzed. Rhombohedral calcite with a very low degree of agglomeration was obtained under supercritical conditions. The carbonation process was also applied to the in situ precipitation of calcite inside of the pores of cellulose paper. (C. Domingo).
Mortar and concrete play an important role in the engineered barrier system of the near field nuc... more Mortar and concrete play an important role in the engineered barrier system of the near field nuclear waste repositories. In these systems, problems appear within the course of time, when the water of the rock formation takes contact with concrete, being this an alkaline ion source that causes a series of physicochemical transformations in other components of the system and diminishes the confinement capacity of radionucleids. The final objective of this work is to improve concrete characteristics of permeability, durability and resistance through carbonation process using SCCO2 as a reagent. First, the reaction of calcium ions with supercritical carbon dioxide in aqueous media was studied. After a deep understanding of the carbonation reaction, several cement types were carbonated at supercritical conditions. The in situ precipitation of calcite between the fibers of cellulose paper is also presented.
h i g h l i g h t s scCO 2 was used to precipitate micro and nanoparticles of CaCO 3 for CO 2 cap... more h i g h l i g h t s scCO 2 was used to precipitate micro and nanoparticles of CaCO 3 for CO 2 capture. At 750°C, microcalcite showed a residual conversion value of 0.65 after 25 cycles. At 900°C, the residual conversion of microcalcite doubled the value of limestone. Micrometric CaCO 3 held higher CO 2 absorption than tight agglomerated nanoparticles. g r a p h i c a l a b s t r a c t Conversion values obtained in the carbonation/calcination cycles, for the synthesised PSCCa(OH) 2 and PSCCaO and SEM images of the carbonated samples taken at cycles 0, 5 and 13.
... Anhydrous Supercritical Carbon Dioxide Method for the Controlled Silanization of Inorganic Na... more ... Anhydrous Supercritical Carbon Dioxide Method for the Controlled Silanization of Inorganic Nanoparticles** By Eva Loste, Julio Fraile, María A. Fanovich, Geert F. Woerlee, and Concepción Domingo* ... [17] C. Domingo, J. García-Carmona, J. Llibre, R. Rodríguez-Clemente, Adv. ...
Porous, stable and functional MOF polymer hybrids can be prepared by the in situ polymerization o... more Porous, stable and functional MOF polymer hybrids can be prepared by the in situ polymerization of otherwise unstable soft crystals.
Materials that combine flexibility and open metal sites are crucial for myriad applications. In t... more Materials that combine flexibility and open metal sites are crucial for myriad applications. In this article, we report a 2D coordination polymer (CP) assembled from CuII ions and a flexible meta-carborane-based linker [Cu2(L1)2(Solv)2]•xSolv (1-DMA, 1-DMF, and 1-MeOH; L1: 1,7-di(4-carboxyphenyl)-1,7-dicarba-closo-dodecaborane). 1-DMF undergoes an unusual example of reversible phase transition on solvent treatment (i.e., MeOH and CH2Cl2). Solvent exchange, followed by thermal activation provided a new porous phase that exhibits an estimated Brunauer-Emmett-Teller (BET) surface area of 301 m2 g−1 and is capable of a CO2 uptake of 41 cm3 g−1. The transformation is reversible and 1-DMF is reformed on addition of DMF to the porous phase. We provide evidence for the reversible process being the result of the formation/cleavage of weak but attractive B–H∙∙∙Cu interactions by a combination of single-crystal (SCXRD), powder (PXRD) X-ray diffraction, Raman spectroscopy, and DFT calculations.
Chemistry (Weinheim an der Bergstrasse, Germany), Jan 8, 2018
The supercritical carbon dioxide synthesis of non-reduced graphene oxide (GO) aerogels from dispe... more The supercritical carbon dioxide synthesis of non-reduced graphene oxide (GO) aerogels from dispersions of GO in ethanol is here reported as a low-cost, efficient and environmentally friendly process. The preparation is carried out at the mild conditions of 333 K and 20 MPa. The high aspect ratio of the used GO sheets (ca. 30 µm lateral dimensions) allowed the preparation of aerogel monoliths by simultaneous scCO2 gelation and drying. Solid state characterization results indicate that a thermally stable mesoporous non-reduced GO aerogel was obtained by using the supercritical procedure, keeping the GO sheets most of the surface oxygenated groups, thus, facilitating further functionalization. Moreover, the monoliths have a very low density, high specific surface area and excellent mechanical integrity, characteristics which rivals with that of most light-weight reduced graphene aerogels reported in the literature.
ABSTRACT A simple modification of a combustion method has been used for the production of ultrapo... more ABSTRACT A simple modification of a combustion method has been used for the production of ultraporous metals in air. Nitrates of different metallic elements were reacted with glycine as a reducing fuel. The glycine to nitrate ratio can be simply used to control the formation of oxides or, in the case of fuel-rich mixtures, the formation of metals such as Ni, Co, Cu or Ag. Furthermore, the metallic monoliths obtained present a remarkable porosity of fractal nature (from macro to nano scales) with pores ranging from many microns down to at least 5 nm. This exceedingly simple approach shows the way for the design and synthesis of complex porous microstructures of metals for the wide variety of applications where interface optimization is crucial.
In this work, the authors studied the influence of citric acid, sucrose, calcium lignosulfonate, ... more In this work, the authors studied the influence of citric acid, sucrose, calcium lignosulfonate, sodium dodecyl sulfate, polyethylene glycol and triethanolamine (1 wt.%) as well as of CaSO 4 Á1/2H 2 O and aerosol OT (0.5 wt.%) on the morphology and aggregation of calcite precipitated by carbonation of slaked lime. It was found that the three first additives modify the precipitation mechanism yielding elongated agglomerates similar to those known as chain-like, precursors of colloidal nanometric calcite. The other additives used do not modify the mechanism and yield scalenohedral calcite of submicrometric/micrometric size, similar to that obtained in the absence of additives. These results are explained in terms of the effect of these additives on the dissolution rate of Ca(OH) 2 and their inhibitory effect in the chain-like to colloidal calcite transformation. Concerning the aggregation phenomena, sucrose and citric acid act aggregating the primary chain-like particles. Lignosulfonate aggregates on the whole size range. The other additives showed a small dispersing effect. D
The formation of powdered calcite from slurries containing a calcium source and carbon dioxide (i... more The formation of powdered calcite from slurries containing a calcium source and carbon dioxide (industrial carbonation route) is a complex process of considerable importance nowadays. In the absence of additives, the rhombohedral morphology can be obtained in precipitation processes by using solution routes, but rarely by the industrial method where the most common morphology of precipitated calcite is the scalenohedral one. In this work, the conditions and mechanisms for producing calcite particles with various shapes and sizes have been investigated in a reaction between aqueous calcium hydroxide and compressed carbon dioxide (compressed vapour, liquid or supercritical). Influence of pressure, temperature and reaction time were analyzed. Rhombohedral calcite with a very low degree of agglomeration was obtained under supercritical conditions. The carbonation process was also applied to the in situ precipitation of calcite inside of the pores of cellulose paper. (C. Domingo).
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Papers by Julio Fraile