Papers by Angel Linares Solano
Actas De La Vi Reunion Del Grupo Espanol Del Carbon 2001 Isbn 84 7723 452 3 Pags 89 90, 2001
Información del artículo Adsorción de voc a bajas concentraciones: influencias de la porosidad y ... more Información del artículo Adsorción de voc a bajas concentraciones: influencias de la porosidad y la química superficial de los carbones activados.
Introduction TiO 2 has been one of the most widely investigated and used materials over the past ... more Introduction TiO 2 has been one of the most widely investigated and used materials over the past decades [1], because it is nontoxic, easy to be made, inexpensive and chemically stable. In recent years, TiO 2 -based nanomaterials have attracted significant research attention due to their broad applications in the fields of water and air purification [2]. However, one of the major factors that limits the efficiency of TiO 2 photocatalysis is the fast recombination of photo-generated electron/hole pairs, which releases energy in the form of unproductive heat or photons. Many efforts have been made to reduce charge recombination and enhance photocatalytic activity of TiO 2 [3]. Recently, synthesis of TiO 2 -CNT composites to increase the photocatalytic efficiency of TiO 2 has attracted significant attention. Synthesis methods of TiO 2 -CNT composites include sol-gel, chemical vapor deposition (CVD) and hydrothermal deposition, using carbon nanotubes as templates. In this work, we inves...
TANSO, 1998
Physical adsorption of gases has been revised in terms of the Theory of Micropore Filling as a te... more Physical adsorption of gases has been revised in terms of the Theory of Micropore Filling as a technique to characterise microporous carbons (carbon fiber, carbon molecular sieve, activated carbon and char). Special attention has been paid to the CO2 adsorption isotherms at 273K, obtained using subatmospheric and high pressures. Because the relative pressure range covered by our CO2 study is similar to the one covered with N2 at 77K, a suitable comparison of both adsorptives has been possible. Thus, we have been able to demonstrate that CO2 is an adsorptive that behaves at 273K similarly to the well-accepted N2 at 77K. In addition, the results show that the narrow microporous carbons should not be characterised only by N2 at 77K, otherwise the results can be useless. We encourage the use of CO2 (i. e. at 273K) as a complement to N2 adsorption. This suggestion is especially relevant considering that the most frequent available adsorption equipments use only N2 at 77K and that most of the researchers limit the characterisation of microporous carbons to this adsorptive.
NATO Science for Peace and Security Series C: Environmental Security, 2008
ABSTRACT
NATO Science for Peace and Security Series C: Environmental Security, 2008
ABSTRACT This chapter presents an overview of preparation and characterization of activated carbo... more ABSTRACT This chapter presents an overview of preparation and characterization of activated carbons (ACs), activated carbon fibres (ACFs) and activated carbon monoliths (ACMs) to be used in different applications. Examples of the performance of these materials in environmental, energy storage and space applications are presented, remarking the importance of carrying out a suitable porous texture characterization of the materials to understand and optimize their performance in each application. Development of narrow microporosity, which is assessed by CO2 adsorption at 273 K, has been demonstrated to be necessary for these applications. This type of porosity has been obtained by chemical alkaline hydroxide activation of carbon precursors with careful control and thorough understanding of the variables affecting the carbon activation process. Keywords: activated carbon; narrow microporosity; VOC adsorption; gas storage; adsorption compressor
Studies in Surface Science and Catalysis, 1991
Lecture Notes in Physics, 2006
... Since their discovery, carbon nanotubes have been proposed for a num-ber of applications, suc... more ... Since their discovery, carbon nanotubes have been proposed for a num-ber of applications, such as gas storage, reinforcement of composites, electrochemical energy storage, catalyst support, where the nanotexture and surface functionality are of fundamental importance. ...
Handbook of Advanced Ceramics, 2013
Physical adsorption of gases is the most employed technique for the characterization of porous so... more Physical adsorption of gases is the most employed technique for the characterization of porous solids. Nâ adsorption at 77 K is the more used and, usually, has a special status of recommended adsorptive. The advantage of Nâ adsorption is that it covers relative pressures from 10â»â¸ to 1, what results in adsorption in the whole range of porosity. The main disadvantage of Nâ adsorption at 77 K is that when used for the characterization of microporous solids, diffusional problems of the molecules inside the narrow porosity (size < 0.7 nm) occur. This paper describes studies concerned with adsorption of carbon dioxide by microporous carbon materials.
Water Science & Technology, 2009
This paper discusses H2S, NH3 and VOCs removal by sewage-sludge-derived materials with outstandin... more This paper discusses H2S, NH3 and VOCs removal by sewage-sludge-derived materials with outstanding chemical and textural properties. These materials were obtained from different precursors using different chemical and thermal treatments. Results show that the H2S removal process entailed a catalytic conversion of H2S to S or SO42− species. On the other hand, adsorption is the main mechanism governing the performance of sludge-based materials for NH3 and VOCs. Retention capacities (x/M values) obtained for some of the sludge–based adsorbents/catalysts are similar to those obtained with commercial activated carbons selected as reference materials.
The Journal of Physical Chemistry B, 2002
Experimental N 2 adsorption isotherms and high-pressure CO 2 and CH 4 adsorption isotherms have b... more Experimental N 2 adsorption isotherms and high-pressure CO 2 and CH 4 adsorption isotherms have been obtained for a series of microporous carbon materials prepared for being used in gas separation and methane storage. The shape of the isotherms is very different, which is due in part to differences in the overall micropore volume but, additionally and importantly, to the significant differences in the micropore size distribution of those samples. Micropore size distributions (MPSDs) have been deduced from those N 2 , CO 2 , and CH 4 isotherms by application of the General Adsorption Isotherm (GAI), according to two different approaches proposed in previous independent works. The comparison of the results has shown that, despite the different characteristics of CH 4 and CO 2 , and the different experimental temperatures and adsorption conditions (298 K, supercritical conditions, and 273 K, subcritical conditions, respectively), a quite good consistency between the MPSDs from these two gases has been obtained for all the samples studied. That suggests that both methods are suitable to analyze more sensibly the changes in the MPSDs of microporous samples. The fact that these MPSDs analysis are based on high-pressure adsorption isotherms and that CO 2 is especially useful for characterizing the narrow microporosity not accessible to N 2 makes both techniques very useful for the characterization of microporous samples.
Microporous and Mesoporous Materials, 2007
ABSTRACT Tunable carbon nanofiber-coated monoliths as carriers for enzyme adsorption are presente... more ABSTRACT Tunable carbon nanofiber-coated monoliths as carriers for enzyme adsorption are presented. Carbon-nanofibers (CNFs) were grown on monoliths with different microstructure. “Classical” cordierite monoliths were compared to novel acicular mullite (ACM) monoliths, with a more open wall structure. This open structure allows for a higher CNF-loading without affecting the open structure of the monoliths. The composites were used as a carrier for lactase from Aspergillus oryzae. ACM monoliths allow for a higher CNF loading, and thus for a higher enzyme loading. Lactase adsorption per gram of carbon increases by 15–20% compared to cordierite samples. The total enzyme adsorption capacity for CNF-coated ACM and cordierite monoliths was found to be 350 and respectively. Oxidation treatment of the CNFs affected the surface chemistry, while the porosity was not affected. The growth catalyst could be removed completely from both the support and the CNFs by treatment in HCl or HNO3, without destroying the carbon structure.
Journal of Materials Science, 1995
... 3.3. Porous structure The Brunauer-Emmett-Teller (BET) surface areas of the specimens are sho... more ... 3.3. Porous structure The Brunauer-Emmett-Teller (BET) surface areas of the specimens are shown in Table I. Only several m2g -t were obtained for the rice hull-derived moulded carbons, which means no formation of micropores occurred after carbonization. ...
Journal of Catalysis, 1989
A series of Pt catalysts supported on carbon black has been prepared; the original support was tr... more A series of Pt catalysts supported on carbon black has been prepared; the original support was treated in such a way as to ensure carbons with the same porous texture but with an increasing amount of oxygen surface groups. Pt catalysts (about 1% loading) were prepared with these carbons using the same experimental procedure and the metal dispersion was calculated from hydrogen chemisorption measurements. Both dispersion and resistance to sintering were found to be a function of the number of oxygen surface groups of the support. 0 19x9 Academic PEW. Inc.
Journal of Catalysis, 1991
A series of carbon-supported platinum catalysts were prepared and characterized; the only variabl... more A series of carbon-supported platinum catalysts were prepared and characterized; the only variable during catalyst preparation was the support used. The influence of different carbon properties on the platinum dispersion is described. The results show that there is not a single carbon property that can be related to dispersion, each one playing a more or less important role. However, the surface area outside the micropores may control the Pt dispersion if the chemical nature of the support is kept constant and vice versa. The large range of platinum particle sizes used in this work-obtained from different carbon supports and sintering treatments-has allowed us to observe that a relationship between platinum particle size and weakly chemisorbed hydrogen exists. The uptake of this kind of hydrogen increases with particle size.
Journal of Applied Polymer Science, 2003
Three carbon fibers (CF) of different characteristics and properties were used to determine the m... more Three carbon fibers (CF) of different characteristics and properties were used to determine the most suitable characteristics for a carbon fiber to reinforce a thermoplastic polyurethane elastomer (TPU) matrix. The TPU was synthesized with a moderate amount of hard segments to bring polarity to the matrix without losing flexibility. On the other hand, the CF were chosen with respect to their different mechanical properties, diameter, and length to study the influence of those parameters on the TPU matrix. Additionally, the fibers were used in different amounts as well as after different oxidation treatments (i.e., different polarity). The mechanical properties and surface characteristics of the composites were analyzed using several experimental techniques (SEM, X-ray photoelectron spectroscopy, dynamic mechanical thermal analysis, and tensile tests). The results obtained showed that the surface polarity, diameter, and length of the CFs are related to the reinforcement of a medial polar TPU matrix, whereas the mechanical properties of the CF do not influence those of the composite.
Journal of Analytical and Applied Pyrolysis, 2007
In the present paper, heat-treatments in N2 atmosphere of mixtures of different precursors and al... more In the present paper, heat-treatments in N2 atmosphere of mixtures of different precursors and alkaline hydroxides are studied. The paper analyses the effect that the precursors’ nature (coals, lignocellulosic materials and carbon fibre) has on the final porosity of the resulting activated carbons. The results show that this physical mixing method can be effectively used for all the selected precursors,
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Papers by Angel Linares Solano