127 results on '"López Antón, María Antonia"'
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2. Noble metal-based sorbents: A way to avoid new waste after mercury removal
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Antuña-Nieto, Cristina, Rodríguez, Elena, Lopez-Anton, Maria Antonia, García, Roberto, and Martínez-Tarazona, M. Rosa
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- 2020
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Catalog
3. Carbon materials loaded with maghemite as regenerable sorbents for gaseous Hg0 removal
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Antuña-Nieto, Cristina, Rodríguez, Elena, López-Antón, María Antonia, García, Roberto, and Martínez-Tarazona, María Rosa
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- 2020
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- View/download PDF
4. Synthesis of Micro- and Mesoporous Carbon Foams with Nanodispersed Metals for Adsorption and Catalysis Applications
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Ministerio de Ciencia e Innovación (España), Principado de Asturias, García Fernández, Roberto [0000-0002-1315-8574], Rodríguez Vázquez, Elena [0000-0001-6835-0371], Díez Díaz-Estébanez, María Antonia [0000-0003-4630-0669], Arenillas de la Puente, Ana [0000-0002-5388-1169], Rey Raap, Natalia [0000-0002-5003-0035], López Antón, María Antonia [0000-0001-9330-5775], Martínez Tarazona, María Rosa [0000-0002-7331-3134], García Fernández, Roberto, Rodríguez Vázquez, Elena, Díez Díaz-Estébanez, María Antonia, Arenillas de la Puente, Ana, Fernández Villanueva, Sara, Rey Raap, Natalia, Cuesta, Cristóbal, López Antón, María Antonia, Martínez Tarazona, María Rosa, Ministerio de Ciencia e Innovación (España), Principado de Asturias, García Fernández, Roberto [0000-0002-1315-8574], Rodríguez Vázquez, Elena [0000-0001-6835-0371], Díez Díaz-Estébanez, María Antonia [0000-0003-4630-0669], Arenillas de la Puente, Ana [0000-0002-5388-1169], Rey Raap, Natalia [0000-0002-5003-0035], López Antón, María Antonia [0000-0001-9330-5775], Martínez Tarazona, María Rosa [0000-0002-7331-3134], García Fernández, Roberto, Rodríguez Vázquez, Elena, Díez Díaz-Estébanez, María Antonia, Arenillas de la Puente, Ana, Fernández Villanueva, Sara, Rey Raap, Natalia, Cuesta, Cristóbal, López Antón, María Antonia, and Martínez Tarazona, María Rosa more...
- Abstract
This work focuses on carbon foams, whose peculiarity is a predominant open macroporous cellular network that can be provided with tailored texture and morphology by the modification of the preparation process. The goal was to obtain macroporous carbonaceous structures capable of being activated by following a simple thermo-foaming procedure using a few reagents. With this purpose in mind, carbon foams with different textural properties were synthesized from sucrose using two foaming processes: at atmospheric pressure and in a pressurized reactor. Iron and silver nitrates added to sucrose gave rise, after carbonization, to materials with iron oxides and elemental silver particles nano-dispersed in the carbon matrix and promoted microporosity in both cases and mesoporosity in the case of iron nitrate. Iron nitrate also catalyzes the graphitization of the carbon material during carbonization. All these findings show the potential of sucrose thermo-foaming process as a viable and sustainable path to produce versatile carbon materials, capable of being used in various applications. more...
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- 2023
5. Sorption of Selenium(IV) and Selenium(VI) onto Iron Oxide/Hydroxide-Based Carbon Materials: Activated Carbon and Carbon Foam
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Ministerio de Ciencia e Innovación (España), Principado de Asturias, Rodríguez Vázquez, Elena [0000-0001-6835-0371], García Fernández, Roberto [0000-0002-1315-8574], Martínez Tarazona, María Rosa [0000-0002-7331-3134], López Antón, María Antonia [0000-0001-9330-5775], López Toyos, Lucia, Rodríguez Vázquez, Elena, García, R., Martínez Tarazona, María Rosa, López Antón, María Antonia, Ministerio de Ciencia e Innovación (España), Principado de Asturias, Rodríguez Vázquez, Elena [0000-0001-6835-0371], García Fernández, Roberto [0000-0002-1315-8574], Martínez Tarazona, María Rosa [0000-0002-7331-3134], López Antón, María Antonia [0000-0001-9330-5775], López Toyos, Lucia, Rodríguez Vázquez, Elena, García, R., Martínez Tarazona, María Rosa, and López Antón, María Antonia more...
- Abstract
Selenium pollution in water is a worldwide issue. Se(IV) and Se(VI) are mainly found in contaminated water due to their high solubility and mobility; their presence poses a serious risk as they can severely harm human health. Although iron oxide and hydroxide nanoparticles can be efficient candidates for the removal of selenium oxyanions due to their high adsorption capacity, the role of each iron species has not been fully elucidated. Furthermore, iron species are often found to be less effective for Se(VI) than Se(IV). The challenge and novelty of this study was to develop a carbon material impregnated with different iron phases, including oxides (magnetite/hematite) and hydroxides (goethite/lepidocrocite) capable of removing both Se(IV) and Se(VI). Since the phase and morphology of the iron nanoparticles play a significant role in Se adsorption, the study evaluated both characteristics by modifying the impregnation method, which is based on an oxidative hydrolysis with FeSO4 7H2O and CH3COONa, and the type of carbonaceous support (activated carbon or sucrose-based carbon foam). Impregnated activated carbons provide better removal efficiencies (70–80%) than carbon foams (<40%), due to their high surface areas and point zero charges. These results show that the adsorption of Se(VI) is more favorable on magnetic oxides (78%) and hydroxides (71%) than in hematite (<40%). In addition, the activated carbon decorated with magnetite showed a high adsorption capacity for both selenium species, even in alkaline conditions, when the sorbent surface is negatively charged. A mechanism based on the adsorption of inner-sphere complexes was suggested for Se(IV) immobilization, whereas Se(VI) removal occurred through the formation of outer-sphere complexes and redox processes. more...
- Published
- 2023
6. Goethite-based carbon foam nanocomposites for concurrently immobilizing arsenic and metals in polluted soils
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Ministerio de Ciencia e Innovación (España), López Antón, María Antonia [0000-0001-9330-5775], Rodríguez Vázquez, Elena [0000-0001-6835-0371], García Fernández, Roberto [0000-0002-1315-8574], Janeiro Tato, Iria, Baragaño Coto, Diego, López Antón, María Antonia, Rodríguez Vázquez, Elena, Peláez Andrés, Ana Isabel, García Fernández, Roberto, Rodríguez Gallego, José Luis, Ministerio de Ciencia e Innovación (España), López Antón, María Antonia [0000-0001-9330-5775], Rodríguez Vázquez, Elena [0000-0001-6835-0371], García Fernández, Roberto [0000-0002-1315-8574], Janeiro Tato, Iria, Baragaño Coto, Diego, López Antón, María Antonia, Rodríguez Vázquez, Elena, Peláez Andrés, Ana Isabel, García Fernández, Roberto, and Rodríguez Gallego, José Luis more...
- Abstract
Although different amendments have been used for the immobilization of metals and metalloids in contaminated soils, in most of them there are still important challenges that need to be faced in order to achieve an optimal result. In this work, a new material based on a carbon foam impregnated with goethite nanoneedles has been developed with the aim of evaluating its effect on the mobility and availability of As, Cd, Cu, Pb and Zn in an industrial soil. For this purpose, leaching, sequential extraction and phytotoxicity studies have been carried out. The results were compared with the same carbon foam without goethite impregnation. When the soil was treated with goethite-based carbon foam nanocomposite, the mobility of metal(loid)s was markedly reduced, with the exception of Zn, which showed moderate immobilization. The presence of acid groups on the surface of the carbon foam, together with a high surface area, led to a strong immobilization of pollutants. Moreover, the modification of the foams using goethite nanoneedles, imply that the novel nanocomposite obtained is effective to remediate simultaneously metal and metalloid-polluted soils, without any relevant effect on soil toxicity. more...
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- 2022
7. Immobilization of mercury in contaminated soils through the use of new carbon foam amendments
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Ministerio de Ciencia e Innovación (España), López Antón, María Antonia 0000-0001-9330-5775, Rodríguez Vázquez, Elena [0000-0001-6835-0371], Martínez Tarazona, María Rosa [0000-0002-7331-3134], Janeiro Tato, Iria, López Antón, María Antonia, Baragaño, Diego, Antuña-Nieto, Cristina, Rodríguez Vázquez, Elena, Peláez, A. I., Gallego, J. R., Martínez Tarazona, María Rosa, Ministerio de Ciencia e Innovación (España), López Antón, María Antonia 0000-0001-9330-5775, Rodríguez Vázquez, Elena [0000-0001-6835-0371], Martínez Tarazona, María Rosa [0000-0002-7331-3134], Janeiro Tato, Iria, López Antón, María Antonia, Baragaño, Diego, Antuña-Nieto, Cristina, Rodríguez Vázquez, Elena, Peláez, A. I., Gallego, J. R., and Martínez Tarazona, María Rosa more...
- Abstract
Background: Mercury (Hg) is recognized as one of the 10 most toxic elements in nature and is much more persistent in soils than in other environmental compartments. However, an effective, environmentally friendly, economical, and large-scale applicable technology for the remediation of soils contaminated by Hg has not yet been established. This study evaluates the feasibility of a new carbon foam-based product for the remediation of three soils contaminated with Hg, and infers the mobilization or immobilization mechanism through a detailed study of Hg speciation. Results: Soil treatment with carbon foams, one of them impregnated with goethite, reduced Hg availability by 75–100%. The proportion of mercury associated to humic acids (Hg–HA) determined the mobility and the availability of Hg when soils were treated with carbon foams. The drop of pH promotes changes in the structure of HA, a consequence of which is that Hg–HA becomes part of the unavailable fraction of the soil along with HgS. The carbon foam impregnated with goethite did not mobilize Fe as occurred with zero valence iron nanoparticles. The presence of acidic groups on the surface of the foam (carboxyl, quinone and phenolic groups) can strongly improve the binding of metal cations, enhancing Fe immobilization. Conclusions: A novel carbon foam-based amendment was efficient in immobilizing Hg in all the soils studied. The carbon foam impregnated with goethite, in addition to not mobilizing Fe, had the additional advantage of its low effect on the electrical conductivity of the soil. This novel approach could be considered as a potential amendment for other industrial and/or abandoned mining areas contaminated with Hg and/or other metal(loid)s. more...
- Published
- 2021
8. An insight into the role of biomass, biocompounds and synthetic polymers as additives to coal for the synthesis of carbon foams
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Principado de Asturias, Rodríguez Vázquez, Elena [0000-0001-6835-0371], Díez Díaz-Estébanez, María Antonia [0000-0003-4630-0669], López Antón, María Antonia [0000-0001-9330-5775], García Fernández, Roberto [0000-0002-1315-8574], Martínez Tarazona, María Rosa [0000-0002-7331-3134], Rodríguez Vázquez, Elena, Díez Díaz-Estébanez, María Antonia, Antuña-Nieto, Cristina, López Antón, María Antonia, García Fernández, Roberto, Martínez Tarazona, María Rosa, Principado de Asturias, Rodríguez Vázquez, Elena [0000-0001-6835-0371], Díez Díaz-Estébanez, María Antonia [0000-0003-4630-0669], López Antón, María Antonia [0000-0001-9330-5775], García Fernández, Roberto [0000-0002-1315-8574], Martínez Tarazona, María Rosa [0000-0002-7331-3134], Rodríguez Vázquez, Elena, Díez Díaz-Estébanez, María Antonia, Antuña-Nieto, Cristina, López Antón, María Antonia, García Fernández, Roberto, and Martínez Tarazona, María Rosa more...
- Abstract
Carbon foams were synthesized from blends of coal and several C-containing additives of different nature, with the aim to study their influence on the foaming step, and hence in the final properties of the obtained foams. The additives included biomass and agricultural products, and thermoplastic and thermosetting polymers, at different concentrations, ranging from 5 to 20 wt%. The effects of the additives on pore structure, carbon matrix and thermal properties of the resulting foams were investigated. The presence of additives during pyrolysis had no effect on the yield of carbonaceous product. However, all the additives, except the polybutadiene phenyl terminated (PBP) elastomer, led to a reduction in the fluidity of the blend. This difference in the effect can be related to the liquid nature of PBP, which favors the impregnation of coal particles, to the decomposition pattern overlapping with that of the coal, and to a high chemical affinity of the degradation products of PBP and coal. Analysis of the fluidity development of the blends and the changes in volatile matter production at different temperature intervals showed that bio-type additives with the maximum emission of volatiles in the coal pre-plastic stage provided improvements in the porosity of the C-foams. In contrast, synthetic polymers like low-density polyethylene (LDPE) and PBP generated most of their thermal degradation products during the plastic and the own thermal degradation stages of coal, leading to a reduction in the porosity of the carbon foams. This behavior can be attributed to a blocking of some macropores in the C-foams by deposition, in the pore mouths, of molten LDPE and/or oligomers from its backbone promoted by the conditions applied during the long residence time inside the reactor. The addition of polyethylene terephthalate (PET) resulted in no foam formation. Regardless of the additive, the resulting foams derived from binary blends showed lower thermal conductivity compared to t more...
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- 2021
9. The retention capacity for trace elements by the flue gas desulphurisation system under operational conditions of a co-combustion power plant
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Córdoba, Patricia, Font, Oriol, Izquierdo, María, Querol, Xavier, Leiva, Carlos, López-Antón, María Antonia, Díaz-Somoano, Mercedes, Ochoa-González, Raquel, Rosa Martinez-Tarazona, M., and Gómez, Pedro more...
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- 2012
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10. Partitioning of trace inorganic elements in a coal-fired power plant equipped with a wet Flue Gas Desulphurisation system
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Córdoba, Patricia, Ochoa-Gonzalez, Raquel, Font, Oriol, Izquierdo, Maria, Querol, Xavier, Leiva, Carlos, López-Antón, Maria Antonia, Díaz-Somoano, Mercedes, Rosa Martinez-Tarazona, M., Fernandez, Constantino, and Tomás, Alfredo more...
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- 2012
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11. Sorbentes regenerables basados en espumas de carbono para el control de mercurio en los procesos de producción de energía
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López Toyos, Lucía, Rodríguez Vázquez, Elena, López Antón, María Antonia, García Fernández, Roberto, Martínez Tarazona, María Rosa, Ministerio de Ciencia e Innovación (España), and Principado de Asturias more...
- Subjects
espuma de carbono ,mercurio ,purificación de gases ,sorbentes regenerables - Abstract
Los autores agradecen la financiación recibida a través de los proyectos de investigación PID2020-113558RB-C43 (MCIN/ AEI/10.13039/501100011033) e IDI/2021/000031 y al CSIC por la beca JAE-Intro ICU concedida a Lucía López Toyos (Ref: JAEICU21-INCAR-27). more...
- Published
- 2022
12. Remediación de suelos contaminados con arsénico, selenio y metales mediante espumas de carbono impregnadas con nanopartículas de goetita
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Janeiro Tato, Iria, López Antón, María Antonia, Baragaño, D., Rodríguez Vázquez, Elena, Pelaez, A.I., García Fernández, Roberto, Gallego, J.R., Martínez Tarazona, María Rosa, Ministerio de Ciencia e Innovación (España), and Principado de Asturias more...
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espumas de carbono ,inmovilización ,goetita ,metales - Abstract
Los autores agradecen la financiación recibida a través de los proyectos de investigación MCI-20-PID2019-106939GB-I00 (AEI/España, FEDER/UE), PID2020-113558RB-C43 (MCIN/ AEI/10.13039/501100011033) e IDI/2021/000031. Diego Baragaño agradece la ayuda Postdoctoral obtenida (Ref. MU-21-UP2021-030 32892642) de la Universidad de Oviedo. more...
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- 2022
13. Espumas de carbono a partir de sacarosa
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López Toyos, Lucía, Janeiro Tato, Iria, Rodríguez Vázquez, Elena, López Antón, María Antonia, Martínez Tarazona, María Rosa, García Fernández, Roberto, Ministerio de Ciencia e Innovación (España), and Principado de Asturias more...
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sacarosa ,materiales macroporosos ,Espumas de carbono - Abstract
Los autores agradecen la financiación de los proyectos PID2020-113558RB-C43 (MCIN/ AEI/10.13039/501100011033) e IDI/2021/000031 y al CSIC por la beca JAE-Intro ICU concedida a Lucía López Toyos (Ref: JAEICU21-INCAR-27) more...
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- 2022
14. Remediación de suelos contaminados con arsénico, selenio y metales mediante espumas de carbono impregnadas con nanopartículas de goetita
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Ministerio de Ciencia e Innovación (España), Principado de Asturias, Janeiro Tato, Iria, López Antón, María Antonia, Baragaño, D., Rodríguez Vázquez, Elena, Pelaez, A.I., García Fernández, Roberto, Gallego, J.R., Martínez Tarazona, María Rosa, Ministerio de Ciencia e Innovación (España), Principado de Asturias, Janeiro Tato, Iria, López Antón, María Antonia, Baragaño, D., Rodríguez Vázquez, Elena, Pelaez, A.I., García Fernández, Roberto, Gallego, J.R., and Martínez Tarazona, María Rosa more...
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- 2022
15. Espumas de carbono a partir de sacarosa
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Ministerio de Ciencia e Innovación (España), Principado de Asturias, López-Toyos, Lucía, Janeiro Tato, Iria, Rodríguez Vázquez, Elena, López Antón, María Antonia, Martínez Tarazona, María Rosa, García Fernández, Roberto, Ministerio de Ciencia e Innovación (España), Principado de Asturias, López-Toyos, Lucía, Janeiro Tato, Iria, Rodríguez Vázquez, Elena, López Antón, María Antonia, Martínez Tarazona, María Rosa, and García Fernández, Roberto more...
- Published
- 2022
16. Sorbentes regenerables basados en espumas de carbono para el control de mercurio en los procesos de producción de energía
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Ministerio de Ciencia e Innovación (España), Principado de Asturias, López-Toyos, Lucía, Rodríguez Vázquez, Elena, López Antón, María Antonia, García Fernández, Roberto, Martínez Tarazona, María Rosa, Ministerio de Ciencia e Innovación (España), Principado de Asturias, López-Toyos, Lucía, Rodríguez Vázquez, Elena, López Antón, María Antonia, García Fernández, Roberto, and Martínez Tarazona, María Rosa more...
- Published
- 2022
17. Eliminación de mercurio en fase gas con sorbentes basados en metales y óxidos metálicos soportados en materiales de carbono
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López Antón, María Antonia, Martínez Tarazona, María Rosa, López Antón, María Antonia [0000-0001-9330-5775], Martínez Tarazona, María Rosa [0000-0002-7331-3134], Antuña-Nieto, Cristina, López Antón, María Antonia, Martínez Tarazona, María Rosa, López Antón, María Antonia [0000-0001-9330-5775], Martínez Tarazona, María Rosa [0000-0002-7331-3134], and Antuña-Nieto, Cristina more...
- Abstract
[EN] This work constitutes a contribution to the knowledge and future development of processes for the reduction of mercury species in the environment, species of known toxicity to human health. Its objectives are circumscribed to those of the Minamata Convention, in force since August 2017, and the first international agreement that obliges all countries that have ratified it to impose measures to control mercury emissions. The work approach also contemplates the fact that mercury not only represents a health risk, but that, in some industrial processes, it is also a technological problem. In CO2 capture and storage processes, and in particular in the condensation process, elemental mercury (Hg0) impurities can damage equipment through corrosion. Furthermore, the presence of Hg0 affects the storage of the condensed CO2, reducing its injectability in the tanks where it is confined. The objective of this research is the elimination of Hg0 in industrial gas streams enriched in CO2 using regenerable sorbents. Up to now, the greatest development in the use of sorbents to capture mercury has been achieved in coal-fired power plants and mainly by injection of single-use activated carbons into the gaseous stream, and subsequent separation of them as waste-containing mercury. In the present work, the use of regenerable sorbents is proposed as an alternative, avoiding the generation of this type of waste. The mercury sorbents used are carbon foams developed from coal and their behavior has been compared to that of a commercial activated carbon considered as a reference. Carbon foams have very interesting thermal, mechanical and electrical properties for different applications, and although they had not been used as mercury sorbents, this work opens the way for their use in this type of application with very promising results. Its properties include open macroporosity, which favours gas circulation through it, making it ideal for use in beds, and modifiable surface characteri, 1. Regenerable noble metal-based sorbents: Their preparation is based on impregnation with a colloidal solution of HAuCl4 in the case of Au and with a solution of AgNO3 for Ag, followed by its reduction to Au0 and Ag0, respectively. The main limitation of noble metal-based sorbents is their price, which makes them often questioned, and forces the balance of benefits obtained from their use to offset the required investments. In this thesis, some approximations have been made, optimizing the dispersion of the metal while maintaining 100% efficiency, and assuming that by combustion, once the sorbent has been exhausted, the noble metal, which represents more than 90% of the total cost, can be recovered. viii 2. Regenerable iron oxide-based sorbents: In the search for alternatives with the same efficiencies and lower cost, sorbents based on iron oxides dispersed on the surface of the same carbon supports as in the case of noble metals have been developed. For this, sorbents impregnated with different iron species (hematite, goethite, magnetite and maghemite), at different concentrations, have been elaborated and evaluated, developing preparation methods that allow obtaining the desired species selectively. The methods are based on impregnation with iron nitrate and subsequent heat treatments. The mercury retention efficiency evaluation has been carried out in a laboratory scale device. It consists of a fixed bed that can be heated to different temperatures, through which synthetic atmospheres are passed, incorporating the gaseous Hg0 generated in a permeation tube. Mercury not retained in the sorbent is recorded in a continuous analyzer, and that which may have been oxidized homogeneously or heterogeneously is retained at the exit of the bed in a resin for later analysis. The results show that sorbents doped with Au reach efficiencies of 100% for a concentration of at least 1% of metal, this efficiency being limited by the particle size, which increases considerably for, [ES] Este trabajo constituye una contribución al conocimiento y futuro desarrollo de procesos para la reducción de las especies de mercurio en el medio ambiente, especies de conocida toxicidad para la salud humana. Sus objetivos se circunscriben a los del Convenio de Minamata, en vigor desde agosto de 2017, y primer acuerdo internacional que obliga a todos los países que lo ratificaron a imponer medidas de control de las emisiones de mercurio. El planteamiento del trabajo contempla, además, el hecho de que el mercurio no solo representa un riesgo para la salud, sino que, en algunos procesos industriales, es también un problema tecnológico. En los procesos de captura y almacenamiento de CO2, y en particular en el proceso de condensación, las impurezas de mercurio elemental (Hg0) pueden dañar los equipos por corrosión. Además, la presencia de Hg0 afecta al almacenamiento del CO2 condensado disminuyendo su inyectabilidad en los depósitos en los que se confina. El objetivo de esta investigación es la eliminación de Hg0 en corrientes gaseosas industriales enriquecidas en CO2 mediante sorbentes regenerables. Hasta el momento, el mayor desarrollo en el empleo de sorbentes para la captura de mercurio se ha logrado en las centrales térmicas de carbón y fundamentalmente por inyección en la corriente gaseosa de carbones activos de un solo uso, y posterior separación de los mismos como residuo conteniendo mercurio. En el presente trabajo se plantea como alternativa el uso de sorbentes regenerables evitándose la generación de este tipo de residuos. Los sorbentes de mercurio se han preparado a partir de materiales de carbono habiéndose desarrollado espumas de carbono a partir de carbón y utilizándose un carbón activo comercial como referencia, comparándose el comportamiento de ambos. Las espumas de carbono presentan propiedades térmicas, mecánicas y eléctricas muy interesantes para diferentes aplicaciones, y, aunque no habían sido utilizadas como sorbentes de mercurio, en este tr, 1. Sorbentes regenerables basados en metales nobles: Su preparación se basa en la impregnación con una disolución coloidal de HAuCl4 en el caso del Au y con una disolución de AgNO3 para la Ag y su reducción a Au0 y Ag0, respectivamente. La principal limitación de los sorbentes basados en metales nobles es su precio, que hace que a menudo sean cuestionados, y que obliga a que el balance de beneficios obtenidos en su utilización deba compensar las inversiones requeridas. En esta tesis se han realizado algunas aproximaciones, optimizando la dispersión del metal manteniendo el 100% eficiencia, y presumiendo que, mediante combustión, una vez el sorbente se ha agotado, pueda recuperarse el metal noble que representa más del 90% del coste total. vi 2. Sorbentes regenerables basados en óxidos de hierro: En la búsqueda de alternativas con las mismas eficiencias y menor coste, se han desarrollado sorbentes basados en óxidos de hierro dispersados en la superficie de los mismos soportes de carbono que en el caso de los metales nobles. Para ello se han preparado y evaluado sorbentes impregnados con distintas especies de hierro (hematita, goethita, magnetita y maghemita), en distintas concentraciones, poniéndose a punto métodos de preparación que permiten obtener la especie deseada de manera selectiva. Los métodos se basan en la impregnación con nitrato de hierro y posteriores tratamientos térmicos. La evaluación de la eficiencia de retención de mercurio se ha llevado a cabo en un dispositivo a escala de laboratorio. Consiste en un lecho fijo que puede ser calentado a diferentes temperaturas, a través del cual se hacen pasar atmósferas sintéticas, a las que se incorpora Hg0 gaseoso generado en un tubo de permeación. El mercurio no retenido en el sorbente se registra en un analizador en continuo, y el que haya podido oxidarse homogénea o heterogéneamente se retiene a la salida del lecho en una resina para su posterior análisis. Los resultados muestran que los sorbentes dopados con more...
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- 2020
18. Effectiveness of amino-functionalized sorbents for co2 capture in the presence of Hg
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Principado de Asturias, López Antón, María Antonia [0000-0001-9330-5775], Martínez Tarazona, María Rosa [0000-0002-7331-3134], Sanz-Pérez, E.S., Lobato Ortega, Belén, López Antón, María Antonia, Arencibia, A., Sanz, R., Martínez Tarazona, María Rosa, Principado de Asturias, López Antón, María Antonia [0000-0001-9330-5775], Martínez Tarazona, María Rosa [0000-0002-7331-3134], Sanz-Pérez, E.S., Lobato Ortega, Belén, López Antón, María Antonia, Arencibia, A., Sanz, R., and Martínez Tarazona, María Rosa more...
- Abstract
The reduction of CO2 emissions is an urgent need that is acknowledged worldwide. Amino-silica sorbents are one of the most promising adsorbents for capturing CO2 from several gas streams due to their excellent textural properties and reversible reactions with CO2. However, gas streams also contain impurities that can affect the retention of CO2 by such sorbents. This study focuses on the effect of the presence of mercury in the gas stream on a series of amino sorbents developed for CO2 capture. Amino-silica adsorbents were functionalized by grafting with aminopropyl-trimethoxysilane (AP) or trimethoxysilylpropyl-diethylenetriamine (DT) and by impregnation with polyethyleneimine (PEI) or tetraethylenepentamine (TEPA). A double functionalization route that combines grafting and impregnation was also assayed. The effect of mercury on the CO2 adsorption capacity of the sorbents was evaluated in a fixed reactor at 40 °C. The double-functionalized adsorbents showed high CO2 uptakes with CO2 adsorption capacities of 5–6 mmol CO2/g (0.15 bar CO2, 40 °C). In addition, their CO2 adsorption capacity was maintained over several cycles. It was established that the presence of mercury undermined the CO2 adsorption capacity of the adsorbents by just 3–16%, demonstrating in general the good selectivity of these materials for CO2, an essential requirement for avoiding the accumulation of mercury during the regeneration process of the solid sorbent and the consequent environmental and technological problems that might ensue. more...
- Published
- 2020
19. Noble metal-based sorbents: A way to avoid new waste after mercury removal
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Principado de Asturias, Rodríguez Vázquez, Elena [0000-0001-6835-0371], López Antón, María Antonia [0000-0001-9330-5775], García Fernández, Roberto [0000-0002-1315-8574], Martínez Tarazona, María Rosa [0000-0002-7331-3134], Antuña-Nieto, Cristina, Rodríguez Vázquez, Elena, López Antón, María Antonia, García Fernández, Roberto, Martínez Tarazona, María Rosa, Principado de Asturias, Rodríguez Vázquez, Elena [0000-0001-6835-0371], López Antón, María Antonia [0000-0001-9330-5775], García Fernández, Roberto [0000-0002-1315-8574], Martínez Tarazona, María Rosa [0000-0002-7331-3134], Antuña-Nieto, Cristina, Rodríguez Vázquez, Elena, López Antón, María Antonia, García Fernández, Roberto, and Martínez Tarazona, María Rosa more...
- Abstract
The development of technologies to control mercury emissions is now a legal requirement imposed by recent international agreements. The use of regenerable sorbents is consistent with this requirement as it allows mercury to be captured from industrial gases without generating new mercury-containing toxic waste. Because regenerable sorbents based on noble metals are often questioned due to the heavy investment they entail, this study assesses the viability of their use in terms of efficiency and cost. Its primary aim is to develop new regenerable sorbents based on an activated carbon support impregnated with Ag in order to compare their cost and behavior in a CO2 enriched gas stream with that of similar materials containing Au. Mercury retention efficiencies of 100 % can be achieved over several adsorption-desorption cycles depending on the type of noble metal used, particle size and impurities in the gas atmosphere. The results suggest that the Hg-Ag amalgamation process differs from the Hg-Au one, in that they show different kinetics of adsorption and temperatures of desorption. The Ag and Au regenerable sorbents developed in this study would be competitive given the environmental and health benefits they offer compared to the single-use activated carbons employed until now at industrial scale. more...
- Published
- 2020
20. Mercury adsorption in the gas phase by regenerable Au-loaded activated carbon foams: a kinetic and reaction mechanism study
- Author
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Ministerio de Economía y Competitividad (España), Principado de Asturias, Rodríguez Vázquez, Elena [0000-0001-6835-0371], López Antón, María Antonia [0000-0001-9330-5775], García Fernández, Roberto [0000-0002-1315-8574], Martínez Tarazona, María Rosa [0000-0002-7331-3134], Antuña-Nieto, Cristina, Rodríguez Vázquez, Elena, López Antón, María Antonia, García Fernández, Roberto, Martínez Tarazona, María Rosa, Ministerio de Economía y Competitividad (España), Principado de Asturias, Rodríguez Vázquez, Elena [0000-0001-6835-0371], López Antón, María Antonia [0000-0001-9330-5775], García Fernández, Roberto [0000-0002-1315-8574], Martínez Tarazona, María Rosa [0000-0002-7331-3134], Antuña-Nieto, Cristina, Rodríguez Vázquez, Elena, López Antón, María Antonia, García Fernández, Roberto, and Martínez Tarazona, María Rosa more...
- Abstract
Mercury has been the focus of environmental concern and scientific research for decades due to the risks associated with its use, release and emission. An international agreement established in 2017 during the UN Minamata Convention highlighted the need for innovative approaches and technology to tackle these problems. The use of regenerable sorbents for mercury removal in the gas phase is a possible solution that can avoid the generation of new mercury-contaminated waste. However, to make significant progress in this field, it is necessary to develop efficient, economic and environmentally friendly sorbents, for which, a good understanding of the mechanism of adsorption in this type of process is needed. In this study, several kinetic models were applied to determine the rate-controlling step in the adsorption process of elemental mercury by regenerable sorbents based on gold. Three diffusional models (Weber and Morris, Bangham and pseudo-first order models) and two adsorptive models (pseudo-second order and Elovich models) were tested. The results of this study show that external diffusion from the gaseous phase to the sorbent particles is the rate-limiting step. The complexity of the process is also reflected in the results obtained, which indicate that pore diffusion plays a significant role over most of the mass transfer zone, while adsorption itself becomes determinant only when the saturation of the sorbent is near. more...
- Published
- 2020
21. Carbon materials loaded with maghemite as regenerable sorbents for gaseous Hg0 removal
- Author
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Principado de Asturias, Rodríguez Vázquez, Elena [0000-0001-6835-0371], López Antón, María Antonia [0000-0001-9330-5775], García Fernández, Roberto [0000-0002-1315-8574], Martínez Tarazona, María Rosa [0000-0002-7331-3134], Antuña-Nieto, Cristina, Rodríguez Vázquez, Elena, López Antón, María Antonia, García Fernández, Roberto, Martínez Tarazona, María Rosa, Principado de Asturias, Rodríguez Vázquez, Elena [0000-0001-6835-0371], López Antón, María Antonia [0000-0001-9330-5775], García Fernández, Roberto [0000-0002-1315-8574], Martínez Tarazona, María Rosa [0000-0002-7331-3134], Antuña-Nieto, Cristina, Rodríguez Vázquez, Elena, López Antón, María Antonia, García Fernández, Roberto, and Martínez Tarazona, María Rosa more...
- Abstract
In a scenario where mercury emission regulations are becoming increasingly stringent, the use of regenerable sorbents is an attractive economic and ecological alternative for the elimination of gaseous mercury. This study attempts to develop cost-effective regenerable sorbents made up of carbon supports loaded with maghemite and evaluate their application for mercury capture in CO2 enriched atmospheres. To achieve this goal, an activated carbon (AC) and a carbon foam (CF) were impregnated with different concentrations of an iron salt and then subjected to thermal treatment to obtain the maghemite oxide. The Hg removal capacity of the prepared sorbents was evaluated at a laboratory-scale at 80 °C under different gas atmospheres. It was found that the characteristics of the carbon support as well as the iron concentration influence the distribution and morphology of the deposited maghemite particles. The CF-derived sorbents exhibited a better Hg0 removal performance than the AC-derived sorbents due to the presence of areas with a high concentration of iron oxide particles on the carbon support, which led to stronger interactions between the Hg and sorbent. The adsorption mechanism seems to occur via an adsorption/oxidation process involving the oxygen lattice of the metal oxide. Consequently, the sorbents lose their Hg retention capacity as the lattice oxygen is consumed. However, the deactivation can be counteracted by adding O2 to the gas stream to regenerate the sorbents. Carbon foams loaded with maghemite possess interesting properties which make them suitable for application at industrial scale. These include their low-cost, design versatility, and easy in-batch producibility. Hence, CF-derived sorbents are a versatile option for Hg capture in regenerable columns, capable of competing with the one-use sorbents, typically injected into flue gas. more...
- Published
- 2020
22. Assessment of mercury pollution sources in beach sand and coastal soil by speciation analysis
- Author
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Consejo Superior de Investigaciones Científicas (España), Ministerio de Economía y Competitividad (España), Principado de Asturias, López Antón, María Antonia [0000-0001-9330-5775], Rodríguez-Gallego, Jose Luis, López Antón, María Antonia, Martínez de la Rosa, Deva, Rodríguez-Valdés, Eduardo, García-González, Nerea, Rodríguez Vázquez, Elena, Martínez Tarazona, María Rosa, Consejo Superior de Investigaciones Científicas (España), Ministerio de Economía y Competitividad (España), Principado de Asturias, López Antón, María Antonia [0000-0001-9330-5775], Rodríguez-Gallego, Jose Luis, López Antón, María Antonia, Martínez de la Rosa, Deva, Rodríguez-Valdés, Eduardo, García-González, Nerea, Rodríguez Vázquez, Elena, and Martínez Tarazona, María Rosa more...
- Abstract
[Background] An essential requisite for controlling and monitoring mercury in the environment is to identify its species in different types of soils and sediments, as this will help not only to establish its mobility in the environment and ecosystem and the degree of its toxicity, but also to establish the source of contamination. The objective of this work was to identify the origin of mercury in beach sands and soil taken from a coastal region with previously high mining and industrial activity by characterizing the mercury species using the technique known as thermal desorption (HgTPD)., [Results] Apart from quartz, the main mineral species identified in the raw sands and soil were calcite, fluorite and barite. The concentration of mercury ranges from 5 to 23 µg g−1, and although it is distributed in different proportions in the function of the size, thermal desorption profiles demonstrated that the mercury species present in the samples do not vary with the mercury concentration and the particle size. By means of HgTPD, mercury oxide (HgO) was identified in the beach sands, whereas mercury sulfide (HgS) was found in the soil sample taken from the vicinity of the beach. Complementary methodologies foster the HgTPD conclusions and verify that mercury is present mostly in insoluble stable (HgS) or low-mobility (HgO) forms in the samples studied. Analyses by ICP-MS after sequential extraction and HPLC separation of mercury species show that inorganic mercury is the predominant form in the samples., [Conclusions] The technique HgTPD is a very useful tool to ascertain the origin of mercury in contaminated beach sands and shoreline soils. In the particular area studied in this work, the species identified indicate that previous mining activity was the source of the mercury and rule out the possibility that contamination is derived from coal combustion activities ongoing in the region. more...
- Published
- 2019
23. Identification of mercury species in minerals with different matrices and impurities by thermal desorption technique
- Author
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Principado de Asturias, López Antón, María Antonia [0000-0001-9330-5775], Martínez Tarazona, María Rosa [0000-0002-7331-3134], Melero, David, Lobato Ortega, Belén, López Antón, María Antonia, Martínez Tarazona, María Rosa, Principado de Asturias, López Antón, María Antonia [0000-0001-9330-5775], Martínez Tarazona, María Rosa [0000-0002-7331-3134], Melero, David, Lobato Ortega, Belén, López Antón, María Antonia, and Martínez Tarazona, María Rosa more...
- Abstract
Because of its low concentration, its unique physico-chemical properties and the analytical difficulties associated with its measurement, the determination of mercury species in solids is not an easy task. Thermal desorption (HgTPD) is an attractive option for the identification of mercury species in solids due to its simplicity and accessibility. However, there are still issues that need to be solved for it to reach its full potential. One such issue is the availability of reference materials that will reproduce real mercury associations. The novelty of this study is the use of six uncommon mercury minerals, taken from around the world, and a sphalerite sample to expand the data base of reference materials for mercury speciation by thermal desorption at programmed temperature. In addition, by using such materials, a number of matrix effects can be ascertained. Different mercury associations were identified depending on the temperature of desorption, thereby validating the thermal desorption as a reliable technique for mercury speciation in solid samples and as a consequence improving the knowledge of the geochemistry of mercury in the environment. more...
- Published
- 2019
24. A candidate material for mercury control in energy production processes: Carbon foams loaded with gold
- Author
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Ministerio de Economía y Competitividad (España), Principado de Asturias, Rodríguez Vázquez, Elena [0000-0001-6835-0371], López Antón, María Antonia [0000-0001-9330-5775], Martínez Tarazona, María Rosa [0000-0002-7331-3134], Antuña-Nieto, Cristina, Rodríguez Vázquez, Elena, López Antón, María Antonia, García Fernández, Roberto, Martínez Tarazona, María Rosa, Ministerio de Economía y Competitividad (España), Principado de Asturias, Rodríguez Vázquez, Elena [0000-0001-6835-0371], López Antón, María Antonia [0000-0001-9330-5775], Martínez Tarazona, María Rosa [0000-0002-7331-3134], Antuña-Nieto, Cristina, Rodríguez Vázquez, Elena, López Antón, María Antonia, García Fernández, Roberto, and Martínez Tarazona, María Rosa more...
- Abstract
Tighter control of pollutant emissions in energy generation from coal combustion is essential for the maintenance of coal as a member of the energy panel in coming years. Coal-fired power plants are the primary source of mercury emission in Europe and the second in the world. This study focuses on the development of regenerable sorbents to mercury capture avoiding the generation of new toxic wastes. The sorbents based on carbon foams impregnated with gold have been optimized to achieve the maximum mercury retention efficiency using the minimum amount of gold. Moreover, the sorbent has been designed to facilitate the recovery of the gold once the sorbent has been exhausted. Although this technology requires a higher initial investment than other alternatives, such as the injection of activated carbons, the apparent high cost of the sorbent is offset by the possibility of using the same material over several cycles. A mercury retention mechanism is proposed based on mercury amalgamation and mercury oxidation/adsorption through the double function of gold and support. The results confirm that the reactions between the mercury and gold depend on the size of the gold nanoparticles and the presence of oxygenated groups on the surface of the carbon support. more...
- Published
- 2018
25. Geochemical speciation of mercury in bauxite
- Author
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Principado de Asturias, López Antón, María Antonia [0000-0001-9330-5775], Martínez Tarazona, María Rosa [0000-0002-7331-3134], Staun, C., Vaughan, J., López Antón, María Antonia, Rumayor Villamil, Marta, Martínez Tarazona, María Rosa, Principado de Asturias, López Antón, María Antonia [0000-0001-9330-5775], Martínez Tarazona, María Rosa [0000-0002-7331-3134], Staun, C., Vaughan, J., López Antón, María Antonia, Rumayor Villamil, Marta, and Martínez Tarazona, María Rosa more...
- Abstract
The presence of trace concentrations of mercury in bauxite is a potential environmental concern in the Bayer alumina refining process. An understanding of the geochemical speciation of mercury in bauxite provides insight into the behavior of mercury in the Bayer process. The speciation of mercury was evaluated using a novel continuous thermal desorption methodology, sequential extractions, alkaline digestion, aqua regia digestion and hydrofluoric acid total dissolution assay. Thermal desorption demonstrated two distinct mercury forms. Labile mercury was found to be present as metacinnabar or organic-associated mercury, while refractory mercury was associated with quartz or other refractory silicates. more...
- Published
- 2018
26. Carbon-based sorbents impregnated with iron oxides for removing mercury in energy generation processes
- Author
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Ministerio de Economía y Competitividad (España), Principado de Asturias, Rodríguez Vázquez, Elena [0000-0001-6835-0371], López Antón, María Antonia [0000-0001-9330-5775], Martínez Tarazona, María Rosa [0000-0002-7331-3134], Rodríguez Trobajo, Jaime, Antuña-Nieto, Cristina, Rodríguez Vázquez, Elena, García Fernández, Roberto, López Antón, María Antonia, Martínez Tarazona, María Rosa, Ministerio de Economía y Competitividad (España), Principado de Asturias, Rodríguez Vázquez, Elena [0000-0001-6835-0371], López Antón, María Antonia [0000-0001-9330-5775], Martínez Tarazona, María Rosa [0000-0002-7331-3134], Rodríguez Trobajo, Jaime, Antuña-Nieto, Cristina, Rodríguez Vázquez, Elena, García Fernández, Roberto, López Antón, María Antonia, and Martínez Tarazona, María Rosa more...
- Abstract
Gaseous phase mercury emissions into the atmosphere from fossil fuel combustion processes for energy production are a matter of serious environmental concern. Several technologies have been studied and proposed to address this problem, but none of them is mature enough from a commercial point of view. This study aims to provide new insights into the interaction between mercury and iron oxides in order to enable the design of cost-effective mercury capture technology based on regenerable sorbents. Different iron oxides supported on an activated carbon were prepared and tested for the removal of elemental mercury (Hg0). It was found that 1) maghemite promoted the removal of mercury to a greater extent than goetite/hematite achieving 100% efficiencies and 2) the mercury-sorbent interaction is determined by the oxygen vacancies present in the iron oxide. The mercury retention efficiency is maintained after the sorbent is regenerated and it is not deactivated by the presence of acid gases. The results obtained with the sorbent loaded with maghemite open new perspectives for the retention of gaseous Hg0, combining high efficiency, good regenerability and lower price in comparison with sorbents developed to date. Once the regeneration capacity is assessed, the adsorption process will be scaled. more...
- Published
- 2018
27. Perspectivas sobre la reducción de emisiones de Mercurio originadas en la producción de energía
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Martínez Tarazona, María Rosa, López Antón, María Antonia, and García Nieves, Roberto
- Published
- 2020
28. A critical study of the thermal desorption technique for the identification of mercury species
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Melero, David, López Antón, María Antonia, Antuña Nieto, Cristina, García, Roberto, and Martínez Tarazona, María Rosa
- Published
- 2019
29. Several approaches on the use of regenerable sorbents for the retention of mercury in the gas phase
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Antuña Nieto, Cristina, Rodríguez Vázquez, Elena, López Antón, María Antonia, García, Roberto, and Martínez Tarazona, María Rosa
- Published
- 2019
30. El mercurio. Sus fuentes de emisión, usos e impactos
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López Antón, María Antonia, Martínez tarazona, María Rosa, López Antón, María Antonia, and Martínez tarazona, María Rosa
- Abstract
Conocido antiguamente como “plata líquida”, “azogue” o “hidrargiro”, el mercurio es un metal que destaca por sus propiedades singulares y su belleza, pero también por su alta toxicidad. Desde la Prehistoria y hasta la actualidad, ha sido utilizado con diversos fines: en los pigmentos de las pinturas rupestres, en ungüentos medicinales (se le ha atribuido incluso el poder de prolongar la vida), en la minería artesanal de oro y plata y en distintos procesos industriales. Su presencia se puede rastrear en multitud de objetos y productos hasta hace poco de usos cotidiano, como termómetros, lámparas fluorescentes, empastes dentales o desinfectantes como la mercromina. Aunque los peligros derivados de su utilización no eran completamente ignorados en el pasado, solo en fechas más recientes se han comenzado a investigar y tomar medidas para el control de sus efectos nocivos en la salud humana y el medio ambiente, a raíz de las graves intoxicaciones que se produjeron en la bahía de Minamata a finales de los años cincuenta en Japón y posteriormente en Iraq. Este libro da una visión general sobre algunos aspectos básicos relacionados con la utilización del mercurio, su comportamiento y toxicidad, destacando el papel de las fuentes industriales de mercurio y las medidas de control de emisiones en dichos procesos. more...
- Published
- 2018
31. Several approaches on the use of regenerable sorbents for the retention of mercury in the gas phase
- Author
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Antuña-Nieto, Cristina, Rodríguez Vázquez, Elena, López Antón, María Antonia, García Fernández, Roberto, Martínez Tarazona, María Rosa, Antuña-Nieto, Cristina, Rodríguez Vázquez, Elena, López Antón, María Antonia, García Fernández, Roberto, and Martínez Tarazona, María Rosa more...
- Published
- 2019
32. Equipment for identifying mercury species in solids
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Rumayor Villamil, Marta, López Antón, María Antonia, Díaz Somoano, Mercedes, and Martínez Tarazona, María Rosa
- Abstract
[EN] The analytical device comprises an solid inlet (1) for the solid sample, a commercial oven (2), an analyzer (4) and a control unit (5). It also comprises a laboratory-assembled oven (additional oven) (6) comprising two chambers, a first chamber (7) connected to the solid inlet (1) for the solid sample and a second chamber (8) connected to the commercial oven (2). The equipment is fitted with a first gas inlet (9) for inert gas, that is located in the additional oven (6), and a second gas inlet (10) for air or oxygen, located in the commercial oven (2). The equipment also comprises three temperature controllers; a first temperature controller (3) in the commercial oven (2), a second temperature controller in the first chamber (7) and a third temperature controller in the second chamber (8). The equipment allows analysis of solid samples., [ES] Equipo de identificación de especies de mercurio en sólidos mediante desorción térmica que permite analizar muestras sólidas y comprende una entrada de la muestra sólida (1), un horno comercial (2), un analizador (4) y una unidad de control (5). Comprende también un horno adicional (6) que está conectado por una primera cámara (7) a la entrada de la muestra sólida (1) y por una segunda cámara (8) al horno comercial (2). El equipo dispone de una primera entrada de gases (9) para gas inerte dispuesta en el horno adicional (6), y una segunda entrada de gases (10) para aire u oxígeno dispuesta en el horno comercial (2). El equipo comprende también un primer controlador de temperatura en la primera cámara (7) del horno adicional, y un segundo controlador de temperatura en la segunda cámara (8) del horno adicional., Consejo Superior de Investigaciones Científicas (España), A1 Solicitud de patente con informe sobre el estado de la técnica more...
- Published
- 2015
33. Mercury policy and regulations for coal-fired power plants
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López Antón, María Antonia [0000-0001-9330-5775], Rallo, Manuela, López Antón, María Antonia, Contreras, M. Luisa, Maroto Valer, Mercedes, López Antón, María Antonia [0000-0001-9330-5775], Rallo, Manuela, López Antón, María Antonia, Contreras, M. Luisa, and Maroto Valer, Mercedes more...
- Abstract
Introduction Mercury is a high-priority regulatory concern because of its persistence and bioaccumulation in the environment and evidence of its having serious adverse effects on the neurological development of children. Discussion Mercury is released into the atmosphere from both natural and anthropogenic sources. Coal-fired utilities are considered to be one of the largest anthropogenic mercury emission sources. The period since the late 1990s has been marked by increasing concern over mercury emissions from combustion systems to the extent that a number of national governments have either already implemented or are in the process of implementing, legislation aimed at enforcing tighter control over mercury emissions and a reduction in mercury consumption. Conclusion This review examines the most important national and international policies and agreements for controlling mercury emissions from coal-fired combustion systems. To provide a global perspective, this study lists the countries with the largest estimated mercury emissions and regulatory efforts to reduce them. more...
- Published
- 2011
34. Impacto ambiental y tecnológico del mercurio en los procesos de oxicombustión del carbón
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Martínez Tarazona, María Rosa, López Antón, María Antonia, Fernández Miranda, Nuria, Martínez Tarazona, María Rosa, López Antón, María Antonia, and Fernández Miranda, Nuria
- Abstract
[EN] The growing demand for energy has led to increasing greenhouse gas emissions (GHG) resulting in significant climate changes with implications at global scale. Within the energy sector, CO2 from coal combustion is the main cause of total GHG emissions. Of the available options for reducing CO2 emissions, carbon capture and storage after oxy-fuel combustion processes, have gained ground as a promising alternative to conventional combustion in air. Oxy-coal combustion technologies ensure a relatively high level of development and exhibit a high versatility when they are implemented in existing facilities. Nevertheless, oxy-fuel processes must still overcome relevant environmental and technological challenges before their operation comes into effect at industrial scale. Of these challenges, a lack of knowledge of the behavior of mercury species during the CO2 capture and purification stages is one of the most notable. The change of the flue gas composition from oxy-coal combustion, as a result of the partial recycling of the stream and the injection of oxygen as comburent may affect the mercury speciation which in turn could have a negative effect on the mercury retention efficiency of the gas cleaning systems. Although from a qualitative point of view, environmental problems originating from the presence of mercury in the flue gas and combustion by-products in oxy-fuel facilities are similar to those produced in a conventional air combustion plant, the presence of trace amounts of elemental mercury (Hg0) causes significant operational problems during the compression of CO2 in that it can accumulate in quantities sufficient to cause a severe attack on and failure of the cryogenic aluminium heat exchangers. In view of the complexity and importance of mercury in these processes, the aim of the present work has been, on the one hand, to study and assess the behavior of mercury in the main gas cleaning systems of coal-fired power plants, and, on the other hand, to eval, The results showed that flue gas composition had a significant influence on the speciation of mercury. The homogeneous oxidation of mercury was affected by the presence of NO and NO2, whose capacity to oxidize mercury depended on the concentration of CO2. The presence of a high amount of H2O, which is characteristic of oxy-coal atmospheres, also influenced mercury oxidation. Assessment of the mercury retention capacity of SCR systems showed there was a high degree of oxidation when an enriched-CO2 stream was employed. As regards mercury retention by the catalysts, a high concentration of H2O and CO2 was found to decrease the number of active sites available for Hg adsorption. Under oxycombustion conditions, fly ashes favored mercury oxidation though its retention predominantly depended on the amount of unburned carbon in the fly ashes. The main mercury species identified in fly ashes were mercury bound to organic matter (Hg-OM) and HgS, whose stability in water confirmed their low degree of lixiviation. The capture of mercury in the WFDG device was significantly affected by the composition of the flue gas. High concentrations of CO2 produced in the oxy-coal combustion processes reduced the pH of the gypsum slurry, thereby decreasing the transformation of oxidized mercury (Hg2+) to Hg0. Mercury retention occurred mainly in the liquid fraction as Hg2+, although the characteristics and composition of the limestones may modify the partitioning of mercury in the by-products of the scrubber. A new sorbent based on a carbonaceous support impregnated with gold nanoparticles demonstrated a 100% efficiency in capturing elemental mercury under oxy-combustion conditions at the end of the cycle. The presence of SO2 and HCl in the gas stream did not have a negative effect on the sorbent. In fact, its retention capacity was improved. The presence of Hg0 in the flue gas decreased the CO2 retention capacity of some solid sorbents employed for CO2 capture, suggesting that competitive more...
- Published
- 2017
35. A New Approach for Retaining Mercury in Energy Generation Processes: Regenerable Carbonaceous Sorbents
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Ministerio de Economía y Competitividad (España), Consejo Superior de Investigaciones Científicas (España), Fernández Miranda, Nuria, Rodríguez Vázquez, Elena, López Antón, María Antonia, García Fernández, Roberto, Martínez Tarazona, María Rosa, Ministerio de Economía y Competitividad (España), Consejo Superior de Investigaciones Científicas (España), Fernández Miranda, Nuria, Rodríguez Vázquez, Elena, López Antón, María Antonia, García Fernández, Roberto, and Martínez Tarazona, María Rosa more...
- Abstract
The energy production processes from fossil fuels represent the first anthropogenic source of mercury emissions in Europe and the second in the world. Among the different possibilities that can be posed to reduce these emissions, this work focuses on the use of regenerable sorbents based on gold nanoparticles dispersed on activated carbon foam. The use of regenerable sorbents would not only allow the objective of reducing mercury emissions, but also avoiding the generation of new toxic wastes. The results showed a retention efficiency of 100% and a retention capacity close to 600 µg·g−1 over several cycles of regeneration. Moreover, acid gases did not poison the support. It was observed that mercury capture in this simulated oxy-combustion atmosphere was a consequence of two mechanisms: (1) the amalgamation of elemental mercury and elemental gold and (2) the oxidation of elemental mercury in the presence of HCl, with the subsequent retention of the oxidized mercury on the surface of the activated carbon foam. The nanodispersion of gold on such supports involves a high initial investment. However, this would be counterbalanced by the remarkable regeneration capacity of the sorbent and the possibility of recovering all the materials used. more...
- Published
- 2017
36. Equipo de identificación de especies de mercurio en sólidos
- Author
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Rumayor Villamil, Marta, López Antón, María Antonia, Díaz Somoano, Mercedes, and Martínez Tarazona, María Rosa
- Abstract
Equipo de identificación de especies de mercurio en sólidos mediante desorción térmica que permite analizar muestras sólidas y comprende una entrada de la muestra sólida (1), un horno comercial (2), un analizador (4) y una unidad de control (5). Comprende también un horno adicional (6) que está conectado por una primera cámara (7) a la entrada de la muestra sólida (1) y por una segunda cámara (8) al horno comercial (2). El equipo dispone de una primera entrada de gases (9) para gas inerte dispuesta en el horno adicional (6), y una segunda entrada de gases (10) para aire u oxígeno dispuesta en el horno comercial (2). El equipo comprende también un primer controlador de temperatura en la primera cámara (7) del horno adicional, y un segundo controlador de temperatura en la segunda cámara (8) del horno adicional., Consejo Superior de Investigaciones Científicas (España), A1 Solicitud de patente con informe sobre el estado de la técnica more...
- Published
- 2015
37. Retención de compuestos gaseosos de Hg, As y S en sorbentes sólidos: aplicación a la combustión y gasificación de carbón
- Author
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López Antón, María Antonia and Martínez Tarazona, Rosa María
- Subjects
Selenium ,Selenio ,Mercurio ,Mercury ,complex mixtures ,Sorbents ,Arsenic ,Arsénico ,Coal combustion - Abstract
Tesis doctoral presentada en el Departamento de Química Orgánica e Inorgánica de la Universidad de Oviedo, 2004., Most elements can be found in coal in different proportions and modes of ocurrence. Although some of them occur in concentrations at the trace element level, they are considered of environmental concern. During coal combustion and gasification, different proportions of mercury, arsenic and selenium toxic compounds, may evaporate or condense on the minute fly ash particles in different proportions. They are then emitted with flue gases into the environment. Mercury and selenium compounds are mostly or entirely emitted in the vapour phase, whereas arsenic is mainly carried out with flue gases in the particulate matter. Although the evaluation of the emissions of these elements from coal utilization processes is at present an issue for discussion, coal combustion may be considered an important antropogenic source of these elements for the environment. However, there is a lack of a similar knowledge concerning the behaviour of these elements at the reducing conditions typical of coal gasification processes. To avoid possible problems from the accumulated emission of toxic trace elements, efficient gas cleaning systems capable of reducing the mercury, arsenic and selenium content in gases produced in coal combustion and gasification need to be developed. The systems currently being studied and developed for gas cleaning, focus on the use of solids sorbents. For this reason the main objective of this project was to develop and ascertain the capability of i) different activated carbons, some of them impregnated with sulphur, and ii) fly ash wastes produced in coal utilization processes, to retain mercury, arsenic and selenium compounds. To attain this objective an experimental study in typical coal combustion and gasification atmospheres was carried out. Different variables were evaluated for the capture. The Hg, Se and As species considered were those theoretically predicted according with thermodynamic equilibrium data. Two commercial activated carbons: Norit RB3 and Norit RBHG3 and three carbons prepared for the activation of a pyrolysed coal (CA, CASU and CAPSU) were evaluated. The fly ashes used came from different sources. The fluidised bed combustion of a bituminous coal (CTP), and a pulverized combustion plant (CTA) fed using with high rank coals. These materials were characterised before and after the experiments by different techniques. The efficiency of the sorbents in different conditions was determined in a laboratory scale reactor, using synthetic gas mixtures, typical of coal combustion and gasification processes. Retention capacity means of was determined by analyzing the solid sorbent after the experiment by means of ICP-MS, ICP-MS/HG, AAS/HG, AAS/CV and an automatic mercury analyser, AMA 254. The results obtained indicated that commercial activated carbons are the best sorbents for elemental mercury retention, while for HgCl2 retention capacity depended on the conditions and type of activated carbon and fly ashes. The retention of arsenic and selenium is always more effective in fly ashes than in activated carbons. In this work it was observed that retention in both coal a combustion and gasification atmosphere is similar, except in case of selenium where retention in a gasification atmosphere is significantly higher than in a combustion atmosphere. Probably, these retentions take place through different mechanisms, but in most of the cases a chemical reaction such as S-Hg, Ca/Fe-As and Ca/Fe-Se occurs. more...
- Published
- 2014
38. Equipment for identifying mercury species in solids
- Author
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Rumayor Villamil, Marta, López Antón, María Antonia, Díaz Somoano, Mercedes, Martínez Tarazona, María Rosa, Rumayor Villamil, Marta, López Antón, María Antonia, Díaz Somoano, Mercedes, and Martínez Tarazona, María Rosa more...
- Abstract
[EN] The analytical device comprises an solid inlet (1) for the solid sample, a commercial oven (2), an analyzer (4) and a control unit (5). It also comprises a laboratory-assembled oven (additional oven) (6) comprising two chambers, a first chamber (7) connected to the solid inlet (1) for the solid sample and a second chamber (8) connected to the commercial oven (2). The equipment is fitted with a first gas inlet (9) for inert gas, that is located in the additional oven (6), and a second gas inlet (10) for air or oxygen, located in the commercial oven (2). The equipment also comprises three temperature controllers; a first temperature controller (3) in the commercial oven (2), a second temperature controller in the first chamber (7) and a third temperature controller in the second chamber (8). The equipment allows analysis of solid samples., [ES] Equipo de identificación de especies de mercurio en sólidos mediante desorción térmica que permite analizar muestras sólidas y comprende una entrada de la muestra sólida (1), un horno comercial (2), un analizador (4) y una unidad de control (5). Comprende también un horno adicional (6) que está conectado por una primera cámara (7) a la entrada de la muestra sólida (1) y por una segunda cámara (8) al horno comercial (2). El equipo dispone de una primera entrada de gases (9) para gas inerte dispuesta en el horno adicional (6), y una segunda entrada de gases (10) para aire u oxígeno dispuesta en el horno comercial (2). El equipo comprende también un primer controlador de temperatura en la primera cámara (7) del horno adicional, y un segundo controlador de temperatura en la segunda cámara (8) del horno adicional. more...
- Published
- 2016
39. Equipo de identificación de especies de mercurio en sólidos
- Author
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Rumayor Villamil, Marta, López Antón, María Antonia, Díaz Somoano, Mercedes, Martínez Tarazona, María Rosa, Rumayor Villamil, Marta, López Antón, María Antonia, Díaz Somoano, Mercedes, and Martínez Tarazona, María Rosa more...
- Abstract
Equipo de identificación de especies de mercurio en sólidos mediante desorción térmica que permite analizar muestras sólidas y comprende una entrada de la muestra sólida (1), un horno comercial (2), un analizador (4) y una unidad de control (5). Comprende también un horno adicional (6) que está conectado por una primera cámara (7) a la entrada de la muestra sólida (1) y por una segunda cámara (8) al horno comercial (2). El equipo dispone de una primera entrada de gases (9) para gas inerte dispuesta en el horno adicional (6), y una segunda entrada de gases (10) para aire u oxígeno dispuesta en el horno comercial (2). El equipo comprende también un primer controlador de temperatura en la primera cámara (7) del horno adicional, y un segundo controlador de temperatura en la segunda cámara (8) del horno adicional. more...
- Published
- 2016
40. Impact of Oxy-Fuel Conditions on Elemental Mercury Re-Emission in Wet Flue Gas Desulfurization Systems
- Author
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Fernández Miranda, Nuria, López Antón, María Antonia, Torre Santos, Teresa, Díaz Somoano, Mercedes, Martínez Tarazona, María Rosa, Fernández Miranda, Nuria, López Antón, María Antonia, Torre Santos, Teresa, Díaz Somoano, Mercedes, and Martínez Tarazona, María Rosa more...
- Abstract
This study evaluates some of the variables that may influence mercury retention in wet flue gas desulfurization (WFGD) plants, focusing on oxy-coal combustion processes and differences when compared with atmospheres enriched in N2. The main drawback of using WFGD for mercury capture is the possibility of unwanted reduction of dissolved Hg2+, leading to the re-emission of insoluble elemental mercury (Hg0), which decreases efficiency. To acquire a better understanding of the mercury re-emission reactions in WFGD systems, this work analyses different variables that influence the behavior of mercury in slurries obtained from two limestones, under an oxy-combustion atmosphere. The O2 supplied to the reactor, the influence of the pH, the concentration of mercury in the gas phase, and the enhancement of mercury in the slurry were the variables considered. The study was performed at laboratory scale, where possible reactions between the components in the scrubber can be individually evaluated. It was found that in an oxy-combustion atmosphere (mostly CO2), the re-emission of Hg0 is lower than under a N2-enriched atmosphere, and the mercury is mainly retained as Hg2+ in the liquid phase. more...
- Published
- 2016
41. Effect of Hg on CO2 capture by solid sorbents in the presence of acid gases
- Author
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Ministerio de Economía y Competitividad (España), Fernández Miranda, Nuria, García López, Susana, López Antón, María Antonia, Martínez Tarazona, María Rosa, Sanz Pérez, E.S., Maroto Valer, Mercedes, Ministerio de Economía y Competitividad (España), Fernández Miranda, Nuria, García López, Susana, López Antón, María Antonia, Martínez Tarazona, María Rosa, Sanz Pérez, E.S., and Maroto Valer, Mercedes more...
- Abstract
Carbon dioxide Capture and Storage (CCS) is the main technology to mitigate CO2 emissions in the energy sector, being reversibly adsorption of CO2 on solid sorbents one of the most promising processes to be operated in post-combustion technology. Given the current state of development a number of problems still need to be addressed before solid sorbents can be employed for CO2 capture. One of these problems is the effect that some impurities in the flue gas have on the behavior of the sorbents. The aim of this work is to identify and evaluate the role of mercury species in flue gas containing acid gases on the performance of sorbents employed for CO2 capture. The influence of mercury on CO2 retention capacity was assessed using three commercial activated carbons (NORIT GCN, AIRPEL 1DS-1 and AIRPEL ULTRA DS5) and two mesostructured silica sorbents containing amino groups (SBA-PEI and SBA-TEPA). When Hg0 was incorporated into the gas stream, the behavior of the sorbents was modified. In general, the CO2 adsorption capacity decreased in the presence of Hg0 suggesting competition by both compounds for the same active sites. The strongest effect of Hg0 on CO2 adsorption was observed in the activated carbon with the highest micropore volume. more...
- Published
- 2016
42. The application of regenerable sorbents for mercury capture in gas phase
- Author
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Ministerio de Economía y Competitividad (España), López Antón, María Antonia, Fernández Miranda, Nuria, Martínez Tarazona, María Rosa, Ministerio de Economía y Competitividad (España), López Antón, María Antonia, Fernández Miranda, Nuria, and Martínez Tarazona, María Rosa more...
- Abstract
Mercury is a well-known toxic element, and flue gas streams emitted from coal-fired utilities are one of the largest anthropogenic sources of this element. This study briefly reviews the proposed technologies for reducing mercury emissions from coal combustion, focusing on an emerging process which involves the use of regenerable sorbents and especially those loaded with noble metals. Among the mercury species formed during coal combustion, elemental mercury is the most difficult to remove from the flue gases due to its low reactivity and insolubility in water. The widespread interest in using regenerable sorbents with metals is due to their ability to retain elemental mercury. With this technology, not only can efficiencies of 100 % be reached in the retention of elemental mercury but also a way to avoid the generation of new wastes loaded with mercury. This study considers the main aspects that must be taken into account when developing effective regenerable sorbents for mercury capture, with special attention to sorbents containing noble metals. The characteristics of this process are compared with those of other processes in a more advanced state of development. more...
- Published
- 2016
43. Impact of a semi-industrial coke processing plant in the surrounding surface soil: Part I: Trace element content
- Author
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Díaz Somoano, Mercedes, López Antón, María Antonia, Suárez Ruiz, Isabel, Calvo Díez, Montserrat, Suárez, Sonia, García Fernández, Roberto, and Martínez Tarazona, María Rosa
- Subjects
Trace elements ,Soil contamination ,Organic particulates ,Coking plant - Abstract
Soil pollution by anthropogenic activities is an important environmental issue especially in industrialized countries. The objective of this study is to evaluate the environmental impact of a coal conversion plant on the surrounding soil by measuring the spatial distribution of particulate organic carbon and determining the concentration of trace elements (part I) and PAHs (part II). The results indicate that the surface soil presents an increase in the content of organic particulates with values exceeding 80% vol. at the centre of the coking plant facilities. The concentrations rapidly decrease as the distance from the plant increases. Although concentrations of As, Cd, Co, Cr, Cu, Hg, Ni, Pb, and Zn in most cases did not exceed the environmental limits, a clear relationship was established between the presence of some of these elements and the high values of particulate organic carbon content found in the proximity of the plant., This work was carried out with the financial support of ECSC (7220-PR/070). J.L. Mijares is acknowledged for providing information in relation to the coking plant activities. more...
- Published
- 2012
44. As and Se interactions with fly ashes
- Author
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López Antón, María Antonia, Díaz Somoano, Mercedes, and Martínez Tarazona, María Rosa
- Subjects
inorganic chemicals ,Selenium ,Selenio ,Coal ,fungi ,technology, industry, and agriculture ,Cenicas volantes ,Carbón ,respiratory system ,Fly ashes ,complex mixtures ,Arsenic ,Arsénico - Abstract
[EN] Arsenic and selenium are toxic element s present in coal in trace concentrations that may be emitted to the environment during coal conversion processes. However, it is possible to retain volatile arsenic and selenium compounds in the fly ashes originated by the process, the proportions retained depending on the characteristics of the ashes and process conditions. This work is focused on the capture of these elements in fly ashes in simulated coal combustion and gasification atmospheres in laboratory scale reactors., [ES] El arsénico y el selenio son elementos tóxicos presentes en el carbón en concentraciones del orden de las trazas que pueden ser emitidos al medio ambiente durante los procesos de conversión del carbón. Sin embargo, los compuestos de arsénico y selenio pueden ser retenidos en las cenizas volantes originadas en el propio proceso en distint as proporciones dependiendo de las características de las cenizas y las condiciones del proceso. Este trabajo se centra en la captura de estos elementos en cenizas volantes en una atmósfera de combustión y gasificación de carbón en reactores a escala de laboratorio., Este trabajo fue financiado por la Comunidad Europea (ECSC Proyectos 7220-ED/069 y 722- ED/095). more...
- Published
- 2012
45. Interacciones As y Se con cenizas volantes
- Author
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López Antón, María Antonia, Díaz Somoano, Mercedes, and Martínez Tarazona, María Rosa
- Subjects
Selenium ,Selenio ,Coal ,Cenicas volantes ,Carbón ,Fly ashes ,Arsenic ,Arsénico - Abstract
[EN] Arsenic and selenium are toxic element s present in coal in trace concentrations that may be emitted to the environment during coal conversion processes. However, it is possible to retain volatile arsenic and selenium compounds in the fly ashes originated by the process, the proportions retained depending on the characteristics of the ashes and process conditions. This work is focused on the capture of these elements in fly ashes in simulated coal combustion and gasification atmospheres in laboratory scale reactors. [ES] El arsénico y el selenio son elementos tóxicos presentes en el carbón en concentraciones del orden de las trazas que pueden ser emitidos al medio ambiente durante los procesos de conversión del carbón. Sin embargo, los compuestos de arsénico y selenio pueden ser retenidos en las cenizas volantes originadas en el propio proceso en distint as proporciones dependiendo de las características de las cenizas y las condiciones del proceso. Este trabajo se centra en la captura de estos elementos en cenizas volantes en una atmósfera de combustión y gasificación de carbón en reactores a escala de laboratorio. Este trabajo fue financiado por la Comunidad Europea (ECSC Proyectos 7220-ED/069 y 722- ED/095). more...
- Published
- 2012
46. A comparison of devices using thermal desorption for mercury speciation in solids
- Author
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Rumayor Villamil, Marta, López Antón, María Antonia, Díaz Somoano, Mercedes, Maroto Valer, Mercedes, Richard, J-H., Biester, H., Martínez Tarazona, María Rosa, Rumayor Villamil, Marta, López Antón, María Antonia, Díaz Somoano, Mercedes, Maroto Valer, Mercedes, Richard, J-H., Biester, H., and Martínez Tarazona, María Rosa more...
- Abstract
The goal of this work is to emphasize the reliability of the thermal desorption technique in identifying mercury species. The analysis of mercury species in solids is essential for assessing the risk of disposal or re-use of mercury-contaminated materials. This study evaluates the accuracy and reliability of thermal desorption as a technique for identifying mercury species by means of different thermo-desorption devices. For this purpose, mercury species present in samples related with coal utilization processes were identified. Three devices were compared for analyzing samples free of carbon or with a low carbon content (fly ashes, gypsums and soils), and a new equipment was developed to analyze samples with a high carbon content (coal). In spite of the fact that the first three devices employ different experimental conditions (i.e., heating rate, gas flow and carrier gas), the mercury species identified in the samples were comparable in all cases. The need for new equipment for mercury speciation in materials containing carbon was a consequence of interferences produced from the pyrolysis products of the organic matter. The new device consists of two furnaces and two gas inlets to allow thermal oxidation of organic pyrolysis products and the identification of mercury species in carbonaceous samples. This new approach offers the application of thermal desorption to mercury speciation in all types of materials contaminated with mercury. more...
- Published
- 2015
47. Mercury Retention by Fly Ashes from Oxy-fuel Processes
- Author
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Ministerio de Economía y Competitividad (España), Fernández Miranda, Nuria, Villamil Rumayor, Marta, López Antón, María Antonia, Díaz Somoano, Mercedes, Martínez Tarazona, María Rosa, Ministerio de Economía y Competitividad (España), Fernández Miranda, Nuria, Villamil Rumayor, Marta, López Antón, María Antonia, Díaz Somoano, Mercedes, and Martínez Tarazona, María Rosa more...
- Abstract
The objective of this study is to determine the mechanism of mercury retention in fly ashes, the main solid waste from coal combustion power plants, and to evaluate the interactions between the type of mercury and fly ashes. The work was based on the results of mercury speciation in the gas and the solid fly ash before and after mercury retention. The identification of the mercury species in the gas was performed using previously validated methods, but the speciation of the mercury retained in the fly ashes was carried out using a mercury temperature-programmed desorption technique (HgTPD) still under development. The fly ashes were sampled from conventional coal combustion in air and oxy-combustion power plants. The main mercury species identified in the raw fly ashes and after they were subjected to an oxy-combustion atmosphere were mercury bound to organic matter and HgS, the ratio of these species depending on the characteristics of the ashes. The results obtained indicate that fly ashes are the route of mercury oxidation in an oxy-combustion atmosphere, although they hardly retain any mercury unless the unburned carbon content is high. HgTPD analysis shows that the main mechanism for mercury retention in the fly ashes is via the carbon matter. more...
- Published
- 2015
48. Study of Mercury Adsorption by Low-Cost Sorbents Using Kinetic Modeling
- Author
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Ministerio de Economía y Competitividad (España), Fuente Cuesta, Aida, Diamantopoulou, Ir., López Antón, María Antonia, Díaz Somoano, Mercedes, Martínez Tarazona, María Rosa, Sakellaropoulos, G.P., Ministerio de Economía y Competitividad (España), Fuente Cuesta, Aida, Diamantopoulou, Ir., López Antón, María Antonia, Díaz Somoano, Mercedes, Martínez Tarazona, María Rosa, and Sakellaropoulos, G.P. more...
- Abstract
In order to make further progress in the field of reducing mercury emissions to the atmosphere, it is necessary to develop efficient and economically viable technologies. Low-cost solid sorbents are a candidate technology for mercury capture. However, kinetic models are required to predict the adsorption mechanism and to optimize the design of the process. In this study, several low-cost materials (biomass chars) were evaluated for the removal of gas-phase elemental mercury and kinetic studies were performed to investigate the mechanism of mercury adsorption. These kinetic studies were also used to predict the behavior of a fixed-bed column. The models applied were pseudo-first-order and pseudo-second-order equations, Fick’s intraparticle diffusion model, and the Yoon–Nelson model. The chars obtained from the gasification of plastic-paper waste demonstrated the best behavior for mercury capture because of their high Brunauer–Emmett–Teller surface area, large total pore volume (mainly micropore volume), and high chlorine content. The Yoon–Nelson model provided a better fitting for the samples with low mercury retention capacities, while in the case of the plastic-paper chars, all of the models provided relatively accurate predictions because their highly microporous structure retarded the internal diffusion process and their increased chlorine content enhanced chemisorption on their surface. more...
- Published
- 2015
49. Mercury oxidation in catalysts used for selective reduction of NOx (SCR) in oxy-fuel combustion
- Author
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Fernández Miranda, Nuria, López Antón, María Antonia, Díaz Somoano, Mercedes, Martínez Tarazona, María Rosa, Fernández Miranda, Nuria, López Antón, María Antonia, Díaz Somoano, Mercedes, and Martínez Tarazona, María Rosa more...
- Abstract
Emissions of mercury (Hg) and their control are a well-known problem for conventional coal combustion power plants but they still represent a challenge for relatively new technologies such as the oxy-combustion. In oxy-fuel combustion systems it is important that Hg be in its oxidized form (Hg2+) because in the form of elemental mercury (Hg0), it can damage the CO2 compression units. In conventional air combustion some catalysts used in selective catalytic reduction (SCR) of NOx could also co-benefit Hg oxidation. This study evaluates the oxidation of Hg in the presence of several SCR catalysts under an oxy-combustion atmosphere focusing on the main differences with conventional air coal combustion. In the experimental conditions of this study, a higher mercury oxidation was observed in the CO2-enriched atmosphere due to the fact that in this atmosphere the conversion of NOx was lower, which resulted in a higher concentration of NO and NO2 free to homogeneously oxidize mercury. In oxy-combustion conditions the high amount of CO2 and H2O present may block the active sites for mercury adsorption. Moreover, the differences between the active sites of catalysts based on V/W/TiO2 and Fe/Zeolite with/without Mn as doping agent were eclipsed by the effect of the flue gas composition. more...
- Published
- 2015
50. A new approach to mercury speciation in solids using a thermal desorption technique
- Author
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Rumayor Villamil, Marta, López Antón, María Antonia, Díaz Somoano, Mercedes, Martínez Tarazona, María Rosa, Rumayor Villamil, Marta, López Antón, María Antonia, Díaz Somoano, Mercedes, and Martínez Tarazona, María Rosa more...
- Abstract
Identification of the chemical form of mercury in coals and during the entire combustion process is essential for successfully controlling mercury emissions. However, the speciation of mercury in coal and, in general, in carbonaceous samples has so far proved elusive because of the limitations of current analytical techniques as a consequence of the detection limits of the equipment or interferences originating from the matrix. In this work a new device based on temperature programmed desorption (HgTPD) has been developed to identify mercury species in carbonaceous materials. The samples studied were coals of different rank obtained from around the world and activated carbons that had previously been used as mercury sorbents in simulated coal combustion atmospheres. The mercury species present in both types of sample were identified without any interference from the matrix. This achievement is extremely important as it will contribute to a better understanding of (i) the behavior of mercury species in coal utilization processes and (ii) the retention mechanisms and subsequent stability of the mercury species captured by carbon sorbents. more...
- Published
- 2015
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