Carbon materials loaded with maghemite as regenerable sorbents for gaseous Hg0 removal
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 supp...
| Autores: | , , , , |
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| Tipo de recurso: | artículo |
| Estado: | Versión aceptada para publicación |
| Fecha de publicación: | 2020 |
| País: | España |
| Institución: | Consejo Superior de Investigaciones Científicas (CSIC) |
| Repositorio: | DIGITAL.CSIC. Repositorio Institucional del CSIC |
| OAI Identifier: | oai:digital.csic.es:10261/200429 |
| Acceso en línea: | http://hdl.handle.net/10261/200429 |
| Access Level: | acceso abierto |
| Palabra clave: | Mercury Regenerable sorbent Maghemite-loaded support Carbon foams |
| Sumario: | 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. |
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