Removal of pharmaceutical industry pollutants by coal-based activated carbons

Peer ReviewedPostprint (author's final draft

Impact of oxy-fuel combustion gases on mercury retention in activated carbons from a macroalgae waste: Effect of water

The aim of this study is to understand the different sorption behaviors of mercury species on activated carbons in the oxy-fuel combustion of coal and the effect of high quantities of water vapor on the retention process. The work evaluates the interactions between the mercury species and a series of activated carbons prepared from a macroalgae waste (algae meal) from the agar–agar industry in oxy-combustion atmospheres, focussing on the role that the high concentration of water in the flue gases plays in mercury retention. Two novel aspects are considered in this work (i) the impact of oxy-combustion gases on the retention of mercury by activated carbons and (ii) the performance of activated carbons prepared from biomass algae wastes for this application. The results obtained at laboratory scale indicate that the effect of the chemical and textural characteristics of the activated carbons on mercury capture is not as important as that of reactive gases, such as the SOx and water vapor present in the flue gas. Mercury retention was found to be much lower in the oxy-combustion atmosphere than in the O2 + N2 (12.6% O2) atmosphere. However, the oxidation of elemental mercury (Hg0) to form oxidized mercury (Hg2+) amounted to 60%, resulting in an enhancement of mercury retention in the flue gas desulfurization units and a reduction in the amalgamation of Hg0 in the CO2 compression unit. This result is of considerable importance for the development of technologies based on activated carbon sorbents for mercury control in oxy-combustion processes.The authors acknowledge the financial support provided by the National Research Program under the project CTM2011–22921 and the Program FEDER of the Principado de Asturias 2007–2013 under the Project PC10-40.Peer reviewe

Dual role of copper on the reactivity of activated carbons from coal and lignocellulosic precursors

The synthesis of copper-doped activated carbons from different origin (i.e., lignocellulosic and bituminous coal) by a wet impregnation and low temperature calcination procedure has been explored, as well as the role of copper particles on the physicochemical and structural features of the resulting materials. The textural characterization and isothermal reactivity analysis of the pristine and doped activated carbons have shown that the role of copper during the calcination step strongly depended on the nature of the carbon matrix. Copper impregnation of a coal-derived activated carbon catalyzed the air gasification of the material at a very low temperature (i.e., 325 °C), bringing about the development of microporosity on the doped carbon. In contrast, when copper was immobilized on a lignocellulose-derived activated carbon, the metallic species act as combustion retardant during the calcination step, protecting the carbon matrix during the catalytic gasification. In both cases, the resulting materials displayed a homogenous distribution of copper within the carbon matrix, while preserving large textural properties.The authors thank the Spanish MICINN for financial support (projects CTM2008-01956/TECNO and Acción Integrada AIB2010PT-00209). MH thanks CSIC for a postdoctoral contract. MA thanks FCT for her PhD fellowship (SFRH/BD/71673/2010). The authors also thank Cordex for kindly providing the sisal residues.Peer reviewe

Carbón activado con alto contenido en nitrógeno y libre de cromo, método de obtención y sus múltiples usos

La presente invención está dirigida a un nuevo carbón activado que se caracteriza por su alto contenido en nitrógeno, así como al método de obtención del mismo a partir de residuos sólidos industriales de curtido vegetal de piel bovina, o de piel bovina sin curtir libre de taninos, desgrasada y deshidratada con acetona, comprendiendo el método las siguientes etapas: triturar el material de partida después de secarlo en el caso de que sea necesario para obtener un precursor, someter el precursor a tratamiento termoquímico de activación con hidróxido de potasio, lavar el material con ácido clorhídrico y agua destilada, y secar el carbón activado. Asimismo, la presente invención trata del uso del carbón activado en procesos de retención de gases, como es la captura de CO2 o la purificación de mezclas CO2/H2.Peer reviewedConsejo Superior de Investigaciones Científicas (España)A1 Solicitud de patente con informe sobre el estado de la técnic

Conventional and microwave pyrolysis of a macroalgae waste from the Agar–Agar industry. Prospects for bio-fuel production

[EN] A comparative study of the pyrolysis of a macroalgae industrial solid waste (algae meal) in an electrical conventional furnace and in a microwave furnace has been carried out. It was found that the chars obtained from both pyrolyses are similar and show good properties for performing as a solid bio-fuel and as a precursor of activated carbon. Bio-oils from conventional pyrolysis have a greater number of phenolic, pyrrole and alkane compounds whereas benzene and pyridine compounds are more predominant in microwave pyrolysis with a major presence of light compounds. The bio-gas fraction from microwave pyrolysis presents a much higher syngas content (H2 + CO), and a lower CO2 and CH4 proportion than that obtained by conventional pyrolysis. Yields are similar for both treatments with a slightly higher gas yield in the case of microwave pyrolysis due to the fact that microwave heating favors heterogeneous reactions between the gases and the char.The financial support for this work was provided by the operating program FEDER of Principado de Asturias 2007–2013 under the Project PC10-40. The authors thank the industry for providing the macroalgae industrial residue used in this work.Peer reviewe

Carbón activado con alto contenido en nitrógeno y libre de cromo, método de obtención y múltiples usos

[EN] The present invention relates to a novel activated charcoal which is characterised by having high nitrogen content, and to the method for obtaining same from solid industrial waste from vegetable tanning of bovine hides, or from tannin-free non-tanned bovine hide, which has been defatted and dehydrated with acetone, said method including the following steps: grinding up the starting material after drying same if necessary in order to obtain a precursor, subjecting the precursor to thermochemical activation treatment with potassium hydroxide, washing the material with hydrochloric acid and distilled water, and drying the activated charcoal. Likewise, the present invention relates to the use of activated charcoal in gas-retention processes, such as the capture of CO2 or the purification of CO2/H2 mixes.[ES] La presente invención está dirigida a un nuevo carbón activado que se caracteriza por su alto contenido en nitrógeno, así como al método de obtención del mismo a partir de residuos sólidos industriales de curtido vegetal de piel bovina, o de piel bovina sin curtir libre de taninos, desgrasada y deshidratada con acetona, comprendiendo el método las siguientes etapas: triturar el material de partida después de secarlo en el caso de que sea necesario para obtener un precursor, someter el precursor a tratamiento termoquímico de activación con hidróxido de potasio, lavar el material con ácido clorhídrico y agua destilada, y secar el carbón activado. Asimismo, la presente invención trata del uso del carbón activado en procesos de retención de gases, como es la captura de CO2 o la purificación de mezclas CO2/H2Peer reviewedConsejo Superior de Investigaciones Científicas (España)A1 Solicitud de patente con informe sobre el estado de la técnic

Hydrochars from industrial macroalgae “Gelidium Sesquipedale” biomass wastes

Macroalgae wastes from the Agar–Agar industry were used as a feedstock to obtain hydrochars by means of hydrothermal carbonization. The effect of temperature (200 °C and 230 °C) and time (2 h and 6 h) on the yield, higher heating value (HHV) and chemical-morphological-textural properties of the hydrochars was studied. The carbon content and the higher heating value were observed to increase with the hydrothermal carbonization. The hydrochars yields (up to 60%) were much higher than yields obtained using conventional char (27.5–33.5%). The hydrochar obtained at 230 °C and after 6 h showed a HHV of 23.25 MJ/kg, which is similar to that of lignite HHV. The H/C and O/C atomic ratios decreased as a consequence of the dehydration and decarboxilation reactions. Hydrothermal carbonization barely changed the vegetal structure of the macroalgae waste. The hydrochars were found to be essentially meso-macroporous with average pore sizes of up to 110.5 nm.The authors thank the company ROKO-AGAR, Asturias-Spain, for providing of the industrial residue, algae meal.Peer reviewe

Valorization of solid wastes from the leather industry: Preparation of activated carbon by thermochemical processes

En: 1st Spanish National Conference on Advances in Materials Recycling and Eco – Energy Madrid, 12-13 November 2009.-- Editors: F. A. López, F. Puertas, F. J. Alguacil and A. Guerrero.-- 4 pages, 4 tables, 4 figures.A study has been conducted to establish conditions for the pyrolysis of leather wastes (LW) in order to recover gas and condensable fractions. The pyrolized sample was later activated by means of alkaline hydroxides in order to develop its porous structure. The activated carbons prepared are microporous with specific surface area values up to 2700 m2/g.R.R.Gil. is grateful to Miquel Farrés Rojas S.A. for financial support through project PETRI (MICINN, PET2007_0421_02).Peer reviewe

Removal of an analgesic using activated carbons prepared from urban and industrial residues

[EN] The removal of an analgesic drug (acetaminophen) from water was investigated using activated carbons prepared from different residues, namely urban wastes (post-consumer plastics), and agro-industrial residues (cork powder and peach stones), comparing their adsorption capacity with that of commercially available carbonaceous adsorbents. The prepared carbon samples were evaluated on the basis of their adsorption capacities and kinetic performances, which were linked with their different properties. The samples prepared from chemical activation of the biomass residues show reasonably high removal efficiencies along with fast rate of adsorption, which are in fact comparable to commercial carbons. The analysis of the carbon samples after adsorbing the analgesic showed that adsorbent–adsorbate affinity is stronger in hydrophobic carbons of basic character that contain a well-developed microporosity. These characteristics are however not sufficient for an overall performance of a carbon in acetaminophen removal. The carbon must also have a well interconnected pore network (to facilitate the accessibility of acetaminophen molecules, thus speeding up adsorption kinetics) and an adequate chemical composition, which ultimately leads to a high adsorption capacity.COA thanks the financial support of MICINN (project CTM2008-01956/TECNO). Salmon & Cia (NORIT) is kindly acknowledged for providing NS sample.Peer reviewe

Activated carbons from lignocellulosic wastes from the extraction of tannins

En: 1st Spanish National Conference on Advances in Materials Recycling and Eco – Energy Madrid, 12-13 November 2009.-- Editors: F. A. López, F. Puertas, F. J. Alguacil and A. Guerrero.-- 4 pages, 3 figures, 5 tables.This paper studies the possibility of obtaining activated carbons from lignocellulosic wastes. Three types of residues, obtained from chestnut shells, acacia pods and grape pips, were studied. To achieve our aim, several parameters commonly used in thermo-chemical processes (pyrolysis, alkaline activation) were evaluated: heating rate, final temperature and maintenance time of final temperature in the pyrolysis, final activation temperature, inert gas flow and the ratio between the activating agent and the sample.Peer reviewe