Summary: In this paper, have been prepared and characterized advanced carbonaceous materials, such as coal airgel monolithic. These materials can be prepared from the polycondensation of certain organic monomers using the sol-gel method. Once the gel organic, it is subject to a supercritical drying so as not to destroy its nascent porous texture and carboniza under an inert atmosphere at high temperatures. Subsequently, the Airgel coal can be activated to increase their surface area and porosity. Basically, airgel coal have a lattice structure formed by the nano-sized primary particles which are interconnected. With regard to its porous structure, the micropores are related to the structure intrapartícula, while the meso-macroporos are the spaces between particles, which is, essentially, that has left the solvent. Therefore, it is possible to control the concentration of micropores and mesoporos independently. This is an advantage of airgel porous materials such as coal. Since the porous texture can be devised and control at the nano-scale, these materials are classified as nanostructured materials. Other advantages of these materials is to be gained with a high purity and with different forms: powder, spheres, movies or monoliths. For all these characteristics airgel the monolithic coal can be used as adsorbents in various applications, such as the elimination of volatile organic compounds (VOC) air. The study of the removal of VOCs has a great interest because of the harmful effects of these pollutants, even at low concentrations. VOCs are emitted from a wide variety of anthropogenic sources: combustion, storage and transport of fuels, the use of solvents and industrial emissions. These compounds play a key role in the formation of tropospheric ozone and other oxidants in the atmosphere that may lead to photochemical smog [1]. The growing evidence of the environmental significance of these contaminants has changed traditional strategies for managing air quality. They have recently been incorporated into the Spanish legal system through royal decrees or laws [2] several European Directives [3] which includes explicitly the VOC. As discussed above, for the removal of VOCs air is important to use adsorbents with a high volume of micropores, as it is there where the adsorption. Because the recovery of adsorbent and the VOC is produced through a process of desorption (passing a flow of gas through the adsorbent), it is necessary to control other parameters textural. Thus, to obtain a coal with a high capacity for work-in other words, so that it can be used in repeated cycles adsorción-desorción-, should desorber the maximum amount of VOCs before withheld. In this connection, we must control the distribution of pore size to allow for a rapid kinetic processes adsorción - desorción. Moreover, when working with high flows of gas, it is necessary to use beds of adsorbents with a suitable form. Its design should allow sufficient contact time for the adsorption of VOCs without incurring at the same time, a high pressure drop across the bed. For this reason, in addition, the monolithic airgel coal is suitable for this application. The objective of this PhD thesis is the study of the preparation and characterization of airgel monolithic as adsorbents for use of organic compounds known as BTX (benzene, toluene and xylenes), which are related to the volume of traffic in urban areas and the use of solvents and paint 8 s indust 114d rials. In preparing the airgel monolithic coal has been used various catalysts, acidic or basic, and solvents in order to study their effect on the surface properties, textural and mechanical end of the materials. The goal is to get adsorbents with adequate porosity for good adsorción - desorción of BTX. Moreover, the mechanical properties of coal airgel monolithic obtained are also important, since they must be able to withstand certain mechanical caused both by their storage as a filler in columns which will be submitted to the weight of adsorbent, for the tensions caused when used in applications where vibration or movement taking place in the bed. The work developed during the conduct of this Doctoral Thesis has been organized in different chapters whose contents are as follows: Chapter II is an introduction to the properties and the process of synthesis of airgel coal. In Chapter III describes the preparation of airgel monolithic coal from the synthesis of the carbonization of organic airgel obtained from mixtures of resorcinol-formaldehído in the presence of a catalyst. Later, some of these monoliths were activated with CO2 at high temperature to develop their porosity. It also describes the techniques used for the characterization of samples by adsorption gas (N2 and CO2), porosimetría mercury, scanning electron microscopy (SEM), thermogravimetry (TG), dispersion rayos-Xa angle small and large (small - and wide angle X-ray scattering, SAXS-WAXS) and measure the mechanical properties. Finally, as described study of the adsorption of BTX in dynamic regime. In Chapter IV describes the study, combining the techniques mentioned above, changes in surface area and porous texture of a monolithic Airgel coal and its activated with CO2. The methodology described here will be used to study the surface area and porosity of the rest of the materials. In Chapter V discusses the changes induced in the surface area and porous texture of airgel monolithic coal obtained by using various catalysts (basic and acidic) and various dilutions in the initial mixture. In Chapter VI is studying the surface area and porosity of a series of airgel coal synthesized by changing the solvent used in the initial mixture. In Chapter VII discusses the mechanical properties of coal prepared airgel monolithic. Finally, in Chapter VIII deals with the discussion of the results obtained during the adsorption of BTX in dynamic regime, through the preparation of columns filled with various airgel studied. Chapter IX is a comprehensive summary in English of the earlier chapters while Chapter X contains a copy of the publications produced to date with some of the work described in this report. These publications were performed in the Carbon magazine and the Journal of Physical Chemistry B. REFERENCES 1. Atkinson, R., Atmospheric Environment 2000, 34, 2063. 2. Ratification of the Protocol to the
1979 Convention on transboundary air pollution over long distances on reducing acidification, eutrophication and ozone in the troposphere, done in Gothenburg -Suecia- on November 30, 1999. 3. Http://www.derecho.com/xml/disposiciones/min/disposicion.xml?id_disposicion=99323&desde=min 4. Directives 94/63, 99/13 http://www.europarl.europa.eu/factsheets/4_9_2_es.htm
