Obtención de gas de síntesis por tratamiento térmico en microondas de biomasa y biogás

En este trabajo se estudia la pirólisis, tanto en microondas como en horno eléctrico, de un residuo procedente de la industria del café, con objeto de comparar la influencia del calentamiento en las características de las fracciones resultantes. La alta proporción de gas de síntesis (H2 + CO) obtenida con el microondas (hasta del 73%) es debida al hecho que la auto-gasificación del carbonizado con el CO2 liberado y que la descomposición catalítica de CH4 se ven favorecidas por este tipo de calentamiento.Así, los experimentos de estas dos últimas reacciones llevadas a cabo de manera individual, con ambos sistemas de calentamiento, demuestran que se dan mayores conversiones en el microondas. En el caso de la descomposición de CH4, la conversión, que inicialmente alcanza valores próximos al 100%, experimentaun descenso importante al cabo de pocos minutos como consecuencia de la formación de depósitos de carbono que bloquean los centros activos de la superficie del catalizador. Sin embargo, una combinación de ambas reacciones, i.e. reformado de CH4 con CO2, mejora el proceso de conversión de CH4 a H2, debido a que el CO2 gasifica los depósitos de carbono generados, permitiendo una regeneración “in situ” del catalizador. Estos resultados han servido como punto de partida para el desarrollo de un nuevo procedimiento que permitiría convertir biogás en gas de síntesis

Oxygen-Induced Decrease in the Equilibrium Adsorptive Capacities of Activated Carbons

Special attention was paid in this work to the role of surface chemistry in the adsorption of phenol and salicylic acid onto activated carbons. To this end, two commercial activated carbons (granular and powdered) were oxidised using ammonium peroxodisulphate [(NH 4 ) 2 S 2 O 8 ] and nitric acid in different concentrations. The structural and chemical properties of the oxidised adsorbents were characterised via nitrogen adsorption isotherms measured at −196°C and Boehm titrations. Phenol adsorption from solution at low concentration was studied at room temperature without specific pH control of the solution. The results showed a significant reduction in the adsorptive capacities towards phenol of the activated carbons as the oxygen content of the latter increased. However, very little effect was observed towards the retention of salicylic acid. The decrease in adsorptive capacity depended not only on the amount of oxygen per unit mass of activated carbon, but also on the textural properties of the latter

Influence of oxygen-containing functional groups on active carbon adsorption of selected organic compounds

International audienc

Effect of microwave and conventional regeneration on the microporous and mesoporous network and on the adsorptive capacity of activated carbons

International audienc

Microwave-induced regeneration of activated carbons polluted with phenol. A comparison with conventional thermal regeneration

International audienc

Kinetics of naphthalene adsorption on an activated carbon: Comparison between aqueous and organic media

International audienc

Characterization of Activated Carbons by the BET Equation — An Alternative Approach

The adsorption isotherms of nitrogen at 77 K have been determined on two series of activated carbons and two samples of activated carbon fibres. The carbons were highly microporous and contained varying amounts of different forms of microporosity. Characterization of the carbons was undertaken using an alternative linear form of the BET equation and the results of the BET parameters obtained have been compared with those obtained from the usual classical linear form of the equation. The surface areas calculated from the two linear forms were similar while the C values were quite different. The C values obtained from the alternative linear form appeared to be more reasonable, being consistent with and related to the microporous character of these carbons. The alternative linear form gave BET plots which were more sensitive to deviations from linearity allowing the relative pressure range for the application of the BET equation to be determined without any ambiguity and more precisely

High value carbon materials from PET recycling

International audienc