A method to characterise the chemical and physical propertiesof activated fibres

摘要

The physical and chemical properties of any activated carbon fibre depend on the elaboration process and can be modified byrngas-solid interactions during storage. In order to determine the specific characteristics of each fibre, a characterisationrnprotocol has been written. This protocol can be useful to understand and to explain any change that may occur after a specificrntreatment or a storage. It can help as well to predict the behaviour of fibres in given conditions. The protocol proposedrnenumerates the techniques adapted to characterise activated fibres. The main characteristics concerned are: hygroscopicity,rnnature and localisation of functional groups and active sites on the fibres, specific area and pore size distribution, surfacernmorphology. For the chemical characterisation, Boehm titration, thermodesorption, thermo-gravimetry, pH-metric titration,rnionic chromatography, Electron Spectrometry for Chemical Analysis have been carried out. Microscopy, isotherms ofrnnitrogen adsorption obtained by volumetric method, X-rays diffraction at low incidence angle made possible structural andrngeometrical determination. The method proposed is illustrated by an example: the characterisation of an impregnatedrnactivated fibre. This characterisation leads to a complete interpretation of the impregnation process. The characterisationrnprotocol can be applied to any activated carbons, either as activated fibres, or as granulated products.