A method to characterise the chemical and physical properties of activated fibres

摘要

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