Author(s):
Valente Nabais, Joao 
; Carrott, Manuela ; Carrott, Peter ; Luz, vania ; Ortiz, Angel
Date: 2006
Persistent ID: http://hdl.handle.net/10174/6576
Origin: Repositório Científico da Universidade de Évora
Subject(s): activated carbons; adsorption
Description
Porous materials are usually heterogeneous both structurally and energetically. Activated carbon
fibres (ACFs) are relatively novel fibrous adsorbents produced for example from pith, cellulose,
lignocellulose, phenol resin and polyacrylonityile (Peebles, 1995; Ryu, 1999). ACFs show important
advantages with respect to conventional activated carbons. Among these advantages it is worth
noting their high adsorption capacity and easiness to handle. Their main inconvenience lays on the
difficulty of choosing adequate activating agents and activation conditions that are required in order
to maintain the fibrous morphology.
The adsorption capacity of ACFs depends on many factors, such as raw materials, activation
process, pore structure and surface functionalities (Suffet, 1981; Park, 1999). Surface roughness is
an important factor that influences the adsorption properties of an activated carbon. Fractal
dimension is a measure of roughness of a surface. The use of the fractal concept is becoming very
popular as a tool to characterize the texture of complex materials, such as porous solids. The fractal
properties of these porous systems were determined by means of several techniques such as gas
adsorption, mercury porosimetry and Small-Angle X-Ray Scattering (SAXS and SANS).
Kenaf is an herbaceous annual plant that belongs to the family of Malvaceae. Kenaf possesses
both, long and short fibre. The aim of this work is to study the influence of the preparation conditions
on the fractal dimension and porous texture of ACFs prepared from long fibres of kenaf by physical
activation using carbon dioxide as activating agent.
* Author
