On porous networks development of activated carbon cloths: influence of the precursor and activation process strategy

M. E. RAMOS; J. D. GONZALEZ; P. R. BONELLI; A. L. CUKIERMAN

Buenos Aires, Argentina

Workshop; Seventh J.J. Giambiagi Winter School; 2005

Departamento de Física J.J: Giambiagi, FCEyN-UBA

Activated carbon cloths (ACC) have attracted growing interest in recent years because they offer several technological advantages over traditional forms of this widely used porous material. The small diameter of the fibers in ACC and pores direct connection to the environment minimize diffusion effects and lead to faster adsorption rates, higher efficiency, larger capacity for adsorption, and low pressure drops in flow units. Besides, ACC can be arranged in different stable configurations, and their contiguous nature is suited for electrical applications. ACC are promoting a new conception in equipment design. The aim of the present work is to gain insight into the influence of the precursor?s intrinsic characteristics and activation process strategy on the development of porous networks of ACC. Pristine and regenerated cellulose in the form of woven cloths are used as precursors. The chemical activation process is applied employing solutions of different chemicals as activating reagents. Thermal treatment of the impregnated precursors is carried out in a bench-scale installation, basically consisting of a stainless steel tubular reactor operated under a flow of inert gas, and externally heated. Main experimental conditions investigated include: concentration of the chemical reagents, final temperature and time of the thermal treatment stage, heating schedule. Surface properties of the ACC, specific surface area, total pore volume, and micropore (< 2 nm) volume, are determined from N2 (-196 °C) adsorption isotherms. Surfaces of the precursors and ACC are also visualized by scanning electron microscopy. Porous networks development of the ACC and their characteristics are discussed in terms of the precursor, activating agent, and operating conditions used. In addition, to explore the feasibility of in situ regeneration of spent ACC after their use in removal of volatile organic compounds by Joule effect heating, macroscopic measurements of the electrical resistance of the ACC are carried out.