Activated Carbon Fibers Prepared from a Phenolic Fiber by Supercritical Water and Steam Activation

Abstract

Supercritical water (SCW) and steam were used to prepare activated carbon fibers (ACFs) to study the different behaviors of these two agents. The results showed that activation with SCW is much faster than with steam and that the lower activation energy observed when SCW is used suggests that the mechanism of gasification with SCW and with steam is different. All the ACFs prepared showed a highly developed micropore structure, with a large specific surface area. The ACFs prepared with SCW had a smaller micropore volume with a broader pore size distribution. In contrast, the ACFs prepared with steam had many small micropores. With SCW, external gasification was greater than with steam, fibers with smaller diameters being obtained, although these latter maintained their structure and their mechanical properties were scarcely altered. However, with steam, external gasification was less marked, but the fibers became fragile and friable.

Preparation of pore-size controllable activated carbon fibers from bamboo fibers with superior performance for xenon storage

“…The most common procedure for preparation of ACFs is physical activation with supercritical water steam or superheated water steam [12,13]. However, it is difficult to get a steady steam flow in physical activation, which may cause an inconsistent quality of ACFs for different batches.…”

Adsorption of phenol on supercritically activated carbon fibres: Effect of texture and surface chemistry

“…In this communication, we compare carbon fibres activated by supercritical fluids [4,5] with conventionally activated carbon fibres obtained from the same precursor. The purpose of the work was to investigate the effect of the activation process on the texture and surface chemistry of the carbon fibres, and the influence of textural and surface chemical properties on the adsorption of phenol.…”

Supercritical Regeneration of an Activated Carbon Fiber Exhausted with Phenol

“…Consequently, when the regeneration procedure of an ACF is performed with supercritical fluids, the textural properties of the ACF may be changed, which would play an important role in the recovery of the adsorption capacity. Although the temperatures at which the gasification of similar fibers begins have been previously probed to be higher than the regeneration temperatures used herein [28,29], the mere exposure of the ACF to CO 2 and water above their critical points may cause certain changes in its porosity.…”

“…Supercritical fluids can be used to prepare ACFs [28,29]. In this application, supercritical fluids react with a raw carbonized fiber at temperatures above 700 • C. The fiber is gasified and its porosity is increased, hence becoming an ACF.…”