REGENERATION OF PAN-BASED ACTIVATED CARBON-FIBERS BY THERMAL TREATMENTS IN AIR AND CARBON-DIOXIDE

PAN-based activated carbon fibers were saturated by dye adsorption and then were regenerated by thermal treatment in carbon dioxide and in a ir. The dye adsorption and the regeneration were carried out in severa l cycles. The changes in fiber physical properties and the capacity of dye adsorption will be discussed. Activated carbon fibers regenerated in air had greater dye adsorption and weaker mechanical properties th an those regenerated in carbon dioxide. The preferred orientation chan ged slightly during air reactivation, but it decreased gradually after carbon dioxide regeneration. The regeneration processes led to a decr ease in the weight and degradation of mechanical properties, but the p rocesses increased the capacity of dye adsorption. After the second re generation, the dye adsorption capacity of activated carbon fibers tha t were recycled by air regeneration was 15% higher than those that wer e recycled by carbon dioxide regeneration. But, after the third regene ration, the fibers recycled by air regeneration lost their mechanical properties. For carbon dioxide regeneration, fibers retained satisfact ory mechanical properties even after the fourth regeneration. This stu dy indicates that multiple effective applications can be accomplished with carbon dioxide treatment in place of air regeneration. The struct ural changes of activated carbon fiber during different regenerations are proposed.