Influence of cuticle layers, temperatures and activators on the properties of size-controllable tubular activated carbon powder from wool waste under air flow

Waste wool have successfully been used to prepare activated carbon powders (ACPs) via chemical activation and carbonization under air flow. Effects of cuticle layers and experimental parameters on the properties of ACPs were analyzed. Cuticle layers showed little relations with tube formation but affected the thermal, textural and morphological properties of ACPs. While, carbonization temperature was the key factor affecting ACPs properties. High carbonization temperature decreased the tube, pore-size and crystallinity of ACPs but increased their specific surface areas (SBET). The tube-size and wall-thickness of obtained ACPs were controllable by the temperature, which ranged between 2.367–4.500 μm and 10.729–18.833 μm, respectively. ACPs exhibited thermal stableness with less than 50% weight loss. However, functional groups on wool surface changed after carbonization. Among all samples, ACPs activated with 30% ZnCl2 and carbonized at 500 °C under air had a much higher SBET of 533.17 m2 g−1 and larger pore volume of 0.359 cm2 g−1.