Impact of storage conditions on preparation of activated carbon from sheep wool fibres

In the European Union, up to 200 thousand tons (Zoccola et al., 2015) of sheep wool fibres, that are not used for textile fabrication, are a secondary by-product with wide field of application possibilities, including preparation of activated carbon. Taking into account, that wool fibres can be stored for long time, under impact of the local climate conditions (including low temperatures) before their application, for example, under variety of temperature, presence of air and light, different moisture conditions, it is necessary to estimate the impact of wool’s storage conditions on the preparation of activated carbon. In the present work, various parameters, such as, temperature, presence of air and daylight as well as humidity, were selected for comparison. After storage of wool fibres under selected various conditions, thermogravimetry/differential thermal analysis (TG/DTA) followed by with Fourier transform infrared (FTIR) spectrometry were used in order to estimate the impact of each parameter on the thermal decomposition processes: release of moisture, sulphur and nitrogen containing compounds and oxidative degradation followed by release of carbon dioxide. It was estimated, that one year of storage under varying conditions does not significantly affect the thermal decomposition properties of the wool fibres. However, minor impact of humidity absorbed from air on wool is observed. Wool samples that were stored at elevated humidity gave higher residual carbon yield (R) in comparison to the fibres stored in dry conditions. The obtained results are used to develop recommendations for preparation of activated carbon from wool fibres and for its application in air filtrating systems.