Preparation and characterisation of activated carbon from waste tea using K2CO3

Biomasses and their wastes have been used to produce various materials including activated carbons (ACs). The properties of the ACs mostly depend on the production method and the type of the raw material. Waste tea that is a biomass as a precursor was employed to prepare activated carbon (AC) in accordance with the conventional method using potassium carbonate (K2CO3). The effects of various process parameters such as carbonisation temperature and period, impregnation ratio and period on the characteristics of the final product were determined. The ACs were characterised in terms of the BET surface area, the true density, the pore volumes, chemical structure and surface morphology. The maximum surface area of the AC was 1722 m2/g produced at 900 °C and impregnation ratio of 1.0. The pore volumes of the samples were found out according to the Non Local Density Functional Theory (NLDFT) method. To produce the AC with high micropore volume fraction, 800 °C is the best convenient temperature for the experiments performed at impregnation ratios of 1.0, 1.5 and 2.0. The BET surface area and the mesopore volume fractions of the AC were substantially increased at 900 °C. The results showed that both the carbonisation temperature and impregnation ratio noticeably affected the micro and mesopore volumes as well as the BET surface area.

► Activated carbons were prepared from combination of the waste tea and K2CO3 according to the conventional method.
► Carbonisation temperature and initial loading of K2CO3 play crucial roles on the amount of final product and its properties.
► Majority of the micropores is formed at the temperatures between 500 °C and 800 °C.
► The waste tea is a potential biomass to produce low cost AC with high surface area and pore volume.