A novel method for production of activated carbon from waste tea by chemical activation with microwave energy

摘要

This study presents the production of activated carbon from waste tea. Activated carbons were prepared by phosphoric acid activation with and without microwave treatment and carbonisation of the waste tea under nitrogen atmosphere at various temperatures and different phosphoric acid/precursor impregnation ratios. The surface properties of the activated carbons were investigated by elemental analysis, BET surface area, SEM, FTIR. Prior to heat treatment conducted in a furnace, the mixture of the waste tea and H_3PO_4 was treated with microwave heating. The maximum BET surface area was 1157 m~2/g for the sample treated with microwave energy and then carbonised at 350 ℃. In case of application of conventional method, the BET surface area of the resultant material was 928.8 m~2/g using the same precursor and conditions. According to the Dubmin-Radushkevich (DR) method the micropore surface area for the sample treated with microwave energy was higher than the sample obtained from the conventional method. Results show that microwave heating reasonably influenced the micropore surface area of the samples as well as the BET surface area. The samples activated were also characterised in terms of the cumulative pore and micropore volumes according to the BJH, DR and t-methods, respectively.