Valorization of used paper cups into high-surface-area activated carbon by microwave-assisted pyrolysis and Taguchi optimization

Used disposable paper cups (UDPCs) are difficult to recycle because of their polyethylene-lined composite structure. In this study, activated carbon (AC) was produced from UDPCs by microwave-assisted pyrolysis (MAP), and the effects of activation conditions were evaluated using the Taguchi method. The influence of microwave power, activating agent, impregnation ratio, and activation stage on the textural properties of the obtained carbons was investigated. The highest BET surface area was obtained for sample S7-K1, reaching 1226.6 m 2 /g. Overall, KOH activation and one-stage treatment produced more favorable porous structures than NaOH activation and two-stage treatment. The results demonstrate that MAP is a promising route for converting UDPC waste into high-surface-area AC and provide useful insight into the optimization of process parameters for this difficult-to-recycle waste stream.