Abstract:

Porous carbon materials were prepared by hydrothermal carbonization (HTC) and KOH activation of camphor leaves and camellia leaves. The morphology, pore structure, chemical properties and CO₂ capture ability of the porous carbon prepared from the two leaves were compared. The effect of HTC temperature on the structure and CO₂ adsorption properties was especially investigated. It was found that HTC temperature had a major effect on the structure of the product and the ability to capture CO₂. The porous carbon materials prepared from camellia leaves at the HTC temperature of 240 °C had the highest proportion of microporous structure, the largest specific surface area (up to 1823.77 m²/g) and the maximum CO₂ adsorption capacity of 8.30 mmol/g at 25 °C under 0.4 MPa. For all prepared porous carbons, simulation results of isothermal adsorption model showed that Langmuir isotherm model described the adsorption equilibrium data better than Freundlich isotherm model. For porous carbons prepared from camphor leaves, pseudo-first order kinetic model was well fitted with the experimental data. However, for porous carbons prepared from camellia leaves, both pseudo-first and pseudo-second order kinetics model adsorption behaviors were present. The porous carbon materials prepared from tree leaves provided a feasible option for CO₂ capture with low cost, environmental friendship and high capture capability.

Key words: Porous carbon, Hydrothermal carbonization, KOH activation, CO₂ adsorption