Preparation of porous carbon from hydrothermal treatment products of modified antibiotic mycelial residues and its use in CO2 capture

Abstract

Antibiotic mycorrhizal residues (AMR) are valuable organic wastes but have become a significant environmental and economic challenge due to their potentially hazardous nature and high treatment costs. In this study, an environmentally friendly and low-cost in situ nitrogen-doped porous carbon material was successfully prepared by hydrothermal carbonisation combined with KOH activation for efficient CO₂ capture. The obtained material was systematically characterized and tested, and its physical and chemical properties were analyzed. By adjusting the activation temperature from 600 to 800 °C, the prepared porous carbon materials exhibited different specific surface areas (648.41–1712.72 m²/g), pore volumes (0.310–0.879 cm³/g), and the nitrogen was uniformly distributed in the carbon skeleton. The optimal N-doped porous carbon demonstrated the adsorption capacities of 3.99 mmol g⁻¹ at 25 ℃ and 5.35 mmol g⁻¹ at 0 ℃ under 1 bar. In addition, the prepared adsorbents exhibited excellent CO₂/N₂ selectivity, high isosteric heat, and good cyclic stability. These excellent CO₂ adsorption properties were attributed to the highly developed microporous structure of the materials and the uniformly distributed nitrogen functional groups in the carbon skeleton. Overall, the results highlight the great potential of this class of heteroatom-doped novel carbon materials as selective CO₂ adsorbents, providing a practical way to seek efficient CO₂ abatement solutions.