Biomass-based hierarchical porous carbon with ultrahigh surface area for super-efficient adsorption and separation of acetone and methanol

•A cost-effective strategy to develop low-cost biomass-based carbon materials were prepared.•The highest surface area of hierarchical porous carbon is up to 3936 m2 g−1.•The porous carbon exhibits record-high acetone and methanol adsorption capacity at 25 °C.•The oxygen groups can enhance the acetone and methanol uptake at relatively low pressure.•The narrow micropore determines the acetone/methanol selectivity at relatively low pressure. In this study, biomass-based hierarchical porous carbons (HPCs) were synthesized by developing a cost-effective strategy that combines pyrolysis with KOH activation. The highest surface area of HPCs is up to 3936 m2 g−1, which presents record-high acetone (26.1 mmol g−1 at 18 kPa) and methanol (46.9 mmol·g−1 at 15 kPa) adsorption capacity at 25 °C. Based on experiments and molecular simulations, the total pore volume mainly determines adsorption amount of acetone and methanol at relatively high pressure. However, the oxygen groups can provide adsorption sites for acetone and methanol at relatively low pressure, which is attributed to electrostatic interaction between gas molecules and carbon frameworks. Additionally, the narrow micropore determines the acetone/methanol selectivity at relatively low pressure, and the oxygen groups have no benefit effect on acetone/methanol selectivity. Therefore, this work provides theoretical and experimental support for the design, preparation, and application of VOCs adsorbents.