Hydrothermal pretreatment for controlling bamboo biomass composition and regulating pore structure of bamboo-based activated carbon for CO2 adsorption

Activated carbon with a narrow distribution of ultra micropores is regarded as a promising CO₂ adsorbent. Although chemical activation increases ultra microporosity, it entails high cost, equipment corrosion, and limited scalability. In this study bamboo was used as the precursor, and hydrothermal pretreatment was introduced prior to carbonization and steam activation to regulate the 0.5–0.7 nm pore-size distribution by adjusting the cellulose/lignin ratio. Biomass composition analysis together with N₂/CO₂ adsorption measurements was employed to establish the composition-structure-performance linkage. Results show that the sample derived from bamboo hydrothermally pretreated at 180 °C for 6 h, is featured with abundant micropores, with a distribution centered at 0.5–0.7 nm and a specific surface area of 1025 m²/g, achieving a CO₂ adsorption capacity of 3.91 mmol/g at 273 K and 1 bar. Overall, this work demonstrates a scalable, reagent-free physical-activation pathway that regulates the narrow distribution of ultra micropores, delivering CO₂ adsorbents suitable for energy and industrial systems.