Amino-modified mesoporous carbon material for CO₂ adsorption in tunnel engineering: materials characterization and application prospects

Developing efficient materials for capturing and storing CO₂ is crucial in addressing the environmental crisis caused by excessive CO₂ emissions. This paper presents the synthesis of amino-modified mesoporous carbon materials with high specific surface areas and efficient adsorption capabilities. The materials were synthesized using resol as the carbon source, F127 as the soft template agent, dicyandiamide as the amino-modified material, and a mixture of ethanol and water as the solvent. The structure and morphology of the amino-modified mesoporous carbon materials were characterized using N₂ adsorption/desorption, X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), and transmission electron microscopy (TEM). The CO₂ adsorption performance and mechanism of the materials were also investigated. The potential application of amino-modified mesoporous carbon materials in carbon capture technology, specifically in shield tunnels, was discussed. The results showed that the amino-modified mesoporous carbon materials exhibited a large surface area (656 m²/g), a highly ordered mesoscopic structure (P6mm space group), and high nitrogen content, which resulted in excellent CO₂ adsorption capability. At 25 ℃, it demonstrated a CO₂ adsorption capacity of 2.85 mmol/g, indicating both high adsorption capacity and rapid adsorption rate. Additionally, the material exhibited good selectivity for CO₂. Moreover, it is estimated that every 5 g of synthesized amino-modified mesoporous carbon material can adsorb 0.627 g of CO₂. The implementation of amino-modified mesoporous carbon materials on the inner surface of all tunnel segments in Beiheng Passageway in Shanghai, China could significantly enhance the daily capacity for CO₂ adsorption, reaching an impressive 181,830 kg. This study incorporates CO₂ capture and storage materials into tunnel engineering, paving a way towards decarbonizing underground space.