Effect of hydrothermal pH values on the morphology of special microspheres of lignin-based porous carbon and the mechanism of carbon dioxide adsorption

• Published in: Bioresource technology 2024-02, Vol.393, p.130171-130171, Article 130171
• Main Authors: Gao, Jing, Wang, Zhi-Qing, Li, Biao, Zhao, Wei, Ba, Zhong-Ren, Liu, Zhe-Yu, Huang, Jie-Jie, Fang, Yi-Tian
• Format: Article
• Language: English
• Subjects: Carbon microspheres; CO2 adsorption mechanism; DFT; Hydrothermal; Lignin
• ISSN: 0960-8524; 1873-2976
• DOI: 10.1016/j.biortech.2023.130171

[Display omitted] •The effect of hydrothermal acid treatment on the formation of lignin-based porous carbon (LPC) has been revealed.•The CO2 adsorption mechanism of LPCs with hydrothermal pretreatment of different pH values was explored.•A feasible method to make highly efficient LPCs for CO2 capture was developed. The study reports the economic and sustainable syntheses of a lignin-based porous carbon (LPC) for CO2 capture application. The pH values of hydrothermal solution affected the polymerization and aromatization of spheroidization, with morphological changes from blocky to microsphere. In addition, the reliable mechanisms of CO2 adsorption were proposed by combining experiments with Gaussian16 simulations based on DFT. The electrostatic attraction of oxygen-containing functional groups and the diffusivity resistance of CO2 in the pores are the key factors for the CO2 adsorption. ​The carboxyl groups have the strongest electrostatic attraction to CO2. LPC-pH 1 has the highest carboxyl group content, possessing a CO2 adsorption capacity of up to 5.10 mmol/g at 0℃, 1 bar. Furthermore, CO2 diffusion resistance became a main factor as the adsorption temperature increases. The innovative combination of quantum chemical calculations and microscopic properties provides a viable pathway for an insight into the future control of lignin-based carbon formation.