Abstract
The CO(2) capture from flue gas using biomass-derived porous carbons presents an environmentally friendly and sustainable strategy for mitigating carbon emissions. However, the conventional fabrication of porous carbons often relies on highly corrosive activating agents like KOH and ZnCl(2), posing environmental and safety concerns. To address this challenge, in the present work sodium metaborate tetrahydrate (NaBO(2)·4H(2)O) has been utilized as an alternative, eco-friendly activating agent for the first time. Moreover, a water chestnut shell (WCS) is used as a sustainable precursor for boron-doped porous carbons with varied microporosity and boron concentration. It was found out that pyrolysis temperature significantly determines the textural features, elemental composition, and CO(2) adsorption capacity. With a narrow micropore volume of 0.27 cm(3)/g and a boron concentration of 0.79 at.% the representative adsorbent presents the maximum CO(2) adsorption (2.51 mmol/g at 25 °C, 1 bar) and a CO(2)/N(2) selectivity of 18 in a 10:90 (v/v) ratio. Last but not least, the as-prepared B-doped carbon adsorbent possesses a remarkable cyclic stability over five cycles, fast kinetics (95% equilibrium in 6.5 min), a modest isosteric heat of adsorption (22-39 kJ/mol), and a dynamic capacity of 0.80 mmol/g under simulated flue gas conditions. This study serves as a valuable reference for the fabrication of B-doped carbons using an environmentally benign activating agent for CO(2) adsorption application.