CO₂ capture from the flue gas is a promising approach to mitigate global warming. However, regulating the carbon-based adsorbent in terms of textural and surface modification is still a challenge. To overcome this issue, the present study depicts the development of cost-effective and high-performance CO₂ adsorbents derived from petroleum coke, an industrial by-product, using a two-step process involving thiourea modification and KOH activation. A series of N,S-codoped porous carbons was synthesized by varying activation temperatures and KOH quantity. The optimized sample exhibited a high specific surface area of 1088 m²/g, a narrow micropore volume of 0.52 cm³/g, and considerable heteroatom doping (1.57 at.% nitrogen and 0.19 at.% sulfur). The as-prepared adsorbent achieved a CO₂ adsorption capacity of 3.69 and 5.08 mmol/g at 1 bar, 25 °C and 0 °C, respectively, along with a CO₂/N₂ selectivity of 17. Adsorption kinetics showed 90% of equilibrium uptake was achieved within 5 min, while cyclic studies revealed excellent stability with 97% capacity retention after five cycles. Thermodynamic analysis indicated moderate isosteric heat of adsorption (Q_st) values ranging from 18 to 47 kJ/mol, ensuring both strong adsorption and efficient desorption. These findings highlight the potential of petroleum coke-derived porous carbons for sustainable and efficient CO₂ capture applications.

The CO₂ 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 ZnCl₂, posing environmental and safety concerns. To address this challenge, in the present work sodium metaborate tetrahydrate (NaBO₂·4H₂O) 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 CO₂ adsorption capacity. With a narrow micropore volume of 0.27 cm³/g and a boron concentration of 0.79 at.% the representative adsorbent presents the maximum CO₂ adsorption (2.51 mmol/g at 25 °C, 1 bar) and a CO₂/N₂ 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 CO₂ adsorption application.

Adsorbing and recycling alcohols and acids from industrial wastewater is of great significance in wastewater treatment; establishing the possible quantitative relationship of alcohol–acid adsorption capacity with the struct0ures of adsorbents and exploring the key factors determining their adsorption performance is very important and challenging in environment science. To solve this difficult problem, the adsorption of C1-5 alcohols, C2-4 acids, and Fischer–Tropsch synthesis (FTS) wastewater on zeolites with similar hydrophobicity and pore structures (β and MFI), similar hydrophilicity but different pore structures (Y and MOR), and similar pore structures but significant differences in hydrophobicity (MOR vs. β and MFI) was systematically investigated. It was found that: (1) For materials with similar pore structures, increased hydrophobicity correlates with enhanced adsorption capacities for alcohols and acids. (2) For materials with similar hydrophobicity, a higher content of ultramicropores leads to increased adsorption of alcohols and acids. (3) Between pore structure and hydrophobicity, it is hydrophobicity that ultimately plays a decisive role in adsorption capacities. The adsorption behavior of zeolites in FTS wastewater exhibits a consistent trend, with β-zeolite demonstrating the highest hydrophobicity (contact angle of 105°) and the greatest adsorption capacity in FTS wastewater, achieving 103 mg/g. Following five adsorption–desorption cycles, the zeolites retained their adsorption capacity without significant degradation, indicating their excellent stability and reusability. The findings identify the critical factors determining adsorption performance and provide a solid foundation for the design and development of high-performance adsorbents for alcohol–acid adsorption.

Developing adsorbents with rapid kinetics and high adsorption capacity is essential for efficient CO₂ capture. Herein, oxygen-rich porous carbons were synthesized from phenolic resin through K₂CO₃ activation. By systematically varying the activation temperature and K₂CO₃/precursor ratio, the evolution of pore structure and its influence on CO₂ adsorption behavior were comprehensively investigated. The reaction between K₂CO₃ and the carbon matrix generated abundant micropores while preserving oxygen-containing surface functionalities, leading to enhanced adsorption affinity toward CO₂ molecules. The optimized carbon exhibited a high specific surface area of 1065 m² g⁻¹ and a narrow micropore volume of 0.54 cm³g⁻¹, delivering equilibrium CO₂ uptake capacities of 5.48 and 3.92 mmol g⁻¹ at 0 and 25 °C under 1 bar, respectively. In-depth analysis revealed that narrow microporosity played a more dominant role than total surface area in determining adsorption performance. Moreover, the optimized adsorbent showed a CO₂/N₂ selectivity of 15; rapid adsorption kinetics, with 90% of equilibrium capacity achieved within 4.5 min; and a dynamic CO₂ capture capacity of 0.91 mmol g⁻¹. The moderate isosteric heat of adsorption (20–36 kJ mol⁻¹) and excellent cyclic stability further confirmed the physisorption-dominated nature of the process. This work highlights the synergistic role of ultramicropore engineering and oxygen-containing surface functionalities in designing efficient porous carbon adsorbents for carbon capture.