Akademik Veri Yönetim Sistemi
Chemical Engineering Science, cilt.333, 2026 (SCI-Expanded, Scopus)
Tetrafluoromethane (CF4) is an exceptionally inert fluorinated gas whose low polarizability weakens adsorbate–surface interactions, motivating narrow micropore-directed sorbent design. Here, hazelnut shell biomass was converted into potassium oxalate-activated porous carbons using K2C2O4 as a green activator. The precursor was carbonized at 500 °C for 2 h under N2 and activated at 800–900 °C with K2C2O4/carbonized precursor mass ratios of 2–4. The resulting carbons exhibit a defect-rich carbon framework with abundant sub-nanometer pores. By systematically tuning the activation conditions, the pore structure is precisely regulated, yielding materials with high surface areas and exceptionally large volumes of narrow micropores. The optimized sorbent achieves CF4 uptake capacities of 2.05 mmol g−1 at 25 °C and 3.01 mmol g−1 at 0 °C under ambient pressure, together with rapid adsorption kinetics, reaching 90% of equilibrium within 5.5 min. Thermodynamic analysis reveals moderate adsorption affinities, consistent with a physisorption-dominated mechanism, while mixed-gas measurements demonstrate favorable CF4/N2 selectivity. Notably, the maximum CF4 uptake correlates strongly with the narrow micropore volume rather than the total pore volume, identifying narrow microporosity as the primary structural descriptor governing CF4 adsorption. These findings establish potassium oxalate activation as an effective and environmentally benign strategy for constructing ultramicroporous carbons and provide clear structure–property insights for the rational design of carbon-based sorbents for fluorocarbon capture.