عنوان مجله
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Chemical Engineering Journal
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چکیده
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Carbon nitride (CN) materials with intrinsic high nitrogen content are potential candidates for acidic gas
adsorption. However, these nanomaterials should be further treated to achieve tunable textural properties for
ultra-high gas adsorption. Herein, we synthesized dual-pore carbon nitride materials (DP-CN) with a series of
ethylenediamine to carbon tetrachloride ratios with different amounts of potassium hydroxide (KOH) as a
chemical activator using nanosilica (SiO2) as a hard template to tune the physicochemical properties of the
materials. The prepared DP-CN adsorbents had a large surface area (up to 2036.9 m2/g), great pore volume (up
to 1.15 cm3/g), and high nitrogen content (10.6 to 15.1 wt%). The best DP-CN displayed ultra-high CO2 and H2S
adsorption capacity at 1 bar (8.3 and 13.8 mmol/g, respectively), 10 bar (16.9 and 23.1 mmol/g, respectively),
and 30 bar (22.9 mmol/g for CO2) at 25 ◦C, which was significantly higher than those of other pure mesoporous
carbon nitrides (M-CN) and carbon-based adsorbents. Moreover, the best adsorbent exhibited good CO2/N2,
CO2/CH4, H2S/N2, and H2S/CH4 selectivity, suitable heat of adsorption, and excellent cyclic stability. According
to density functional theory calculations, H2S adsorbs more strongly than CO2 on carbon nitride surfaces, and the
adsorption energies of CO2 and H2S are related to charge-transfer values from the surface to the adsorbed species.
The results revealed that the exceptional textural properties and high nitrogen content of the materials could play
the main role in the superior adsorption of CO2 and H2S. This generation of CN materials is expected to be
practical for a various range of separation processes, catalysis, capacitors, and energy storage
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