Breakthrough analysis on selective adsorption of CO₂ from biogas by polyethylenimine-impregnated resins

Polymer resin-based solid amine are prospective adsorbents used in removing CO₂ from biogas. Two commercial resins with different porous structures, AB-8 and ADS-17, were selected as supports to explore the influence of the support structures on adsorbent performance. It was discovered that macroporous channels greatly boost CO₂ adsorption at higher PEI loadings (≥ 30%), and their influence is more critical than total pore volume or specific surface area, though their impact is minimal at low PEI loadings. ADS-17-40% PEI demonstrated outstanding CO₂ adsorption of 208 mg·g⁻¹ in its 16th cycle under specific operating conditions. Increasing gas flow rate to 200 mL·min⁻¹ could promote CO₂ adsorption capacity and initial adsorption rate constant (k₀) calculated by the deactivation model. The highest adsorption capacity was achieved at 55 °C, when the temperature ranged from 25 to 90 °C.