CO2 adsorption on polyethylenimine-modified ZSM-5 zeolite synthesized from rice husk ash

Mesoporous ZSM-5 zeolite as the adsorbent supporting material was synthesized from rice husk ash (RHA), and then impregnated with polyethylenimine (PEI) for amine functional modification. A series of adsorbents (ZSM-5-PEI-X) with different PEI loading ratios were characterized by XRD, FTIR, TGA/DTG, nitrogen adsorption-desorption, SEM and EDX techniques. The measurement of the adsorption capacity at different temperatures was indicated that ZSM-5-PEI-30 had the highest adsorption capacity at 120 °C (1.96 mmol/g). The experimental data were fitted by adsorption kinetic models and isotherm models, indicated that fractional-order model and the Dual-site langmuir model can be used to describe the adsorption mechanism and predict the adsorption performance. The high CO2 adsorption selectivity and regeneration stability suggested that this adsorbent is a potential candidate in the adsorption and separation of CO2 in industrial flue gas.