Facile Synthesis, Characterization, and Performance Study of a Low-Cost Structured Adsorbent for CO2 Capture

In this study, different commercial microfibrous fabric cloths were efficiently functionalized with polyethylenimine (PEI) and optimized with respect to amine loading for adsorptive removal of CO2 from flue gas. The synthesized adsorbents were characterized by various techniques such as field emission scanning electron microscopy (FESEM), atomic force microscopy (AFM), Fourier transform infrared (FTIR) analysis, and tensile properties of the fabrics. The CO2 adsorption capacities of amine-functionalized fabric sorbents were measured by using a thermogravimetric analyzer. It was found that an optimal PEI loading of 60 wt % on polyester-based fabric cloth (PEFC) resulted in the highest CO2 adsorption capacity with the fastest kinetics while studying the effects of PEI loading and CO2 partial pressures (in the range of 5–100 kPa) on CO2 adsorption performance under atmospheric pressure. The equilibrium CO2 adsorption capacities for 60 wt % PEI-loaded PEFC at 75 °C were 1.60 and 1.93 mmol CO2/g sorbents in a 10% CO2/N2 gas mixture and pure CO2, respectively. The multicycle temperature swing adsorption/desorption was also investigated using simulated flue gas in both dry and humid flue gas conditions, and it was observed that the working CO2 uptake capacities after 15 cycles were 1.07 and 1.15 mmol of CO2/g of sorbents. Moreover, the breakthrough performance study of the sorbents at three different flow rates using single- and double-layer bed configurations under 10% CO2/N2 flue gas stream at 75 °C and atmospheric pressure shows promising results. For a double-layer bed and under a volumetric gas flow of 100 mL/min, the adsorption capacity at the breakthrough and saturation points obtained was 0.50 and 0.84 mmol of CO2/g of sorbents, respectively.