Surface Modification of Activated Carbon Fibers for the Adsorption Capture of Carbon Dioxide in Flue Gas

Tetraethylenepentamine (TEPA) and K2CO3 were utilized as modifiers to optimize the surface properties of ACFs and enhance their CO2 adsorption performance. The results show that the TEPA modification leads to an increase in the nitrogen content, while the K2CO3 modification enhances the proportion of oxygen elements in ACFs. Both unmodified and modified ACFs predominantly consist of carbon elements, accounting for over 80 wt.% of the total composition. TEPA modification can improve both the adsorption capacity and adsorption rate of CO2, while K2CO3 modification only enhances the adsorption capacity. The modification using 4 wt.% exhibits an excellent CO2 adsorption capacity of 27.6 mL/g, while the modification using 0.8 mol/L K2CO3 demonstrates a good CO2 adsorption capacity of 28.1 mL/g. The simulation study reveals that the modified ACFs are more likely to bind with CO2 molecules compared to unmodified ACFs, whereas TEPA-modified ACFs have almost the same CO2 adsorption performance as K2CO3-modified ACFs.