Enhanced Pore Size in Solid Amine Adsorbent Pellets with PEG Porogen for High-Performance CO2 Capture

The introduction of a porogen into a solid amine adsorbent was effective in enhancing the CO2 capture performance, structural stability, and long-term cycling stability. This study selected polyethylene glycol (PEG) as a porogen and prepared a series of CSP-nP-mT pellets, in which ZSM-5 served as the support, chitosan (CS) as the binder, and tetraethylenepentamine (TEPA) as the amine source. The results demonstrated that PEG effectively optimized the adsorbent pore structure, which enhanced the CO2 diffusion and improved accessibility to active amine sites. The structural optimization resulted in a significant increase in the CO2 adsorption capacity by 48.8% (from 1.74 to 2.59 mmol·g–1) compared to the sample without PEG. In addition to the improved adsorption performance, the compressive strength of CSP-1P-0.2T was 23% higher than that of CSP-0.2T. For the characterization of the adsorbent, N2 adsorption–desorption tests were employed to evaluate the pore structure of adsorbent pellets. SEM was used to measure the morphology of adsorbent pellets with different amounts of porogens. FT-IR and TGA were utilized to analyze the variation of functional groups and weight loss during the adsorption process. Furthermore, the adsorbents exhibited excellent cycling stability, retaining 87.2% of their initial capacity after 30 adsorption–desorption cycles. These results demonstrated that the incorporation of PEG in the adsorbent can effectively enhance the adsorption performance of solid amine adsorbents, which provided a strategy for developing high-performance adsorbents.