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Article Citation - WoS: 6Citation - Scopus: 6Optimized Porous Carbon Particles From Sucrose and Their Polyethyleneimine Modifications for Enhanced Co2 Capture(Mdpi, 2024) Ari, Betul; Inger, Erk; Sunol, Aydin K.; Sahiner, NurettinCarbon dioxide (CO2), one of the primary greenhouse gases, plays a key role in global warming and is one of the culprits in the climate change crisis. Therefore, the use of appropriate CO2 capture and storage technologies is of significant importance for the future of planet Earth due to atmospheric, climate, and environmental concerns. A cleaner and more sustainable approach to CO2 capture and storage using porous materials, membranes, and amine-based sorbents could offer excellent possibilities. Here, sucrose-derived porous carbon particles (PCPs) were synthesized as adsorbents for CO2 capture. Next, these PCPs were modified with branched- and linear-polyethyleneimine (B-PEI and L-PEI) as B-PEI-PCP and L-PEI-PCP, respectively. These PCPs and their PEI-modified forms were then used to prepare metal nanoparticles such as Co, Cu, and Ni in situ as M@PCP and M@L/B-PEI-PCP (M: Ni, Co, and Cu). The presence of PEI on the PCP surface enables new amine functional groups, known for high CO2 capture ability. The presence of metal nanoparticles in the structure may be used as a catalyst to convert the captured CO2 into useful products, e.g., fuels or other chemical compounds, at high temperatures. It was found that B-PEI-PCP has a larger surface area and higher CO2 capture capacity with a surface area of 32.84 m(2)/g and a CO2 capture capacity of 1.05 mmol CO2/g adsorbent compared to L-PEI-PCP. Amongst metal-nanoparticle-embedded PEI-PCPs (M@PEI-PCPs, M: Ni, Co, Cu), Ni@L-PEI-PCP was found to have higher CO2 capture capacity, 0.81 mmol CO2/g adsorbent, and a surface area of 225 m(2)/g. These data are significant as they will steer future studies for the conversion of captured CO2 into useful fuels/chemicals.Article Citation - WoS: 4Citation - Scopus: 3Crosslinked Polyethyleneimine-Based Structures in Different Morphologies as Promising Co2 Adsorption Systems: a Comprehensive Study(Wiley, 2024) Demirci, Sahin; Inger, Erk; Bhethanabotla, Venkat; Sahiner, NurettinAlthough there are many studies on CO2 adsorption via PEI-modified carbon particles, metal-organic frameworks, zeolitic imidazolate frameworks, and silica-based porous structures, only a limited number of studies on solely cross-linked PEI-based structures. Here, the CO2 adsorption capacities of PEI-based microgels and cryogels were investigated. The effects of various parameters influencing the CO2 adsorption capacity of PEI-based structures, for example, crosslinker types, PEI types (branched [bPEI] or linear [lPEI]), adsorbent types (microgel or cryogel), chemical-modification including their complexes were examined. NaOH-treated glycerol diglycidyl ether (GDE) crosslinked lPEI microgels exhibited higher CO2 adsorption capacity among other microgels with 0.094 +/- 0.006 mmol CO2/g at 900 mm Hg, 25 degrees C with 2- and 7.5-fold increase upon pentaethylenehexamine (PEHA) modification and Ba(II) metal ion complexing, respectively. The CO2 adsorption capacity of bPEI and lPEI-based cryogels were compared and found that lPEI-GDE cryogels had higher adsorption capacity than bPEI-GDE cryogels with 0.188 +/- 0.01 mmol CO2/g at 900 mm Hg and 25 degrees C. The reuse studies revealed that NaOH-treated GDE crosslinked bPEI and lPEI microgels and cryogels showed promising potential, for example, after 10-times repeated use >50% CO2 adsorption capacity was retained. The results affirmed that PEI-based microgels and cryogels are encouraging materials for CO2 capture and reuse applications.