Polyethyleneimine‐Functionalized Polyamide Imide (Torlon) Hollow‐Fiber Sorbents for Post‐Combustion CO₂ Capture

Abstract

Carbon dioxide emitted from existing coal-fired power plants is a major environmental concern due to possible links to global climate change. In this study, we expand upon previous work focused on aminosilane-functionalized polymeric hollow-fiber sorbents by introducing a new class of polyethyleneimine (PEI)-functionalized polymeric hollow-fiber sorbents for post-combustion carbon dioxide capture. Different molecular weight PEIs (M(n) ≈600, 1800, 10,000, and 60,000) were studied as functional groups on polyamide imide (PAI, Torlon) hollow fibers. This imide ring-opening modification introduces two amide functional groups and was confirmed by FTIR attenuated total reflectance spectroscopy. The carbon dioxide equilibrium sorption capacities of PEI-functionalized Torlon materials were characterized by using both pressure decay and gravimetric sorption methods. For equivalent PEI concentrations, PAI functionalized with lower molecular weight PEI exhibited higher carbon dioxide capacities. The effect of water in the ring-opening reaction was also studied. Up to a critical value, water in the reaction mixture enhanced the degree of functionalization of PEI to Torlon and resulted in higher carbon dioxide uptake within the functionalized material. Above the critical value, roughly 15% w/w water, the fiber morphology was lost and the fiber was soluble in the solvent. PEI-functionalized (Mn ≈600) PAI under optimal reaction conditions was observed to have the highest CO2 uptake: 4.9 g CO2 per 100 g of polymer (1.1 mmol g(-1)) at 0.1 bar and 35 °C with dry 10% CO2/90% N2 feed for thermogravimetric analysis. By using water-saturated feeds (10% CO2 /90% N2 dry basis), CO2 sorption was observed to increase to 6.0 g CO2 per 100 g of sorbent (1.4 mmol g(-1)). This material also demonstrated stability in cyclic adsorption-desorption operations, even under wet conditions at which some highly effective sorbents tend to lose performance. Thus, PEI-functionalized PAI fibers can be considered as promising material for post-combustion CO2 capture.

In situ Formation of a Monodispersed Spherical Mesoporous Nanosilica–Torlon Hollow‐Fiber Composite for Carbon Dioxide Capture

“…Previously, APS‐ and PEI‐based fiber sorbents produced by a standard spinning procedure using commercial silica particles (3–10 μm) with a high silica loading (>60 wt %) were evaluated in a CO 2 capture application, and CO 2 sorption capacities of 1.1 and 0.82 mmol g fiber −1 were reported, respectively . Moreover, pure Torlon fibers functionalized with amines showed a relatively high CO 2 capacity of 1.4 mmol g fiber −1 but with poor kinetics because of the collapse of the outer surface layer …”

“…If the amine group in the activated APS attacks the imide ring in the backbone of the silica–Torlon hollow fiber and if the methoxy group hydrolyzes in the presence of the trace water, an optimum situation is reached. The fiber functionalization process for fibers without a silica nanoparticle surface layer proppants is shown in Scheme . This leads to the covalent functionalization of the Torlon matrix.…”

Development of monolithic adsorbent via polymeric sol–gel process for low-concentration CO2 capture

“…Among available techniques, amine scrubbing is the current state-of-the-art technology for CO 2 capture on an industrial scale. Although amines, especially aqueous solutions of monoethanolamine (MEA), are effective at capturing CO 2 , they show several disadvantages, including corrosion, oxidative degradation, high energy consumption for regeneration, and secondary pollution resulting from its high volatility [7][8][9][10]. For example, the parasitic energy consumption required for regeneration is considerable (up to 30%) when MEA is applied to flue gas purification in conventional absorber/ stripper systems in power plants [11].…”

Aminosilanes Grafted to Basic Alumina as CO2 Adsorbents—Role of Grafting Conditions on CO2 Adsorption Properties

“…Alternatively, a variety of porous solids have also been developed and used for such CO 2 capture applications. In these materials, amine groups are introduced onto porous supports by a variety of methodologies, such as the wet impregnation of polymeric amines onto the supports (class 1 materials), [39][40][41][42][43][44][45] by grafting Solid oxide-supported amine sorbents for CO 2 capture are amongst the most rapidly developing classes of sorbent materials for CO 2 capture. [36][37][38] Solid-supported amine materials, such as silica-supported amines, are unique among the array of available sorbents as they can be used at low temperatures but are chemisorbants, with strong CO 2 -surface interactions.…”