Direct Access to Primary Amines and Particle Morphology Control in Nanoporous CO2 Sorbents

Abstract

capture capacity of the modified sorbent was increased up to four times of the starting nanoporous network with a high heat of adsorption (98 kJ/mol). Surface area can be easily tuned between 1 and 354 m2/g. Average particle size (~50 µm) is also quite suitable for CO2 capture applications where processes like fluidized bed require spheres of micron sizes. Experimental - AN/DVB beads were synthesized by a pre-polymerization step followed up with a conventional suspension polymerization. The aqueous phase was prepared at 338K with 500 mg poly (vinyl alcohol) in 50 mL water. The solution containing monomers (AN and DVB), porogen and initiator (AIBN) was sonicated for 10 minutes to dissolve AIBN completely at room temperature. The sonicated mixture was introduced to the aqueous phase in a dropwise manner. Polymerization was carried out at 348 K during 24 h. After polymerization, the beads were filtered and washed with 2x100 mL of methanol and dried under vacuum. The synthesized polymers are referred to as Covalent Organic Polymer 122 (COP-122).

Results and Discussion - Chemisorption of CO2 by amine groups is evident in COP-122-G1 (Image 2, red plot) from the hysteretic Type I isotherm that rapidly increases at low partial pressures. The original COP-122 is mainly a physisorptive solid, hence low capacity with negligible hysteresis.

Conclusions - In summary, acrylonitrile-divinylbenzene copolymers with nanoporous nature have been designed and synthesized for effective and cheap post-combustion CO2 capture. The synthesized COP-122 polymer is obtained in the form of spherical beads with up to 100 µm diameter with hollow core mesoporous shell structure. Surface area and pore volumes can be altered by employing different types of porogens, while highest observed surface area was 354 m2/g. The hollow core inside of each single particle shows potential for acting as a carrier for various cargos, such as drugs. The amine impregnation and functionalization of ]COP-122 particles make them promising candidates for CO2 capture operations. Furthermore, this material is easy to handle because of its large particle size and non-corrosive nature, providing low attrition potential. References [1] Dogan, N. A., Ozdemir, E. and Yavuz, C. T. (2017), ChemSusChem, 2017 doi:10.1002/cssc.201700190