Investigation of the Diffusion and Kinetic Properties of Amine Impregnated 3D and 2D Porous Silica Materials

Investigation of the diffusion and kinetic properties of amine impregnated 3D and 2D porous silica materials

Justin Ramberger, Thomas P Nigl, Alyssa Stavola, Rebecca Chinn, Jillian Zummo, Christopher F Cogswell, Wei Fan, Sunho Choi

Department of Chemical Engineering, Northeastern University, 313 Snell Engineering Center, 360 Huntington Avenue, Boston, Massachusetts 02115-5000

Abstract

Carbon dioxide capture from flue gases and atmospheric streams is becoming more important as concerns for the global environment grow. Solid adsorbents are currently being investigated as possible replacements for the current liquid amine systems because of their low heats of adsorption and high surface areas. In order to overcome certain challenges, such as low CO₂ selectivity and relatively low capture capacity,^1-4 solid adsorbents have been functionalized with amine groups either through physical impregnation, covalent bonding, or in situ polymerization.^5-11 However, a clear understanding of the kinetics and diffusion properties of these impregnated materials has not been established. Recently, a new silica nanostructure has been developed, termed 3D mesoporous silica.¹² This material is composed of porous spheres of zeolite-β that have connected pore channels within the spheres and larger void spaces between the spheres. This material and a 2D porous silica nanostructure, MCM-36, were impregnated with varying amounts of two amine group containing polymers, tetraethylenepentamine (TEPA) and polyethyleneimine (PEI). The surface area, crystal structure, and chemical species present inside the samples were analyzed, and the CO₂ capture trials were performed using Thermo-Gravimetric Analysis. The adsorption half times of impregnated 3D-m silica were, in general, lower than those of MCM-36, and the CO­₂ capture capacities were higher, suggesting the pore system of the MCM-36 becomes clogged with polymer while the pore system of the 3D-m silica is relatively unobstructed. For example, at approximately 15 weight percent PEI, the adsorption half time of 3D-m silica was approximately 215 minutes, while that of MCM-36 was approximately 458 minutes. Therefore, it is possible that the 3D pore system does not undergo significant clogging or loss of adsorption capacity as observed for 1D and 2D support systems.¹¹ Previous work has questioned the utility of using 2D sorbents as CO₂ capture platforms, but these preliminary results suggest that 3D porous supports are one potential solution to this problem.

References:

1.        Aruldoss, D., Saigoanker, R., Savarimuthu, J. Das & R., J. Amine-grafted zeolites-mesoporous ceramics: Synthesis and adsorption characteristics. Ceram. Int. 40, 7583–7587 (2014).

2.        Choi, S., Drese, J. H., Eisenberger, P. M. & Jones, C. W. Application of amine-tethered solid sorbents for direct CO2 capture from the ambient air. Environ. Sci. Technol. 45, 2420–7 (2011).

3.        Choi, S., Drese, J. H. & Jones, C. W. Adsorbent materials for carbon dioxide capture from large anthropogenic point sources. ChemSusChem 2, 796–854 (2009).

4.        Hiyoshi, N., Yogo, K. & Yashima, T. Adsorption characteristics of carbon dioxide on organically functionalized SBA-15. Microporous Mesoporous Mater. 84, 357–365 (2005).

5.        Kumar, P., Kim, S., Ida, J. & Guliants, V. V. Polyethyleneimine-Modified MCM-48 Membranes : Effect of Water Vapor and Feed Concentration on N 2 / CO 2 Selectivity. 201–208 (2008).

6.        Li, W. et al. Structural changes of silica mesocellular foam supported amine-functionalized CO2 adsorbents upon exposure to steam. ACS Appl. Mater. Interfaces 2, 3363–72 (2010).

7.        Yang, S.-T., Kim, J.-Y., Kim, J. & Ahn, W.-S. CO2 capture over amine-functionalized MCM-22, MCM-36 and ITQ-2. Fuel 97, 435–442 (2012).

8.        Liu, F.-Q. et al. Amine-Tethered Adsorbents Based on Three-Dimensional Macroporous Silica for CO2 Capture from Simulated Flue Gas and Air. ACS Appl. Mater. Interfaces 6, 4371–81 (2014).

9.        Drese, J. H. et al. Synthesis-Structure-Property Relationships for Hyperbranched Aminosilica CO 2 Adsorbents. Adv. Funct. Mater. 19, 3821–3832 (2009).

10.      Drese, J. H. et al. Effect of support structure on CO2 adsorption properties of pore-expanded hyperbranched aminosilicas. Microporous Mesoporous Mater. 151, 231–240 (2012).

11.      Cogswell, Christopher F., et al. Effect of Pore Structure on CO2 Adsorption Characteristics of Aminopolymer Impregnated MCM-36. Langmuir 31.15, 4534-4541 (2015).

12.      Chen, Huiyong, et al. "Hydrothermal synthesis of zeolites with three-dimensionally ordered mesoporous-imprinted structure." Journal of the American Chemical Society 133.32, 12390-12393 (2011).