Enhanced CO2 adsorption kinetics with hierarchical zeolite 5A

Abstract. In this work, hierarchical zeolite LTA (H-4A and H-5A) was synthesized using dimethyloctadecyl[3-(trimethoxysilyl)propyl]ammonium chloride surfactant and characterized through various analyses. N2 physisorption analysis shows that H-4A and H-5A exhibited a hierarchical structure with coexisting microporous and mesoporous domains. The existence of mesoporosity within the crystals is accountable for the decreased diffraction peaks as observed in the XRD analysis of H-4A and H-5A. This observation is also consistent with the FESEM images, where H-4A and H-5A with hierarchical structures display as spherical particles while bulk zeolite LTA (B-4A and B-5A) showcase as well-defined and uniform cubic shape crystals. Investigation of CO2 and N2 adsorption has shown that the synthesized zeolites displayed a significant CO2 adsorption capacity compared to N2. Furthermore, by measuring the CO2 fractional uptake, it is concluded that H-5A improves CO2 adsorption kinetics significantly as compared to B-5A. This attractive characteristic is expected to be able to be applied effectively in the carbon capture and storage process as an improved overall processing rate of adsorbents under repetitive adsorption- desorption cycling can be achieved.

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