Experimental and theoretical investigation of the Na+  → Li+ cation exchange in mordenite and its effect on CO2 adsorption properties

SERRA, RAMIRO M.; DE VILHENA, FELIPE S.; GUTIERREZ, LAURA B.; JÚNIOR, JOSÉ M. S.; FERREIRA, GLÁUCIO B.; DOS SANTOS, THIAGO CUSTÓDIO; RONCONI, CÉLIA M.; DE CARNEIRO, JOSÉ W. M.; BOIX, ALICIA V.

ADSORPTION-JOURNAL OF THE INTERNATIONAL ADSORPTION SOCIETY

SPRINGER

Lugar: Berlin; Año: 2021

0929-5607

Anthropogenic CO2emissions are the major drivers of global warming and climate change. The adsorption of CO2is oneof the strategies to mitigate these emissions. In this sense, different materials have been used as adsorbents as is the caseof zeolites. In this work,experimental infrared and X-ray analyses together with DFT (Density Functional Theory)theoreticalcalculations were employed to study the adsorption of CO2on mordenite zeolites (Na-MOR). Ion exchange followedby chemical analysis showed that the Na+of Na-MOR was not completely substituted under the experimental conditionsemployed. The XRD (X-ray Diffraction) analysis indicated that Na+exchanged for Li+did not affect the crystallinity of thematerials. The infrared results showed that CO2interacted linearly with the sodium and lithium cations present in the mainchannel of the mordenite framework. Sodium in dry samples favored the formation of carbonates and hydroxycarbonatespecies, as did the presence of low water content in the LixNa-MOR. The DFT periodical calculation of dehydrated mordenitemodels led to CO2adsorption energies in the range of − 31.6 to − 34.2 kJ mol−1, with the highest adsorption energyfound for sodium mordenite.The asymmetric stretching ν3 (CO2) vibration mode resulted intense and presented a shift whichindicated a higher CO2interaction of Na-MOR. The presence of some water molecules in the mordenite framework causeda decrease in the adsorption energy.