Ecofriendly novel hydrophobic core-shell zeolite@MOF nanoadsorbent for CO2 capture
Fatemeh Bahmanzadegan, Ahad Ghaemi, Reza Norouzbeigi
Abstract
Zeolite 13X is a widely studied adsorbent for CO 2 capture due to its high surface area, thermal stability, and strong affinity for acidic gases. However, its inherent hydrophilicity can hinder adsorption efficiency in humid conditions. This study synthesized a novel core–shell zeolite 13X@ZIF-8, via a two-step in situ growth method using diethanolamine (DEA) as a surface functionalizing agent to promote uniform shell formation. Structural and morphological analyses confirmed the successful integration of a nanocrystalline ZIF-8 shell onto the zeolite 13X core without compromising the crystalline integrity of either phase. The composite exhibited a hierarchically porous structure and enhanced microporosity. CO 2 adsorption experiments revealed a maximum uptake of 1.6 mmol/g at 25 °C and 1 bar, surpassing the performance of both parent materials. Isotherm analysis indicated the best fit with the Temkin model, suggesting energetically heterogeneous adsorption sites, while kinetic modeling highlighted Elovich behavior, indicative of surface heterogeneity and potential chemisorption. Thermodynamic studies confirmed an exothermic and spontaneous adsorption process. Notably, the composite retained 94.5 % of its original capacity over 40 consecutive adsorption–desorption cycles. It demonstrates excellent stability and presents a scalable, cost-effective, and energy-efficient route to fabricating hierarchical Zeolite@MOF adsorbents with enhanced CO 2 adsorption.