MOF-5（Cu） Modified By Palladium-Containing Activated Carbon For Promoted CO₂/C₂H₄ Separation Efficiency Via Adsorption

Nowadays,environment protection and climate warming prevention are urgent issues facing all over the world.Global warming resulted from CO₂ emissions has drawn extensive attention as it has become a major concern.To address this issue,various approaches for CO₂capture and sequestration have been introduced so far,and among them,adsorption is promising by its effectiveness and selectivity,energy-saving,low-cost adsorbents,and renewability of used adsorbents.Higher-efficiency adsorbents are essential for advancing this technique.In this context,the metal-organic framework（MOF）has been considered to be the newest and most promising material for CO₂adsorption.In this study,MOF-5（Cu）was selected as sample to investigate the effect on the performance of carbon dioxide separation from a gas mixture by modifying with palladium containing activated carbon.The adsorbent MOF-5（Cu）was successfully prepared using a solvothermal method.The adsorption performance towards separation CO₂ from C₂H₄ was evaluated by attaching palladium containing activated carbon to MOF-5（Cu）using sucrose bridging method,changing the specific surface area and pore size of the adsorbent,and performing carbon dioxide adsorption on the adsorbent in an Intelligent Gravimetric Analyzer（IGA）to evaluate the adsorption performance.CO₂ adsorption capacities of MOF-5（Cu）and modified MOF-5（Cu）-Pd/AC were 2.01 and 2.5 mmol g^-1respectively,measured at 25℃.BET specific surface areas of MOF-5（Cu）and MOF-5（Cu）-Pd/AC were measured as 184 and 113 m²g^-1 with the pore volumes of 0.42 and 0.22 cm³g^-1,respectively.The CO₂ adsorption capacity of these materials（MOFs）was enhanced with Pd-containing activated carbon.The modified and unmodified materials were modelled and hence the framework’s structures,adsorption energies,and main structural parameters of CO₂ and C₂H₄ on MOF-5（Cu）and MOF-5（Cu）-Pd/AC have been provided and presented thoroughly.The results showed that the pore size and specific surface area of MOF-5（Cu）-Pd/AC decreases due to the wrapping phenomenon of palladium-containing activated carbon attached to MOF-5（Cu）.However,the performance for adsorption and separation of CO₂ were promoted due to the interaction between partially negatively charged polarized oxygen atoms and partially positively charged carbon of CO₂ molecules;again,the partial interaction between the negatively charged oxygen atoms and positively charged Pd metal facilitates the adsorption and separation of CO₂ due to its low electronegativity.