Cu-BTC/Aminated Graphite Oxide Composites As High-Efficiency CO₂ Capture Media

Abstract

CO₂ adsorption isotherms on Cu-BTC/aminated graphite oxide composites were measured in the pressure range up to 1.5 MPa at three different temperatures close to ambient. Adsorption capacity, isosteric heat of adsorption, and regenerability were investigated. They are considered as significant factors determining the practical application of materials for CO₂ capture. The results indicate a significant improvement in the performance of the composites as CO₂ adsorbents in comparison with the parent Cu-BTC MOF. Among all samples analyzed, the composite of Cu-BTC and modified graphite oxide with the highest N content (MOF/GO-U3) is the best performing sample. On its surface 13.41 mmol/g CO₂ was adsorbed at room temperature and 1.5 MPa. A high selectivity for CO₂ adsorption over that of CH₄ was found. The selectivities for CO₂ adsorption over N₂ are governed by the properties of the MOF phase. A relatively low heat of CO₂ adsorption and the high degree of surface homogeneity cause that the composites can be fully regenerated and used in multicycle adsorption with the minimum energy demand