Mechanism of CO2 adsorption on Mg/DOBDC with elevated CO2 loading

Abstract

Understanding the nature of CO 2 adsorption in porous materials is important to developing the next generation high performance adsorbents for CO 2 capture. The mechanism of CO 2 adsorption in a typical metal organic framework (MOF) material, named Mg/DOBDC (DOBDC = 1,4-dioxido-2,5-benzenedicarboxylate), was investigated by experiments and theoretical calculations. Needle-shaped Mg/DOBDC crystals were synthesized and characterized. CO 2 adsorption isotherm at ambient conditions on Mg/DOBDC was converted to obtain open metal site coverage by CO 2 with pressure. Binding energies of CO 2 on open metal site and organic linker site were calculated separately using density functional theory (DFT). Furthermore, step-by-step DFT calculations were performed by adding CO 2 molecules into Mg/DOBDC pores

Mg2+ embedded MIL‐101(Cr)‐NH2 framework for improved CO2 adsorption and CO2/N2 selectivity

“…[21] Researchers found that Mg 2+ cations act as coordinately unsaturated sites that are highly affinities toward CO2. [8,34,35] In order to further confirm the role of Mg 2+ , CO2 -TPD experiments were performed and the results are shown in figure 8. The CO2-TPD curve of MIL-101(Cr)-NH2 displayed a desorption peak at low temperature of ~ 53 °C, assigned to the desorption of CO2 adsorbed on the unsaturated Cr-metal; meanwhile, the desorption peak at higher 250 o C could be attributed to the desorption of CO2 adsorbed on the amine sites.…”

Metal–organic frameworks for carbon dioxide capture

“…9) are loaded in a single pore, each CO 2 symmetrically interacts with the MOF at the same distances and angles. 155 Due to higher affinity of amine solutions for CO 2 , a number of MOFs based on Lewis basic sites such as NH 2 and alkyl-and aryl-amines have been prepared, the amine being tethered to unsaturated OMSs or to organic linkers. For example, in diamine-tagged MOFs, two CO 2 adsorption models were identified.…”

SBA-15 Functionalized with Amines in the Presence of Water: Applications to CO2 Capture and Natural Gas Desulfurization

“…Additionally, due to its corrosive and poisonous nature, hydrogen sulfide (H 2 S) is another gas that needs removal during the energy generation process. Therefore, significant efforts are being undertaken to develop technologies to curb CO 2 emissions and efficiently remove H 2 S. − In the past 20 years, the most promising and researched materials used for adsorption of harmful gases are zeolites, activated carbons, metal organic frameworks, and amine-functionalized mesoporous silica (silica gels, MCM-41, and SBA-15) due to their favorable porous properties. − …”