Preparation & Synthesis of Metal-Organic Frameworks for Acid-Gas Adsorption and Separation

Preparation & Synthesis of Metal-Organic Frameworks for Acid-Gas Adsorption and Separation
Timon Abraham (Missouri University of Science & Technology, Rolla, MO 63701)
Gernot Rother (Oak Ridge National Laboratory, Oak Ridge, TN 37830)
Carbon dioxide (CO2) level in the air is increasing every day, due to continuous emissions of flue and greenhouse gases. Researchers are developing economical and practical methods to reduce CO2 emissions, because of its effect on the climate changes and several industrial applications. CO2 is the major contributor between greenhouse gases to the global warming and ocean acidification. The U.S. Department Of Energy (DOE) issued a carbon sequestration program in 2009 to achieve 90% CO2 capturing at an increase in the cost of electricity of less than 35% by 2020. In addition, removing trace CO2 is critical and required in various key industrial applications. Mitigating and removing CO2 from the air is substantial important in air purification during the separation process of nitrogen and oxygen (cryogenic distillation process), because CO2 becomes frozen during the liquefaction process which blocks the heat exchange equipment, and causes contamination to the adsorbent during oxygen production by pressure swing adsorption. Recycling CO2 and resupply fresh air is also critical and sensitive in closed areas like mining, submarines and diving. In our project, we developed and synthesized novel porous materials, namely metal-organic Frameworks (MOFs) to adsorb mixture of nitrogen and CO2, and selectively and efficiently separate CO2. MOFs are high and stable porous materials with big surface area. We synthesized copper trimesate (HKUST-1) crystals by reacting 0.5M cooper nitrate trihydrate with 0.24M tricarboxylic acid at 78°C and evacuation at 140°C for sixteen hours. The second experiment was the adsorption and separation process using the gravimetric method in the Rubotherm system through calculating and measuring the sample and bulk liquid density. In conclusion, HKUST-1 exhibits very high CO2 sorption. We are currently working on developing new different MOFs that have better pore sizes and surface areas for use in trace CO2 removal.