Ø Therefore, a big concern has been raised for CO2 depletion, and the development of
relevant CO2 capture technologies ar...
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Published on: Mar 3, 2016
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Transcripts - Nadeen_PSRS_2015

  • 1. Ø Therefore, a big concern has been raised for CO2 depletion, and the development of relevant CO2 capture technologies are in demand in order to reduce CO2 emission and accordingly the average atmospheric CO2 level to 350 ppmv,4 and also to reduce CO2’s contribution to the global warming from 60% to 19% by 2050.2 Corresponding Author Contact Details: Dr Xiaolei Fan School of Chemical Engineering and Analytical Science (SCEAS) The University of Manchester Sackville Street Manchester M13 9PL Email: xiaolei.fan@manchester.ac.uk Nadeen Al-Janabi PhD Candidate The University of Manchester School of Chemical Engineering and Analytical Science Email: nadeen.al-janabi@manchester.ac.uk 1. Introduction Engineering novel metallic-organic-frameworks (MOFs) for selective carbon dioxide capture from flue gases Nadeen Al-Janabi, Flor Siperstein, Xiaolei Fan* Ø Flue gas (emitted at 50~75ºC and 1 bar, with 5~15 vol% CO2, 5~7 vol% H2O and N2)1, 2 is one of the main sources of CO2 emission. Electricity Generation Petrochemical Plants Refineries Ø In this work, investigation was carried out to evaluate and modify a benchmark metallic-organic-framework (HKUST-1) for selective CO2 sorption from flue gases. Experimental tests of the adsorption ability and hydrothermal stability of HKUST-1 were performed, in addition to molecular simulation studies. Ø The Intergovernmental Panel on Climate Change (IPCC) predicted that, by the year of 2100, the amount of CO2 in the atmosphere may reach a value up to 570 ppmv, which can cause the mean global temperature to arise by 1.9°C and the mean sea level to increase by 3.8 m.3, 4 2. Gas and vapour adsorption Grand Canonical Monte Carlo (GCMC) simulation of carbon dioxide and water adsorption onto HKUST-1 Ø  Hydrothermal stability of porous adsorbents is a key design parameter for adsorption with wet streams. Experimental results show that HKUST-1 decompose at 50ºC with 70% relative humidity. Ø  GCMC simulation showed that water prefers to adsorb adjacent to the copper sites in the primary pores, while CO2 prefers to adsorb in side pockets. CO2 adsorption Water vapour adsorption In order to (i) enhance the selectivity of CO2 over N2 which is the main constituent in the flue gases, and to (ii) reduce the adsorption capacity of water vapour i.e. improve the hydrothermal stability of HKUST-1, glycine molecules were attached to the copper sites of HKUST-1 to form a novel MOF (Gly-HKUST-1). CO2 adsorption on HKUST-1 and Gly-HKUST-1 3. Hydrothermal stability Ø  Adsorption selectivity to water molecules is reduced significantly after modification, i.e. ca. 33mmol/g for HKUST-1 vs. 6 mmol/g for Gly- HKUST-1. Ø  Adsorption isotherm change from Type II to Type I after modification, indicating exclusion of water molecules adsorption from the primary pores of Gly-HKUST-1. 35 30 25 20 15 10 5 0 AdsorptionCapacity(mmol/g) P/Pº HKUST-1 Exp. Gly-HKUST-1 Exp. DSLF Model 25 20 15 10 5 0 AdsorptionCapacity(mmol/g) P/Pº HKUST-1 Gly-HKUST-1 DSLF Model Vapour adsorption at 25°C and atmospheric pressure Vapour adsorption at 50°C and atmospheric pressure Ø  HKUST-1 decompose and lose its porous structure at 50°C when the relative humidity is high (> 70%), i.e. unsatisfactory moisture stability for potential practical application. Ø  The accumulation of water molecules in the primary pores of HKUST-1is suspected to displace the organic ligands from the Cu centres. Ø  Moisture stability is improved by using glycine to modify HKUST-1. Decomposition of HKUST-1 4. Conclusions and future work ü  Facile method for post-synthesis modification of HKUST-1 was developed. ü  Developed Gly-HKUST-1 showed better moisture stability and lower water vapour adsorption uptake than original HKUST-1. Ø  The effect of glycine loading on adsorption capacity and selectivity will be investigated. Ø  Structure details of Gly-HKUST-1 will be established by using different characterisation techniques. References 1.  Sabouni et al. Environmental science and pollution research international, 2014, 21, 5427-5449. 2. Yu and Tan, Aerosol and Air Quality Research, 2012, 12, 745–769. 3. Mondal et al., Energy, 2012, 46, 431-441. 4. Hansen et al., The Open Atmospheric Science Journal, 2008, Vol. 2, 217-231. The CO2 adsorption capacity of the Gly-HKUST-1 was found to be dependent on the amount of glycine loaded onto the HKUST-1. The more the glycine used the lower CO2 adsorption capacity, which can be attributed to the blockage of the pores by the possible agglomeration of glycine. The Table below shows the adsorption capacity of CO2 of Gly- HKUST-1 with two different loadings of glycine in comparison to HKUST-1 sample. Sample CO2 adsorption capacity at 1bar and 25˚C (mmol/g) HKUST-1 / original sample 5.1 Gly-HKUST-1 (50 wt% of glycine used) 2.1 Gly-HKUST-1 (20 wt% of glycine used) 3.6 : Chemical structure of CO2

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