Inorganic Microporous Membranes for Gas Separation in Fossil Fuel ...

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4 Results and discussion Intensity (a.u.) DTA in µV/mg 0,05 0,00 -0,05 -0,10 -0,15 -0,20 -0,25 exo 200 400 600 800 1000 1200 85 1400 Temp [ºC] Figure 30 DTA/TG results of DOH synthesised by means of the NH3 route (5ºC/min) 10 15 20 25 30 2Theta [º] 59 As-made 900ºC /5 hours Figure 31 XRD pattern of DOH sample as-made (black) and calcined at 900ºC for 5 hours (grey) The cage occupancy is calculated from the experimentally determined Si/C molar ratio of the DOH samples. 34SiO2:1ADA:xN2 69 is the chemical composition of DOH. C10NH17 is the chemical composition of ADA. The cage occupancy is 100 % when the Si/C ratio is 3.4. 105 100 95 90 TG weight %
4 Results and discussion The coupled loss of SDA and crystallinity during calcination might be explained by the collapse of the DOH surface structure. While the inner part of the DOH crystals maintains their crystal structure including the trapping of some of the template and the outer part of the DOH crystals collapses. In principle, O2 with a kinetic diameter of 3.46 Å, CO of 3.70 Å and CO2 of 3.30 Å are inaccessible to the DOH structure due to the smaller window opening compared to the kinetic diameter of these gasses. However, the DOH structure might ‘breathe’ (elastic vibration) at elevated temperatures allowing the transport of these gasses. This behaviour has been observed for other zeolites. 134 The remains of the burned out ADA might react with the oxygen from the silica framework at elevated temperatures. This could explain the decrease in cage occupancy coupled with the DOH structure loss. This might occur preferentially at the outer surface of the DOH crystals. SDA combustion is studied by DTA/TG measurements in air and in nitrogen. DTA/TG plots show similar behaviour for both gasses indicating that the weight loss is independent of the atmosphere and could explain the internal combustion. In a nut shell, conventional calcination at ambient pressure removes only a part of the organic SDAs. 2) Catalytic oxidation by titanium incorporation in the DOH framework Titanium was incorporated into the DOH framework in order to enhance the conventional calcination by means of catalytic oxidation. Small amounts of titanium isopropoxide or titanium n-propoxide were added to the silica source or to the final sol composition. Similar attempts have been performed to incorporate iron or aluminium and have resulted in multi phase zeolite products. Highly crystalline Ti-DOH products are obtained after ~27 days of crystallisation at 200ºC in the presence of a small amount of titanium in the gel (molar ratio Si/Ti 10-∞, see Table 17). Electron energy dispersive X-ray analysis and Inductively Coupled Plasma analysis confirm the presence of titanium in the samples. Raman spectroscopy presents bands at 960 cm -1 indicating the presence of Ti-O-Si bonds. Table 17 Cage occupancy of as-made and after calcination for samples with different Si/Ti molar ratios Sample # Crystal size Si/Ti Cage occupancy As-made Calcined at 900ºC Ti-1 Ca. 100 µm ∞ 91% 31% Ti-2 100 76% 24% Ti-3 Ca. 40 µm ∞ - 11% Ti-4 100 - 4% 60
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Mitglied der Helmholtz-Gemeinschaft
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Forschungszentrum Jülich GmbH Inst
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List of Abbreviations Ac Acetyl Ace
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Summary CO2 capture and storage mig
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Zusammenfassung Die Abtrennung und
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Content Content CONTENT............
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1 Introduction and aims 1 Introduct
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1 Introduction and aims Candidate m
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2 Theoretical background 2 Theoreti
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Page 22 and 23: 2 Theoretical background Table 2 Ox
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Page 32 and 33: 2 Theoretical background the materi
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Page 38 and 39: 2 Theoretical background due to its
Page 40 and 41: 2 Theoretical background 2.3.3.2 Mi
Page 42 and 43: 2 Theoretical background 2.4 Microp
Page 44 and 45: 2 Theoretical background Figure 15
Page 46 and 47: 2 Theoretical background wall inter
Page 48 and 49: 3 Experimental 3 Experimental The m
Page 50 and 51: 3 Experimental vacuum sample holder
Page 52 and 53: 3 Experimental o of as-made DOH cry
Page 54 and 55: 3 Experimental Another solution was
Page 56 and 57: 3 Experimental 3.4 Characterisation
Page 58 and 59: 3 Experimental Element analysis The
Page 60 and 61: 3 Experimental Additionally, the hy
Page 62 and 63: 4 Results and discussion Abundance
Page 64 and 65: 4 Results and discussion 4.2 Zeolit
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Page 68 and 69: 4 Results and discussion hours usin
Page 72 and 73: 4 Results and discussion The carbon
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Page 100 and 101: 4 Results and discussion V micro /V
Page 102 and 103: 4 Results and discussion In pure Ti
Page 104 and 105: 4 Results and discussion In summary
Page 106 and 107: 4 Results and discussion Intensity
Page 108 and 109: 4 Results and discussion nanonic YS
Page 110 and 111: 4 Results and discussion ~50nm TiO2
Page 112 and 113: 4 Results and discussion Raman Inte
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4 Results and discussion He Permean
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5 Conclusions and recommendations m
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5 Conclusions and recommendations m
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6 References 22. Shao, Z., Dong, H.
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6 References 65. Van den Berg, A. W
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6 References 108. Wen, T. L., Heber
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Curriculum Vitae - George van der D
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Last but not least, I would like to
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Band | Volume 8 ISBN 978-3-89336-52
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