Role of Salts in Phase Transformation of Clathrate Hydrates under Brine Environments

Transcription

1 Supporting Information for Role of Salts in Phase Transformation of Clathrate Hydrates under Brine Environments Donghoon Shin, Jong-Won Lee, Yesol Woo, Minjun Cha, Yongjae Lee, Seen Ae Chae, Sun Ha Kim, c Hee Han, and Ji-Ho Yoon - The number of pages: 15 (Pages S1 S15) - The number of figures: 12 (Figures S1 S12) - The number of tables: 1 (Table S1) - The number of references: 3 (References S1 S3) S1

2 XRD pattern si hydrate Ice Intensity (a.u.) θ (degree) Figure S1. Powdered X-ray diffraction pattern of pure R22 hydrate formed at 274 K and 4.5 bar. S2

3 XRD pattern si hydrate Ice NaCl 2H 2 Intensity (a.u.) θ (degree) Figure S2. Powdered X-ray diffraction pattern of R22 hydrate formed in 10 wt% NaCl aqueous solution at 274 K and 4.5 bar. S3

4 XRD pattern si hydrate Ice NaCl 2H 2 Intensity (a.u.) θ (degree) Figure S3. Powdered X-ray diffraction pattern of R22 hydrate formed in 20 wt% NaCl aqueous solution at 274 K and 4.5 bar. S4

5 XRD pattern si hydrate Ice MgCl 2 12H 2 Intensity (a.u.) θ (degree) Figure S4. Powdered X-ray diffraction pattern of R22 hydrate formed in 4 wt% MgCl 2 aqueous solution at 274 K and 4.5 bar. S5

6 (a) Temperature ( o C) Ice NaCl. 2H2 NaCl(s) NaCl (wt %) (b) 250 Temperature ( o C) Ice MgCl. 12H2 2 MgCl. 8H2 2 MgCl. 6H2 2 MgCl. 4H2 2 MgCl. 2H2 2 MgCl 2 (s) MgCl 2 (wt %) Figure S5. Schematic temperature composition (T x) diagram of (a) NaCl water and (b) MgCl 2 water binary systems at ambient pressure. S1 S3 S6

7 T = 253 K T = 233 K T = 213 K Chemical shift (ppm) Figure S6. 23 Na MAS NMR spectra of a solid mixture of ice and hydrated salts, NaCl 2H 2, formed from 10 wt% NaCl aqueous solution. 23 Na MAS NMR spectra were acquired at 10 khz spinning rate using a 600 MHz NMR spectrometer. The 23 Na resonance peaks at 0.5 and 5 ppm can be assigned as Na + in aqueous brine solution and hydrated salt NaCl 2H 2, respectively. S7

8 10 wt% NaCl 7 wt% NaCl 4 wt% NaCl 2 wt% NaCl Chemical shift (ppm) Figure S7. 23 Na MAS NMR spectra at 233 K of R22 hydrates formed in various NaCl solutions. 23 Na MAS NMR spectra were acquired at 10 khz spinning rate using a 600 MHz NMR spectrometer. The 23 Na resonance peaks at 0.5 and 5 ppm can be assigned as Na + in aqueous brine solution and hydrated salt NaCl 2H 2, respectively. S8

9 10 wt% NaCl 7 wt% NaCl 4 wt% NaCl 2 wt% NaCl Chemical shift (ppm) Figure S8. 23 Na MAS NMR spectra at 213 K of R22 hydrates formed in various NaCl solutions. 23 Na MAS NMR spectra were acquired at 10 khz spinning rate using a 600 MHz NMR spectrometer. The 23 Na resonance peaks at 5 ppm can be assigned as Na + in hydrated salt NaCl 2H 2. S9

10 10 wt% NaCl 7 wt% NaCl 4 wt% NaCl 2 wt% NaCl 0 wt% NaCl Chemical shift (ppm) Figure S9. 19 F MAS NMR spectra at 233 K of R22 hydrates formed in various NaCl solutions. 19 F MAS NMR spectra were acquired at 2.5 khz spinning rate using a 400 MHz NMR spectrometer. The broad resonance peaks at near 81.6 ppm should be assigned as R22 molecules trapped in the large cages of si clathrate hydrate. S10

11 T = 253 K T = 243 K T = 233 K Chemical shift (ppm) Figure S F MAS NMR spectra of R22 hydrates formed in 4 wt% MgCl 2 aqueous solution. 19 F MAS NMR spectra were acquired at 2.5 khz spinning rate using a 400 MHz NMR spectrometer. The broad resonance peaks at near 81.6 ppm should be assigned as R22 molecules trapped in the large cages of si clathrate hydrate. The relatively narrow resonance peaks at near 76.5 ppm, which split due to the J-coupling effect, are attributed to R22 gas arising from the partial decomposition of R22 clathrate hydrates. S11

12 XRD pattern sii hydrate Ice NaCl 2H 2 Intensity (a.u.) θ (degree) Figure S11. Powdered X-ray diffraction pattern of CH 4 hydrate formed in 3 mol% THF and 4 wt% NaCl aqueous solution at 274 K and 12 bar. S12

13 T = 253 K T = 243 K T = 233 K Chemical shift (ppm) Figure S C MAS NMR spectra of binary CH 4 and THF hydrate formed in 3 mol% THF and 4 wt% NaCl aqueous solution at 274 K and 12 bar. 13 C MAS NMR spectra were acquired under proton decoupling at 7 khz spinning rate using a 400 MHz NMR spectrometer. ). The 13 C resonance peaks at 4.4 and 11.0 ppm can be assigned as CH 4 trapped in the small cages of sii clathrate hydrate and CH 4 gas released by clathrate hydrate decomposition, respectively. S13

14 Table S1. Crystal structure, lattice parameter, and unit cell volume of clathrate hydrates formed with and without salts. Hydrate system Structure Space group Lattice parameter (Å) Unit cell volume (Å 3 ) R22 si Pm3n a = , R wt% NaCl si Pm3n a = , R wt% NaCl si Pm3n a = , R wt% NaCl si Pm3n a = , R wt% MgCl 2 si Pm3n a = , CH wt% NaCl si Pm3n a = , SF wt% NaCl sii Fd3m a = , THF (5.56 mol%) + 4 wt% NaCl sii Fd3m a = , CH mol% THF + 4 wt% NaCl sii Fd3m a = , S14

15 References S1. Marion, G. M.; Farren, R. F., Mineral solubilities in the Na-K-Mg-Ca-Cl-S 4 -H 2 system: A re-evaluation of the sulfate chemistry in the Spencer-Moller-Weare model. Geochim. Cosmochim. Acta 1999, 63, S2. Linke, W. F., Solubilities of Inorganic and Metal rganic Compounds; American Chemical Society: Washington D. C., S3. Koop, T.; Kapilashrami, A.; Molina, L. T.; Molina, M. J., Phase transitions of sea-salt/water mixtures at low temperatures: Implications for ozone chemistry in the polar marine boundary layer. J. Geophys. Res. 2000, 105, S15