Equilibrium, Kinetics, and Spectroscopic Studies of SF sub( 6) Hydrate in NaCl Electrolyte Solution

• Published in: Environmental science & technology 2015-05, Vol.49 (10), p.6045-6045
• Main Authors: Seo, Youngrok, Moon, Donghyun, Lee, Changho, Park, Jeong-Woo, Kim, Byeong-Soo, Lee, Gang-Woo, Dotel, Pratik, Lee, Jong-Won, Cha, Minjun, Yoon, Ji-Ho
• Format: Article
• Language: English
• ISSN: 0013-936X

Many studies have focused on desalination via hydrate formation; however, for their potential application, knowledge pertaining to thermodynamic stability, formation kinetics, and guest occupation behavior in clathrate hydrates needs to be determined. Herein, the phase equilibria of SF... hydrates in the presence of NaCl solutions (0, 2, 4, and 10 wt %) were monitored in the temperature range of 277-286 K and under pressures of up to 1.4 MPa. The formation kinetics of SF... hydrates in the presence of NaCl solutions (0, 2, and 4 wt %) was also investigated. Gas consumption curves of SF... hydrates showed that a pure SF... hydrate system allowed fast hydrate growth as well as high conversion yield, whereas SF... hydrate in the presence of NaCl solutions showed retarded hydrate growth rate as well as low conversion yield. In addition, structural identification of SF... hydrates with and without NaCl solutions was performed using spectroscopic tools such as Raman spectroscopy and X-ray diffraction. The Raman spectrometer was also used to evaluate the temperature-dependent release behavior of guest molecules in SF... and SF... + 4 wt % NaCl hydrates. The results indicate that whereas SF... hydrate starts to decompose at around 240 K, the escape of SF... molecules in SF... + 4 wt % NaCl hydrate is initiated rapidly at around 205 K. The results of this study can provide a better understanding of guest-host interaction in electrolyte-containing systems. (ProQuest: ... denotes formulae/symbols omitted.)