title: Equilibrium, Kinetics, and Spectroscopic Studies of SF6 Hydrate in NaCl Electrolyte Solution.
abstract: 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 SF6 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 SF6 hydrates in the presence of NaCl solutions (0, 2, and 4 wt %) was also investigated. Gas consumption curves of SF6 hydrates showed that a pure SF6 hydrate system allowed fast hydrate growth as well as high conversion yield, whereas SF6 hydrate in the presence of NaCl solutions showed retarded hydrate growth rate as well as low conversion yield. In addition, structural identification of SF6 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 SF6 and SF6 + 4 wt % NaCl hydrates. The results indicate that whereas SF6 hydrate starts to decompose at around 240 K, the escape of SF6 molecules in SF6 + 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.
authors.affiliation: †Department of Energy and Resources Engineering, Korea Maritime and Ocean University, Busan 606-791, Korea.
authors.forename: Youngrok
authors.initials: Y
authors.lastname: Seo
authors.affiliation: †Department of Energy and Resources Engineering, Korea Maritime and Ocean University, Busan 606-791, Korea.
authors.forename: Donghyun
authors.initials: D
authors.lastname: Moon
authors.affiliation: †Department of Energy and Resources Engineering, Korea Maritime and Ocean University, Busan 606-791, Korea.
authors.forename: Changho
authors.initials: C
authors.lastname: Lee
authors.affiliation: †Department of Energy and Resources Engineering, Korea Maritime and Ocean University, Busan 606-791, Korea.
authors.forename: Jeong-Woo
authors.initials: JW
authors.lastname: Park
authors.affiliation: †Department of Energy and Resources Engineering, Korea Maritime and Ocean University, Busan 606-791, Korea.
authors.forename: Byeong-Soo
authors.initials: BS
authors.lastname: Kim
authors.forename: Gang-Woo
authors.initials: GW
authors.lastname: Lee
authors.affiliation: §Department of Environmental Engineering, Kongju National University, Chungnam 330-717, Korea.
authors.forename: Pratik
authors.initials: P
authors.lastname: Dotel
authors.affiliation: §Department of Environmental Engineering, Kongju National University, Chungnam 330-717, Korea.
authors.forename: Jong-Won
authors.initials: JW
authors.lastname: Lee
authors.affiliation: #Department of Energy and Resources Engineering, Kangwon National University, Gangwon 200-701, Korea.
authors.forename: Minjun
authors.initials: M
authors.lastname: Cha
authors.affiliation: †Department of Energy and Resources Engineering, Korea Maritime and Ocean University, Busan 606-791, Korea.
authors.forename: Ji-Ho
authors.initials: JH
authors.lastname: Yoon
mesh_terms: D052918:Environmental Restoration and Remediation; D005740:Gases / Q000737:chemistry*; D007700:Kinetics; D012965:Sodium Chloride / Q000737:chemistry*; D013059:Spectrum Analysis, Raman; D013459:Sulfur Hexafluoride / Q000737:chemistry*; D013816:Thermodynamics; D018508:Water Purification; D014961:X-Ray Diffraction
chemical_list: D005740:Gases; D012965:Sodium Chloride; D013459:Sulfur Hexafluoride