Thermodynamic stability and formation kinetics of CHClF2 hydrates in the presence of NiCl2 SCIE SCOPUS

Cited 2 time in WEB OF SCIENCE Cited 2 time in Scopus
Title
Thermodynamic stability and formation kinetics of CHClF2 hydrates in the presence of NiCl2
Author(s)
Woo, Yesol; Jeong, Jae Hak; Lee, Jong-Won; Park, Jeasung; Cha, Minjun; Kim, Dongseon; Yoo, Kyoungkeun; Yoon, Ji-Ho
KIOST Author(s)
Kim, Dongseon(김동선)
Publication Year
2019-07-20
Abstract
A hydrate-based technology is suggested for the desalination of industrial effluents, especially electro-plating effluents including NiCl2. To decrease the required energy for operating a hydrate-based desalination (HBD) process, chlorodifluoromethane (CHClF2) was used as a guest for hydrate formation at relatively mild conditions. The phase equilibria of CHClF2 hydrates formed in aqueous NiCl2 solutions were investigated to identify the effect of NiCl2 on the thermodynamic stability of CHClF2 hydrates. The dissociation phase boundary of CHClF2 hydrates in the presence of NiCl2 was shifted to higher pressures and lower temperatures as the salinity of aqueous solutions increased. To confirm the feasibility of NiCl2 separation from wastewaters via the HBD process, X-ray diffraction and Raman spectroscopic measurements were performed. The results showed that the Ni2+ and Cl- ions did not participate in the hydrate framework, which revealed that the HBD process could be used to remove NiCl2 from effluents. The formation kinetics of CHClF2 hydrates were analyzed by a new kinetic model adopting transient time-dependent apparent rate constants, which significantly depends on the sub-cooling temperature and the concentration of NiCl2 in the aqueous solutions. Thermodynamic approximations regarding the Ni2+ and Cl- ion exclusion from the clathrate framework and the full occupancy of CHClF2 molecules in the large cages of structure I clathrate hydrate were confirmed by comparing the calculated Ni2+ concentrations in the liquid phase in equilibrium with CHClF2 clathrate hydrates with the experimental measurements. These results provide good information for separating metal ions from wastewater streams by HBD processes. (C) 2018 Elsevier Ltd. All rights reserved.
ISSN
0009-2509
URI
https://sciwatch.kiost.ac.kr/handle/2020.kiost/572
DOI
10.1016/j.ces.2018.09.002
Bibliographic Citation
CHEMICAL ENGINEERING SCIENCE, v.202, pp.529 - 536, 2019
Publisher
PERGAMON-ELSEVIER SCIENCE LTD
Subject
GAS HYDRATE; PHASE-EQUILIBRIA; ECONOMIC-EVALUATION; CARBON CAPTURE; WASTE-WATER; RECOVERY; METHANE; SYSTEM; NACL; REFRIGERANTS
Keywords
Gas hydrate; Desalination; CHClF2; Phase equilibria; Formation kinetics
Type
Article
Language
English
Document Type
Article
Publisher
PERGAMON-ELSEVIER SCIENCE LTD
Related Researcher
Research Interests

Biogeochemistry,Carbon cycle,Ocean acidification,생지화학,탄소순환,해양산성화

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