|
|||||
|
|
Effects of concentration and freeze-thaw on the first hydration shell structure of Zn2+ ions |
|
| Authors: | WANG Wenhua ZHAO Lin YAN Bo TAN Xin QI Yun HE Bo |
| Institution: | 1. School of Environmental Science and Engineering, Tianjin University, Tianjin 300072, China;Institute of Seawater Desalination and Multipurpose Utilization, State Oceanic Administration, Tianjin 300192, China 2. School of Environmental Science and Engineering, Tianjin University, Tianjin 300072, China 3. National Synchrotron Radiation Laboratory, University of Science and Technology of China, Hefei 230029, China |
| Abstract: | To investigate the effects of salt concentration and freeze-thaw (FT) on the first hydration shell of Zn2+ ions in Zn(NO3)2 aqueous solutions, extended X-ray absorption fine structure (EXAFS) spectroscopy was used to examine Zn K-edge EXAFS spectra of Zn(NO3)2 aqueous solutions with various concentrations before and after FT treatment. The influences of salt concentration and freeze-thaw on the structural parameters of the first hydration shell of Zn2+ ions, including hydration number, Zn-O distance and thermal disorder, were analyzed. The results show that Zn2+ ions have 3.2–6.8 nearest oxygen neighbors with the Zn-O distance being 0.202–0.207 nm. In highly concentrated solutions, Zn2+ ions are hydrated with four water molecules in a tetrahedral form. The dilution of Zn(NO3)2 aqueous solutions increases the number of water molecules in the first hydration shell of Zn2+ ions to six with their octahedral arrangement. Both the hydration number in the first hydration shell of Zn2+ ions and the degree of thermal disorder increase when the FT treatment is operated in Zn(NO3)2 aqueous solutions. |
| Keywords: | EXAFS Zn (NO3) 2 aqueous solution first hydration shell hydration number concentration freeze-thaw |
| 本文献已被 CNKI 维普 万方数据 SpringerLink 等数据库收录！ | |