Sodium fluoride ion-pairs in seawater |
| |
| Authors: | Gerard R Miller Dana R Kester |
| |
| Institution: | Graduate School of Oceanography, University of Rhode Island, Kingston, R.I. U.S.A. |
| |
| Abstract: | Laboratory investigations were conducted on the formation of NaF° ion-pairs at the ionic strength of seawater using specific ion electrodes. Sodium and fluoride ion electrodes produced results which are consistent with the ion-pairing model for these ionic interactions. The stoichiometric association constant for NaF°, , was determined at 15, 25, and 35°C. It was assumed that was a function of temperature, pressure, and ionic strength but not of solution composition. The value for at 25°C and I = 0.7 m is 0.045 ± 0.006. increased with decreasing temperature. This result was used to recompute values of and accounting for the presence of NaF° ion-pairs. The value for indicates that 1.1% of the fluoride in seawater is ion-paired with sodium at 25°C and 35‰ salinity. This fraction increases to approximately 2% at the lower temperatures found in the deep ocean. The percentage of free fluoride in natural seawater was measured at 15, 25, and 35°C to verify the speciation calculated from equilibrium constants. |
| |
| Keywords: | |
| 本文献已被 ScienceDirect 等数据库收录！ |
|
