Spectrophotometric measurement of the (vapour + liquid) equilibria of (sulfur dioxide + water)

Abstract

In 1996 we published a paper dealing with the description of a new apparatus, which allows the study of phase and chemical equilibria in aqueous systems of volatile weak electrolytes. (1) The apparatus was used to study (sulfur dioxide + water) at T = 293 K. The molality of the dissolved sulfur dioxide and its partial pressure were calculated from the measured initial gas phase concentration c 1 (SO 2 ) and the thermodynamic equilibrium concentration c 2 (SO 2 ). The molality of the dissolved SO 2 is correct, as confirmed by independent ion chromatographic (i.c.) measurements, but there is an error in the evaluation of the partial pressures, which were wrongly converted using a standard pressure of 101.325 kPa. Equation (23) should be replaced bywhere p(SO 2 ) is the partial pressure of SO 2 ; c 2 is the gas phase equilibrium concentration of SO 2 and T 2 is the equilibrium temperature. The partial pressures reported in reference 1 and in a subsequent communication (2) should be corrected by multiplying the previous values with the pressure ratio ( p 2 /101.325), where p 2 is the equilibrium pressureThe published partial pressures are about 4 per cent low. The correct partial pressures are listed in table 1 of the present note. Consequently, the correlation of (vapour + liquid) equilibrium changes as well. Henry's constant was fitted to reproduce our own experimental results for p(SO 2 ) at T = 293 K to T = 333 K; however, all the other equilibrium constants remain unchanged. Because the measurements were performed at high dilution we used Pitzer's method (3) for the Debye-Hückel term, which required no further substance-specific parameters. The new values for the thermodynamic quantities using p o = 100 kPa for the reaction: SO 2 (g) = SO 2 (aq)

Absorption Equilibria of Dilute SO2 in Seawater

“…Table 4 reports the selected expressions for the variation of H m °and the equilibrium constants with temperature. The correlations for H m °and K 1 were established previously 8 under the same experimental conditions as the present work and fits well with data from Goldberg and Parker 11 and Siddiqi et al 12 The correlation for K 2 11 is frequently used as a reference correlation for the H 2 SO 3 second dissociation constant. 13 The correlation for K 3 14 fits also very well with literature data.…”

SO2 Solubility in 50 wt % H2SO4 at Elevated Temperatures and Pressures

“…It is clear from Figure that the solubility of SO 2 in water increases proportionally with an increase in the partial pressure of the SO 2 gas. This linear dependence between solubility and pressure has also been observed at other acid concentrations ,− when maintaining a constant temperature. A 95% confidence level was obtained for both the regression intercepts and slopes when the data presented in this study is compared with the data obtained by Shaw et al This confirms that the experimental setup proposed in this study was adequate in determining the SO 2 solubility in pure water.…”