SOLUBILITY OF HYDROGEN IN AQUEOUS-SOLUTIONS OF SODIUM AND POTASSIUM BICARBONATE FROM 293 TO 333 K

An experimental study is presented of the hydrogen solubility in aqueo us salt solutions containing sodium and potassium bicarbonate from 293 to 333 K. For this purpose, gas consumption measurements have been pe rformed by determining the ultimate pressure decrease in an intensivel y stirred, high pressure autoclave. Experiments were carried out at sa lt concentrations up to 1.0 mol kg(-1). At higher salt molalities, the hydrogen solubility was too low to be measured reliably. It was demon strated that the hydrogen solubility followed the well-known Sechenov salt concentration dependence. At 298 K, the Sechenov or salting-out p arameters were equal to 0.41 and 0.32 kg mol(-1) for sodium and potass ium bicarbonate, respectively. Fairly good agreement was obtained with the salting-out parameters predicted by a recently developed empirica l estimation method. The concentration ratio of the bicarbonate and ca rbonate ions showed only a minor influence on the hydrogen solubility. Furthermore, the Sechenov parameter was found to be a weak function o f temperature. Virtually the same, linear temperature dependence was o bserved for both bicarbonate salts studied, i.e. -0.0023 and -0.0024 k g mol(-1) K-1 for sodium and potassium bicarbonate, respectively.