Solubility of gases in water

Solubility of gases in water decreases with increasing temperature. 

An analogous law was established in 1803 by W. Henry for the solubilities of gases in water hence, this expression is called the Henry isotherm. The adsorption coefficient B (units dmVmol) depends on the heat of adsorption B = B° e,xp(q RT). The Henry isotherm is valid for low surface coverages (e.g., at 9 < 0.1). 

Table 5.4 lists a few Henry s law constants, which relate to the solubility of gases in water. 

Battino s selected values between 273 and about 350 K, Potter and Clynne s new values, and selected older literature data on the solubility of gases in water at temperatures up to 600 K have been combined, and fitted to an equation to give the inverse of the limiting low pressure value of Henry s constant over the temperature interval of 273 to 600 K. Battino s equations [1-5] are recommended for use over the 273 to 350 K range and the equations of the present work are tentative equations for the 350-600 K range of temperature. 

Battino has used the above equation in his evaluation of the solubility of gases in water at one atmosphere gas pressure at temperatures between 273 and about 350 K. Tables II and III and Figure 1 summarize his evaluation of the solubility data. 

The literature was searched, and the data on the solubility of gases in water between the temperatures of 350 and 600 K were compiled. The measurements in the 350 to 600 K temperature range were usually made at moderate gas partial pressures. The solubility at... 

The composition of the subsurface gas phase may change as a result of gas dissolution into the liquid phase. The solubility of gases in water depends on the type of gas, temperature, salt concentration, and the partial pressure of the gases in the atmosphere. The most soluble gases are those that become ionized in water (CO, NHj, H S), while and are much less soluble (Table 1.2). 

The focus in this chapter has primarily been on solid solutes in liquid solvents. The solubility of gases in water and other liquids... 

Loomis, A. G., Solubilities of Gases in Water, in International Critical Tables, Vol. Ill, pp. 255-261, McGraw-Hill, New York, 1928. 

It is evident that CL is a function of Henry s constant and the concentration of the gas (or its partial pressure). It is clear from Figure 1.1 that Henry s constant increases till the temperature of 100 °C and then decreases. As a result, under constant gas-phase concentration (or partial pressure), the solubility of oxygen decreases up to 100 °C and then increases. Consequently, the common belief of continuous decrease in the solubility of gases in water by increasing temperature is true up to a point (Debellefontaine et al., 1996, 2000). There is a certain temperature, different for each gas species, above which this picture is reversed. Moreover, above a certain temperature, the volatilization of water decreases the partial pressure of the gas, and thus the solubility could be further decreased even if Henry s constant is decreased at the same time. 

TABLE 4.1 Solubility of Gases in Water Explanation of the column headings... 

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