Turbulence effects on volatilization rates of liquids and solutes

Volatilization rates of neat liquids (benzene, toluene, fluorobenzene, bromobenzene, ethylbenzene, m-xylene, o-xylene, o-dichlorobenzene, and 1-methylnaphthalene) and of solutes(phenol, m-cresol, benzene, toluene, ethylbenzene, o-xylene, and ethylene dibromide) from dilute water solutions have been measured in the laboratory over a wide range of air speeds and water-stirring rates. The overall transfer coefficients NO for individual solutes are independent of whether they are in single- or multi-solute solutions. The gas-film transfer coefficients (k(G)) for solutes in the two-film model, which have hitherto been estimated by extrapolation from reference coefficients, can now be determined directly from the volatilization rates of neat liquids through a new algorithm. The associated liquid film transfer coefficients (k(L)) can then be obtained from measured K-L and k(G) values and solute Henry law constants (H). This approach provides a novel means for checking the precision of any k(L) and k(G) estimation methods for ultimate prediction of K-L. The improved k(G) estimation enables accurate K-L predictions for low-volatility (i.e., low-H) solutes where K-L and k(G)H are essentially equal. In addition, the prediction of K-L values for high-volatility (i.e., high-H) solutes, where K-L congruent to k(L), is also improved by using appropriate reference k(L) values.