Effect of humidity on dynamic foam stability

Effect of Environmental Humidity on Static Foam Stability

“…In the case of a foam column, a nearlinear global humidity gradient in the freeboard far from the free surface has been previously observed. 13 However, at the scale of the bubbles at the very top of a foam layer, a humidity distribution as that schematically shown in the right panel of Figure 8 is expected. In the direction normal to the bubble surface, the humidity gradient is a maximum at the apex of the bubble and decreases as the position on the bubble surface falls away from the top.…”

“…CTAB was specifically chosen as Hutzler et al 11 suggested that it is less stable than SDS (sodium dodecyl sulfate), which we had previously used. 13 The concentration of 0.5 g/L was used because there are literature data showing that at this concentration the equilibrium surface tension of a CTAB solution is the least sensitive to temperature changes. 20 A glass tube with an internal diameter of 12 mm and a length of 145 mm was inserted into the beaker to support the foam.…”

“…This observation is consistent with previous studies on dynamic foams stabilized by SDS solutions of different concentrations. 13 Experimental results also show that conventional foam decay models based solely on foam drainage 8−11 or on uniform evaporation 16 are incomplete and not always effective. A new mechanism based on the Marangoni effect induced by nonuniform evaporation of the foam film is proposed to explain the strong dependence of foam stability on environmental humidity has been proposed.…”

Evaluation of a steady-state test of foam stability

“…In the Bikerman test [1], which recently attracted renewed interest for the characterisation of foams used in froth flotation [5,6], gas is sparged at a constant flow rate through a foam solution and the foam is collected in a vessel. After an initial increase, the height of the foam column reaches a maximum, whose value depends on the flow-rate Q of the gas.…”

Foaming of CO2-Loaded Amine Solvents Degraded Thermally under Stripper Conditions

“…It is then suggested that the foaminess is independent of gas flow rate through the liquid and the total volume of liquid used; additionally, the tube shape and dimensions are said to have no impact. Recently, concerns have been highlighted over the failure of Bikerman's model to account for the environmental conditions, particularly humidity 9 . As a result of these and other limitations, other empirical models have been suggested as replacements for the Bikerman model, to incorporate more physical properties.…”