Effects of Inorganic Salts and Polymers on the Foam Performance of 1-Tetradecyl-3-methylimidazolium Bromide Aqueous Solution

The foaming performance of 1-tetradecyl-3-methylimidazolium bromide (C14mimBr) aqueous solution, in the presence of polymers (PEG or PVA) or inorganic salts (NaBr, MgCl2, NaNO3, Na2SO4 or Na3PO4), was investigated at 25.0 °C by using the self-made apparatus and the conductivity method. The experimental results show that the foaming ability and foam stability of the ternary aqueous systems of C14mimBr coexisting with PEG or PVA are stronger than those of the C14mimBr solutions in the absence of a polymer, and both the efficiency of foaming ability and foam stability of the surfactant solutions are evidently enhanced with an increase in polymer concentration. However, the addition of inorganic salts can decrease the foaming ability and foam stability of C14mimBr solution. Especially, the inorganic salts, with high valence state of the anion (SO4 2− and PO4 3−), are good antifoam agents which can remove and inhibit foam quickly. For the aqueous solution of the surfactant, the effect of temperature on foaming properties was also examined. The results show that both the foaming ability and stability of the foams of the surfactant solutions decrease with an increase in the temperature within the range from 25.0 to 45.0 °C.