Estimation of Water−Organic Interfacial Tensions. A Linear Free Energy Relationship Analysis of Interfacial Adhesion

Abstract

The work of adhesion between water and a series of immiscible organic liquids has been found to obey a linear solvation free energy relationship (LSER) on the basis of solute parameters for the organic compound. This relationship, together with the surface tensions of water and of the pure organic liquids, allows reasonably accurate estimation of the corresponding interfacial tensions and provides insight into the nature of intermolecular forces at the water−organic interface. Furthermore, the similarity of this multiparametric LSER to that for partitioning of organic solutes between water and the gas phase (log L W) leads to a much simpler two-parameter relationship. Estimation of the interfacial tension with this latter relationship requires a knowledge of only two parameters, log L W and the surface tension of the pure organic liquid. Since reasonably accurate group contribution methods are available for estimating both log L W and surface tensions from molecular structure, this result provides a novel approach for a priori estimation of the water−organic interfacial tension directly from the chemical structure of the organic compound itself.

Mobilization of Manufactured Gas Plant Tar with Alkaline Flushing Solutions

“…The measured IFT for DCM in DDI was 27.7 ± 0.6 mN/m (n=7), in good agreement with literature values, which ranged from 27.4–28.3 mN/m (47–51). The IFT from (47) was measured at 20°C, while all other literature values were reportedly measured at room temperature.…”

“…The IFT from (47) was measured at 20°C, while all other literature values were reportedly measured at room temperature.…”

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“…Interfacial tension data support these findings where polymer adsorption is observed as a decline in surface tension between pH 1.5 and 4, but tension then rises from pH 4 to 4.5; interfacial tension reaches a constant value of 44 mN∕m, which is very near the neat interfacial tension value of CCl 4 -water (38,39). For PAA, complete desorption occurs over the pH range 4-4.5 and according to the titrations in this laboratory, it occurs at 20% deprotonation of the polymer in bulk, far below the known pK a .…”

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“…2B, red data points), with interfacial tension values dropping to ~30 mN/m compared to the neat CCl 4 -H 2 O value of ~45 mN/m. 78 At pH ≥ 4.5 (Fig. 2B, blue data points), the interfacial tension does not change significantly compared to that of the neat CCl 4 -H 2 O interface, supporting that the lack of VSF signal at these pH values signifies an absence of polymer at the interface.…”