Thermodynamic quantities of surface formation of aqueous electrolyte solutions X. Aqueous solution of 2:1 valence-type salts

Abstract

The behaviors of a series of calcium halides and of alkali earth metal chlorides in the air/water surface region were studied in comparison with those of alkali metal halides by measuring the surface tension increments of solutions. The effect of salts with divalent cation on the surface tension increments is pronounced than that of uni-univalent salts, but there are some similarities between these two types. It seems that the anions cause a marked effect on surface tension which is proportional to the magnitude of hydration in the bulk water. We also observed the decrease in the entropy change of surface formation with increasing concentration. The importance of electrical double layer at the surface was discussed in relation to these surface tension increments.

Synergistic Effect of Brine System Containing Mixed Monovalent (NaCl, KCl) and Divalent (MgCl2, MgSO4) Salts on the Interfacial Tension of Pure Hydrocarbon–Brine System Relevant for Low Salinity Water Flooding

“…A continuous increase or decrease in IFT trend was also reported at a relatively very high salt concentration (0.5–1.5 M for NaCl and KCl) in brine and large difference in salt concentration (0.5 M) between two consecutive trials for hydrocarbon–brine system . The increase in the trend of IFT for hydrocarbon–brine system was reported by other researcher as well. ,,, Lima et al justified that the abrupt behavior of IFT could be due to variable ionic size and chemical potential. Recently, one of our studies reported the impact of low salt concentration on the IFT of hydrocarbon–water system.…”

“…The reason for drop and rise of IFT was explained using the Gibbs adsorption isotherm. However, the conclusions drawn on the trend of IFT by various investigators 12,29,33 on hydrocarbon−brine system were not identical. The contradictory statements could be due to the consideration of different ranges of salt concentration by the investigators during their study.…”

“…29 The increase in the trend of IFT for hydrocarbon−brine system was reported by other researcher as well. 22,23,33,34 Lima et al 29 justified that the abrupt behavior of IFT could be due to variable ionic size and chemical potential. Recently, one of our studies 12 reported the impact of low salt concentration on the IFT of hydrocarbon− water system.…”

Soil-water contact angle as affected by the aqueous electrolyte concentration

“…The addition of electrolytes into pure water would increase the surface tension of the solutions (Jones and Ray 1941;Bostrom et al 2001;Ozdemir et al 2009;Matubayasi et al 2011;Holthusen et al 2012). These surface tension increments can be related to the force balance at the three-phase contact line formed by the drops of electrolyte solutions on the soil surfaces, and therefore to the contact angle.…”

“…In general, the surface tension of water increases when inorganic salts (such as sodium chloride (NaCl), potassium chloride (KCl), sodium sulfate (Na 2 SO 4 ), calcium chloride, (CaCl 2 ), etc.) are dissolved (Jones and Ray 1941;Bostrom et al 2001;Ozdemir et al 2009;Matubayasi et al 2011;Holthusen et al 2012), while it decreases when organic substances (ethanol, methanol, fatty acids, soaps, detergents, etc.) are added.…”