Effects of Electrolytes in Hydrophobic Systems. I. Electric Mobility and Stability.

Hazel, Fred

doi:10.1021/j150410a002

Cited by 4 publications

(6 citation statements)

References 12 publications

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“…In the Aerosol solution, where a much greater degree of dispersion is postulated, this second factor becomes inconsequential. The greater sedimentation volume found with the more acid water is probably attributable to an increase in aggregation resulting from lowering of the zeta potential by adsorption of hydrogen ion, since manganese dioxide is known to be negatively charged in aqueous dispersion (16,36).…”

Section: Sedimentation Volumesmentioning

confidence: 99%

Suspension of Manganese Dioxide in Detergents.

Greiner¹,

Vold²

1949

J. Phys. Chem.

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The controlled formation of stable dispersions of solid powders in liquids is of both theoretical and practical interest. The suspendibility of a powder depends upon and aids in the understanding of the surface properties of the disperse phase, as these affect, cohesion between particles in various media and as they result, in selective adsorption of ions or molecules from solution. Moreox-er many commercial products, such as paints and printing inks, consist of finely clix idecl solids dispersed in liquids. It also seems likely that the relative effectiveness of detergents may be closely related to their ability to stabilize suspensions of removed dirt.In the present work the effectixre particle-size distribution of powdered manganese dioxide was determined in a number of media to aid in ascertaining the mechanism whereby relat.ix'ely stable dispersions may be produced in aqueous solutions. The amounts remaining in suspension after a 4-hr. settling period xvere also determined as a function of concentration in aqueous solutions of Aerosol OT, Oronite, Hyamine 1622, Triton X-100, sodium oleate, and p-t.oluenesulfonic acid. Characteristically, the curxres of amount suspended vs. concentration of dispersing agent pass through a maximum at low concentrations. It seems likely that the shapes of these cuives, as well as the differences between different, detergents, are explicable in terms of varying effectix'eness in disgregation of the aggregates xvhich normally form on introducing a powder of given ultimate particle size into a pure liquid. The mechanism by xvhich this is accomplished appears to be through change in the zeta potential effected by adsorption of ions from solution. MATERIALS Baker's c.p. manganese dioxide powder was used throughout this work without further purification.Aerosol OT was obtained from the American Cyanamid Company in the form of "100%" pellets and used directly. It is the sodium salt of dioctylsulfosuccinic acid.Oronite Actix'e, made by the California Research Company, was a sample receix'ed through the courtesy of the Lever Brothers Company, and described as 1 ITesentcd at the Twenty-second National Colloid Symposium, which was held under the auspices of the Division of Colloid Chemistry of the American Chemical Society at Cambridge. Massachusetts, .June 23-2.5, 1948.

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Section: Sedimentation Volumesmentioning

confidence: 99%

Suspension of Manganese Dioxide in Detergents.

Greiner¹,

Vold²

1949

J. Phys. Chem.

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“…As opposed to the characteristics which are associated with the coagulation of a sol of a given concentration with a strongly adsorbable polyvalent ion, the phenomena associated with the flocculation of the same sol by an electrolyte of the potassium chloride type are as follows: (1) a high concentration of electrolyte is required; and (2) coagulation occurs at a high critical mobility. These phenomena have been discussed in a previous communication (5), where it was proposed that compression of the electric double layer at high electrolyte concentrations played an important róle in the precipitation of sols with univalent ions of low adsorbability.…”

Section: Resultsmentioning

confidence: 85%

“…The effects of electrolytes on the mobility and the stability of a manganese dioxide sol and of an arsenic trisulfide sol of different concentrations were studied in the present investigation. The same stock samples of sols were used in this work as were employed in the critical mobility studies previously reported (5), and, in both cases, the experimental techniques were the same.…”

Section: Introductionmentioning

confidence: 99%

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Effects of Electrolytes in Hydrophobic Systems. II. Sol Concentration and Electrolyte Stability.

Hazel¹

1941

J. Phys. Chem.

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“…In a previous communication (2) an explanation was offered to account for the high critical mobilities toward certain poorly adsorbable monovalent ions. It was concluded that compression of the double layer at high electrolyte concentrations was of primary importance in the coagulation of sols by ions of this valence type.…”

Section: Discussionmentioning

confidence: 99%

Effects of Electrolytes in Hydrophobic Systems. III. Studies with Mixtures of Electrolytes: Ion Antagonism.

Hazel¹

1941

J. Phys. Chem.

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The flocculation value of a mixture of two electrolytes for an arsenic trisulfide sol can be computed additively, if the precipitating power of each of the electrolytes is of the same order of magnitude (4), while, if the electrolytes differ markedly in their precipitating power, as do potassium chloride and barium chloride, the flocculation value of the mixture is greater than the additive value (7).The phenomenon of ion antagonism has been observed for a number of electrolyte pairs with several colloidal systems, e.g., Odén's sulfur sol (1), copper ferrocyanide sol (6), mercuric sulfide sol (3) and selenium sol (3). The explanation offered by Freundlich and Scholz (1), namely, that hydration is a critical factor in determining ion antagonism, has been evaluated by Weiser (7), who has pointed out that other factors also must be considered: (1) the antagonistic effect of each precipitating ion on the adsorption of the other, and (ß) the stabilizing influence of the ions having the same charge as the sol. Kruyt and van der Willigen (3) correlated flocculation data with electrophoretic measurements and reached the conclusion that, whenever a salt raises the charge (mobility) of the particles, its addition also will raise the flocculation value of a second salt.The present study is concerned with the electrophoretic and the coagulating behaviors of the salt pairs potassium chloride-barium chloride and potassium chloride-chromium chloride with a manganese dioxide sol and an arsenic trisulfide sol. The investigation is the third of a series of reports which have dealt with anomalies of monovalent ions as applied to the above colloidal systems. The same stock samples of sols were used throughout the investigations and the experimental methods wrere the same. results Flocculation data for the two sols, each at three different concentrations, are given in tables 1 and 2 in terms of millimoles of. electrolyte per liter. The experiments wrere conducted by adding 2 cc. of sol to 3 cc. of electrolyte mixture. The amounts of barium chloride and of chromium chloride required to coagulate the colloidal systems were determined when each of these electrolytes was present with 25, 50, and 75 per cent of the flocculating concentration of potassium chloride.

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Effects of Electrolytes in Hydrophobic Systems. I. Electric Mobility and Stability.

Abstract: 1. The critical mobilities of several monovalent ions of different co" agulating power have been determined for colloidal manganese dioxide.2. These values were found to be higher the lower the coagulating power EFFECTS OF ELECTROLYTES IN HYDROPHOBIC SYSTEMS. II

Cited by 4 publications

References 12 publications

Suspension of Manganese Dioxide in Detergents.

Suspension of Manganese Dioxide in Detergents.

Effects of Electrolytes in Hydrophobic Systems. II. Sol Concentration and Electrolyte Stability.

Effects of Electrolytes in Hydrophobic Systems. III. Studies with Mixtures of Electrolytes: Ion Antagonism.

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