Dispersing phase characteristics and examples

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Philip Kelley

The dispersant phase It is the component of dispersions in which a set of particles that make up the dispersed phase are suspended. It is characterized by being continuous, and although it is thought to be liquid, it can have all the physical states of matter. It is considered the abundant phase in the dispersions.

The colloidal system is a form of dispersion, in which the dispersing phase is the substance in which the colloidal particles are suspended. Compared to true solutions, the dispersing phase equals the solvent.

Source: Pixabay

Regarding the dispersant, although it is accepted that it is the continuous phase of a dispersion, it can be objected that it is always the most abundant.

For example, if 15 g of solid potassium iodide (KI) are dissolved in 10 g of water, it can be concluded that the most abundant substance is potassium iodide; but it is still considered that the dispersant or the dispersant phase is constituted by water. The resulting homogeneous and liquid mixture is said to be a solution of potassium iodide in water..

Article index

  • 1 Features
  • 2 Types of colloids
    • 2.1 Sun
    • 2.2 Gel
    • 2.3 Emulsion
    • 2.4 Aerosol
    • 2.5 Foam
  • 3 Examples of dispersant phase
    • 3.1 Aerosols
    • 3.2 Solid aerosols
    • 3.3 Foam
    • 3.4 Emulsion
    • 3.5 Sun
    • 3.6 Solid foam
    • 3.7 Gel
    • 3.8 Solid solutions
    • 3.9 Crude oil
  • 4 References

Characteristics

The dispersant or dispersant phase in colloids is made up of particles with a diameter less than 10-9 m. Therefore, they are smaller in size than dispersed phase particles having a diameter between 10-9 m and 10-6 m. The dispersant particles are introduced between the particles of the dispersed phase.

For this reason we speak of the continuity of the dispersing phase compared to the dispersed phase that is discontinuous and formed by discrete particles..

Colloids (colloidal dispersions) represent an intermediate type of mixing in which the analogous particles, the solute or the dispersed phase, are suspended in a phase analogous to the solvent, or dispersing medium..

All combinations of solids, liquids and gases can form the different types of colloids..

Types of colloids

Sun

It is a liquid or solid colloid. The dispersing phase is usually liquid, while the dispersed phase is solid in nature..

Gel

It is a colloid characterized by having a solid dispersing phase and a dispersed phase in liquid state.

Emulsion

It is a colloid or liquid colloidal system constituted by the mixture of a liquid dispersant phase as well as the dispersed phase. To avoid the separation of the phases an emulsifying substance is incorporated.

Aerosol

It is a gaseous colloid formed by a gaseous dispersant phase and the dispersed phase can be liquid or solid.

Foam

It is a colloid whose dispersant phase can be liquid or gaseous, and the dispersed phase a gas (generally air or carbon dioxide).

Examples of dispersant phase

Aerosol sprays

In the gaseous state, it combines with the colloidal dispersed phase in the liquid state, giving rise to an aerosol-type colloid. Of them there are the following examples:

-The fog

-Steam

-Hairspray

Solid aerosols

In the gaseous state, it combines with the colloidal dispersed phase in the solid state, giving rise to solid aerosols. Among them are:

-Smoke

-Clouds and particles in the air.

Under the same conditions, the combination of the dispersant phase with the dispersed phase of the coarse dispersions gives rise to solid aerosols. Example: dust.

Foam

In the liquid state, it combines with the disperse colloidal phase in the gaseous state, giving rise to the foam-like colloid. An example of this is whipped cream and shaving cream..

Emulsion

In the liquid state, it combines with the disperse colloidal phase in the gaseous state, giving rise to the emulsion-type colloid, with the following examples: mini-emulsion and micro-emulsion.

Under the same conditions, the combination of the dispersant phase with the dispersed phase of the coarse dispersions produces the emulsion. Examples: milk and mayonnaise.

Sun

In liquid state, it combines with the colloidal dispersed phase in solid state, giving rise to the sol-type colloid, with the following examples: pigmented ink and plasma.

Under the same conditions, the combination of the dispersant phase with the dispersed phase of a coarse dispersion, gives rise to suspensions. Examples: mud (soil, clay, or silt) suspended in water.

Solid foam

In solid state, it combines with the disperse colloidal phase in the gaseous state, giving rise to the solid foam-like colloid:

-Airgel

-Styrofoam

-Pumice stone

Under the same conditions, the combination of the dispersing phase with the dispersed phase of a coarse dispersion causes the foam. Example: dry foam.

Gel

In solid state, it combines with the colloidal dispersed phase in liquid state, giving rise to the gel-like colloid. You have the following examples:

-Agar

-Gelatin

-Silica gel and opal.

Under the same conditions, the combination of the dispersant phase with the dispersed phase of a coarse dispersion, gives rise to a wet sponge..

Solid solutions

In solid state, it combines with the colloidal disperse phase in solid state, giving rise to solid solutions. Example: cranberry glass.

Under the same conditions, the combination of the dispersant phase with the dispersed phase of a coarse dispersion, gives rise to gravel and granite..

Crude oil

It has been seen so far that any compound or substance can act as a dispersing phase. However, there is a complex mix that stands out from the rest: crude oil.

Why? Because it is composed of hydrocarbons and other organic compounds in liquid, gas or solid phase. Inside the liquid part, known as oil, lie emulsions of water and some macromolecules known as asphaltenes.

Considering only the water, the crude oil is a black oil with aquatic microemulsions stabilized by asphaltenes; and observing only the latter, their colloidal polymeric aggregates confer part of the characteristic black color of crude oil..

Of all the dispersant phases, this is perhaps the most complex of all. In fact, its dynamics is still the object of study, whose objective or north is the increase in oil activity; such as, for example, increasing the profitability of extracting extra heavy crudes compared to light crudes that are highly valued in the world market.

As long as there are particles that can be grouped and isolated from a molecular environment (although without being able to avoid its effects) with which it does not have much affinity, there will always be dispersing phases.

References

  1. Jiménez Vargas, J and Macarulla. J. Ma. Fisicoquímica Fisiológica (1984) Sixth edition. Editorial Interamericana.
  2. Whitten, Davis, Peck & Stanley. Chemistry. (8th ed.). CENGAGE Learning.
  3. Rodríguez S. (October 13, 2014). Types of colloids. Recovered from: auladeciencia.blogspot.com
  4. Chemistry Learning. (May 16, 2009). Colloidal Dispersions. Recovered from: chemistrylearning.com
  5. Emulsions and Emulsifiers. [PDF]. Recovered from: cookingscienceguy.com

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