Mixtures

There are three main mixtures to be aware of during separation, suspensions, emulsions, and solutions. The properties of the different kinds of mixtures reflect the properties of the compounds that make them up. For example, solutions mean that your compound is soluble in the chosen solvent. As a result, from looking at the mixture alone we can start thinking of separation techniques.

Suspensions

Suspensions contain solids or solid particles in a solvent. The particles are large enough, so that they are insoluble in that solvent. Eg. pebbles flowing in river water.

Suspensions can be separated using filtration.

Emulsions

Emulsions contain liquids that are immiscible, the liquids do not mix, which creates a liquid-liquid phase separation. Eg. silver bromide emulsion used to develop polaroids.

When immiscible liquids settle, the phase separation forms a boundary layer, where the more buoyant or lighter liquid sits on top of the more dense liquid.

Settled emulsions can be separated by aptly named separating funnels.

Solutions

Solutions are aqueous liquids that contain any number or amount of solute uniformly dissolved in a solvent. Eg. sugar in your morning coffee. The sugar is the solute, the hot water is the solvent and the solution is your resulting coffee.

Solutions are separated by a range of techniques depending on the properties of the solute and solvent.

Figure 1: Image depicting suspensions, emulsions and solutions