Physicochemical Processes: Precipitation

Study Notes

Precipitation occurs through a chemical reaction that forms an insoluble compound out of two or more soluble compounds.
It involves the separation of solids from a solution by altering the substance to an insoluble form or the solvent composition to lessen solubility.
A precipitate is the solid formed when a precipitation reaction occurs in liquids.
A precipitant is a substance that causes a precipitate to form when added to a solution or suspension (e.g., lime, caustic soda).
Supernatant is the remaining liquid above the precipitate.
Precipitation reactions occur when cations and anions of aqueous solutions combine to form an insoluble ionic solid (precipitate).
Factors affecting properties of the final product include temperature, pH, solvent, raw materials, additives, concentration, and composition.

Advantages:
- Helps create pure and homogeneous materials.
- It is a sensitive technique.
- Useful in determining the presence of a certain element in a solution.
- Very specific components can be removed without affecting other substances.
Disadvantages:
- Generates large volumes of salt-containing solutions.
- Requires product separation after precipitation.
- Difficulty in maintaining constant product quality throughout the process.
- Long reaction time.

Lyophilisation is a low-temperature dehydration process involving freezing the sample, lowering pressure, and removing ice by sublimation.
The process involves three stages: freeze, vacuum, and dry.

Ceramics: creates formable powders.
Food processing: instant meals, soups, juices, cheese, yoghurt, meats, probiotics, etc.
Dairy industry: high-value proteins.
Nutraceuticals: aloe vera, shark cartilage, etc.
Pharmaceuticals: proteins, enzymes, hormones, vaccines, biological products, etc.
Research.