List of purification methods in chemistry

Purification in a chemical context is the physical separation of a chemical substance of interest from foreign or contaminating substances. The following list of chemical purification methods should not be considered exhaustive.

• gases by passing the feed stream through a porous sheet such as a cloth or membrane, which retains the solids and allows the liquid to pass through.
• Centrifugation separates solids from liquids, or separates two immiscible liquids, on the basis of density.
• solutes which cannot be done through filtration due to the small size of the substances.
• Extraction removes an impurity, or recovers a desired product, by dissolving it in a insoluble.
• crystals. The pure solid crystals are then separated from the remaining liquor by filtration or centrifugation. In analytical and synthetic chemistry work, purchased reagents of doubtful purity may be recrystallized, e.g. dissolved in a very pure solvent, then crystallized and the crystals recovered, in order to improve and/or verify their purity.
• Chromatography employs adsorption and desorption on a packed bed of a solid to purify multiple components of a single feedstream.
• chemicals to the ore and heating it up to the melting point of the metal.
• Refining is used primarily in the petroleum industry, whereby crude oil is heated and separated into stages according to the condensation points of the various elements.
• ethanol separates volatile liquids on the basis of their boiling point.
• Water purification combines a number of methods to produce potable or drinking water.
• insulin.
• Fractionation refers to a purification strategy in which some relatively inefficient purification method is repeatedly applied to isolate the desired substance in progressively greater purity.
• Electrolysis refers to the breakdown of substances using an electric current. This removes impurities in a substance that an electric current is run through