A separation process divides a mixture into streams with different compositions by exploiting a difference in physical or chemical behaviour. Distillation uses volatility, filtration uses particle or pore-scale exclusion, and solvent extraction uses partitioning between phases. Separation need not create chemically pure products, and recovery of one component can trade against its purity. A mass balance relates feed and product streams; thermodynamics and transport determine which separations are feasible and how rapidly they proceed.
Transfer of constituents from a solid into a contacting liquid. A measured solution inventory can underestimate total solid alteration when secondary precipitation or sorption retains released constituents.
Reversible exchange of ions between a solution and an ion-bearing solid. Selectivity, competing dissolved ions and the solid exchange capacity control contaminant removal.
A polymeric ion exchanger with fixed charged sites and mobile counterions. Exhausted resin is a secondary waste; ion exchange is not an unrestricted removal method for neutral dissolved molecules.
Transfer of a solute between immiscible liquid phases according to its relative chemical affinities. complexation and oxidation state can change the distribution; selective back-extraction is often called stripping. Extraction efficiency alone does not establish separation from a second solute.
Alcoholic extraction uses an alcohol-containing solvent, commonly ethanol mixed with water, to transfer soluble components from a material into a liquid phase. The composition extracted depends on solvent composition, solute interactions and the starting matrix. It is a form of solvent extraction, not a reaction that necessarily creates alcohol. Partitioning and mass transfer distinguish the equilibrium preference for a solute from the rate at which it leaves a particle or tissue. An extracted mixture can contain multiple compounds, so the extraction solvent alone does not establish purity or identity.
