The ability of the zeolite to adsorb some molecules and to reject others gives it the ability to act as a molecular sieve. For example, in the manufacture of ethanol from ethene or from biomass, an aqueous solution of ethanol is produced, in which there is 4% water still present even after repeated distillations. Further purification of ethanol requires the use of a zeolite which absorbs the water preferentially. Table 2 gives examples of industrial processes involving zeolites.