Molecular Sieves
For the distillation of ethanol for gasoline addition, the most common means of breaking the azeotrope is the use of molecular sieves. Ethanol is distilled to 96%, then run over a molecular sieve which adsorbs water from the mixture. The concentration is now above 96% and can be further distilled. The sieve is heated to remove the water and reused.
Read more about this topic: Azeotropic Distillation