water (an undesirable byproduct from ethanol production) from ethanol process streams due to the formation of an azeotrope at around 95.6 percent concentration by weight, molecular sieve beads are used to separate ethanol and water on a molecular level by adsorbing the water into the beads and allowing the ethanol to pass freely. Once the beads are full of water, temperature or pressure can be manipulated, allowing the water to be released from the molecular sieve beads. 3Å molecular sieves are stored at room temperature, with a relative humidity not more than 90%. They are sealed under reduced pressure, being kept away from water, acids and alkalis. 4Å Chemical formula: Na2O•Al2O3•2SiO2•9/2H2O Silica-alumina ratio: SiO2/ Al2O3≈2 Production Production of 4Å is relatively straightforward and requires neither high pressures nor particularly high temperatures. Combine aqueous solutions of sodium silicate and sodium aluminate at 80 °C mix/agitate for a time, then "activate" by "baking" at 400 °C 4A sieves serve as the precursor to 3A and 5A sieves through cation exchange of sodium for potassium (for 3A) or calcium (for 5A) Usage Drying solvents 4Å molecular sieves are widely used to dry laboratory solvents. They can absorb water and other molecules with a critical diameter less than 4 Å such as NH3, H2S, SO2, CO2, C2H5OH, C2H6, and C2H4. They are widely used in the drying, refining and purification of liquids and gases (such as the preparation of argon). Polyester agent additives These molecular sieves are used to assist detergents as they can produce demineralized water through calcium ion exchange, remove and prevent the deposition of dirt. They are widely used to replace phosphorus. The 4Å molecular sieve plays a major role to replace sodium tripolyphosphate as detergent auxiliary in order to mitigate the environmental impact of the detergent. It also can be used as a soap forming agent and in toothpaste. Harmful waste treatment 4Å molecular sieves can purify sewage of cationic species such as ammonium ions, Pb2+, Cu2+, Zn2+ and Cd2+. Due to the high selectivity for NH4+ they have been successfully applied in the field to combat eutrophication and other effects in waterways due to excessive ammonium ions. 4Å molecular sieves have also been used to remove heavy metal ions present in water due to industrial activities. Other purposes The metallurgical industry: separating agent, separation, extraction of brine potassium, rubidium, caesium, etc. Petrochemical industry, catalyst, desiccant, adsorbent Agriculture: soil conditioner