Distilled water is water that has been purified by a process called distillation. This process removes impurities, including minerals, salts, and microorganisms, leaving behind pure H₂O. It’s commonly used in laboratories, medical settings, and industries where impurities in water could affect outcomes.
Distillation Process
Distillation involves boiling water to produce steam and cooling the steam to condense it into a liquid. The impurities, which do not vaporize at the same temperature as water, remain behind, allowing for the collection of pure water.
Instruments and Parts for Water Distillation
The main equipment used to distillate water is a distillation apparatus, commonly known as a water still. Here are the essential parts:
- Boiling Chamber (Heater/Boiler)
- This is where the water is heated to its boiling point to generate steam. It contains a heating element to raise the temperature of the water.
- Condenser
- A cooling system where the steam is condensed back into liquid form. The condenser usually consists of a coiled tube that passes through cool water, facilitating the condensation of the vapour into pure water.
- Cooling Water Inlet and Outlet
- These ports allow cold water to flow into the condenser to maintain a cool temperature, which is essential for efficient steam condensation.
- Collection Container
- A sterile container is used to collect the distilled water after condensation. It should be made of a material that does not react with water, like glass or high-grade plastic.
- Thermometer
- A thermometer is often attached to the boiling chamber to monitor the temperature of the water to ensure proper boiling.
- Vents or Exhaust
- To allow the release of non-condensable gases or excess pressure from the system.
Preparation of Distilled Water
The process of preparing distilled water is simple but requires precision. Here is a step-by-step guide:
- Filling the Boiling Chamber
- Fill the boiling chamber of the water distiller with tap water. Be careful not to overfill to prevent spillage during boiling.
- Heating the Water
- Turn on the heater to boil the water. The water will begin to evaporate and rise as steam.
- Condensing the Steam
- The steam passes into the condenser, which is cooled down using water from the cooling water inlet. This cooling process condenses the steam back into liquid form.
- Collection of Distilled Water
- The condensed steam is collected in a sterile collection container as distilled water. Be sure the container is clean to avoid contamination.
- Optional Filtration (Post-Distillation)
- For additional purification, the water may be filtered using activated carbon filters to remove any volatile organic compounds or gases that may have passed through the distillation process.
Storage of Distilled Water
Distilled water must be stored properly to maintain its purity. Here are the steps for proper storage:
- Sterile Containers
- Always use sterile, non-reactive containers (glass or high-quality plastic) cleaned and dried thoroughly. Avoid metal containers, as they can leach ions into the water.
- Sealed Lid
- Make sure the container is tightly sealed to prevent contamination from dust, microorganisms, or airborne particles.
- Cool, Dry Location
- Store the water in a cool, dry environment away from direct sunlight, which could promote algae growth if any contaminants are introduced.
- Avoid Long-Term Storage
- Use the distilled water within a reasonable period, as even properly stored water can eventually pick up contaminants from the air or the storage container.
Applications of Distilled Water
- Laboratory Use: Prevents contamination in experiments.
- Medical Use: Utilized in autoclaves, sterilization, and preparation of medications.
- Industrial Use: Used in mineral-free water processes, like car batteries or steam irons.
- Aquariums: Helps control water purity for fish health.