Making Distilled Water

Distilled water is water that has been purified by boiling and then condensing the steam back into liquid. This process removes impurities, including minerals, salts, and other contaminants, resulting in pure water. Distilled water is commonly used in laboratories, medical facilities, and for various household tasks.

In this guide, we’ll explore different methods of making distilled water, along with the chemical processes behind each method.

Method 1: Simple Distillation

Simple distillation is the most common method for making distilled water. It works by heating water until it vaporizes and then condensing the vapor back into liquid form. This process separates the water from its impurities, as they have higher boiling points than water and remain behind.

Steps for Simple Distillation

  • Step 1: Pour tap water into a large heatproof container (such as a pot).
  • Step 2: Place a small heat-resistant bowl in the center of the pot. This will collect the distilled water.
  • Step 3: Cover the pot with an inverted lid. The lid should be placed upside down so that the steam condenses and drips into the bowl.
  • Step 4: Heat the water to a boil. As the water evaporates, the steam will rise, condense on the lid, and then drip into the bowl, leaving impurities behind.
  • Step 5: Once enough water has collected in the bowl, turn off the heat and let the system cool.
  • Step 6: The water in the bowl is now distilled and ready for use.

The equation for this process can be expressed as:

\( \text{H}_2\text{O (l)} \xrightarrow{\text{boiling}} \text{H}_2\text{O (g)} \xrightarrow{\text{condensation}} \text{H}_2\text{O (l)} \)

Method 2: Steam Distillation

Steam distillation is often used when you need to separate water from volatile compounds, like essential oils. This method is similar to simple distillation but involves passing steam through the water to speed up the evaporation process.

Steps for Steam Distillation

  • Step 1: Heat water in a flask until it begins to produce steam.
  • Step 2: Direct the steam into another container filled with impure water, causing the water to evaporate faster.
  • Step 3: The steam from both the impure water and the original flask is collected in a condenser, where it cools and condenses back into liquid.
  • Step 4: The condensed liquid is distilled water, free of volatile compounds and impurities.

This method is commonly used in the purification of substances that are sensitive to high temperatures or would degrade at the boiling point of water.

Method 3: Solar Distillation

Solar distillation uses the sun’s energy to purify water. This method is often used in arid regions or emergency situations where conventional heating is not available. It mimics the natural water cycle, where water evaporates, condenses, and then falls back as rain.

Steps for Solar Distillation

  • Step 1: Place impure water in a shallow basin or tray inside a solar still (a device designed to capture solar energy).
  • Step 2: Cover the basin with a transparent lid or plastic sheet, slanted downward.
  • Step 3: The sun heats the water, causing it to evaporate.
  • Step 4: As the water vapor rises, it condenses on the underside of the plastic or glass cover.
  • Step 5: The condensed water droplets roll down the slanted cover and collect in a separate container, leaving impurities behind.

This process harnesses solar energy and can be expressed as:

\( \text{H}_2\text{O (l)} \xrightarrow{\text{solar energy}} \text{H}_2\text{O (g)} \xrightarrow{\text{condensation}} \text{H}_2\text{O (l)} \)

Method 4: Reverse Osmosis

Reverse osmosis (RO) is a filtration process where water is forced through a semi-permeable membrane that removes impurities. While this method doesn’t involve distillation, it achieves a similar level of purity and is widely used for producing clean drinking water.

Steps for Reverse Osmosis

  • Step 1: Water is pressurized and pushed through a semi-permeable membrane, which allows only water molecules to pass through.
  • Step 2: Impurities, including salts and minerals, are left behind and discarded.
  • Step 3: The filtered water is collected as pure, “distilled-like” water.

This process can be represented as:

\( \text{H}_2\text{O (l)} \xrightarrow{\text{pressure}} \text{H}_2\text{O (pure)} \)

Conclusion

Making distilled water is a relatively simple process, with several methods available depending on your resources and needs. Whether you use simple distillation, steam distillation, solar distillation, or reverse osmosis, each method effectively removes impurities from water.