Preparing CDS at home: The steps

Preparing chlorine dioxide (CDS) at home is a simple process to do, as long as you follow the steps and proportions precisely. In this guide, we will show you how to make CDS effectively using specific ingredients. It is important to follow the recommendations to ensure optimal results.

Materials and ingredients needed

Before you begin, make sure you have all of the following items for a smooth preparation:

1. Sodium chlorite (NaClO2) 25%

25% sodium chlorite is the main ingredient that when activated with acid releases chlorine dioxide. This product is essential for the chemical reaction, and it is important to use a 25% solution to achieve a reliable and effective result.

2. 4% hydrochloric acid (HCl)

Hydrochloric acid is used to activate sodium chlorite. At a concentration of 4%, this acid allows chlorine dioxide to be released when the two components are combined. It is important not to use other acids for this preparation in order to ensure that the reaction runs smoothly.

3. Distilled or mineral water (500 ml)

The water used must be of excellent quality to avoid any impurities. Distilled water is ideal for this preparation, as it is free of minerals or substances that could interfere with the reaction. Mineral water can also be used if it is pure and of good quality.

4. 500 ml glass container with airtight lid

A glass container with a capacity of 500 ml is required to contain the chemical reaction. It should be equipped with a tight-fitting lid to prevent any leakage of chlorine dioxide gas. Glass is the material of choice to avoid any unwanted interaction with the chemicals.

5. Measuring syringe

A syringe is essential for accurately measuring the volumes of sodium chlorite and hydrochloric acid. It ensures that the exact proportions are respected, thus ensuring good reactivity.

6. Small glass (10 ml)

This small glass will be placed inside the large container to hold the mixture of sodium chlorite and hydrochloric acid. It is essential that this glass remains isolated from the distilled water so that the chemical reaction produces chlorine dioxide gas without the liquids mixing.

Steps to prepare CDS

Here are the steps to get chlorine dioxide at home:

1. Prepare the container

Place the 500 ml glass container on a flat surface and open it. Position the small glass in the center of the container. Then, pour 500 ml of distilled water into the large container, being careful not to submerge the small glass. The goal is to leave the small glass inside without it coming into contact with the water.

2. Mix the reagents

Use the syringe to draw 5 ml of 25% sodium chlorite and pour it into the small glass placed inside the container. Then, using the same syringe (well rinsed beforehand), draw 5 ml of 4% hydrochloric acid and pour it also into the small glass. When these two reagents combine, the chemical reaction begins, producing chlorine dioxide in gaseous form.

3. Close the container

Quickly close the container with its tight-fitting lid to prevent any chlorine dioxide gas from escaping. Then place the container in a cool, dark place, such as a cupboard, and let it sit for about 12 hours. During this time, the chlorine dioxide gas will dissolve in the distilled water, turning it slightly yellow.

4. Repeat the process to increase concentration

After 12 hours, the distilled water in the container will have taken on a slight yellow tint, indicating that the chlorine dioxide has dissolved well. If you wish to obtain a higher concentration of CDS (up to 3,000 ppm), it is necessary to repeat the process.

To do this, carefully remove the small glass from the container without spilling the contents. Then, add 5 ml of 25% sodium chlorite and 5 ml of 4% hydrochloric acid back into the small glass. Place it back inside the large container, close the lid tightly, and let the chemical reaction continue for another 12 hours. This process will result in a more concentrated CDS.

CDS storage

Once the CDS is prepared, store it in opaque glass bottles to prevent light from degrading the solution. Keep it in a cool place, away from heat, to preserve its stability and effectiveness.