Chlorine dioxide is a synthetically produced gas. It is normally greenish-yellow and will have a smell similar to chlorine. It should be noted, however, that this gas has a different chemical composition than chlorine and interacts differently with other molecules. Chlorine dioxide is usually produced as a gas or liquid solution. The most common use is as household and industrial bleach.
Chlorine dioxide was discovered in 1814 by Sir Humphrey Davy, after he mixed sulphuric acid with potassium chlorate. Today, it is used in many industries. The paper industry is one that relies heavily on the use of the liquid form. It is used to bleach wood pulp and to strengthen the fibers of the paper that is produced from it. The medical industry uses the gas form for sterilization.
Chlorine dioxide is a hazardous material with the potential to be very dangerous. It can have a variety of negative effects on humans, such as causing skin burns and respiratory damage. Proper protective equipment, including gloves and gas masks, are necessary when dealing with this material at high concentrations. A gas mask, for example, is not generally necessary for household strength bleaching products if the area is well ventilated.
This material can be highly explosive. This is true even when it is concentrated in the air. Transportation of raw chlorine dioxide is kept to a minimum due to the risks posed by it. Furthermore, it is usually stored at cool temperatures in the liquid form, since this is when it is most stable and, therefore, most safe.
Storing chlorine dioxide as a gas under pressure increases the risk of explosion. It also reduces the amount of time the material can be stored before it will begin to separate into more basic components. Storing the material as a liquid solution, therefore, helps to extend the shelf life. It is also important that this material be kept in a cool area because heat and sunlight can cause it to break down.
Many people are aware of the use of chlorine for the disinfection of water. Chlorine dioxide is, however, an even better disinfectant. A small amount is often enough to eliminate both microbial and chemical pollution.
It has the ability to kill fungi, bacteria, and viruses. The way that it acts to kill each of these differs. In many cases, such as when giardia and cryptosporidium need to be eliminated, chlorine dioxide can be the most preferable choice. In the industrial setting, it is often used to disinfect drinking water and sewage water. At the household level, it is often used to disinfect items such as garbage containers and toilets.