The principle is that the tested carbon is put in contact with iodine in order to calculate the amount that can adhere to it. Typically, the retention rate of iodine by activated carbon varies between 500 - 1200 mg/g which is approximately equivalent to an adherence surface of 900 to 1100m2/g.
The Iodine Index Test
Although it is not the only test that allows the identification of the porosity of a carbon, the iodine index is widely used because it is a relatively accurate and simple test. For your information, the iodine value is a measure of the degree of absorption of a substance or material. The higher the rate of absorption or adsorption, the higher the iodine value.
- Iodine is an element of the periodic table that is part of the halogens. It is generally found in the food industry and in the production of soap.
The importance of the iodine value of carbon in the water treatment environment
Although it is rare that this index must be referred to, it happens that for particular uses, the activated carbon chosen must have a higher porosity.
It is generally in hospital, pharmaceutical or any other field where the water must be ultra pure that these demands are common.
In short, as mentioned above, the iodine value of the activated carbon allows identifying its adherence surface. This means that a smaller amount of carbon can provide a better extraction rate. So, let's say you are using activated carbon for dechlorination of your water and you have limited space. By choosing a carbon with a higher iodine value, you may be able to save space while still performing your treatment properly.