Activated carbons are commonly used in a lot of industries, but what are they? While these carbons are available, many people do not fully understand what they are or how they are made. If you are going to be using activated carbons, you need to know as much about them as possible.
What Is Activated Carbon?
Activated carbon is a highly porous and absorbent material which has a complex structure. As the name suggests, the structure is primarily made up of carbon, for an in depth overview, you can learn more about carbons here. The material has a network of pores which create channels in the skeletal structure of disordered layers of carbons. The channels are connected using chemical bonds and are stack unevenly. This is important because it will create the porous nature of the material.
The structure of these channels, cracks and nooks will help the activated carbon to remove impurities. It can remove these impurities from both liquid and gases. This is done through the process of absorption.
To make activated carbons a range of materials will be used. They can be made with coconut shells, lignite coal, olive pits, peat and wood. These materials will be put through either high-temperature steam activation mechanisms or chemical activation.
The Key Properties Of Activated Carbon
There are certain properties that activated carbon will have that you should know about. The first is the surface area. The higher the internal surface area of the material, the more effective the carbon will be. Activated carbon will have a very impressive surface area. Research has found that a spoonful of activated carbon will have a surface area that is the same as a soccer field.
The activation process used to create the activated carbon will create the large surface area. If steam activation is used, steam molecules at 1000°C will burn holes into carbonised raw materials. IF chemical activation is used, the phosphoric acid will build up the pores at a much lower temperature.
Another property is the total volume of pores. The pore space in the carbon is expressed using millilitres per gram or ml/g. This is volume relative to the weight. The higher the pore volume, the more effective the activated carbon will be. However, the size of the impurities to be absorbed will also need to be considered. They need to match the pore size or the full pore volume will not be used.
The last property is the pore radius which is important for absorption. The average pore radius is measured using angstroms and this will differ depending on the type of activated carbon. There are 3 common forms of activated carbon which are powder, granular and extruded. Each of these forms will also have varying sizes.
Activated carbon is a complex material that is commonly used to absorb impurities in gasses and liquid. This material can be made using two processes and have a number of properties that are key for their job. There are also different forms of activated carbon and they should be used for different purposes.