How to make coconut shell acitvated carbon

What is activated carbon?

There are many kinds of activated carbon in the market such as coal, anthracite, peat, charcoal …. When we speak of activated carbon, it is implied that we talk about coconut shell activated carbon made from coconut shells due to its uses and popularity.

How is activated carbon manufactured?

In Vietnam, there are many places where coconuts are planted a like Ben Tre (the West), Binh Dinh (the Central)Products made from coconuts can be used in the form of fresh fruit to get coconut juice or desiccated coconut to make coconut oil.

After taking the coconut meat out of the dry coconuts, the coconut shels are thrown away. Recently, coconut shells are used to make handicraft products…and these are the valuable export products, creating more jobs in local.

However, handicraft products only solve part of the large amount of coconut shells.One part is used to replace the wood burning in the household or burned in manufacturing incinerators because they produce high heat and are flammable.

Most of the rest are used to make coconut shell charcoal and coconut shell activated carbon because it is a good charcoal which does not contain heavy metals and toxic substances such as some types of coal and peat.

Production process of coconut shell charcoal is as follows:
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The selection of raw materials is the first important step to ensure a good quality product.
Select old coconut shell to have charcoal that has hard structure, not crumble into soot in the next stage.

 

The selected Coconut shells will be added to the furnace in the absence of oxygen at a high temperature of about 1200oC. Due to lack of oxygen, the combustion process takes place not completely, forming charcoal.
Charcoal at this stage is in pre-active form, in the form of shavings, used for water purification, waste water filtration.

To get porous structure and much lighter activated carbon, charcoal must experience the steam activation at temperature of 800 – 900 ° C.
During the activation process, charcoal is burned to generate tiny holes in it. Depending on the activation period, there will be many  kinds of charcoal with different properties.

When the activation is slow, the burning degree is low and charcoal has little holes (hole diameter from 0.1 – 15 A0 angstron): This charcoal is good at adsorbing gases, using to absorb toxic gases, solvent vapors and chemicals.

When the activation is fast, burning degree is high and charcoal has medium holes (hole diameter of 15 – several hundred A0) and is capable of bleaching, absorbing color in solution : This charcoal is used to remove color in solution, liquid products.

The holes are created aimlessly, interlaced in charcoal, creating porous structures. With the same volume of charcoal but after activation, the private surface area of ​​activated carbon increases thousands of times.

Because of its porous structure, activated carbon has the ability to absorb strongly smells and toxic gases in the air and it is good at keeping residues, heavy metal ions in water.

Therefore, the activated carbon is widely used in civil and manufacturing.

Besides tablet, granular activated carbon is also milled smoothly to cover in other materials in order to create carbon cloth for masks, carbon silk for respirators and porous carbon for air filter frame ….

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