The Making Of Wood Based Activated Carbon
In order to make wood based activated carbon, it would entail steam processing at extremely high temperature. When charcoal is being physically activated, the whole process needs to be thoroughly controlled.
Activated carbons which are wood based are seen to have highly porous nature and their internal surface area is well developed too. The whole structure of these carbon molecules is formed by using the grapheme layers which have imperfect sectioning. These layers are then bound together to give rise to a 3D structure. Owing to the presence of different layers and alternate surfaces, the molecules get their porosity. It is this layering which significantly improves the bulk density along with mechanical strength and related physical properties as well.
In order to bring in the right changes in activated carbon, there are various conditions which have to be met. In order to ensure that there is product uniformity, the carbons are all analyzed as per a sift basis with regards to the properties such that one can offer the best quality to the customers.
One major concern when making the products is to take care of de-colorization. All the different forms of activated carbon are derived from solid, liquid or gaseous carbonaceous substances by one of two of the general methods. Both these methods need the starting material to be thermally decomposed. Let us take a look at the methods.
The first method involves oxidation of a carbonaceous substance that has been previously charred at extremely high temperature.
The next method involves chemical activation of carbonaceous materials with the help of different dehydrating agents including the likes of Zinc Chloride, KOH and so on.
Owing to the porous nature, activated carbon is capable of offering an extremely high surface area per unit volume and that too at relatively low cost when compared to other adsorbents that offers similar uses.
There are various separation processes which have industrial importance and they help in de-colorization of wood based activated carbon. Let us take a look at some of them.
- Removing small concentration of those products that have no taste, color or even odor but tend to cause poor crystal habit.
- Removing the different constituents which causes foam or even other surface active phenomena which is likely to interfere with processes like air blowing, evaporation and more.
- Removing impurities which lead to bad taste, color changes or even bad odor.
- Removing water in trace quantities from organic solvents which are water immiscible.
- Removing ionic metals in trace quantities by using organic reagent which is absorbable and thereby adsorbing the complex.
- Removing impurities which have no original color, but when processed, they may change color or even lead to changes in main component after packaging.
- Removing impurities that tend to cause turbidity or even haze. These include those products which do not precipitate and thereby leads to poor shelf life.
Removing the impurities from the liquid by using a little amount of immiscible solvent and then using adsorption process on the resulting solution. This can help when direct adsorption fails.