What is Activated Carbon?

Adsorption on Activated Carbon

 Adsorption on activated carbons means physical adsorption ,which refers to an adsorptive phenomenon caused by the attractive forces between molecules (the Van der Waals Force) on a carbon surface without chemical reaction involved.

 Adsorption can be retained by a certain chemical combining power on a carbon surface in some adsorbates . This is called chemical adsorption whose reaction could be utilized in some special adsorbents.

For this reason, it can be said that the wider the surface area, the greater the probability of adsorption. The surface area of activated carbon is between 1,000 m2/g and 2,000m2/g , which makes it an ideal material as an adsorbent.



History of Activated Carbon

 It is described that wood carbon was used as fuel, metalwork and medicines before the Common Era.
In the 18th century : Refining of cane sugar with wood carbon
In the 19th century : Uses of bone char and blood carbon for cane sugar and sugar beet
           Utilization of gas adsorption from coconut charcoal and development
           of powdered carbon
In the 20th century : Use of gas mask made from coconut charcoal during WW I.
           Developments of production and applied technologies of granulated
           and powdered activated carbons

 The First World War triggered off the rapid expansion of applications of granulated activated carbon such as the purification of various gases, air ,industrial chemicals,etc.

 In recent years, the demand for activated carbons has been growing for the application for the environmental protection. The carbons for improving the quality of water and removing dioxin has grown in great demand.



Raw Materials to make activated carbon

 Activated carbon can be made from various materials : sawdust, coconut shell,etc. from plant sources, , and lignite, bituminous coal, anthracite,etc. from mineral sources for industrial production.
 The raw material exercises a large influence on the characteristics and performance of activated carbon. The right activated carbon should properly be chosen for the specific application.


Pores of Activated Carbon

 Activated carbon pores are comprised of micro pores, transport pores and macro pores.
 It is regarded that adsorptive functions vary depending on pore size.
 Macro pores are considered to act mainly as the path for the adsorbates to reach the adsorption pores where they are adsorbed.
 In the meanwhile, most adsorption occurs in the micro pores which develop in every carbon.

 The degree to which micro pores develop and the number of macro pores and transport pores vary depending on manufacturing methods or raw materials ,which lead to different adsorptive capabilities.


Methods for Manufacturing Activated Carbon

Powdered activated carbon     granulated activated carbon   Fibrous carbon
┌── ─┴─ ──┐            
Chemical activation   Steam activation Steam activation Steam activation






┌── ─┴─ ──┐    











   
crushed carbon   pelletized carbon        
       
Sawdust Sawdust Coconut and coal Coconut and coal        









       
Carbonizing Crushing        
       
Immersion Particle size regulation Pelletizing        






       
Carbonizing Carbonizing Burning
       
Burning Burning











Burning Burning Cutting and crushing












       
Chemical recovery Crushing











Material processing
       
Washing Washing Washing Product processing
Sheet

  Molded form

  Speciality

Drying Drying Drying    

Crushing and grading Grading Screening Screening

 





       
Preparation Preparation  

Finishing processing

           
Measurement and packaging Measurement and packaging Measurement and packaging Measurement and packaging Packaging
       
Shipment Shipment Shipment Shipment Shipment