One of the most porous materials with a large surface area is activated carbon, also referred to as activated charcoal. With these features, the material becomes an excellent absorbent. It has wide applications in water purification, air filtration systems, medicine, and even beauty products. Coconut shells are one of the most viable and cheap sources of activated carbon. The following blog is a step-by-step and detailed guide on the extraction of activated carbon from coconut shells, elaborating on each step from its preparation to its final activation process.
Why Coconut Shells?
Coconut shells are a perfect raw material for producing activated carbon, basically carbon, renewable, and by-product from coconut processing. Therefore, not only does this account for the reutilization of waste products of coconut processing but also gives an eco-friendly and renewable resource alternative. By reusing the coconut shells, you put less waste into the environment, ensuring your future generation a safe and unpolluted world.
Step-by-Step Procedure in the Extraction of Activated Carbon
Collection and Cleaning of Coconut Shells
Collection: Begin by collecting coconut shells from processing houses or directly from coconuts. The coconut shells are normally wasted but hold good carbon material that is feasible to be converted into activated carbon.
Cleaning: The collected shells should be cleaned in an effort to remove any possible remains of coconut flesh, dirt, amongst others. This stage entails washing shells in water to rid off organic matter and later drying them completely. Proper cleaning is necessary to prevent contamination during the successive stages of processing.
Carbonization
Objective: Next in the process is carbonization, involving the changing of cleaned and dried coconut shells into charcoal. This is simply a process of heating the shells in an oxygen-free environment through a process called pyrolysis.
Method: Place the prepared coconut shells in a carbonization kiln or furnace. Such a kiln shall be able to hold a temperature between 400°C to 700°C. Gradual heating of the shell must be made to avoid sudden decomposition for its complete carbonization.
Process: It involves high temperature treatment of the shells in an inert atmosphere whereby they thermally decompose into charcoal while emitting gases and tar as volatile compounds. The process is normally several hours long. In this stage of the process, coconut shell charcoal results, and it is a precursor to activated carbon.
Result: A carbon-rich solid material from this step called coconut shell charcoal results at the end.
Crushing and Screening
Objective: The charcoal should be reduced into suitable particles for activation.
Method: Crush the charcoal into smaller pieces using a crusher or grinder. This brings the different charcoal particles down to a uniform size, a prerequisite for effectiveness during activation.
Process: Sieve the crushed charcoal to sort out the particles into sizes. Some applications may require different sizes of particles. For example, medical or cosmetic uses may require finer particles, while granules are more appropriate in water or air filtration.
Result: Charcoal particles of uniform size, ready for activation.
Activation
Objective: The activation process increases the surface area of the charcoal and forms a network of pores inside that increase its adsorption capabilities. There exist two methods of activation: physical and chemical.
Physical Activation:
Process: Put the charcoal in an activation furnace and heat it to temperatures between 800°C and 1100°C in the presence of some oxidizing agent like steam or carbon dioxide.The high temperature and oxidizing agent create a porous structure within the charcoal.
Result: The steam or carbon dioxide would react with the carbon atoms in the charcoal to give a highly porous material of large surface area.
Chemical Activation:
Procedure: Mix charcoal with a chemical activating agent like phosphoric acid, potassium hydroxide, or zinc chloride. After that, this mixture is to be heated in temperatures varying from 400°C to 700°C.
Process: During this process, the chemical agent will develop the pore structure inside the charcoal. The mixture will be washed properly after activation to remove residual chemicals.
The activated charcoal is washed with deionized water until the wash water is neutral and then dried at a temperature of about 110°C. This step is undertaken to ensure that the impurities and residual chemicals are eliminated.
Final Screening and Packaging
Objective:Ensure uniform size of activated carbon and ready to use.
Method: Finally, pass the activated charcoal through a last sieve for classifying particles by size. This then homogenizes it and makes it appropriate for different uses.
Process: Pack the reworked activated carbon in hermetically sealed containers or bags to retain quality and prevent contamination.
Result: Activated carbon ready to be used in different applications is obtained from coconut shells.
Uses of Activated Carbon
The versatility of coconut shell-based activated carbon is very high, and multiple applications are obtainable, such as:
Water Purification: Removes impurities, chlorine, and organic compounds from drinking water.
Air Filtration: Adsorbs odors, gasses, and volatile organic compounds for use in air purifiers and HVAC systems.
Medical Application: Poisons and overdoses are treated by adsorbing the toxins in the gastrointestinal tract.
Cosmetics: It is used in face masks and scrubs because of its detoxifying features.
Industrial Processes: This is used in the purification of gasses and liquids in chemical processing, food and beverage production, and pharmaceutical industries.
National Minerals is just one of the pioneers in this environment-friendly process for producing activated carbon from coconut shells. By addressing this sustainability factor, National Minerals does not merely recycle wastes but also provides an efficient and environment-friendly adsorbent for industries.