Do you need to purify your water?
Coconut shell activated carbon is an ideal choice for your water treatment needs. It’s made from renewable materials, so it’s environmentally friendly and sustainable. It has a high affinity for many nasty contaminants such as chloramines, PFAS, VOCs, and chlorine. Plus, it can be used in a variety of applications including removing impurities from drinking water and air filtration systems. You can even use it in aquariums!
If you want clean, fresh-tasting water then you should consider using coconut shell carbon. This adsorbent will give you great tasting drinking water while removing a wide variety of contaminants. It’s also a great choice for people who want to reduce their environmental impact.
Continue reading to learn everything you need to know about coconut shell activated carbon and its many benefits!
Table of Contents
What Is Activated Carbon
Activated carbon is an adsorption media that has been specially manufactured to create millions of tiny pores. These pores give activated carbon a very high surface area, which provide adsorption sites for contaminants to bind to. A gram of activated carbon has over 500 square meters of surface area. Some types of carbon can have as much as 3,500 square meters.
Activated carbon can be made from a variety of materials including coal, wood, peat, and coconut shells. The base material that is used to produce carbon is important because it provides important properties to the final product. Engineers specify the exact source material and activation process to produce an activated carbon that can remove specific contaminants or have desirable properties.
Read my comprehensive article on designing an activated carbon treatment system.
How activated carbon is made
Activated carbon is made from an organic material. Raw materials that are used to manufacture carbon include:
- bituminous coal
- lignite coal
- wood
- peat
- coconut shells
- sugarcane bagasse
- soybean hulls
Step 1 – Pyrolysis: Activated carbon is produced by pyrolysis of organic materials. This is done by heating the base material in a low oxygen environment, usually under a blanket of nitrogen or argon gas. The pyrolysis step is generally conducted at temperatures between 600 and 900 °C. This process drives off the water, hydrogen, and other volatile elements.
At the end of pyrolysis, the only thing left is carbon. This material is referred to as charcoal.
Step 2 – Activation: Once the organic material has been converted into carbon, it must be activated to create the thousands of pores. This is done by exposing it to oxygen or steam at temperatures in the range of 600 to 1200 °C.
The high temperature steam causes the carbon particles to crack and fracture. This is how the pores are created. The temperature and quantity of steam affect the size and number of pores that are created.
Step 3 – Crushing: The activated carbon is formed into the desired type: powdered, granular or extruded. Each has its own unique application and function for any given process. The activated carbon coconut shell product can be delivered in several formats:
- Powdered activated carbon (PAC): This consists of particles fine enough to pass through an 80 mesh sieve. PAC is often used in public water supply treatment plants because of its small size.
- Granular activated carbon (GAC): GAC consists of larger particles and is available in a variety of sizes. This media is ideal for carbon filters because it doesn’t create a lot of friction loss
- Extruded activated carbon: This media is produced by mixing activated carbon particles with a binder and ramming it through a pellet machine. This creates particles with a uniform size and shape which results in very low frictional losses.
- Carbon block: Some of the most effective water filters use carbon block technology. This is powdered carbon that is formed into a dense and very effective filter cartridge.
How adsorption works
Activated carbon has thousands of tiny pores which creates a significant amount of surface area.
Adsorption is a physical process that is driven by the attraction between two solid surfaces. This force is similar to gravity, but it is completely different. The surface area within the carbon’s pores attracts the contaminant from the water until it “captures” the molecule.
You can think of adsorption working like a magnet (it’s not magnetism, but the principle is similar). The contaminant molecule is pulled into the pore where it is held on the carbon’s surface by the adsorption force.
Pore size
Activated carbon has pores with a wide range of sizes. These pores can vary in size as shown below:
Micro-pores: Pores that are less than 2 nanometers
Meso-pores: Pores from 2 to 50 nanometers
Macro-pores: These are the largest pores, and are greater than 50 nanometers
The size of the pore opening affects the size of the molecules that are adsorbed (i.e., removed). Smaller openings are better suited for small molecular weight contaminants. Large openings are ideal for large molecules. A wide range of pore sizes is good for a mixture of contaminants with varying sizes and molecular weights.
In these filters carbon is used to remove a wide range of contaminants. The coconut-based filter media is extremely effective.
Benefits of Using Coconut Shells to Make Activated Carbon
What is it about coconut shells that makes them such a good material for making activated carbon? Theare several benefits to using coconut shells to produce activated carbon
Abundance of micropores
Carbon made from coconut shells has a lot of micropores. These are pores that are less than 2 nanometers in diameter.
Coconut shell activated carbon has 50% more micro-pores than carbon made from coal. These tiny micropores match the size of most water-based contaminants – this is why coconut shell activated carbon is ideal in water purification applications.
Small pores preferentially attract and remove small molecules with low molecular weights. This includes contaminants such as:
- chloramines
- chlorine
- PFAS
- trihalomethanes (THM)
- chlorinated VOCs
- taste and odor compounds
Enhanced adsorption
The physical properties of coconut shell carbon provide enhanced adsorption for many contaminants, including those that coal-based and wood-based carbons aren’t effective for. Examples of these contaminants includes PFAS, pesticides, herbicides, and many pharmaceuticals.
Renewable material
Coconuts are a renewable resource, and the shells are typically a waste product left over after the coconut milk and meat are harvested. Using a plant-based material to make activated carbon helps to reduce the environmental impact of activated carbon production.
Sustainability
The use of a sustainable raw material like coconut shells to make activated carbon helps to improve the overall sustainability of the process. Coconuts are harvested without having to cut down the tree itself – unlike when wood or peat are used as the raw materials.
High mechanical strength
Coconut shell carbon is very hard and resistant to breakage and crumbling. As a result, it can be recycled much more effectively than other forms of carbon. It also produces less dust and ash which can create an off taste with drinking water treatment.
How Are Coconut Shells Converted into Activated Carbon
There are two major processes used to create activated carbon from coconut shells. The first process utilizes pyrolysis, which converts the shells into char by heating it at high temperatures (450 degrees) in a low oxygen environment.
Once the charcoal is produced, it is transferred to a fluidized bed reactor (FBR). In the FRB, high temperature steam is pumped in to create the pores that make it an effective adsorbent.
The activated carbon produced from coconut shells is 97% pure.
Once the carbon has been activated, it is crushed to the desired particle size. Carbon particles are measured in mesh size. A mesh size of 100 means the particles are one-hundredth of an inch in size. The most common particle sizes for activated carbon are 12 to 50 mesh.
Activated carbon used for water treatment typically has a mesh size between 8 and 30. Other sizes are available depending on the process requirements.
Applications for Coconut Shell Carbon – Filter Housings
Coconut shell activated carbon is the preferred carbon to remove volatile organic compounds (VOC’s) and other impurities from drinking water. This adsorption media is used in many processes, including:
- Drinking water purification: Coconut shell carbon, because it has a high proportion of micropores (more than 80%), can efficiently remove impurities with a micropore molecular structure, such as those found in drinking water.
- Wastewater treatment: The wide range of contaminants that coconut shell carbon can remove make it very desirable in wastewater applications.
- Vapor treatment: Coconut shell carbon’s high affinity for small molecules makes it ideal for vapor and gas treatment systems.
- Precious metal recovery: The high abrasion resistance and exceptional chemical and physical characteristics of coconut shell carbon make it ideal in gold recovery applications.
- Contaminant removal in beverage production: Coconut shell activated carbon is very hard and produces very little ash or dust which can affect taste and quality of drinks.
- Pharmaceutical manufacturing: Coconut shell carbon has a very high purity because it is plant based. Coal-based carbons often have trace contaminants of heavy metals which makes it unfit for medical applications.
- Refrigerator water filters: Coconut shell carbon is very effective at removing chlorine from drinking water. Learn about chlorine removal and refrigerator filters in my article.
FAQs
What contaminants does coconut shell carbon remove?
Coconut shell carbon removes chlorine, chloramines, hydrogen sulfide, and VOCs from water. It also removes objectionable tastes and odors commonly found in tap water. A quick view of alternatives suggest that this type of carbon is the best solution for many contaminants.
Is coconut shell carbon better than coal based activated carbon in water filters?
Coconut shell-based activated carbons are an excellent choice for water purification as they have the highest hardness and porosity among all types of carbon. These qualities make them well suited to organic chemical adsorption in virtually all filter housings. Add this material to your cart to ensure you’re getting the purest drinking water.
Is coconut shell activated carbon good for purifying drinking water?
Coconut shell activated carbon is a great filter for purifying water. It adsorbs most herbicides or pesticides present in water, as well as VOCs like formaldehyde and tetrachloroethylene. Make sure the filter has the proper fittings for your application.
Final Review of Coconut Shell Activated Carbon
Coconut husk activated carbon is an ideal choice for water purification. The porous structure of the coconut shells results in a high surface area, which provides more adsorption sites for contaminants to bind. Using activated coconut carbon for filtered water treatment is beneficial in many ways.
Additionally, as the material is made from a renewable resource, it’s an environmentally friendly option that helps reduce your carbon footprint. If you are looking for an activated carbon product to use in your water purification system, coconut shell activated carbon provides many advantages over conventional carbon.