Activated Carbon: What Is It and How Does It Work?


Activated carbon has become an essential component of the modern world in various industries, including cosmetic, medical, and agricultural applications. It has also been a crucial component for the best water filtration systems, making it a powerful purifier for drinking water. Today, activated carbon is used in a vast range of applications from mercury removal to sewage treatment.

If you were wondering what exactly is it, and how does it work, we’re here to give you a bit of insight.


What is activated carbon?

Activated carbon, also known as activated charcoal, is an inert solid absorbent material commonly used to dissolve contaminants from water and process gas-phase streams. Due to its pore structure, high surface area, and a high degree of surface reactivity, it can be used to dechlorinate, purify, decolorize, and deodorize vapor and liquid applications.

Activated carbon derives from carbonaceous source materials including coal, coconut shell, wood, and others, and it has been used as an adsorbent for centuries. Its tiny, low-volume pores provide a surface for adsorption or chemical reactions. Activated carbon is broadly categorized by its size, method of preparation, and industrial application.  

There are 150 different kinds of activated carbon and some of the most common are granular, powdered, extruded, bead, polymer, impregnated, and woven. Note that 1 gram of activated carbon has more than 32.000 square feet of surface area, or simply 1 teaspoon has roughly the area of a football field. This is what makes it extremely useful for various applications, and can undergo further chemical treatment to increase its adsorption properties.  


How does it work?

The main way in which activated carbon filters out a given substance is through physical adsorption. As liquid or air comes into contact with it, intermolecular forces pull the molecules into the pockets and pores on its surface. It can also facilitate chemical reactions, and a common example includes chlorine molecules.

When activated carbon and chlorine come into contact, both molecules react to form chlorine ions, effectively removing chlorine from water. How activated carbon works to remove contamination from the air and water depends on different factors like the type and amount of pollution, how long the air and water spend in contact with the activated carbon, and the acidity and temperature of the water or air.

The specific type of activated carbon determines the level of filtration and it is often labeled by the adsorption potential. Activated carbon is safe to ingest, and there are no traces of it left in drinking water after it has been properly treated. Note that activated carbon doesn’t last forever, so it needs a periodic change-out with reactivated carbon.


Activated carbon uses

As we already mentioned, activated carbon is used in a vast range of applications, and some of the most common uses include air purification, air filters in respirators and gas masks, teeth whitening or other cosmetic products, hydrogen and methane storage, and metal extraction.

Activated carbon is used in the medical community to treat poisoning and overdoses, but can be also purchased as tablets or capsules to alleviate indigestion problems and diarrhea. In cosmetics, it is a popular ingredient in toothpaste, shampoos, and face masks, because it traps toxins and contaminants so they can be washed away.

Water purification is another major use of activated carbon. Activated carbon filters are used in small-scale and large-scale products since they can remove impurities from residential applications as well as community-wide water systems. Air and gas purification is another common use where activated carbon filters out pollutants, odors, and volatile organic compounds.  


Production of activated carbon

Activated carbon can be produced by one of 2 methods:

  • Thermal Activation

In this type of activation, the source material is formed into activated carbon by utilizing hot gases. This activation is done through a process that involves the reduction of moisture, carbonization, reduction of volatiles, and steam treatment.

  • Chemical activation

In this type of activation, the chemicals are added to the raw source material before the process of carbonization. The chemical used is a strong base, salt or acid. After the material is exposed to heat, thus, it activates quickly.


In closing

The usage of activated carbon has revolutionized a wide range of industries. It has been established as an incredibly diverse material lending itself to thousands of applications through its adsorbent capabilities, like effectively removing pollutants, contaminants, and other impurities from the air, water, food, pharmaceuticals, and more. Knowing more about its uses and how it works, sure helps us feel safer purchasing a water filter or air purifier.