Complete Guide to Activated Carbon

What is Activated Carbon?

Activated carbon, often referred to as “activated charcoal” is an extremely porous form of carbon that is used in the purification of water and air. The material has been specifically processed to give it a porous quality, increasing the surface area of the product.

Activated carbon is often suited for many uses, including air purification, water treatment, sewage treatment, and smoke removal. It is commonly used to treat municipal drinking water, but it also has a body-cleansing quality that has been linked to life-saving practices. Because it can be used to cleanse bodies, it’s a common product in emergency kits and hospitals.

Activated carbon can purify a wide range of physical substances. So, it is often used to deodorize air and water. Some people have found it useful for removing odors from refrigerators or removing a strong smell from the air, making it a popular material in A/C filters.

Essentially, the raw carbon material is full of other substances, such as organic matter, that fill microscopic holes, or pores, in the carbon. The process starts by removing these substances and leaving behind pure (or nearly pure) carbon. The microscopic pore sizes that were filled with other substances are now empty, drastically increasing the surface space of the carbon. The measure of the void in the material is known as porosity.

But the process is not complete. Now the carbon needs to be “activated” through oxidation. Once the material goes through the activation process, it will be ready to grab and hold toxins and molecules. 

There are two commonly-used processes for activating the carbon (or charcoal) material. The first is called steam activation, also known as physical activation. During this process, the raw material is converted using hot gasses, followed by air which burns out the gasses. Physical activation uses either carbonization or activation/oxidization and can require temperatures over 600 degrees Celsius.

The other process used for activating carbon is chemical activation. During this process, the raw material is impregnated with a chemical, usually an acid, base, or a type of salt. The material is then processed at a lower temperature, usually around 450 to 900 degrees Celsius. Because of the lower required temperatures, chemical activation is often the more efficient and effective method for activating carbon.

Steam-Activated vs Chemical-Activated Carbon: Is there a Difference?

After the processes of activation are completed, is there a difference between the two products?

Does the process result in activated carbon that behaves, filters, and performs in different ways?

In general, the two different processes result in extremely similar products, but there can be slight variations that make large differences in filtration performance. For example, steam-activated carbon goes through an acid wash, which purifies the carbon. Chemical activation, however, does not require an acid wash.

Steam activation usually produces activated carbon that is about 1 to 3 millimeters in thickness. These pieces are then crushed and screened to remove dust and other impurities and to meet certain specifications.

Chemical activation, on the other hand, produces powdered carbon that usually does not need further crushing. It may, in fact, need to be made larger to meet certain needs. Small pieces, if required, can be impregnated with an activating agent that results in larger grains. Also, chemically-activated carbon can be given a second round of steam activation, which will give it additional properties.

So, the bottom line is this: yes, steam and chemical activation produce different products, but they can often be modified through further processing to create similar results.

The Surface Area: Why it Matters

At its most fundamental level, the surface area in activated charcoal is what matters the most. Activated carbon is extremely porous, filled with microscopic and submicroscopic pores that create a dense network of holes in the material. With these millions of pores in a small amount of activated carbon, there is a massive surface space for water or air to pass through. This massive surface space grabs onto toxins and holds them in place, giving activated carbon its fantastic purifying ability.
 
When the activation process is complete, 50 grams of activated charcoal has the physical surface space of roughly 10 football fields. That’s right, thanks to all those microscopic pores, a small amount of activated carbon has a stunning, nearly unbelievable, surface space!

Activated Carbon: What do the Health Studies Say?

Whenever we discuss filtration technology and its impact on health, we always want to support our information with independent research and scientific studies. With that in mind, let’s look at a three important studies and reports that have examined the effectiveness of activated carbon.

A study by the U.S. Department of Energy found that HVAC filters using activated carbon removed 60 to 70% of ozone from air that passed through it, while filters without activated carbon had almost no effect on the amount of ozone.

Another study, also commissioned by the U.S. Department of Energy, found that activated carbon filters were capable of removing up to 80% of volatile organic compounds and up to 30% of formaldehyde, a common air pollutant.

The Centers for Disease Control, which provides information on a wide range of health issues, released a report in 2003 that stated that activated carbon is “excellent for most organic chemicals.”

While the basic result is similar, absorption and adsorption are two very different processes. Understanding how the process of adsorption and absorption work will help you understand the effectiveness of activated charcoal.

Absorption
The process, or at least the term, you are probably more familiar with is absorption. During absorption, one substance enters the bulk of another substance. It involved molecules literally entering the volume of a material. During this process, the two materials come together and essentially form a new material.

Adsorption
Adsorption is slightly different. During this process, a substance basically attaches itself to another material, but doesn’t enter the material. Adsorption happens on the surface level and does not create a new substance, but rather to substances hanging on to each other.

Handy analogy: Think of absorption like people riding in a boat, while adsorption is like skiers attached to the boat; the skiers are along for the ride, but they’re not inside.

GAC is ground, or “granulated,” carbon that can be so fine it resembles a loose powder. The product is made by taking solid pieces of carbon and pulverizing it into much smaller grains. The pulverized carbon is then sifted through sieves to separate it into uniform sizes. This allows manufacturers to separate GAC into large, small, and even dust-like activated carbon.

We use Granular Activated Carbon filters in our TrueCarbon™ air purifiers to achieve a solid filter that outperforms the competition. It's over 2" deep with no air holes like other sheets of carbon filtration. 

Coconut shells are one of the most commonly-used raw materials for creating activated carbon. Activated carbon made from coconut shells are high in micro pores. In fact, roughly 85 to 90% of the surface area is micro pores.

Why does this matter? Because smaller pores often match the size of contaminant molecules in air and drinking water, and therefore make coconut shell activated carbon highly effective at trapping them.

There are numerous benefits to using coconut shell activated carbon as opposed to other materials, and the advantages go beyond the product’s effectiveness. The raw material, coconuts, is a renewable source of carbon that grows throughout the year and can be harvested up to four times annually. There is no mining required, and unlike wood activated carbon, you don’t need the entire tree, only the coconuts.

A History of Activated Carbon

While few people are aware of the impact activated carbon has had on mankind’s history, it’s arguably one of the most important innovations we have ever discovered. It’s believed that the use of carbon as a cleaning and purifying agent has been known for millennia. Some even believe humans were using charcoal for cleaning for over 3,500 years.

Throughout history, carbon was used to reduce odors in the air and to purify water. It was used in hospitals to reduce smells, and ancient sailors learned to use activated charcoal on the inside of their water barrels to keep drinking water safe for a longer period.

While regular carbon was used for centuries, activated carbon has only been around for less than 200 years.

In World War I, activated carbon was used extensively in gas masks, saving countless lives from gas poisoning. Activated carbon is now found in nearly every hospital and clinic, it’s used in food refinement, dry cleaning, pharmaceuticals, and more.

Activated Carbon Compared to Other Air Purification Options

Activated Carbon vs HEPA Filters

There are big differences between activated carbon filters and pleated HEPA filters. This is because HEPA filters are meant to remove airborne particulates (dust, mold spores, pet dander, pollen, etc) whereas carbon is used to remove gasses, chemicals and VOCs.

The main component of this filter is a thin fiberglass or polypropylene material, that is effective for trapping minute particles.

Activated carbon in contrast is often made from coal, charcoal, or coconut shell and is designed to act as an adsorbent to remove smaller range of particle sizes for items like gases, chemicals and VOCs. Gases are so small they will simply pass through the fibers in a HEPA filter.

Activated Carbon vs UV Light

UV light is another technology that is used to filter contaminants from the air. However, UV light is only effective on organic and living matter, especially mold and mildew. UV light attacks a cell’s DNA, disrupting or outright killing the cells. Any mold or mildew spores that pass through a UV-light purifier will be destroyed. The technology may also be used to kill viruses and bacteria, but more research is required in this regard.

So, while UV light kills living cells, activated carbon can trap particles, living or inanimate. This makes activated carbon and UV light an effective combination for air cleaning and purification; the carbon traps particles of most types, while the UV light can kill potentially harmful mold, bacteria, and viruses.

Activated Carbon vs Ionizers

Ionizers are a controversial way to destroy mold, remove odors, and “purify” the air in a home. Ionizers and ozone generators, a similar product, release ozone into the air, which then attacks cells and destroys them at the molecular level.

This sounds great, but it doesn’t just attack mold, it can also attack skin cells, lung cells, and any other cells it comes into contact with. Therefore, activated carbon, which traps particles and does not harm our cells and is a far more preferable treatment.

Activated Carbon vs. Electrostatic Precipitators

Electrostatic precipitators essentially use static cling to grab airborne particles and trap them in place. They can be effective for removal of harmful particles and allergens, but they have one specific problem: they release ozone as a byproduct. For this reason, electrostatic precipitators are, in most cases, only used for industrial purposes, like cleaning steam and smoke before it is released into the atmosphere.

Activated carbon, therefore, is preferred for home use. If you are looking to improve the quality of your indoor air, you should seriously consider using air purifiers with activated carbon filters. Fortunately, Oransi has a full selection of options for you to choose from...

While many of our purifiers use activated carbon to clean the air, these are a few examples of the quality Oransi products that use this incredibly effective material.

The Mod+ covers both small and large rooms at 1,361 square foot coverage with 2 air changes per hour. The Mod+ has a sleek design with a glass interface and a neutral gray handle that makes the portable product easy to carry. This purifier helps to remove allergens, dust, mold spores, pet dander, and smoke.

TrueCarbon™ 200C Air Purifier
If your main concerns are smoke, odors, and VOCs then this is the perfect air purifier for you. The TrueCarbon™ products have a Granular Activated Carbon filter that targets smoke, odors and VOCs and filters them out of your indoor air.  

If you are looking for an extremely reliable air purifier for your home or office, Oransi is here to help. We are a global leader in air purification, so browse our full selection of air purifiers and place your order today!

Want to learn more about cleaning your air? Check out the Beginners Guide to an Air Purifier or chat with our customer service team!