Activated Carbon

Technical specifications of an activated carbon sample

Introduction

Activated carbon, abbreviated AC, also called medicinal carbon (Latin Carbo medicinalis ), is a porous, finely grained carbon with a large internal surface area that is used, among other things, as an adsorbent in chemistry and medicine. , drinking water purification, wastewater treatment as well as ventilation and air conditioning technology. Activated carbon is used in granulated or compressed form in the form of tablets (charcoal tablets). It also serves as a carrier material for catalysts for heterogeneous catalysis.

Activated carbon is flammable and consists mainly of carbon (usually more than 90%) with a highly porous structure. The pores are open pores and are interconnected like a sponge. The internal surface area is between 300 and 2000 m²/g of coal, so the internal surface area of ​​four grams of activated carbon corresponds approximately to the area of ​​a football field. The density of activated carbon is in the range of 0.2 to 0.6 g/cm³.

Pore ​​size and pore size distribution are divided into four large orders: submicropores (< 0.4 nm), micropores (0.1 to 2 nm), mesopores (also called transitional pores, 2 to 50 nm), and macropores (greater than 50 nm).

Macropores and mesopores are the access routes for gases or liquids into the coal and play a significant role in the diffusion and mass transfer processes to the deeper regions of the grain. The majority of adsorption occurs at the micropore surface. The size of this area determines the effective surface area and, consequently, the adsorption properties of the coal. The size of the internal surface area relative to the volume of the activated carbon is shown in the data below. For a cube with an edge length of 1 cm, the internal surface area is more than 100,000 times greater than the external surface area.

In essence, the absorbability of a compound increases

• Increased molecular weight
• Increasing the number of functional groups such as double bonds or halogen ligands
• Increasing the polarizability of the molecule

Activated carbon usually adsorbs smaller molecules. The iodine value is the determining parameter for the adsorption performance of activated carbon. The activation of activated carbon is measured. The adsorption performance is often given in mg/g. This is the standard method for liquid applications.

The iodine number is defined as the number of milligrams of iodine adsorbed by one gram of activated carbon. Water treatments typically have an iodine number of 600-1100. This parameter is also used to measure the extent of use of activated carbon. However, this can only be recommended if the adsorbent is free from chemical interactions and a correlation between iodine number and degree of use has been proven for the intended application.

Other types of activated carbon are more efficient at absorbing larger molecules. The molasses number indicates the efficiency of absorbing larger molecules. A high molasses number corresponds to high absorption of larger molecules.

Tannins are a mixture of large and medium molecules. Activated carbon in combination with macro and mesopores adsorbs tannins. Tannin adsorption performance is measured in parts per million. Values ​​recorded range from 200 ppm to 362 ppm.

Activated carbon can also help with dechlorination. The half-life for dechlorination is a very important number to measure. It measures the effectiveness of the activated carbon in removing chlorine.

The wear number measures the resistance of activated carbon to wear. There are many differences between different types of activated carbon. The wear number is significantly affected by the initial raw materials and activation.

The finer the particles, the better the surface access and the faster the adsorption. A good assessment of the particle size can lead to significantly better results in the adsorption performance. For the adsorption of minerals such as gold, the particle size should be between 1.4 and 3.35 mm. Particles smaller than 1 mm are no longer sufficient for the washing process. During this process, the minerals are removed from the activated carbon.

Activated carbon is made from plant, animal, mineral or petrochemical materials such as brown coal, hard coal or various plastics. When hydrogen is produced using the Kværner process, activated carbon is produced as a by-product. Activated carbon made from raw materials such as wood, peat, coconut fiber and nut shells is also known as biochar.

As Latin charcoal. Carbo animalis is the name given to activated carbon made from animal blood (blood carbon) or bone (bone carbon). Sugar charcoal refers to activated carbon made from glucose or another sugar as the starting product.

Two methods can be used for generation and activation:

• Gas activation and
• Chemical activation

During chemical activation production, a mixture of uncharred raw materials is treated with chemicals.

This is usually done using dehydrating agents (such as zinc chloride or phosphoric acid) at temperatures of 500 to 900 °C. Another process is dry distillation (coking), in which the material is heated in an oxygen-free atmosphere and the volatile components are removed at temperatures of about 800 °C.

The crude activated carbon thus obtained is then oxidatively activated at 700-1000°C with steam or carbon dioxide, and sometimes with air. During this activation, some of the carbon is converted to carbon monoxide using the water gas process, creating additional pores and increasing the surface area of ​​the coal.

For some uses, activated carbon is treated (impregnated) with additional chemicals to improve the separation effect.

Filter carbon for respiratory filters in gas masks is coated with metal salts, which improves the separation effect of many chemical toxins. Silver-coated activated carbon is particularly suitable for filtering drinking water. Silver greatly suppresses the contamination of these filters during operation.

Activated carbon is primarily used as an adsorbent to remove undesirable colors, tastes, and odors from gases, vapors, and liquids. The main advantage of activated carbon is its thermal reactivation capability. Biological reactivation is also possible with activated carbon used for wastewater treatment.

Activated carbon is mainly used in the form of granules, powder or pellets. Activated carbon fabrics are also available in the market.

For example, activated carbon can be used to remove the following:

• Chlorine, ozone and other taste and odor disruptors as well as water bacteria, sweeteners, glycerin and chemical liquids
• Dyes and liquid flow contaminants in the chemical or food industries
• Airborne toxins (filters in respirators, ventilation systems in tanks and shelters, exhaust air in production facilities)
• Desnitration of flue gases from glass melting furnaces, waste incineration plants and other exhaust gases
• Uranium hexafluoride from air in nuclear technology (fuel production)
• Gasoline vapors from exhaust air from tank systems
• Chlorinated hydrocarbons from exhaust air and exhaust gases, e.g. in dry cleaning
• Tar from cigarette smoke in cigarette filters
• Unwanted flavors from vodka and other spirits
• Undesirable colors from white rum and other spirits
• Sweaty smell in shoes (due to insoles containing activated carbon)
• Fermentation by-products such as body oils and beer esters
• Contaminants in aquarium and pool filters
• Annoying odors from the air coming out of the room’s ventilation system
• Anesthetic gases from exhaled air of sedated patients
• Fine dust, pollen and odors in the vehicle’s supply air (see cabin air filter)

• Tooth discoloration

In wastewater treatment, activated carbon is used to absorb soluble and sorbent wastewater materials (e.g. trace elements) from water.

When using powdered activated carbon with a high specific adsorption surface area, some of the loaded carbon is re-depleted through the sewage sludge, but an additional filtration step is necessary for the fine fraction remaining in the water phase.

This process step is usually only used when less expensive methods such as biological processes, precipitation and flocculation do not provide the desired results. It can also be used to clean minor streams in industry with the aim of recovering residual materials.

Wastewater from textile dyeing plants contains dyes that are often only removed by adsorption on activated carbon. This can be done economically with biologically regenerated activated carbon.

Another notable application of activated carbon is in cabin air filters  for the automotive industry.

This class of filter has been used in air conditioning systems since the mid-1990s. So-called hybrid filters (this is a special class of cabin air filter) contain a layer of activated carbon that filters harmful gases from the air, thereby protecting passengers from these pollutants. More than 5,000 tons of activated carbon are processed worldwide for this application every year.

Air filters equipped with activated carbon are also used in hospitals for anesthesia.

The activated carbon in the filters binds exhaled volatile anesthetics, thereby protecting patients, the surgical team, and the environment. The collected anesthetic gases can be processed and reused for anesthesia.

This allows hospitals to save part of their greenhouse gas emissions – an important area of ​​action for climate neutrality in the healthcare system, according to the German Medical Association.

In the exhaust air sections of nuclear power plants, activated carbon filters are used as a delay section for short-lived radioactive noble gases. Due to temporary absorption, the noble gases pass through the filter sections much more slowly than the rest of the exhaust air. Radioactive decay significantly reduces the amount of radioactive noble gases in the exhaust air.

Water purification also uses adsorption on activated carbon to purify raw water.

Activated carbon can also be used in absorption pumps to create vacuum due to its high adsorption capacity.

Activated carbon has only a limited loading capacity. Regeneration is usually carried out by heating to several hundred degrees Celsius. On the one hand, part of the load (e.g. organic solvents) evaporates, and another part can coke, then the activated carbon must be reactivated with steam, as in production.

Saturated activated carbon can be reactivated using a thermal process at high temperatures (up to 900 °C), for example in rotary kilns or multi-day kilns.

Thanks to modern, intensive flue gas cleaning, saturated activated carbon can be recycled from a wide range of applications.

The complete reactivation process includes the following steps:

1. Drying of materials up to +105°C.
2. Evaporation of absorbed volatile components up to +300°C.
3. Decomposition of the adsorbed non-volatile components into smaller molecules up to +600°C, which are decomposed in the furnace atmosphere by pyrolysis to form amorphous carbon on the inner surface.
4. Gasification of amorphous carbon using steam above 800°C.

The reaction of amorphous carbon with water vapor at high temperatures to form carbon monoxide (CO) and ultimately carbon dioxide (CO2) creates micropores that form a large specific surface area.

By rationally using natural raw materials through reactivation, a reduction in CO2 emissions by a factor of 5 is achieved.

In medicine, activated charcoal is primarily used to remove toxins from the digestive tract. For harmless diarrheal illnesses, such as gastroenteritis, for example, charcoal compresses are commonly used.

In poisoning emergencies, activated charcoal is used in large doses to remove ingested toxins that are in the digestive tract or are exposed to enterohemorrhagic circulation from the organism. The dosage in such cases is 0.5 to 1 g of charcoal per kg of body weight for adults.

Inactivated charcoal, such as activated birch charcoal, is also used as a bowel regulator.

Activated carbon-based catalysts are used in chemistry. Activated carbon acts as a carrier for transition metals such as palladium, platinum or rhodium. A typical area of ​​application for these catalysts is catalytic hydrogenation.

Activated carbon is used as an electrode material in supercapacitors. Due to the very large surface area of ​​these electrodes, very high capacities can be achieved.

In Germany, medicinal charcoal was approved for use as a food colorant as Carbo medicinalis from 1959 onwards through the Color Act.

In order to incorporate into national law the Council Directive on the approximation of the laws of the Member States concerning colouring matters which may be used in foodstuffs, the Colours Directive was adopted in 1966 and the E number 153 for Carbo medicinalis vegetabilis was adopted in 1978, its use in Germany being regulated by the Additives Authorisation Directive.

Regulation (EC) No 1333/2008, which entered into force on 20 January 2009, regulates the use of biochar as a food additive uniformly throughout the European Economic Area. Carbo medicinalis can be added without any quantitative restrictions (quantum satis).

E 153 is classified in group II (food colours without maximum limits) together with other colours such as riboflavin, carotene and carotenoids and is used, for example, in the following: B. It is used in fruit juice concentrates, jellies, jams, confectionery and in black wax coatings on cheese. Only activated carbon of vegetable origin is permitted as a food additive.

Activated carbon is also found in thermal bags.

Face masks, exfoliators, shower gels, and toothpaste often contain powdered activated carbon made from bamboo, charcoal, or coconut shells to absorb unwanted substances. However, since they are washed off after cleansing anyway, its effectiveness is questionable.

Activated carbon filters: What do they remove from water?

If you are concerned about the quality of your water, you should look into different water purification options. Water filters are generally very effective in reducing contaminants, unpleasant odors, and bad tastes in water. Activated carbon filters have extraordinary capabilities that are not found in conventional filters.

However, activated carbon water filters can target and remove specific contaminants in water. It is important to know what contaminants it removes or reduces.

Today, carbon filters are the leader in water purification. Activated carbon filters may have unique properties that can effectively remove up to 99 percent of total suspended solids, volatile organic compounds, sediment, heavy metals, chloramines, and other contaminants from drinking water.

What is a carbon filter?

Activated carbon filters, also known as activated charcoal filters, are not like traditional water filters. They are made up of small, porous sponges or black beads that have been processed to better trap impurities.

It is first infused with heat or steam to increase the carbon’s surface area. The activation process opens up more pores so the carbon can absorb and trap a wider range of contaminants. This makes the carbon much more effective as a filter media.

Carbon particles have a large surface area.

Which allows them to be exposed to as many active sites in the filter medium as possible. This ensures that contaminants are adsorbed/removed with maximum potential. One pound (450 grams) of activated carbon has a surface area of ​​about 100 acres. That’s about three times the size of the Pentagon.

This, along with other amazing properties, makes activated carbon an excellent means of removing impurities from water by adsorption. It is also used to make respiratory masks and in exhaust fans and air conditioners to eliminate unwanted odors such as pet dander and smoke.

What do activated carbon filters do to water?

Water is purified by carbon cartridge filters using a process called adsorption. Activated carbon acts like a sponge, absorbing contaminants in the water by absorbing them. Simply put, activated carbon acts like a sponge with a large surface area and absorbs contaminants.

Impurities in the liquid solution move to areas with the strongest gravitational forces. Since the gravitational forces that dissolve the contaminants in the fluid are stronger than their own gravity, the contaminants are adsorbed to the carbon surface. The purified water then moves on to the next stage, if necessary.

Activated carbon filters are used to remove chemicals such as chlorine or other chemicals that do not stick to carbon. The catalytic activated carbon, which is more reactive than regular carbon, chemically changes chlorine molecules and turns them into salts.

Are all carbon filters the same?

Although activated carbon filters can remove many more pollutants than regular carbon, there are some differences. Some filters have more activated carbon than others.

This can affect the filtering ability, absorption rate and other factors. High levels of activated carbon can extend the life of the filter. So it requires less replacement and produces purified water for longer.

Types of activated carbon filters

Activated carbon filters come in two types: granular activated carbon (GAC) filters and block carbon filters  .  GAC filters contain loose, millimeter-sized granules made of activated carbon. These filters can identify and filter contaminants that might otherwise go unnoticed by other types.

These filters use coconut shells, coconut husks, wood, coal and other media, and coconut shell carbon is renewable. GAC filters have many advantages. However, sometimes contaminants can pass through GAC filters.

Block carbon filters, on the other hand  , are made of finely ground granules, usually less than 1 micron in size, and a binding agent. This holds the granules together so they don’t move. The pellets are combined with the binding agent and heated to form blocks. There are three types of media that can be used in a carbon filter: coconut shell media and bituminous coal.

GAC filters have 7-10 times the surface area of ​​carbon filters and prevent channeling. The compact structure of the granules may result in slower flow rates. This can be a problem for some.

What contaminants do carbon block water filters remove?

Activated carbon filters are excellent at removing many contaminants from water. This includes chemicals, gases, and physical impurities. NSF International and the Environmental Protection Agency (USA) claim that activated carbon filters can remove 60 to 80 chemicals from water and reduce 30 others. They also reduce an average of 22 other contaminants. When determining a system’s ability to remove or reduce these contaminants, two things are important.

1. Activated carbon type (GAC or block)
2. Activated carbon quality

You need to make sure your tap water is free of any problematic contaminants. The EPA recommends activated carbon filtration technology for water purification. This technology is capable of removing almost all known herbicides, pesticides, and mineral contaminants.

These are just a few of the water contaminants that activated charcoal filters can remove or reduce.

PFOS

Perfluorooctane sulfonic acid, or PFOS for short, is a synthetic water- and stain-resistant compound that is widely used to make carpets, fire-fighting foams, furniture, food packaging, clothing fabrics, and other materials that are resistant to water, grease, or stains. PFOS chemicals can be difficult to break down, meaning they can persist in the environment and water supplies for decades. Exposure to PFOS chemicals at higher levels can cause adverse effects. These include birth defects, cancers, and liver effects. Activated carbon filters can effectively remove PFAS, including PFAS and PFOS, as well as PFNA.

Pharmacy

High-quality activated carbon filters can remove pharmaceutical residues from drinking water. The World Health Organization describes pharmaceuticals as “man-made and naturally occurring chemicals that are potentially found in prescription drugs, over-the-counter medications, and veterinary drugs.” They can also enter water supplies through human waste, improper disposal of medications (for example, flushing drugs down the sink or toilet), or agricultural runoff containing livestock manure. Pharmaceutical residues can have a significant impact on aquatic life if they are allowed to accumulate in the environment. Even worse, they can leach into water wells.

Phosphate

There are many sources of phosphate in water, including runoff, human and pet waste, chemical production, and other sources. Although phosphate is essential for plant growth, excess phosphate can cause water to become cloudy from algae blooms. High-quality charcoal filters can remove up to 90 percent of phosphate from water.

Chlorine

The American water disinfectant of choice is chlorine. Nearly every U.S. water supplier uses chlorination before distributing water to customers. Chlorine is used to kill bacteria and other pathogens that can cause bad tastes and odors in water. However, despite its amazing disinfecting power, studies show that people who drink chlorinated water are at least 93 percent more likely to get sick than those who drink unchlorinated water. Some activated carbon filters can be used to remove chlorine and the unpleasant odors and tastes it causes. Premium activated carbon filters can remove 95 percent of free chlorine from some water sources.

Corian by-products

When chlorine used to purify water naturally reacts with compounds in the water, harmful chlorine byproducts such as VOCs and THMs can form. Long-term exposure to some of these toxic byproducts can lead to cancer, birth defects, and other unwanted diseases. An activated carbon filter is the best way to remove chlorine byproducts. According to the EPA, this technology removes 32 of the most commonly reported chlorine byproducts. This includes the most common byproduct reported in tap water: total THMs (TTMs).

Chloride

Chloride is a key element in drinking water chlorination. The WHO states that chloride levels above 250 mg/L can cause a noticeable salty taste in water. This is especially true for those on low-sodium diets and those with certain health conditions.

Pesticides

Activated carbon filters are tested and designed to remove 14 pesticides found in water. These pesticides include chlordecone/CLD/capone, chlordane, and heptachlor. Lindane is also included in Round-up. The National Institute of Environmental Health Sciences defines pesticides as any substance used to kill, repel, or control certain types of plant or animal life as pests. These substances include herbicides and fungicides. These agricultural chemicals can easily reach groundwater aquifers because of their widespread use. Short-term adverse health effects can be caused by pesticides, but long-term effects can persist for months or even years.

Herbicides

Global agriculture has used herbicides for centuries. This is primarily to control unwanted weeds and increase yields. These chemicals can sometimes be uncontrolled and end up in water supplies, affecting non-target aquatic organisms as well as humans. Some herbicides may cause cancer in humans. Activated carbon has been tested and shown to be able to remove 12 common herbicides, including the herbicide 2,4-D and atrazine.

Lithium

Lithium, a rare metal that occurs naturally in soil and mineral formations on Earth, is also found in water. The presence of lithium in tap water can be used as a stress reliever and antidepressant. We should be aware of the potential health risks that the metal can have on our bodies, even as more research is being conducted. The lithium content in drinking water can be reduced by up to 90 percent with charcoal filters.

Do you need a carbon block filter?

The type and concentration of contaminants in the water will determine whether you should use a carbon or non-carbon filter in your home. If an activated carbon filter can remove or reduce any of the harmful contaminants, it may be worth installing one.

Home water quality testing can be used to quickly and accurately check the quality of the water in your home. These tests are affordable and easily accessible. They also provide fast, useful results that are easy to understand. We offer reliable, high-quality, and affordable water testing kits that test for many contaminants in drinking water in minutes.

You can also contact your local water provider to request a copy of their annual water quality report. This usually contains useful information about the water quality in your area. Or, if you want to go the more expensive, time-consuming, but more accurate route, you can take a water sample from your home and send it to a lab in your area for testing.

To the question “Should you install a carbon block filter?” If your water quality tests positive for any of these contaminants, a carbon filter can be a smart investment. You can still install one even if your tests are negative.

If you want to purchase and install an activated carbon filter, you have two options available to you.

Point of Entry (POE) filters.

POE filters are connected to your main water line. They filter all the water that passes through your home before it reaches the water heater. This includes faucets, toilets, and showers, as well as kitchen and laundry water. Whole-house filtration systems are the most popular type of POE system. Whole-house filters are used to remove contaminants from your water source before it reaches your faucet.

The Paragon Waters Solutions water filtration system uses the same POE technology and other unique materials to deliver clean, great-tasting purified water.  It uses catalytic activated coconut shell carbon  and other innovative filtration techniques and technologies to remove 99.9 percent of harmful water contaminants including PFOS and PFOA.

Our whole house systems use catalytic activated coconut carbon made from high quality coconut shells. This activated carbon greatly improves pollutant removal efficiency and accelerates the breakdown of chloramines, chlorine byproducts and other chemicals.

The preferred carbon in POE systems is coconut shell activated carbon. This is likely because it removes VOCs and THMs, as well as hydrogen peroxides and hydrogen sulfides. Additionally, it is more environmentally friendly than other forms of activated carbon because coconut trees are not destroyed during harvesting.

The CF1 has significant filtration capabilities that prevent water pressure drops. It is easy to install and maintain. The system comes with a lifetime warranty, a six-month money-back guarantee, and free shipping.

Point of Use (POU) filters.

Although they achieve similar results, POU filters should not be confused with POE systems. They are generally less expensive and offer a more consistent experience. POU filters can be installed in a location to purify water right where it is needed, usually under a bathroom or kitchen sink.

The most popular type of system is the reverse osmosis system. These systems include the Paragon Waters Solutions Reverse Osmosis Water Purification System, which can be placed under the sink. These filtration systems can remove contaminants such as lead, copper, and fluoride from water, as well as chlorine and arsenic. Aluminum, chloramines, herbicides, and pesticides. They can be installed under almost any sink and deliver up to 75 gallons of water to your home each day. These are the ideal solution if you need to purify water from certain faucets in your home.

Final thoughts

Activated carbon filters are a great technology for water purification. They can solve many of the water pollution problems that most of us deal with every day. However, there are a few exceptions to consider.

Be sure to do your research before purchasing an activated carbon filter.

• What specific pollutants is it able to remove and reduce?
• Type of activated carbon used (granules, blocks, etc.).
• What filter media does it use (such as wood, coconut shell carbon, or charcoal)
• You can use any of the above methods to determine the current water quality in your home.
• You should filter water where you live, in specific spots or throughout your home.
• Your budget

What is activated carbon?

Is there a difference between activated carbon and activated charcoal?

What does activated carbon remove?

What is activated carbon made of?

How is activated carbon made?

Which activated carbon should I use?

How do I use activated carbon?

How long does activated carbon last?

Does activated carbon absorb A b or absorb Ad?

Which carbon filter is best for me?

I don’t have any specific information about activated carbon. Can you recommend it to me or provide some examples?

Absolutely yes, we have activated carbon usage and solutions for all kinds of applications and our technical team will provide cooperation. If you need samples, we will provide them for free.

Activated carbon hardness (ASTM D3802-89)

Hardness is a measure of the mechanical strength of activated carbon. The hardness index y is an important parameter when selecting activated carbon for a particular application, as it can affect carbon performance, the life of the adsorption system, and the production of fines or dust that can cause operational problems or slow down the rate. The efficiency of the adsorption process is usually expressed as a percentage or index, indicating the fraction of the activated carbon that remains intact after a standardized abrasion test.

Common tests for measuring the hardness of activated carbon include the ball disc hardness test (also known as the ball abrasion test) and the ASTM D3802 hardness test.

In the ball mill hardness test, a sample of activated carbon is subjected to a specified number of rotations in a ball mill containing a specified number of steel balls. After the test is completed, the amount of carbon remaining on the specified sieve is used to calculate the percentage hardness.

In the ASTM D3802 hardness test, activated carbon is subjected to a specified number of rotations in a rotating drum with a specified number of steel rods. At the end of the test, the carbon particles remaining on the specified sieve are weighed and the hardness index is calculated as a percentage of the original mass remaining.

The hardness of activated carbon can be affected by a variety of factors, including the raw material, the activation process, and the particle size. In general, activated carbon from harder materials (e.g. coconut shells) has a higher hardness value. Activation processes and post-treatment steps can also affect hardness, with processes that result in more crystalline structures or chemical impregnation typically resulting in harder carbon.

In applications where activated carbon is subjected to mechanical stress, such as backwash water treatment systems, pulsed air filters, or high flow rate packed beds, higher hardness is desired to minimize fines generation and maintain optimum performance. Carbon over time In gold recovery in gold mines, where coconut shell activated carbon is used, there are also high requirements for activated carbon hardness.