Activated carbon is not typically used for hydrogen storage, primarily because it does not offer the necessary storage capacity or efficiency for storing hydrogen gas. Hydrogen storage is a critical component of hydrogen-based energy systems, such as fuel cells and hydrogen fuel vehicles.
activated Carbons
There are several methods for hydrogen storage, and each has its advantages and limitations. Some of the most common methods for hydrogen storage include:
Compressed Hydrogen Gas: This method involves storing hydrogen gas at high pressures (typically 350-700 bar) in specially designed tanks. Activated carbon is not used in this method.
Liquid Hydrogen: Hydrogen can be stored as a cryogenic liquid at extremely low temperatures. Specialized cryogenic containers are used for this purpose.
Metal Hydrides: Certain metals and alloys, such as magnesium or lithium hydrides, can absorb and release hydrogen gas reversibly. These materials are capable of storing significant quantities of hydrogen, but they require controlled temperature and pressure conditions and are typically not associated with activated carbon.
Chemical Hydrogen Storage: Some chemical compounds can bond with hydrogen and release it when needed. These compounds are generally not related to activated carbon.
Activated carbon is known for its high surface area and porosity, which makes it suitable for adsorption of gases and liquids. However, it is not used for hydrogen storage because it cannot achieve the necessary storage density (mass of hydrogen per unit volume) and efficiency required for practical applications. Researchers have explored various materials, including metal-organic frameworks and porous materials, for hydrogen storage due to their ability to achieve higher storage capacities.
But Some Researches show that activated carbon can store hydrogen:
Carbon fiber can be used for hydrogen storage, but it is not a standalone storage medium for hydrogen. Instead, carbon fiber is used as a component of a composite material in high-pressure hydrogen storage tanks. These tanks are designed to store hydrogen gas at high pressures, which is one of the common methods for hydrogen storage.
Here’s how it works:
Carbon Fiber Reinforced Composite Tanks: Carbon fiber-reinforced composites are used to create lightweight, high-strength pressure vessels. These tanks are designed to withstand the high pressures required for storing hydrogen gas. The carbon fiber provides the strength and durability while keeping the tank’s weight relatively low.
Gas Pressure: Hydrogen is stored within these tanks at high pressures, typically in the range of 350-700 bar (5,000-10,000 psi). The carbon fiber composite tank ensures that the high pressure can be safely contained.
Safety: Safety is a critical consideration when storing hydrogen at high pressures. Carbon fiber tanks are designed to meet safety standards and are tested rigorously to ensure that they can withstand various stresses and conditions.
While carbon fiber is an integral part of high-pressure hydrogen storage tanks, it’s important to note that the capacity of such tanks depends on their size and design. These tanks are typically used in applications like hydrogen fuel cell vehicles, where the high-pressure storage allows for a reasonable amount of hydrogen to be stored in a relatively small space. However, they may not achieve the same level of hydrogen storage capacity as some other hydrogen storage methods like metal hydrides or liquid hydrogen.
Activated charcoal (also known as activated carbon) consists of small, black beads or a solid black porous sponge. It is used in water filters, medicines that selectively remove toxins, and chemical purification processes.
Activated Carbon Powder
Activated charcoal is carbon that has been treated with oxygen. The treatment results in highly porous charcoal. These tiny holes give the charcoal a surface area of 300-2,000 m2/g, allowing liquids or gases to pass through the charcoal and interact with the exposed carbon. The carbon adsorbs a wide range of impurities and contaminants, including chlorine, odors, and pigments. Other substances, like sodium, fluoride, and nitrates, are not as attracted to the carbon and are not filtered out.
Since adsorption works by chemically binding the impurities to the carbon, the active sites in the charcoal eventually become filled. Activated charcoal filters become less effective with use and have to be recharged or replaced.
What Activated Charcoal Will and Won’t Filter
The most common everyday use of activated charcoal is to filter water. It improves water clarity, diminishes unpleasant odors, and removes chlorine. It’s not effective for removing certain toxic organic compounds, significant levels of metals, fluoride, or pathogens. Despite persistent urban legend, activated charcoal only weakly adsorbs alcohol and it not an effective means of removal.
It will filter:
Chlorine
Chloramine
Tannins
Phenol
Some drugs
Hydrogen sulfide and some other volatile compounds that cause odors
Small amounts of metals, such as iron, mercury, and chelated copper
It won’t remove:
Ammonia
Nitrates
Nitrites
Fluoride
Sodium and most other cations
Significant amounts of heavy metals, iron, or copper
Significant amounts of hydrocarbons or petroleum distillates
Bacteria, protozoa, viruses, and other microorganisms
Activated Charcoal Effectiveness
Several factors influence the effectiveness of activated charcoal. The pore size and distribution varies depending on the source of the carbon and the manufacturing process. Large organic molecules are absorbed better than smaller ones. Adsorption tends to increase as pH and temperature decrease. Contaminants are also removed more effectively if they are in contact with the activated charcoal for a longer time, so flow rate through the charcoal affects filtration.
Activated Charcoal De-Adsorption
Some people worry that activated charcoal will de-adsorb when the pores become full. While the contaminants on a full filter aren’t released back into the gas or water, used activated charcoal is not effective for further filtration. It is true that some compounds associated with certain types of activated charcoal may leach into the water. For example, some charcoal used in an aquarium might start to release phosphates into the water over time. Phosphate-free products are available.
Recharging Activated Charcoal
Whether or not you can or should recharge activated charcoal depends on its purpose. It’s possible to extend the life of an activated charcoal sponge by cutting or sanding off the outer surface to expose the interior, which might not have fully lost its ability to filter media. Also, you can heat activated charcoal beads to 200 C for 30 minutes. This will degrade the organic matter in the charcoal, which can then be rinsed away, but it won’t remove heavy metals.
For this reason, it’s generally best to just replace the charcoal. You can’t always heat a soft material that has been coated with activated charcoal because it might melt or release toxic chemicals of its own, basically contaminating the liquid or gas you want to purify. The bottom line here is that you possibly could extend the life of activated charcoal for an aquarium, but it’s inadvisable to try to recharge a filter used for drinking water.
Activated charcoal may sound like a funny thing to put on your plate or lather on your face, but recently, it’s been appearing in everything from waffles and smoothies to face wash and toothpaste. Why?
activated charcoal
Many users believe the black powder can brighten teeth, temper body odor and help the body detox.
How effective is it?
Natural Medicines Comprehensive Database rates effectiveness based on scientific evidence according to the following scale: Effective, Likely Effective, Possibly Effective, Possibly Ineffective, Likely Ineffective, Ineffective, and Insufficient Evidence to Rate.
The effectiveness ratings for ACTIVATED CHARCOAL are as follows:
Possibly effective for…
Poisoning. Activated charcoal is useful for trapping chemicals to stop some types of poisoning when used as part of standard treatment. Activated charcoal should be given within 1 hour after a poison has been ingested. It does not seem to be beneficial if given for 2 or more hours after some types of poisoning. And activated charcoal doesn’t seem to help stop all types of poisoning.
Insufficient evidence to rate effectiveness for…
Diarrhea caused by cancer drug treatment. Irinotecan is a cancer drug known to cause diarrhea. Early research shows that taking activated charcoal during treatment with irinotecan decreases diarrhea, including severe diarrhea, in children taking this drug.
Reduced or blocked flow of bile from the liver (cholestasis). Taking activated charcoal by mouth seems to help treat cholestasis in pregnancy, according to some early research reports.
Indigestion (dyspepsia). Some early research shows that taking certain combination products containing activated charcoal and simethicone, with or without magnesium oxide, can reduce pain, bloating, and feelings of fullness in people with indigestion. It’s unclear if taking activated charcoal by itself will help.
Gas (flatulence). Some studies show that activated charcoal is effective in reducing intestinal gas. But other studies don’t agree. It’s too early to come to a conclusion on this.
Hangover. Activated charcoal is included in some hangover remedies, but experts are skeptical about how well it might work. Activated charcoal doesn’t seem to trap alcohol well.
High cholesterol. So far, research studies don’t agree about the effectiveness of taking activated charcoal by mouth to lower cholesterol levels in the blood.
High levels of phosphate in the blood (hyperphosphatemia). Early research shows that taking activated charcoal daily for up to 12 months appears to reduce phosphate levels in people with kidney disease, including those on hemodialysis who have high phosphate levels.
Wound healing. Studies on the use of activated charcoal for wound healing are mixed. Some early research shows that using bandages with activated charcoal helps wound healing in people with venous leg ulcers. But other research shows that activated charcoal does not help treat bed sores or venous leg ulcers.
Other conditions.
More evidence is needed to rate the effectiveness of activated charcoal for these uses.
How does it work?
Activated charcoal works by “trapping” chemicals and preventing their absorption.
Are there safety concerns?
When taken by mouth: Activated charcoal is LIKELY SAFE for most adults when taken by mouth, short-term. Taking activated charcoal long-term by mouth is POSSIBLY SAFE. Side effects taking activated charcoal by mouth include constipation and black stools. More serious, but rare, side effects are a slowing or blockage of the intestinal tract, regurgitation into the lungs, and dehydration.
When applied to the skin: Activated charcoal is LIKELY SAFE for most adults when applied to wounds.
Special precautions & warnings:
Pregnancy and breast-feeding: Activated charcoal might be safe when used short-term if you are pregnant or breast-feeding, but consult with your healthcare professional before using if you are pregnant.
Gastrointestinal (GI) blockage or slow movement of food through the intestine: Don’t use activated charcoal if you have any kind of intestinal obstruction. Also, if you have a condition that slows the passage of food through your intestine (reduced peristalsis), don’t use activated charcoal, unless you are being monitored by your healthcare provider.
And while there may be truth to some of those claims, not every charcoal product is safe to use.
Many people are looking for ways to reduce inflammation and detox, so there’s a huge market for these products. The problem is, there’s no agency overseeing the safety or effectiveness of activated charcoal, and it’s not governed by the Food and Drug Administration (FDA).
Breaking Down the Facts on Activated Charcoal
Before you slip some activated charcoal in your morning protein shake, it’s important to note that activated charcoal is not the same as the charcoal you buy at Home Depot for your backyard barbeque, nor is it made from the same stuff as the char on your overdone toast. Instead, it comes from burning specific types of wood — including bamboo, birch and balsam — at super-high temperatures, then oxidizing it.
The particles left behind are almost pure carbon, so they’re able to suck up moisture and chemicals. But that doesn’t mean using it is safe or should be done without medical supervision.
Here are six facts you should know before you purchase anything with activated charcoal:
It draws out impurities. Charcoal has a rich history as a medical treatment. Its porous texture binds to toxins and prevents your body from absorbing them. That’s one reason it’s a staple in hospital emergency rooms. Doctors commonly use it as an antidote for food poisoning and drug toxicity.
Putting it in food can be dangerous. There’s no way of knowing what is in an activated charcoal product. It’s a completely uncontrolled industry, so it’s best to leave it out of your diet.
It’s abrasive. While activated charcoal is marketed as a tooth-whitening agent, it can be abrasive and ruin tooth enamel, particularly if it’s used on a regular basis.
It can bind to medications, vitamins and minerals. Activated charcoal does bind to chemical toxins to flush them out, but it also binds to nutrients. Take too much and you could compromise your nutrient status or interfere with the way your body absorbs medication. It can make blood pressure medication and even birth control pills less effective.
It can help patients with kidney disease. For patients with end-stage renal disease, activated charcoal may be a viable alternative to dialysis. The reason: It binds to urea and other toxins, reducing the number of waste products that filter through your kidneys. If you have kidney disease, talk to your doctor.
It can minimize body odor. For people who suffer from something called Fish Odor Syndrome, activated charcoal can bind to the stinky compounds the body produces and help reduce unpleasant odors.
The Bottom Line
Activated charcoal is still a largely unstudied and misunderstood compound and as far as safety goes, consumers are at the mercy of the manufacturer. Any chemical that has the potential to do good also has the potential to harm. Only use activated charcoal under the direction of a medical professional, particularly if you’re planning to ingest it.
Activated charcoal is a fine black powder made from bone char, coconut shells, peat, petroleum coke, coal, olive pits or sawdust.
The charcoal is activated by processing it at very high temperatures. The high temperatures change its internal structure, reducing the size of its pores and increasing its surface area
This results in a charcoal that is more porous than regular charcoal.
activated Charcoal
Activated charcoal shouldn’t be confused with charcoal briquettes that are used to light your barbecue.
While both can be made from the same base materials, charcoal briquettes have not been activated at high temperatures. Moreover, they contain additional substances that are toxic to humans.
Activated charcoal is sometimes used to help treat a drug overdose or a poisoning.
When you take activated charcoal, drugs and toxins can bind to it. This helps rid the body of unwanted substances.
Charcoal is made from coal, wood, or other substances. It becomes “activated charcoal” when high temperatures combine with a gas or activating agent to expand its surface area.
Activated charcoal US Brand Name
Actidose-Aqua
Charcoal
Diarrest
Di-Gon II
Donnagel
EZ-Char
Kaodene NN
Kaolinpec
Kaopectate
Kaopek
Kerr Insta-Char
Canadian Brand Name
Aqueous Charcodote Adult
Aqueous Charcodote Pediatric
Charcodote
Charcodote Pediatric
Charcodote Tfs
Charcodote Tfs Pediatric
Descriptions
Activated charcoal is used in the emergency treatment of certain kinds of poisoning. It helps prevent the poison from being absorbed from the stomach into the body. Sometimes, several doses of activated charcoal are needed to treat severe poisoning. Ordinarily, this medicine is not effective and should not be used in poisoning if corrosive agents such as alkalis (lye) and strong acids, iron, boric acid, lithium, petroleum products (e.g., cleaning fluid, coal oil, fuel oil, gasoline, kerosene, paint thinner), or alcohols have been swallowed, since it will not prevent these poisons from being absorbed into the body.
Some activated charcoal products contain sorbitol. Sorbitol is a sweetener. It also works as a laxative, for the elimination of the poison from the body.Products that contain sorbitol should be given only under the direct supervision of a doctor because severe diarrhea and vomiting may result.
Activated charcoal has not been shown to be effective in relieving diarrhea and intestinal gas.
Activated charcoal may be available without a doctor’s prescription; however, before using this medicine, call a poison control center, your doctor, or an emergency room for advice.
This product is available in the following dosage forms:
Suspension
Powder for Suspension
How Does Activated Charcoal Work?
Activated charcoal works by trapping toxins and chemicals in the gut, preventing their absorption.
The charcoal’s porous texture has a negative electrical charge, which causes it to attract positively charged molecules, such as toxins and gases. This helps it trap toxins and chemicals in the gut.
Because activated charcoal is not absorbed by your body, it can carry the toxins bound to its surface out of your body in feces.
Why do people take activated charcoal?
People take activated charcoal to manage a poisoning or overdose.
When used along with other treatments, activated charcoal may be effective for an acute poisoning. But it is NOT useful in some cases, including poisoning from:
Cyanide
Lithium
Alcohol
Iron tablets
It also is not used to treat poisons such as strong acids or bases.
With a poisoning, don’t guess about the right thing to do. Call your local poison control center immediately. And get to an emergency room. You need to use activated charcoal as soon as possible if it is recommended.
Other less studied uses of activated charcoal include:
Treat a condition of pregnancy in which the normal flow of bile is affected (cholestasis)
Prevent gas
Reduce high cholesterol
Prevent a hangover
Early research about using activated charcoal to treat cholestasis of pregnancy is very limited. More studies are needed to prove its safety and effectiveness.
It’s not clear whether activated charcoal helps improve gas and cholesterol. That’s because the research results so far have been inconsistent.
As for hangover remedies with activated charcoal, there isn’t really any evidence that it works.
The activated charcoal that is used to treat a poisoning is a powder that is mixed with a liquid. Once mixed, it can be given as a drink or through a tube that has been placed through the mouth and into the stomach.
Activated charcoal is also available in tablet or capsule forms to treat gas. This form is not used to treat a poisoning.
Activated Charcoal as an Emergency Poison Treatment
Thanks to its toxin-binding properties, activated charcoal has a variety of medical uses.
For instance, activated charcoal is often used in cases of poisoning.
That’s because it can bind a wide variety of drugs, reducing their effects. In humans, activated charcoal has been used as a poison antidote since the early 1800s.
It may be used to treat prescription drugs overdoses, as well as overdoses of over-the-counter medications like aspirin, acetaminophen and sedatives.
For instance, studies show that when a single dose of 50–100 grams of activated charcoal is taken within five minutes of drug ingestion, it may reduce drug absorption in adults by up to 74% .
This effect decreases to around 50% when the charcoal is taken 30 minutes after drug ingestion and 20% if it’s taken three hours after the drug overdose .
The initial dose of 50–100 grams is sometimes followed by two to six doses of 30–50 grams every two to six hours. However, this multiple dosage protocol is used less often and may only be effective in a limited number of poisoning cases .
It’s important to note that activated charcoal is not effective in all cases of poisoning. For instance, it appears to have little effect on alcohol, heavy metal, iron, lithium, potassium, acid or alkali poisonings.
What’s more, experts warn that activated charcoal shouldn’t be routinely administered in all cases of poisoning. Rather, its use should be considered on a case-by-case basis .
Activated Carbon May Promote Kidney Function
Activated charcoal may help promote kidney function by reducing the number of waste products that the kidneys have to filter.
This could be particularly beneficial in patients suffering from chronic kidney disease, a condition in which the kidneys can no longer properly filter waste products.
Healthy kidneys are normally very well equipped to filter your blood without any additional help. However, patients suffering from chronic kidney disease generally have a harder time removing urea and other toxins from the body.
Activated charcoal may have the ability to bind to urea and other toxins, helping your body eliminate them.
Urea and other waste products can pass from the bloodstream into the gut through a process known as diffusion. In the gut, they become bound to activated charcoal and excreted in the feces .
In humans, activated charcoal has been shown to help improve kidney function in those suffering from chronic kidney disease.
In one study, activated charcoal supplements may have helped lower blood levels of urea and other waste products in patients with end-stage kidney disease.
That said, the current evidence is weak, and more high-quality studies are needed before strong conclusions can be made.
Reduces Symptoms of Fish Odor Syndrome
Activated charcoal may help reduce unpleasant odors in individuals suffering from trimethylaminuria (TMAU), also known as fish odor syndrome.
TMAU is a genetic condition in which trimethylamine (TMA), a compound with an odor similar to that of rotting fish, accumulates in the body.
Healthy individuals are usually able to convert fishy-smelling TMA into a non-smelly compound before excreting it in urine. However, people with TMAU lack the enzyme needed to perform this conversion.
This causes TMA to accumulate in the body and make its way into urine, sweat and breath, giving rise to a foul, fishy odor (13Trusted Source).
Studies show that activated charcoal’s porous surface may help bind small odorous compounds like TMA, increasing their excretion.
One small study in TMAU patients analyzed the effects of supplementing with 1.5 grams of charcoal for 10 days. It reduced TMA concentrations in the patients’ urine to levels found in healthy individuals (14Trusted Source).
These results seem promising, but more studies are needed.
May Reduce Cholesterol Levels
Activated charcoal may also help reduce cholesterol levels.
That’s because it can bind cholesterol and cholesterol-containing bile acids in the gut, preventing the body from absorbing them (15Trusted Source, 16Trusted Source).
In one study, taking 24 grams of activated charcoal per day for four weeks lowered total cholesterol by 25% and bad LDL cholesterol by 25%. Good HDL cholesterol levels also increased by 8% (17Trusted Source).
In another study, taking 4–32 grams of activated charcoal daily helped reduce total and bad LDL cholesterol by 29–41% in those with high cholesterol levels (18Trusted Source).
In this study, the larger dosages of activated charcoal seemed the most effective.
Similar results were reported in most, but not all, studies (19Trusted Source, 20Trusted Source, 21).
However, it’s interesting to note that all studies related to this topic were conducted in the 1980s. More recent studies would help confirm the link.
Other Uses of Activated Carbon ?
Activated charcoal is also a popular home remedy with multiple uses, though it’s important to note that not all of these are supported by science.
Its most well-known home uses include:
Gas reduction: Some studies report that activated charcoal may help reduce gas production following a gas-producing meal. It may also help improve the odor of gas. However, not all studies observed this benefit (22, 23Trusted Source).
Water filtration: Activated charcoal is a popular way to reduce heavy metal and fluoride content in water. However, it doesn’t appear to be very effective at removing viruses, bacteria or hard water minerals (4, 24, 25Trusted Source).
Tooth whitening: Using activated charcoal to brush your teeth is anecdotally said to whiten them. It’s said to do so by absorbing plaque and other teeth-staining compounds. However, no studies could be found to support this claim.
Hangover prevention: Activated charcoal is sometimes used as a hangover cure. While consuming it with alcohol may reduce blood alcohol levels, its effects on hangovers haven’t been studied (26Trusted Source).
Skin treatment: Applying this charcoal to the skin is touted as an effective treatment for acne and insect or snake bites. However, only anecdotal reports could be found on this topic.
Can you get activated charcoal naturally from foods?
Activated charcoal is a manufactured product. You cannot find it naturally in foods.
Dosage Instructions
Those interested in trying activated charcoal can find a wide selection of it on Amazon. Make sure to follow dosage instructions similar to those used in the studies mentioned above.
In the case of drug poisoning, it’s important to seek medical help immediately.
A dosage of 50–100 grams can be administered by a medical professional, ideally within an hour of the overdose. Children normally receive a lower dose of 10–25 grams (8Trusted Source).
Dosages for other conditions range from 1.5 grams to treat fishy odor disease to 4–32 grams per day to lower cholesterol and promote kidney function in end-stage kidney disease (11Trusted Source, 14Trusted Source, 17Trusted Source).
Activated charcoal supplements can be found in pill or powder forms. When taken as a powder, activated charcoal may be mixed with water or a non-acidic juice.
Also, increasing your water intake may help prevent symptoms of constipation.
What are the risks of taking activated charcoal?
When used to treat a poisoning or overdose, activated charcoal is usually safe, but it needs to be administered only in a health care facility.
Side effects are more likely when it is used on a long-term basis to treat conditions like excess gas.
Side effects. When you take it by mouth, activated charcoal can cause:
Black stools
Black tongue
Vomiting or diarrhea
Constipation
In more serious cases, it can cause gastrointestinal blockages.
Risks. Do not combine activated charcoal with drugs used for constipation (cathartics such as sorbitol or magnesium citrate). This can cause electrolyte imbalances and other problems.
Interactions. Activated charcoal may reduce or prevent the absorption of certain drugs. This may include drugs such as:
Acetaminophen
Digoxin
Theophylline
Tricyclic antidepressants
Do not use activated charcoal as a supplement if you take these medications. Activated charcoal may also reduce absorption of certain nutrients.
The U.S. Food and Drug Administration (FDA) does regulate dietary supplements; however, it treats them like foods rather than medications. Unlike drug manufacturers, the makers of supplements don’t have to show their products are safe or effective before selling them on the market.
Be sure to tell your doctor about any supplement you’re taking, even if it’s natural. That way, your doctor can check on any potential side effects or interactions with medications, foods, or other herbs and supplements. They can let you know if the supplement might increase your risks.
Granular activated carbon (GAC) is a type of water treatment commonly used to remove chemical contaminants and for taste and odor control. GAC filters come in a variety of types and sizes and can be used to treat the water at a single tap or all the water in your home. As with all treatment types, GAC units must be operated and maintained properly to ensure the water supplying your home remains safe.
GAC can be used to remove or reduce:
Unwanted tastes and odors
Radon
Organic chemicals
Pesticides and Herbicides
Chlorine
Per- and Polyfluoroalkyl Substances (PFAS)
GAC is not considered effective to remove or reduce:
Microorganisms (i.e. bacteria, viruses) Some metals
Nitrates
How Granular Activated Carbon Treatment Works
GAC media is an effective adsorbent because it is highly porous and provides a large surface area for contaminants to adsorb onto. GAC media is made by heating a carbon source such as coal, coconut shells, wood or peat. GAC media is placed inside a filter tank. When untreated water passes through, certain contaminants are attracted to the media and become adsorbed by its surface, becoming trapped in its pores.
The effectiveness of any GAC filter unit will depend on the type of GAC media installed, the concentration and type of contaminants in the water, and the size of the GAC filter.
Types of Units
GAC filters come in both whole house (also known as point-of- entry (POE)) units and point-of-use (POU) units, which refers to the location where the treatment unit is installed.
Produced by The State of Connecticut Department of Public Health Environmental Health Section, Private Well Program 410 Capitol Avenue, MS#11PWP, PO Box 340308, Hartford, CT 06134 Phone: 860-509-8401 Fax: 860-509-7295
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POU units treat water only at a specific tap ; usually the kitchen sink to treat the water you drink and cook with. POU units can be pour through units, faucet mount units, in-line devices, or line bypass units:
Pour-through GAC units: Untreated water is poured into the top of the pitcher, then passes through a small carbon filter. Treated water is collected at the base of the pitcher. These units are not connected to the water supply and usually sit on counter tops. Pour-through devices only treat small quantities of water at a given time, and are not recommended for removal of organic chemicals.
Faucet mount units are attached to the faucet or placed on the counter with connections to the faucet. Some of these units may be equipped with a bypass option to selectively filter water (usually for cooking and drinking) which helps to prolong the life of the carbon cartridge. Faucet-mount units are typically not recommended for removal of organic chemicals. Certain faucet mount units may be effective at reducing lead in water. Always consult with manufacturer’s specifications to determine effectiveness against specific contaminanants in your water.
The line-bypass unit is attached to the cold water plumbing beneath the kitchen sink and has a separate faucet installed that provides treated water for uses such as cooking and drinking. The regular tap delivers untreated water. This design may increase the life expectancy of the carbon by allowing a choice of either treated or untreated water.
The in-line device is installed beneath the kitchen sink on the cold water plumbing to treat water for uses such as drinking or cooking. If both hot and cold water come from a single faucet, the treated cold water can mix with the untreated hot water. Treated water is provided only when using cold water for uses such as drinking and cooking.
Whole House Treatment (POE) GAC units are typically installed where the water line enters your house and will treat all the water in your household plumbing.
Whole house treatment or POE is recommended for treatment of most volatile organic compounds (VOCs), pesticides, herbicides or chemicals. Whole house treatment also prevents the inhalation of hazardous vapors for those contaminants that can easily vaporize from water into air, such as radon and VOCs. Whole house treatment also prevents skin absorption from bathing and showering from chemicals such as VOCs, pesticides and herbicides.
Unit Effectiveness
The effectiveness of a GAC unit depends on the time of contact between the carbon and the untreated water. The longer the contact time, the better the adsorption of contaminants onto the GAC filter media. Over time, channels can form within the GAC filter media, which may allow some untreated water to pass through the filter media through these channels. Since treatment depends on the GAC media adsorbing the chemical contaminants, these channels decrease the effectiveness of the GAC filter unit.
Some types of GAC filters are better at treating for certain contaminants than others. Discuss your options with a GAC product distributor or water treatment company. Always confirm that the treatment unit you are choosing has been tested to meet manufacturer’s claims.
In order for GAC filtration to be most effective, it is important to follow manufacturer’s maintenance requirements. Filter media should be replaced over time as needed. Consult with your water treatment company installing the GAC treatment unit or the manufacturer to determine maintenance requirements.
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Backwash Wastewater Generated
Treatment backwash is sometimes necessary to lift the GAC filter media and reduce sediment from it.
This process may help eliminate any channels that may have formed in the filter media.
Water treatment equipment will not perform satisfactorily unless it is maintained in accordance with manufacturer’s recommendations for maintenance, cleaning and part replacement. It is recommended that you keep a record of equipment maintenance and repairs.
GAC filter units need to have the GAC media inside changed regularly. For small point of use specialty units, the entire cartridge filter is normally replaced. POE GAC filters are often used in line with a pre-treatment filter to remove sediment and iron particles that can clog the carbon filter. If installed, pre-treatment filters will also need to be replaced periodically.
GAC filter media eventually becomes saturated and can no longer adsorb contaminants. This is called ‘breakthrough’. When this occurs, the GAC filter media can no longer remove contaminants from the water. If left for too long after this point, contaminant concentration levels in the water supplying your house could actually be higher than the untreated water entering the GAC filter. Two GAC filters may be placed in series to prevent breakthrough contaminants from reaching your home’s water supply. Changing the filter media on a regular basis will also help to prevent breakthrough from occurring.
GAC maintenance frequency will vary based on the size of the filter unit, household water usage, contaminant concentration levels, and overall water quality. Water quality testing can help determine when GAC media needs to be replaced. A water meter installed at the filter may be helpful in determining when carbon replacement is necessary. Refer to the two sections below for more information.
GAC media can sometimes provide a medium for bacterial growth, reducing the effectiveness of the filter. If bacterial growth coats your GAC media it may also enter your household plumbing system. If test results indicate bacteria is present in the water, replacement of the GAC filter media and disinfection of your well water and household plumbing may be needed. Use of GAC media infused with an antibacterial coating to help prevent bacterial growth may also be considered.
Depending on the types and concentrations of the contaminant being removed, GAC filter media may require special waste handling and disposal. Ask your water treatment company beforehand about disposal costs, disposal requirements and whether alternative treatment methods should be considered before making a decision to install a GAC treatment system.
Alternative options may include use of bottled water, installing a new well in another location that is not contaminated, or connecting to a public water system when available and feasible. Using bottled water for drinking and cooking may be an option, however, when contaminant levels are high, or, pose a risk during bathing and showering, whole house GAC treatment may be the best option. In many cases use of bottled water can serve as a viable temporary solution until a long term solution has been made.
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GAC Unit Installation and Water Testing Considerations
Always confirm with your water treatment installer that your GAC unit is installed according to manufacturer’s specifications. Retain a copy of your GAC unit manufacturer’s specifications for reference and follow any required maintenance protocols. Confirm with your water treatment installer that all State and Local requirements will be met during its installation.
After installation, test both the untreated water (raw water from the well) and treated water (water after GAC treatment) at a state certified laboratory. Compare the results of the treated and untreated water to determine if the GAC unit is properly removing contaminants. Test untreated and treated water annually or more frequently if high levels of contaminants are present in the untreated water. Frequent testing will help you determine how well your treatment system is working and whether maintenance or replacement of components may be necessary.
It is a good idea to install sample taps before (pre) and after (post) GAC filtration. Periodic testing both pre and post filter will help determine when the filter media needs to be changed and to ensure that breakthrough hasn’t occurred. Installing a water meter and recording water meter readings when new filter GAC media is added can also help determine about how many gallons the GAC filter treated before service was needed. You can then use this number to estimate approximately how many gallons the GAC filter can treat before it is no longer effective and how often you should test water quality after filtration to determine if breakthrough has occurred.
If you have two GAC filters installed in series, sample taps can be installed pre, mid and post GAC filtration. Periodic testing can be performed pre, mid and post filtration to determine when service is needed or if breakthrough has occurred. Once the mid -stream water quality sample indicates that the GAC filter media should be changed, the second GAC filter is often times swapped to the front position and a filter with new GAC media is moved to the second filter position.
Questions to Ask Before you Buy
Before purchasing a water treatment device, have your water tested at a state certified laboratory to determine the contaminants present and their concentrations. This will help you determine if GAC is an effective treatment method for the water quality parameters identified through the test results. See Publication #19: Questions to Ask When Purchasing Water Treatment Equipment,for more information.
The parameters that indicate the adsorption capacity of activated carbon are:
Iodine value test
1. Iodine value (400 ~ 1300): refers to the amount of iodine adsorbed by activated carbon in 0.02N12 / KL aqueous solution. The iodine value is related to the pore surface area with a diameter greater than 10A. The iodine value is one of the criteria for judge the price of activated carbon.
2. Butane value: Butane value is the amount of butane adsorbed per unit weight of activated carbon after saturated air and butane pass through the carbon bed at a specific temperature and specific pressure.
3. Ash content (6-16): There are two types of ash of activated carbon, one is surface ash and the other is internal ash content. Normally, the ash of activated carbon refers to internal ash.
4. Water content (<5): It is a measure of how much water is contained in carbon, that is, the percentage of the weight of water adsorbed in activated carbon.
5. Hardness: The hardness value refers to the resistance of the granular activated carbon to the decay movement of the steel ball in the RO-TAP instrument. Hardness is an indicator for measuring the mechanical strength of activated carbon.
6. Carbon tetrachloride CTC (%): The carbon tetrachloride value is an indicator of the total pore volume, which is measured with a saturated CCI4 gas flow of zero degrees Celsius through a 25 degree carbon bed. That is, the adsorption function of activated carbon depends on the carbon tetrachloride value. The measurement method is to use activated carbon to adsorb carbon tetrachloride, and the measured result is the adsorption rate of activated carbon. Generally, the highest carbon tetrachloride value of activated carbon is 80. Activated carbon manufacturers in Beijing and Hebei have more than 80% to reach 60%.
7. Molasses value: The molasses value is a method to measure the relative decolorization ability of activated carbon in boiling molasses solution. The molasses value is interpreted as a surface area with a pore diameter greater than 28A. Because molasses is a mixture of multiple components, this parameter must be tested in strict accordance with the instructions. The molasses value is obtained by calculating the ratio of the optical density of the filter by treating the molasses liquid with a standard sample of activated carbon and a sample of activated carbon to be tested.
8. Bulk weight (400-600): Bulk weight is a method of measuring the quality of a specific amount of carbon. By gradually adding activated carbon to a graduated drum to 100cc, and measuring its mass. This value is used to calculate the amount of activated carbon needed to fill a specific adsorption device. Simply put, the bulk weight is the weight of activated carbon per unit volume.
9. Particle density – The particle density is the weight of the particulate carbon per unit volume, excluding the particles and the space between cracks greater than 0.1 mm.
10. Methythioninium Chloride (100-300): The Methythioninium Chloride value refers to the number of milligrams of Methythioninium Chloride absorbed when a solution of 1.0 g of carbon and a concentration of 1.0 mg / L of Methythioninium Chloride reaches equilibrium.
11. Wear value
The wear value is an index for measuring the wear resistance of activated carbon. The wear value of granular activated carbon indicates that the particles reduce the resistance of the particles during the treatment process. It is calculated by determining the ratio of the average diameter of the final particles to the average diameter of the original particles.
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Carbon filtering is a method of filtering that uses a bed of activated carbon to remove contaminants and impurities, using chemical adsorption.
Carbon Filter
Each particle, or granule, of carbon provides a large surface area, or pore structure, allowing contaminants the maximum possible exposure to the active sites within the filter media. One gram of activated carbon has a surface area in excess of 3,000 m2 (32,000 sq ft).
Activated carbon works via a process called adsorption, whereby pollutant molecules in the fluid to be treated are trapped inside the pore structure of the carbon substrate. Carbon filtering is commonly used for water purification, air filtering and industrial gas processing, for example the removal of siloxanes and hydrogen sulfide from biogas. It is also used in a number of other applications, including respirator masks, the purification of sugarcane and in the recovery of precious metals, especially gold. It is also used in cigarette filters and in the EVAP used in cars.
Active charcoal carbon filters are most effective at removing chlorine, particles such as sediment, volatile organic compounds (VOCs), taste and odor from water. They are not effective at removing minerals, salts, and dissolved inorganic substances.
Typical particle sizes that can be removed by carbon filters range from 0.5 to 50 micrometres. The particle size will be used as part of the filter description. The efficacy of a carbon filter is also based upon the flow rate regulation. When the water is allowed to flow through the filter at a slower rate, the contaminants are exposed to the filter media for a longer amount of time.
Hydrogen production
For small-scale production of hydrogen, water purifiers are installed to prevent formation of minerals on the surface of the electrodes and to remove organics and chlorine from utility water. First the water passes through a 20 micrometer interference (mesh or screen filter) filter to remove sand and dust particles, second, a charcoal filter (activated carbon) to remove organics and chlorine, third stage, a de-ionizing filter to remove metallic ions.[citation needed] A test can be done before and after the filter for proper functioning on barium, calcium, potassium, magnesium, sodium, and silicon.
Activated charcoal is a sponge-like substance that is made from different carbon-containing substances of natural origin. Activated Charcoal is charcoal that has been treated with oxygen. The treatment results in a highly porous charcoal. It is made at very high temperatures and as a result, activated charcoal is a substance which is almost one hundred percent composed of carbon.
The chemical composition of charcoal is very similar to graphite. Useful properties of activated charcoal can be contributed to the huge number of pores and hence activated charcoal exhibits very high absorbent and catalytic properties.
Activated carbon is used in methane and hydrogen storage, air purification, decaffeination, gold purification, metal extraction, water purification, medicine, sewage treatment, air filters in gas masks and respirators, filters in compressed air, teeth whitening, and many other applications.
Activated carbon industrial application
One major industrial application involves use of activated carbon in metal finishing for purification of electroplating solutions. For example, it is the main purification technique for removing organic impurities from bright nickel plating solutions. A variety of organic chemicals are added to plating solutions for improving their deposit qualities and for enhancing properties like brightness, smoothness, ductility, etc. Due to passage of direct current and electrolytic reactions of anodic oxidation and cathodic reduction, organic additives generate unwanted breakdown products in solution. Their excessive build up can adversely affect plating quality and physical properties of deposited metal. Activated carbon treatment removes such impurities and restores plating performance to the desired level.
Medical uses
Main article: Activated charcoal (medication)
activated Carbons for Medical Uses
Activated charcoal for medical use
Activated carbon is used to treat poisonings and overdoses following oral ingestion. Tablets or capsules of activated carbon are used in many countries as an over-the-counter drug to treat diarrhea, indigestion, and flatulence.
However, activated charcoal shows no effect of intestinal gas and diarrhea, and is, ordinarily, medically ineffective if poisoning resulted from ingestion of corrosive agents such as alkalis and strong acids, iron, boric acid, lithium, petroleum products, or alcohol. Activated carbon will not prevent these chemicals from being absorbed into the human body.
It is particularly ineffective against poisonings of strong acids or alkali, cyanide, iron, lithium, arsenic, methanol, ethanol or ethylene glycol.
Incorrect application (e.g. into the lungs) results in pulmonary aspiration, which can sometimes be fatal if immediate medical treatment is not initiated.
Activated Charcoal is a powerful tool for emergency cleansing of the gastrointestinal tract, perhaps the most effective remedy known today. It can be used in cases of poisoning from virtually any toxic substance. Activated charcoal reduces the absorption of poisonous substances up to 60%.
One teaspoon of activated charcoal has a surface area of approximately 10 000 square feet. It adsorbs and helps eliminate toxins, heavy metals, chemicals, pharmaceutical drugs, morphine, pesticides from your body.
Poisoning by various chemical substances, drugs, toxic heavy metals, alkaloids
Overall body detoxification
Food poisoning
Treating stomach pain caused by excess gas, diarrhea, or indigestion.
Body odor and bad breath
Hepatitis: chronic and acute viral
Withdrawal syndrome (as a rule, is used for drinking, not for drug addiction)
Intoxication caused by chemotherapy or radiotherapy
Various skin ailments
Inflammation
Helps lower cholesterol, triglycerides and lipids found in the blood.
Analytical chemistry applications
Activated carbon, in 50% w/w combination with celite, is used as stationary phase in low-pressure chromatographic separation of carbohydrates (mono-, di-trisaccharides) using ethanol solutions (5–50%) as mobile phase in analytical or preparative protocols.
Environmental applications
Activated carbon is usually used in water filtration systems. In this illustration, the activated carbon is in the fourth level (counted from bottom).
Activated carbon is usually used in water filtration systems. In this illustration, the activated carbon is in the fourth level (counted from bottom).
Carbon adsorption has numerous applications in removing pollutants from air or water streams both in the field and in industrial processes such as:
Spill cleanup
Groundwater remediation
Drinking water filtration
Air purification
Volatile organic compounds capture from painting, dry cleaning, gasoline dispensing operations, and other processes.
During early implementation of the 1974 Safe Drinking Water Act in the US, EPA officials developed a rule that proposed requiring drinking water treatment systems to use granular activated carbon. Because of its high cost, the so-called GAC rule encountered strong opposition across the country from the water supply industry, including the largest water utilities in California. Hence, the agency set aside the rule. Activated carbon filtration is an effective water treatment method due to its multi-functional nature. There are specific types of activated carbon filtration methods and equipment that are indicated – depending upon the contaminants involved.
Activated carbon is also used for the measurement of radon concentration in air.
Agriculture uses
Activated carbon (charcoal) is an allowed substance used by organic farmers in both livestock production and wine making. In livestock production it is used as a pesticide, animal feed additive, processing aid, nonagricultural ingredient and disinfectant. In organic winemaking, activated carbon is allowed for use as a processing agent to adsorb brown color pigments from white grape concentrates.
Activated carbon has been used as a purification agent since ancient Egypt and India. It was introduced to the modern world via the sugar refineries of 1800s Europe, and its use quickly swept the globe. Rapidly evolving technology has led to its expansion ever since, and today activated carbon plays a key role in a vast number of industries, from wastewater treatment to pharmaceutical manufacturing. It is also used in agriculture to improve crop yields.
activated carbon adsorbs and removes targeted compounds along its vast surface area. Although it has been used in modern agriculture for only a decade or so, research shows that activated carbon can boost agriculture in several important ways.
Seed Protection
Fungicides and herbicides are absolutely essential to modern agriculture, preventing harmful species from taking over and destroying crops. Unfortunately, these products can also be damaging to newly planted seeds. When mixed with fertilizer or used to coat vulnerable seeds, activated carbon can ensure the survival of the vast majority of seeds. The surface chemistry of the activated carbon can even be manipulated to ensure the best pH for different types of seeds. In some cases, activated carbon can also be mixed into the soil to protect fields from accidental spills of fungicides or herbicides.
Time-Release Nutrient Delivery
Although most popular applications of activated carbon involve removing toxic or noxious compounds, activated carbon’s tremendous storage abilities also allow it to deliver helpful compounds on a timed basis. For agriculture, activated carbon can store nutrients that are essential to plant health and then release them over time. For example, activated carbon can be impregnated with ethylene, the naturally occurring hormone that causes plants to ripen. The ethylene can then be delivered to help all of the fruits in a crop ripen at the same time.
Herbicide Catalyst
Activated carbon is a powerful catalyst for oxidation, and can be used for this purpose in the production of herbicides. It is important to choose a powdered activated carbon (PAC) with strong characteristics of filtration and sedimentation. When specifically prepared for this purpose, PAC can help to create a highly effective herbicide.
Purification and Decolorization
Like any other chemical product, agrochemicals need to be pure and clean to create the desired results. Colorization also matters in consumer preferences, with homogeneously colored products being seen as more desirable. Activated carbon is used in the agrochemical industry to remove unwanted compounds and create the pure, decolorized products that consumers deserve.
Agriculture is a relative newcomer to the list of industries that have been revolutionized by the use of activated carbon. Yet research shows that it works across a wide range of agricultural applications. Activated carbon comes in many types and forms, each with its own unique characteristics. For the best results, it is important to consult with an activated carbon expert who can help you sort through the options and select just the right product to meet your needs.
Are you interested in purchasing activated carbon for a specific application? Do you require expert guidance in choosing the right impregnation for your needs? With more than 70 years of experience in the activated carbon industry, Oxbow Activated Carbon is proud to provide the most diverse line of activated carbon products on the market today. We provide both standard and custom impregnations, spent carbon disposal and reactivation, and numerous other specialized services. We pride ourselves on our individualized customer service, and we look forward to becoming your one-stop shop for all your activated carbon needs.
Distilled alcoholic beverage purification
Activated carbon filters (AC filters) can be used to filter vodka and whiskey of organic impurities which can affect color, taste, and odor. Passing an organically impure vodka through an activated carbon filter at the proper flow rate will result in vodka with an identical alcohol content and significantly increased organic purity, as judged by odor and taste.[citation needed]
Fuel storage
Research is being done testing various activated carbons’ ability to store natural gas[2][1] and hydrogen gas.[1][2] The porous material acts like a sponge for different types of gases. The gas is attracted to the carbon material via Van der Waals forces. Some carbons have been able to achieve bonding energies of 5–10 kJ per mol. The gas may then be desorbed when subjected to higher temperatures and either combusted to do work or in the case of hydrogen gas extracted for use in a hydrogen fuel cell. Gas storage in activated carbons is an appealing gas storage method because the gas can be stored in a low pressure, low mass, low volume environment that would be much more feasible than bulky on-board pressure tanks in vehicles. The United States Department of Energy has specified certain goals to be achieved in the area of research and development of nano-porous carbon materials. All of the goals are yet to be satisfied but numerous institutions, including the ALL-CRAFT program,[1][2][13]are continuing to conduct work in this promising field.
Gas purification
Filters with activated carbon are usually used in compressed air and gas purification to remove oil vapors, odor, and other hydrocarbons from the air. The most common designs use a 1-stage or 2 stage filtration principle in which activated carbon is embedded inside the filter media.
Activated carbon filters are used to retain radioactive gases within the air vacuumed from a nuclear boiling water reactor turbine condenser. The large charcoal beds adsorb these gases and retain them while they rapidly decay to non-radioactive solid species. The solids are trapped in the charcoal particles, while the filtered air passes through.
Chemical purification
Activated carbon is commonly used on the laboratory scale to purify solutions of organic molecules containing unwanted colored organic impurities.
Filtration over activated carbon is used in large scale fine chemical and pharmaceutical processes for the same purpose. The carbon is either mixed with the solution then filtered off or immobilized in a filter.
Mercury scrubbing
Activated carbon, often infused with sulfur[14] or iodine, is widely used to trap mercury emissions from coal-fired power stations, medical incinerators, and from natural gas at the wellhead. This carbon is a special product costing more than US$4.00 per kg.
Since it is often not recycled, the mercury-laden activated carbon presents a disposal dilemma. If the activated carbon contains less than 260 ppm mercury, United States federal regulations allow it to be stabilized (for example, trapped in concrete) for landfilling. However, waste containing greater than 260 ppm is considered to be in the high-mercury subcategory and is banned from landfilling (Land-Ban Rule). This material is now accumulating in warehouses and in deep abandoned mines at an estimated rate of 100 tons per year.
The problem of disposal of mercury-laden activated carbon is not unique to the United States. In the Netherlands, this mercury is largely recovered and the activated carbon is disposed of by complete burning, forming carbon dioxide (CO2).
Scientists at NASA’s Glenn Research Center have developed a unique water purification method that can be used for water recycling or point-of-use applications. Originally developed as a means to recycle water in space, this technology has applications in industrial water treatment, water recycling, and water purification for military bases, disaster sites, and regions without easy access to clean water.
Relying on only electrical energy, this technology uses plasma-generated reactive species to decompose organic contaminants, ranging from submicron particles to water soluble organics like glycol, ethanol, and industrial dyes.
Benefits
Environmentally friendly: Does not introduce toxic chemicals into liquids
Readily available: Provides clean water on-demand
Accessible: Accommodates large-volume, high-throughput applications and works with in-volume and in-line water feed systems
Simple: Operates without filters, which can often become fouled or punctured
Durable: Housed in a self-contained unit
Highly antiseptic: Attacks and destroys microbes
Applications
Wastewater treatment
Pharmaceutical and food and beverage water treatment
Pretreatment of contaminants
Point-of-use drinking water
Groundwater treatment
EPA Superfund site cleanup
Hydraulic fracturing water reuse
The Technology
The Glenn water purification system has application in wastewater treatment
Highly oxidizing water treatments, like ozonation and UV-ionization, have proven useful in removing organics from water, but they require high capital costs and high amounts of wasteful energy consumption.
Glenn’s approach to water purification uses high-voltage, nanosecond-pulsed, non-equilibrium plasma to treat water. The pulsed electrical discharge destroys micro-organisms in liquid, essentially sterilizing the water, without the use of toxic chemicals or filters. The plasma creates highly reactive OH radicals (e.g. hydroperoxl, hydrogen peroxide, super oxide O2) that break down organic contaminants into carbon dioxide and water.
The nano-pulses ensure that only enough energy is produced to destroy the contaminant without heating up the water, eliminating the need for cooling loops or downtime that is associated with other processes (such as UV-ionization). NASA’s water purification technology relies only on electricity and can be scaled to meet a wide range of needs, from small portable units that purify drinking water in disaster relief to million-gallons-per-day industrial applications.
This technology is simple, straightforward, and low cost, with virtually no consumables nor byproducts. Furthermore, the plasma pulse technology can function as a stand-alone purification process or as an add-on to existing solutions as a polishing step.
removal at a number of stages in municipal sewage treatment. Odours can develop at a number of points in municipal waste water treatment plants where sewage is agitated or where sludge accumulates. This includes pumping stations, head works, trickling filters, digesters and at sludge handling and storage areas.
The Carbon Filtering Process is generally used for Indoor Air Purification/(quality), (Odor) control and (emission control) Processing. Activated carbon is a general term of adsorbents that have been manufactured from a variety of carbon-based materials. Each base material results in an activated carbon with unique physical characteristics that determine its suitability for treatment applications.
The ability of activated carbon filters to remove impurities from the air is one of the reasons it is commonly used for indoor air quality, odor control and emission control systems. Carbon Filter use continues to increase as more industries and consumers consider their environmental impact.
Carbon filters have been used for several hundred years and are considered one of the oldest means of water purification. Historians have shown evidence that carbon filtration may have been used in ancient Egyptian cultures for medical purposes and as a purifying agent. 2000 B.C. Sanskrit text refers to filtering water through charcoal (1905 translation of “Sushruta Samhita” by Francis Evelyn Place). The first recorded use of a carbon filter to purify potable water on a large scale occurred in 19th century England.
Currently, carbon filters are used in individual homes as point-of-use water filters, groundwater remediation, landfill leachate, industrial wastewater and, occasionally, in municipal water treatment facilities. They are also used as pre-treatment devices for reverse osmosis systems and as specialized filters designed to remove chlorine-resistant cysts, such as giardia and cryptosporidium.
Because of activated charcoal’s incredible adsorption ability, it is an ideal choice for air and water filters. When used appropriately, charcoal filters will effectively clean the air and water by electrostatically binding pollutants to its vast surface area.
Many people use activated charcoal filters in outdoor ponds and aquariums to keep the water clean and the marine life healthy.
Many of us strive to live in a chemical-free world, but doing so is not always easy. Many of the contaminants that we come into contact with on a daily basis actually come from our homes–a place that is supposed to be a safe haven for ourselves and our families. The more we can do to eliminate these chemicals from our lives, the healthier we will all be.
Carbon filteringis a method of filtering that uses a bed ofactivated carbonto remove contaminants and impurities, using chemicalabsorption.
Each particle/granule of carbon provides a large surface area/pore structure, allowing contaminants the maximum possible exposure to the active sites within the filter media. One pound (450 g) of activated carbon contains a surface area of approximately 100 acres (40 Hectares).
Activated carbon works via a process calledadsorption, whereby pollutant molecules in the fluid to be treated are trapped inside the pore structure of the carbon substrate. Carbon filtering is commonly used forwater purification, inair purifiersand industrial gas processing, for example the removal ofsiloxanesandhydrogen sulfidefrombiogas. It is also used in a number of other applications, includingrespiratormasks, the purification ofsugarcaneand in the recovery of precious metals, especiallygold. It is also used in cigarette filters.
Active charcoal carbon filters are most effective at removingchlorine,sediment,volatile organic compounds(VOCs), taste andodorfrom water. They are not effective at removingminerals,salts, and dissolved inorganic compounds.
What carbon filtration doesn’t do can be seen in the remaining three categories of the EPA contaminant list. Carbon is mentioned as a treatment for only one of the four Microbiological contaminants listed: turbidity.
It is not recommended for coliform removal or for cysts, though ironically, some of the very tight solid carbon block filters now on the market remove bacteria (though manufacturers seldom make this claim) and cysts like giardia and cryptosporidium quite handily. Multipure solid carbon blocks, in fact, were the first filtration device certified by NSF (the most prestigious independent agency that tests and certifies product performance) for removal of cryptosporidium.
Multipure and some other very tight carbon block filters remove cysts simply because of their restricted pore size. Multipure blocks are absolute 1/2 micron filters, making cryptosporidium organisms about ten times too fat to go through the holes. Thus, although other types of very tight filtration might work as well, the very dense carbon block filters now on the market are very effective against certain forms of microbiological contaminants.
Activated Carbon for drinking water Treatment
Potable or drinking water is a commodity with stringent requirements of being safe and pure. Granular Activated Carbons (GACs) and Powder Activated Carbons (PACs) is your ideal solution in making drinking water free from taste and odor forming compounds such as MIB and geosmin, undesired colors, endocrine disrupting compounds and other micropollutants, chlorinated hydrocarbons, Trihalomethanes and other disinfection byproducts, VOCs, pesticides and their byproducts.
You can treat drinking water with the high quality, standard, and specially processed products complying with NSF 61, NSF 42, PROP 65 certifications with low dechlorination half values, superior flow characteristics, consistent particle size distributions to facilitate pressure drop and adsorption kinetics requirements, extensive pore structures with an ideal balance of both adsorption and transport pores, and high mechanical strength resulting in minimal operational and pressure drop issues. These superior features have made granular carbon products the industry choice for Point of Use (POU) and Point of Entry (POE) water filters.
Activated Carbon for Municipality water treatment
In the treatment of municipal water, removal of organics including VOCs, inorganics and toxins inherent in the rivers, lakes, reservoirs and other surface water sources and ground water systems is essential. You can find a tailor made series of products for surface and ground water treatment in municipality water treatment systems to deliver consistent performance in removing these contaminants.
These products are also geared to adsorb hazardous pesticide and herbicide residues, chlorinated hydrocarbons, disinfectant byproducts, inhibitory compounds for biological treatment systems, non-biodegradable organic compounds, and undesired colored and smell compounds. Our carbons are effective in lowering of Biochemical Oxygen Demand (BOD), Chemical Oxygen Demand (COD), Total Organic Content (TOC) and toxicity. In addition, the high purity of the carbon products prevents the release of contaminants that may damage sensitive membrane systems used in other in-process filtration systems. We also offer custom designed products and total purification solutions to best suit your requirement.
Activated carbon adsorbs. The chemical process of absorption is commonly compared to a sponge soaking up water. The water is fully integrated into the sponge, not being limited to the surface area. Differently, adsorption is a process whereby molecules stick to the surface area only. As mentioned above, activated carbon has a large surface area due to being a porous material. The unwanted substance sticks to the surface area of the carbon particles.
One of the common utilizations of this porous carbon is to filter gas. Not as in fuel, but the gaseous substances that are either naturally produced or expelled from various machinery. Take, for example, air filters. Air is technically a gas, and when the air contains impure elements, a purifier in the form of a filter will help remove these impurities. In a slightly different form, the activated charcoal will perform the same function with water—a use common in fish tanks.
Yet one of the long-standing functions of activated charcoal is oral ingestion. Companies make pills that contain activated charcoal which dissolve in the stomach, allowing the granular carbon to remove toxins. You can find a ton of claims on the Internet about the magic that taking a dose of activated charcoal performs, many of which aren’t medically confirmed, however, it is common for hospitals to use activated charcoal for this use. It is widely known to be safe to ingest and acts as a poultice.
Another use gaining momentum is using activated carbon as a teeth stain removal device. Your teeth’s health is important, and the way activated charcoal works also helps to bind plaque, making it an effective whitening tool. Put some of it on your toothbrush with liquid water. It will be weird to brush with at first—seeing the black get smeared on your teeth will feel counterproductive. However, it will rinse off your teeth easily enough and you’ll love the results. Just be careful to avoid staining your sink—keep soap handy to quickly clean up any messes which ensue. Many people swear by this method to whiten their teeth, and its use on teeth as a cleaner and whitener goes back for centuries.
One of the things that using active charcoal as a filter does is the loss of odors in gasses. Odors, and any other prone elements of the gas, get trapped in the activated charcoal through a process called adsorption. Through adsorption the particles bind to the surface of the activated charcoal—which is why it is imperative that activated charcoal actually be activated; the greater the available surface, the better the grade it gets for trapping.
It is effective enough that there are underpants available for purchase which make use of activated charcoal for moments of flatulence. Let’s face it—suspension of flatulence detection would do everyone a world of good. If only they could make activated underwear for dogs and cats; the media would have a field day!
Activated carbon is the major adsorbent in global adsorbent market occupying more than 65% of the volume market share due to its high adsorption capacity and large surface area. Activated carbon is mainly divided into three types; powdered, granular and extruded. It has become the preferred option for use in potable water purification, waste water treatment, aquariums, swimming pools and sewage water treatment as well as air and gas filtration. These applications are gaining popularity due to increasing pollution levels, health concerns and stringent government regulations.
Apart from this, activated carbon is used for decolorization and deodorization of food and beverages; and purifies vitamins antibiotics and active pharma ingredients in pharmaceutical industry and 1medical applications. Some of the other applications of activated carbon include control gas emissions in automobiles; personal protection in defense sector; gold and precious metal recovery; and as catalyst in removal of mercaptan in oil refineries.
Scarcity of raw material and increasing concerns over supply chain, the activated carbon market is currently facing pricing issues; however, the market for activated carbon is on rise due to its extensive use in liquid phase and gas phase applications.
Activated Charcoal Applications:
industrial/pharmaceutical/chemical/military/agricultural/environmental – adsorption of unwanted chemicals
neutralize toxic compounds
medical
food purification
metalurgy
carrier for chemical catalysts
soil enrichment
greenhouse gas reduction
soundwave/microwave/radiowave capture
Activated Charcoal Uses:
Air filters in gas masks, filter masks, air compressors.
Food coloring
Gas purification
Gold purification
Medicine: liver and kidney dialysis machines, laser surgery, breast cancer surgery, stomach decontamination from drug/food poisoning, wound dressing…
Metal extraction
Metal finishing – the purification of electroplating solutions, as in bright nickel-plating solutions.
Nuclear Biological Chemical (NBC) suits
Nuclear power plants
Recycling solvents
Rye grass seed industry
Sewage treatment
Snow avalanche control – helping to melt snow
Soil enhancement
Sound systems – “cleaning” out bad background noise
Toxic soil cleanup from chemical spills or accumulation of chemical spraying
Volatile organic compounds capture: from painting, dry cleaning, gasoline dispensing operations, and other processes.
Water purification: aquariums, swimming pools, domestic & municipal water systems, recycling precious water on the orbiting space station (cost $10,000/liter)
Applications are divided broadly into two groups: air/vapor filter and water/fluid filter applications. Air and vapor filters tend to use the larger sizes of GAC, while water and fluid applications use smaller GAC or even powdered activated charcoal (PAC).
The flow rate of the medium through the charcoal filter will determine the size of the charcoal particle. Sufficient contact time with the charcoal is paramount. The smaller the charcoal particles in the filter bed the faster they will work, but the smaller particles will also restrict the flow rate. The perfect formula will match the particle size to the desire flow rate.
The molecular size of the target contaminant is the next deciding factor. There are three basic activated carbon pore structures: micro (smallest – less than 20 Å) meso (intermediary – 20 Å – 50 Å) and macro (largest – greater than 50 Å)
The target contaminant is matched to an activated carbon with a particular pore size.
Activated charcoal produced from coconut shell is known for its micro pore structure which works well for small air/gas molecules. Wood-based charcoal has a more mid-range pore structure and coal-based has larger macro-pores that accommodate the larger color and protein molecules.
Carbon filtering is a method of filtering that uses a bed of activated carbon to remove contaminants and impurities, using chemical absorption.
Activated Carbon is a non-graphite form of carbon which could be produced from any carbonaceous material such as coal, lignite, wood, paddy husk, coir pith, coconut shell, etc. Activated carbon manufactured from coconut shell is considered superior to those obtained from other sources mainly because of small macrospores structure which renders it more effective for the adsorption of gas/ vapor and for the removal of colour and odour of compounds.
Activated carbon has the strongest physical adsorption forces or the highest volume of adsorbing porosity of any material known to mankind. Activated carbon can have a surface of greater than 1000m²/g.
Each particle/granule of carbon provides a large surface area/pore structure, allowing contaminants the maximum possible exposure to the active sites within the filter media. One pound (450 g) of activated carbon contains a surface area of approximately 100 acres (40 Hectares).
Activated carbon works via a process called adsorption, whereby pollutant molecules in the fluid to be treated are trapped inside the pore structure of the carbon substrate.
Carbon filtering is commonly used for water purification, in air purifiers and industrial gas processing, for example the removal of siloxanes and hydrogen sulfide from biogas. It is also used in a number of other applications, including respirator masks, the purification of sugarcane and in the recovery of precious metals, especially gold. It is also used in cigarette filters.
Active charcoal carbon filters are most effective at removing chlorine, sediment, volatile organic compounds (VOCs), taste and odor from water. They are not effective at removing minerals, salts, and dissolved inorganic compounds.
Typical particle sizes that can be removed by carbon filters range from 0.5 to 50 micrometres. The particle size will be used as part of the filter description. The efficacy of a carbon filter is also based upon the flow rate regulation. When the water is allowed to flow through the filter at a slower rate, the contaminants are exposed to the filter media for a longer amount of time.
There are 2 predominant types of carbon filters used in the filtration industry: powdered block filters and granular activated filters. In general, carbon block filters are more effective at removing a larger number of contaminants, based upon the increased surface area of carbon. Many carbon filters also use secondary media such as silver to prevent bacteria growth within the filter. Alternatively, the activated carbon itself may be impregnated with silver to provide this bacteriostatic property.
Activated carbon can be considered as a material of phenomenal surface area made up of millions of pores – rather like a “molecular sponge”. Activated carbon is a microporous inert carbon matrix with a very large internal surface (700 to 1 500 m²/g). The internal surface is ideal for adsorption. Activated carbon is made from materials containing amorphous carbon, such as wood, coal, peat, coconut shells… It is formed via a thermal process, where volatile components are removed from the carbon-laden material (raw material) in the presence of oxygen.
The process by which such a surface concentrates fluid molecules by chemical and/or physical forces is known as ADSORPTION (whereas, ABSORPTION is a process whereby fluid molecules are taken up by a liquid or solid and distributed throughout that liquid or solid).
In the physical adsorption process, molecules are held by the carbon’s surface by weak forces known as Van Der Waals Forces resulting from intermolecular attraction. The carbon and the adsorbate are thus unchanged chemically. However, in the process known as CHEMISORPTION molecules chemically react with the carbon’s surface (or an impregnant on the carbon’s surface) and are held by much stronger forces – chemical bonds.
In general terms, it is necessary to present the molecule to be adsorbed to a pore of comparable size. In this way the attractive forces coupled with opposite wall effect will be at a maximum and should be greater than the energy of the molecule.
For example, a fine pored coconut shell carbon has poor decolorizing properties because color molecules tend to be larger molecular species and are thus denied access to a fine pore structure. In contrast, coconut shell carbons are particularly efficient in adsorbing small molecular species. Krypton and Xenon, for instance, are readily adsorbed by coconut shell carbon but readily desorb from large pored carbons such as wood.
Maximum adsorption capacity is determined by the degree of liquid packing that can occur in the pores. In very high vapor pressures, multi-layer adsorption can lead to capillary condensation even in mesopores (25A).
Activated Carbon Adsorption Capacity
The effectiveness at which activated carbon can remove contaminants from a stream is not based on the quantity of carbon, but, the activated carbon adsorption capacity. The greater the capacity, the more contaminants the activated carbon will be able to adsorb in volume. However, due to natural carbon’s limitations, it is not able to adsorb certain contaminants, as there molecular weight are to low to be treated through this process alone.
Active carbon is most effective against compounds that hold a high molecular weight and low solubility due to activated carbon having a high molecular weight as well. If there is ever an uncertainty if a specific contaminant will be removed in the adsorption process, referral is to be made to the solubility and molecular weight of said containment.
If adsorption capacity is plotted against pressure (for gases) or concentration (for liquids) at constant temperature, the curve so produced is known as an ISOTHERM. Adsorption increases with increased pressure and also with increasing molecular weight, within a series of a chemical family. Thus, methane (CH4) is less easily adsorbed than propane (C3H8).
Efficiency is determined by the type of pollutant, the type of activated carbon which is used and the temperature and humidity of the waste gases. An effective installation can be expected to realise a yield between 95 – 98 % for input concentrations of 500 – 2 000 ppm.
If effective, concentrations can typically be brought from 400 – 2 000 ppm to under 50 ppm.
In foundries, an end concentration of 20 mg/Nm³ VOC has been established
Mercury can be brought down to less than 0.05 mg/Nm³. Dioxins to less than 0.1 ng TEQ/Nm³ and, for odour and H2S, yields of 80 – 95 % have been established
This is a useful fact to remember when a particular system has a number of components.
Activated carbon adsorption mechanism
After equilibrium, it is generally found that, all else being equal, the higher molecular weight species of a multi-component system are preferentially adsorbed. Such a phenomenon is known as competitive or preferential adsorption – the initially adsorbed low molecular weight species desorbing from the surface and being replaced by higher molecular weight species. Physical adsorption in the vapor phase is affected by certain external parameters such as temperature and pressure.
The adsorption process is more efficient at lower temperatures and higher pressures since molecular species are less mobile under such conditions. Such an effect is also noticed in a system where moisture and an organic species are present. The moisture is readily accepted by the carbon surface but in time desorbs as the preferred organic molecules are selected by the surface.
This usually occurs due to differences in molecular size but can be also attributable to the difference in molecular charge. Generally speaking, carbon surfaces dislike any form of charge – since water is highly charged (ionic) relative to the majority of organic molecules the carbon would prefer the organic to be adsorbed.
Primary amines possess less charge on the nitrogen atom than secondary amines that in turn have less than tertiary amines. Thus, it is found that primary amines are more readily adsorbed than tertiary amines.
High levels of adsorption can be expected if the adsorbate is a reasonably large bulky molecule with no charge, whereas a small molecule with high charge would not be expected to be easily adsorbed.
Molecular shape also influences adsorption but this is usually of minor consideration. In certain situations, regardless of how the operating conditions can be varied, some species will only be physically adsorbed to a low level. (Examples are ammonia, sulfur dioxide, hydrogen sulfide, mercury vapor and methyl iodide). In such instances, the method frequently employed to enhance a carbon’s capability is to impregnate it with a particular compound that is chemically reactive towards the species required to be adsorbed.
Since carbon possesses such a large surface (a carbon granule the size of a “quarter” has a surface area in the order of ½ square mile!) coating of this essentially spreads out the impregnant over a vast area. This, therefore, greatly increases the chance of reaction since the adsorbate has a tremendous choice of reaction sites. When the adsorbate is removed in this way the effect is known as CHEMISORPTION.
Unlike physical adsorption the components of the system are changed chemically and the changed adsorbate chemically held by the carbon’s surface and desorption in the original form is nonexistent. This principle is applied in many industries, particularly in the catalysis field, where the ability of a catalyst can be greatly increased by spreading it over a carbon surface.
The effect of activated carbon on the adsorbate in water comes from two aspects: on the one hand, physical adsorption, the internal force of the activated carbon is in a balanced state under the force from all directions of the water body, and the external molecules are not balanced, so that the molecules adsorb to the activated carbon On the surface; on the other hand, it is chemical adsorption, because there is a chemical interaction between activated carbon and the adsorbed substance.
The adsorption of activated carbon on pollutants in water is the result of the combined action of the above two kinds of adsorption. There are four steps in the adsorption process of activated carbon on the adsorbate in water: first, due to the convection effect of the water body, the adsorbate diffuses onto the surface of the activated carbon; second, the adsorbate molecules diffuse into the large pores of the activated carbon through the liquid film; Third, the adsorbate molecules reach the micropores due to surface diffusion; fourth, the adsorbent molecules in water are adsorbed on the surface of the activated carbon pores.
Activated carbon adsorption equilibrium is a state of dynamic equilibrium. When the adsorption rate and the desorption rate of activated carbon in the solution are equal, that is, when the amount of activated carbon adsorption per unit time is equal to the amount of desorption, the concentration of the adsorbed substance in the solution and the concentration on the surface of the activated carbon will no longer change. For adsorption equilibrium.
Adsorption capacity and adsorption speed are two important indicators to measure the adsorption process of activated carbon. The adsorption capacity is reflected by the adsorption amount qe, which is mainly affected by the pore size and structure of activated carbon. In addition, temperature and pH value also affect the adsorption capacity of activated carbon.
Adsorption speed refers to the amount of material adsorbed per unit weight of adsorbent per unit time, which is mainly determined by the contact time of water and adsorbent. Because the adsorption reaction is an exothermic reaction, low temperature is usually beneficial to accelerate the adsorption rate.
PRIVATE WELL WATER
POU units treat water only at a specific tap ; usually the kitchen sink to treat the water you drink and cook with. POU units can be pour through units, faucet mount units, in-line devices, or line bypass units:
Backwash Wastewater Generated
GAC Unit Installation and Water Testing Considerations
