Several factors determine how long activated carbon lasts in a filter. These include the type of pollutants, their concentration, environmental humidity, and usage frequency. Typically, a carbon air filter lasts between three to six months. However, this duration can vary significantly depending on these factors.
Typically, a good activated carbon air filter lasts for about six months and would need to be replaced once every year.
How often is it recommended to change the activated carbon? As a practical criterion, it is recommended to change the activated carbon every year.
Granular activated carbon used in water treatment systems, for example, has a service life of 6 to 12 months. However, in industrial applications where more concentrated contaminants are present, the activated carbon may need to be replaced more frequently.
Once all that space is covered with the pollutant film, the carbon can no longer do its job effectively. In fact, if left too long, an activated carbon filter can start to release certain pollutants in favor of other ones that are more attracted to the adsorption site.
Disadvantages of Activated Carbon Filtration
Short lifespan: An activated carbon filter has a maximum filter capacity (the maximum amount of contaminants that can be trapped in the media until the media is eventually fully clogged).
The reactivation of activated carbon involves its thermal treatment at high temperatures, generally between 600 and 900 °C, in the absence of oxygen. This process burns the impurities adsorbed on the surface of the carbon without significantly deteriorating its porous structure.
Activated carbon is highly effective because it is able to trap particles of the smallest sizes. Many other filters will not trap extremely small particles – think gases, chemicals and VOCs.
Reactivation – in practice
At our plant, the exhausted activated carbon is heated to approximately 900°C, in the presence of steam in a non-oxidizing atmosphere. Impurities are released by the carbon surface, and enter the gas phase. Large impurities (humic acids, dark color bodies, proteins etc.)
If regeneration is not used, the carbon can be disposed of in an approved landfill.
STEP 1 – Rinse the activated carbon: Place the activated carbon in a strainer and rinse it thoroughly with cold water. This will help remove any loose particles or dust that may have accumulated during storage. STEP 2 – Soak the activated carbon: Fill a large container with cold water and add the activated carbon.
Disadvantages of Activated Carbon Filter:
These types of filters are not effective when eliminating non-carbon chemicals (e.g. heavy metals, nitrates, fluoride, sodium, etc.).
Activated carbon, often infused with sulfur or iodine, is widely used to trap mercury emissions from coal-fired power stations, medical incinerators, and from natural gas at the wellhead. However, despite its effectiveness, activated carbon is expensive to use.
Several factors determine how long activated carbon lasts in a filter. These include the type of pollutants, their concentration, environmental humidity, and usage frequency. Typically, a carbon air filter lasts between three to six months. However, this duration can vary significantly depending on these factors.
Contaminants Not Removed by Activated Carbon Filtration
AC filters will not remove microbial contaminants (such as bacteria and viruses), calcium and magnesium (hard water minerals), fluoride, nitrate, and many other compounds.
Activated carbon is only broken down under extreme conditions - such as heating under reflux with concentrated sulphuric acid/nitric acid mixtures - when the carbon will eventually oxidise to CO2. Activated carbon cannot be rendered into a soluble form capable of being absorbed.
Activated carbon has no shelf life. It will keep its pore structure and, hence, its adsorption characteristics until the activated carbon is put in contact with compounds that can be adsorbed. We recommend keeping it dry, separate from volatile organic chemicals and secure from rodent attacks.
Biochar is an excellent material for air and water filtration. This is because, similar to activated carbon, it has a porous structure that may absorb odor and pollutants. Like activated carbon, activated alumina is porous and has a large surface area.
Activated carbon filters are one of the most common types used in gravity water filters, reverse osmosis systems, under sink water purifiers, pitchers, and other applications. But after some time, they can become clogged and stop working efficiently.
Activated carbon is expensive. It is usually purchased in large amounts to get it down to the USD4,000 /ton level. It tends to ratchet up like mad in retail amounts. It's a little mean unless compressed into little bricks or vacuum packed into foil in small volumes as the dust is considered dangerous goods.
It is recommended to put your bamboo charcoal pouch outside under direct sunlight for 2-3 hours per side every 30-60 days (whether it is -30°C or +30°C) for best results. The UV from the sunlight is what activates the bamboo charcoal. During this process, the UV gets into the charcoal and the pores expand.
Both materials are hard and porous, allowing contaminants to be captured. Activated carbon is a preferred choice as it is carbon-rich and high-purity.
Once the activated carbon has reached capacity, it can no longer be effectively used. The now “spent” carbon can either be sent to a landfill or incinerator for disposal, or recycled through regeneration.
Activated carbon works because contaminant molecules stick to it, so after time all of the possible sticky spots are used up and it needs to be discarded and replaced.