Activated carbon filter for water

What is an activated carbon filter?

To understand how an activated carbon filter works , you need to know what activated carbon actually is. At the end of the 18th century, it was discovered that charcoal has a so-called adsorption effect , which means that it removes certain substances from water, liquids or gases. For example, it can bind toxins or decolorize liquids.

Modern activated carbon production began with a patent in 1901. Since then, it has been widely used in various disciplines and industries – for example in medicine ¹ , the automotive industry ² , the chemical industry ³ (e.g. textile dyeing) and recently also in the food industry ⁴ and cosmetics ⁵

You can find further information about the different applications of activated carbon in our article: What is activated carbon?

...because they each have a different functionality and filter performance.

• Chlorine
• tastes and smells

• Microplastics
• Drug residues
• lime (without ion exchanger)
• Hormones
• and many other pollutants that are found in Tapwater (can be) located.

The efficiency of an activated carbon filter can therefore vary. This means that there are large differences in quality that are related to the manufacturing process. In general, there are three types of activated carbon products for activated carbon filters:

• powdered activated carbon (rather unusual in drinking water filters )
• broken activated carbon as granules (e.g. in table jug water filters)
• molded activated carbon (e.g. an activated carbon block filter)

How does an activated carbon block filter work

When it comes to activated carbon filters, people usually only talk about a single “filter performance”, but strictly speaking, an activated carbon block filter works in three different ways , cleaning the water of a number of (toxic/harmful) substances through three mechanisms of action.

1. mechanical effect

The mechanical filtering is made possible by the many delicate channels of the activated carbon block : These prevent particles that are too large from passing through the activated carbon filter. They are held back in a similar way to a sieve. This method keeps your drinking water free from, among other things:

• sand and rust (particles)
• Asbestos fibers
• Suspended particles
• Bacteria
• Legionella
• Parasites

2. catalytic effect

Unlike mechanical filtration, the catalytic principle works here: small particles are transformed as they pass through the fine pores and channels of the activated carbon filter and then no longer have anything in common with their original form. 

In this way, the activated carbon block contributes to the breakdown and elimination of chlorine and chlorine compounds (e.g. CFCs). The catalytic effect also ensures that the unpleasant taste and smell of chlorinated water is eliminated and the drinking water becomes more drinkable again.

3. adsorptive effect

Finally, the adsorptive effect of activated carbon block filters is particularly effective: substances that are smaller than the pores inside are absorbed or bound by the carbon. Since the many channels have a particularly large internal surface , the water has to travel a long way, and a particularly large number of organic and inorganic substances stick to them. 

The adsorptive filter effect of activated carbon blocks is very effective and is similar to that of a strong magnet. The substances that are adsorptively filtered include:

• herbicides, pesticides and fungicides
• Hormone residues
• Drug residues
• heavy metals (e.g. lead, copper)
• odor and taste-impairing substances

What is sintered activated carbon?

Particularly high-quality activated carbon block filters are made from sintered activated carbon. During the sintering process, the activated carbon block is heated to a high temperature and compressed under high pressure . This increases the number of pores and the internal surface area - and consequently optimizes the "performance" of the activated carbon. 

filter performance of activated carbon block filters

With the activated carbon filter, the water is treated by flowing through the activated carbon block . In addition to its adsorptive (i.e. "absorbing" effect), the filter also has a mechanical and catalytic effect.

High-quality activated carbon filters are therefore ideal for removing harmful and taste-impairing substances from the water. The adsorptive properties of the activated carbon act like a magnet on organic contaminants and dissolved substances (e.g. chlorides) and bind them. The following table gives you an overview of the most important substances that an activated carbon filter can remove from the water.

Substances that activated carbon block filters can filter

Minerals

Hormones

Pesticides

Germs and bacteria

Legionella

Drug residues

Microplastics

Asbestos

Heavy metals

PFC

Chlorine

Plasticizer

Does an activated carbon filter also remove minerals?

A good activated carbon water filter basically has the property of leaving important substances in the water. These include minerals that are important for the human body - a key reason why water filters with activated carbon are ideal for household use and for filtering drinking water. 

Risk of contamination? Even with activated carbon block filters?

How safe is a water filter that only binds certain substances in the water? The product quality of a drinking water filter made of activated carbon and the perfect condition of the water filter are crucial. Activated carbon has a limited storage capacity. As soon as this is exhausted, the filter cartridge must be replaced. 

Otherwise, not only will the effect be reduced, but there is also a risk of contamination because accumulated substances are released back into the water and germs can multiply in the water and on the filter. But is this the case with all activated carbon filters? Not necessarily.

• With table jug filters there is a risk of contamination if the filter medium is not changed in time.
• With permanently installed activated carbon block filters, the pore size is crucial in determining whether bacteria can get into the filter outlet. A pore size of approx. 0.3 µm and less is a prerequisite for activated carbon block filters to be considered germ-proof.

The overall structure of the filter product is also important, for example which other mechanical processes for water filtration are built into the filter. Consumers can find out the safe efficiency of their activated carbon filter through certificates and manufacturer information. Filters are tested by TÜV or relevant university institutes, for example.

How environmentally friendly is the life cycle assessment of an activated carbon filter?

Good activated carbon filters are made from plant-based materials and are characterized by a low proportion of binding agents. Alb Filter also produces its cartridges from the renewable organic raw material lignin .

According to studies, drinking water from the tap is by far the most environmentally friendly beverage ⁷ . If you consume less water from glass or plastic bottles at home thanks to an activated carbon filter, you will save money and significantly reduce your carbon footprint. For comparison: Still mineral water in a (disposable) bottle causes 90 to 1,000 times more environmental pollution than the consumption of Tapwater . 

If you have special requirements, such as the need for extremely reliable filtering of viruses and bacteria , we recommend that you contact the dealer or manufacturer to find the right product.

changing activated carbon filter cartridges

All activated carbon filter cartridges become saturated after a certain time and their filtering performance decreases. Depending on the cartridge used, the cartridge should be changed every 4-6 months . Modern activated carbon block filters can be replaced without any problems. The flow rate of the water is also crucial. For example, after 5,000 liters, a filter change may be necessary. Information on replacing the filter cartridges can be obtained from the respective activated carbon filter manufacturer.

Unfortunately, there are no indicators for when exactly a change is necessary , unless you have the water regularly tested in a laboratory. Since this is far too time-consuming, it is better to stick to the manufacturer's instructions.

activated carbon filter for the faucet

How useful is an activated carbon filter?

For private consumers and normal households, an activated carbon filter for the water pipe is a good choice because it combines several advantages: The filter products are cost-effective compared to other filter systems and deliver a high level of efficiency.

If you have special requirements, such as the need for extremely reliable filtering of viruses and bacteria , we recommend that you contact the dealer or manufacturer to find the right product.

Are there other water filters for the home?

An activated carbon water filter is suitable for water treatment in every household , but not for every application. Consumers today have a wide range of water filters available. The most important variants and methods for filtering drinking water include:

What you should consider when buying an activated carbon filter

Activated carbon filters are user-friendly and relatively inexpensive. Depending on your personal requirements, it is important to seek advice from a manufacturer or retailer when deciding on an activated carbon filter.

Activated carbon filters for water filtration are widely used today . When choosing a drinking water filter with activated carbon, the following criteria should be taken into account:

• What type of activated carbon product is it? (e.g. activated carbon granules? Activated carbon block? Sintered activated carbon?)
• What efficiency is guaranteed by the manufacturer?
• Is it a sustainable and environmentally friendly drinking water filter whose materials can be recycled ?
• Do I have a very high water flow and how often do I have to change the filter cartridge?
• Does the manufacturer offer a reminder and advice service ?

Activated carbon filters are now used in business and industry to purify the air and to treat (municipal) groundwater and wastewater. They are also particularly suitable for treating drinking water and improving the water quality in your own home. Their versatility means they can be used easily in both industrial environments and private households . They are also cost-effective and efficient, especially compared to mineral water.

Activated carbon block filters offer the most advantages of the common water improvement processes. They are particularly suitable for private households that want a taste and odor improvement effect as well as a large removal of pollutants from their Tapwater wish.

FAQs

What does an activated carbon filter filter out of the water?

Good activated carbon filters can remove many substances from the water, e.g.:

• tastes and smells
• Microplastics
• Drug residues
• Hormones
• Chlorine

Activated carbon block filters in particular can also filter out many other ingredients found in Tapwater .

What does an activated carbon filter do in water?

The many ultra-fine pores , which are connected to one another in a labyrinthine manner, give the activated carbon filter an enormously large surface area. When flowing through the filter, the water has to travel a long way and any harmful and toxic substances remain stuck in the pores inside the carbon: this is called adsorption.

Can activated carbon filter limescale?

Activated carbon itself does not filter limescale. An activated carbon block filter in combination with an ion exchanger can remove limescale from the water. A suitable faucet filter cannot remove limescale 100%, but - depending on the water hardness - it can significantly reduce it.

Can activated carbon filter hormones?

Unfortunately, many municipal water treatment plants do not filter hormone residues out of the water at all or only inadequately. However, they can reliably remove these substances from drinking water using activated carbon filters. A high-quality activated carbon block filter removes not only hormones but also drug residues , such as residues of antibiotics and hormones such as estradiol or ethinylestradiol.

How do activated carbon filters differ?

The most important variants of activated carbon filters include:

• countertop water filter
• Under-sink water filter
• travel or camping filter
• Table can filter

What is so special about activated carbon filters?

The special thing about activated carbon are the ultra-fine pores , which are labyrinthine and interconnected and therefore form an enormously large surface structure.

However, when it comes to pore sizes, a distinction is made between:

• Mikroporen (<1 Nanometer) 
• mesopores (1-25 nanometers) 
• Macropores (>25 nanometers)

The quantity and distribution of the pore sizes ultimately determine the adsorption properties of the activated carbon, i.e. how well it can bind certain substances.

What is so special about activated carbon filters?

Sintered activated carbon is a special form of activated carbon. Sintering optimizes the "performance" of the activated carbon by maximizing the absorption capacity , i.e. the number of pores. In addition to the high adsorptive effect, sintered activated carbon retains minerals and trace elements and does not filter them out - as is the case with activated carbon granules, for example.

Where are activated carbon filters used?

As a powerful cleaning and filtering medium, activated carbon is of great value in medicine, chemistry, water treatment, ventilation technology, agriculture and, more recently, the cosmetics and food industries. However, its value in the last two areas of application is highly controversial in scientific terms.

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