For thousands of years, mankind has been using the activated carbon or charcoal for water purification. In recent years, carbon filters are being used commonly for removing harmful gas and chemicals to purify water and air. These filters are made of a sheet of activated carbon or charcoal through which gas or water is passed and the volatile organic compounds are removed from household products.
Although the filters are not suitable for removing pollen, dust or mold from air, these act as great options to remove odour like that of tobacco smoke from air. Instead of HEPA filters used in air conditioners for removal of particle pollution, nowadays many air conditioning manufacturers are using carbon sheets to keep gas molecules from mixing in the air.
Adsorption And Carbon Filters
Adsorption, not absorption, is the distinct process of treating organic compounds chemically with activated carbon and in air purifying process, this process is used to stick pollutants on the filter. Activated carbon is granular, porous and in powdered form –more porous carbon filters can capture more contaminants.
As carbon atoms remain connected to each other, its activation helps increasing the surface area so that the contaminants get greater area to get stuck. However, over time, the gaseous and dissolving pollutants fill up the adsorption areas of the carbon bed and therefore, a saturated bed is not efficient in trapping the pollutants any more.
Changing Carbon Filters
The chemicals that have greater affinity towards adsorption often displace those with lesser affinity and this affinity for sorbent depends on relative humidity and temperature. With the change of these conditions, the filter might release different chemicals. If you can smell a strange smell emanating from the carbon filters, it means that the filters have become saturated and need to be changed. Before changing the filter, you should consider the following –
- Well-made and high-quality filters will be more long-lasting than the cheap and shoddy filters
- If the air is filled with gaseous contaminants or the water has relatively greater amount of contaminants, the filters need changing regularly as adsorbate grows faster and without new filter it will not offer proper adsorption.
- If the liquid or the gas volume is significantly high you will require new carbon filters.
- The manufacturers of air conditioning or water purifier systems will give you an idea about the frequency of changing the filters, although changing might be necessary earlier or later according to the usage habits.
When To Change Carbon Filters
Your usage of the purification system plays a vital role in durability of each filter –the more frequently and heavily you use, the earlier you need to change carbon filters. However there are a few symptoms –
- The air conditioner starts to have a distinct smell
- The water coming out of the filter is not odourless
- Water pressure is reduced (might be due to clogging)
It is better to get the filters looked at regularly instead of waiting for the above. If you are unsure, take help from the professional or ask the manufacturer who will know whether the filters will last more or not.
Benefits Of Using Carbon Filters
To get rid of unwanted pollutants from water or air, the carbon filters are used. Consider the following –
- These can be combined with HEPA to trap impurities and allergens like lint, dust, smoke, pet hair, spores, benzene and different VOCs and household chemicals.
- Filters with minimal amount of carbon are not beneficial –get a minimum of 5 pounds of carbon for the filters to help in better adsorption.
- Sufficient “dwell time” is needed during which water or air passes through the filters. Filters with proper thickness and greater dwell time ill last longer and be more effective.
Conclusion: As a matter of fact, carbon filter used with HEPA can reduce up to 99.97% pollutants off 0.3 microns of thickness and greater. Those who suffer from allergies or have someone smoking inside the house, should get these filters to maintain respiratory health.
