Firstly, before we start with what activated carbon is, we should decide what it should be called it as it seems to go by many different names. We, at SPCB, will always call it activated carbon, so the granules that we use & sell, for our water filtration systems, are named Activated Carbon TE, Activated Carbon TE 100 and Activated Carbon TTS 100. However, it is also widely known as activated charcoal, active charcoal & active carbon. It seems to be that different countries and, to a lesser extent, different industries use different names but, providing that you are purchasing your activated carbon from a known and reputable supplier you should be safe in the knowledge that you are buying the right product whichever name it's going by. But don't be confused with the word charcoal, this is not the same material as the black, dusty lumps (or dust) that you find at the bottom of your BBQ or even the charcoal that you buy for your BBQ.
Activated carbon is a type of carbon that is most commonly used to filter many different types of contaminants from water or air. It has many other uses but we use it to filter contaminants from industrial waste water such as that holding surface coatings such as paint & lacquer, glues, oil, NDT and many types of metal treatment and pre-treatment. Activated carbon can be made from carbonaceous materials (materials that consist of carbon) such as bamboo, coconut husk, peat, coconut fibre and wood. These materials are heated to very high temperatures and undergo a number of processes that eventually result in the activated carbon that we use.
Activated carbon is available in many forms depending upon how it is to be used and what you are looking to filter. The vast majority of our use is granular as, we feel, this is the most efficient for pressurised liquid filtration which is how our EpurWater filtration systems operate. Due to the shape of the granules and how they compress and work with each other, the flow through rate for the water is much more rapid than other forms of carbon hence why we use the granulated form of activated carbon. However, on the downside, granular carbon has a lower absorption capacity than some other forms as it has a lower absorption/surface area but the flow through rate coupled with ease of use and quality of filtration is the reason why we use Granulated Activated Carbon (also known as GAC). Other types of activated carbon are Powered Activated Carbon (PAC), Extruded Activated Caron (EAC), Polymer Coated Carbon, Impregnated Carbon and Bead Activated Carbon (BAC).
So why is activated carbon so good at filtering contaminants? Each granule has an incredibly large porous surface area that is very porous which means that it not only absorbs and holds onto the contaminants but it has a very high capacity for absorption. Each gram of activated carbon can have a surface area of between 500 and 3000 square metres, our carbon products have around 1000 square metres per gram. We feel that people can read these numbers and not think about them but 3000 square metres per gram means that 1 gram of activated carbon can have the same surface area as 9 tennis courts! Wikipedia explain, in very good, plain language how this is possible, 'Under an electron microscope, the high surface-area structures of activated carbon are revealed. Individual particles are intensely convoluted and display various kinds of porosity; there may be many areas where flat surfaces of graphite-like material run parallel to each other, separated by only a few nanometres or so. These micropores provide superb conditions for adsorption to occur, since adsorbing material can interact with many surfaces simultaneously.'
Hopefully this has given you a very basic understanding of what activated carbon is, how it works and why we use it for the filtration of industrial waste water. However, please don't think that we only use activated carbon for filtering our waste water. Firstly, the waste water must be chemically treated in order to separate the contaminants held within the water. Once treated, the water is pumped through a primary filter that will remove the vast majority of separated solids, after which it goes through a second filter to ensure that all of the separated solids have been removed. It is only after these two passes that the water meets the activated carbon. The reason for this is that you only want the activated carbon to be in contact with water that has had all of the solids removed so that it can concentrate on removing the contaminated particles that the larger filters are unable to hold. This way we ensure a good lifespan for the carbon and allow it to work to its maximum potential which it will be unable to do if it is blocked by separated solids.
If you have any questions regarding our use of activated carbon or if you feel that we may be able to help you with your industrial waste water then please get in touch.
