What is Activated Charcoal?
Activated Charcoal is nothing but ordinary charcoal that has been treated with oxygen in order to open up hundreds of thousands of microscopic pores between the carbon atoms. This process reduces activated charcoal to a finely grained state and results in the formation of a very large surface area, (far greater than that of regular charcoal), through which adsorption takes place. Adsorption in layman’s terms is the accumulation of numerous atoms and molecules on a given surface. The micro porosity of this form of carbon makes it very useful for filtering purposes.
Through adsorption, activated charcoal is capable of removing both harmful organic substances like benzene, pesticides and animal residue, as well as, metal substances like metal, chlorine and radon. Furthermore, Activated charcoal also removes any bad taste or bad odor that may be present. It achieves this by attracting these molecules and causing them stick to its surface. However, it must be kept in mind that activated charcoal is only capable of trapping and removing carbon-based impurities. So any other impurity (like sodium or nitrates, for instance), will pass right through it. Another important point to remember is that activated charcoal filters stop working when its surface area has been completely utilized to trap impurities. How Do Charcoal Water Filters Purify Water?
Activated charcoal may be placed in filters that contain openings for the water to enter and exit. The filters are placed in the path of the water flow. The impurities are then adsorbed in the charcoal and purified water exits. The charcoal water filters must be regularly replaced as the power of the filter will decrease as time progresses. These filters must also be cleaned to avoid the growth of bacteria that occurs due to the abundance of organic substances in the filter. The Portable Solution!
Since this water filter technique is simple, charcoal water filters can be used in portable water purification. The activated charcoal may be filled in a cloth and put in an earthen pot. The charcoal purifies the water and the earthen pot keeps the water cool. Though activated charcoal does not purify the water from all chemicals or harmful substances but it can be used as a preliminary step in multi stage water purification methods.