Coconut shells (without meat)
25 percent concentrated solution of calcium chloride (CaCl2) or zinc chloride (ZnCl2)
Before starting the procedure, you can strip off coconut shells, wash thoroughly with clean water and allow them to dry completely. If drying is not done properly, they will be difficult to burn.
→ Hoping that the coconut shells are free of moisture, add them in the burning sink (or drum). Measure the temperature and make sure it is adjusted to about 600 – 900 degrees Fahrenheit. Maintain the recommended temperature range and burn continuously for about 4 ½ hours or until the coconut shells turn into ash. For safe handling, you can leave the ash until it cools down.
→ After the ash has cooled down, take it out carefully from the sink and transfer into a clean plastic pail. Then, pour the 25 percent concentrated solution of calcium chloride or zinc chloride into the plastic pail.
→ The amount of calcium chloride or zinc chloride solution should be such that the ash is soaked completely into the solution. Cover the pail with a lid and leave for 20 – 24 hours. During this process, the chemicals are impregnated into the ash and further treatment will transform the ash into activated charcoal. The next step is removing the charcoal from the chemical solution and transferring it into a draining tray. Allow the treated charcoal to drain for about 1 hour.
→ For removal of trace chemicals from the charcoal, you can wash and rinse it repeatedly with sterilized water. Thorough washing is essential in order to get rid of the chemical solution, which otherwise will remain in the charcoal. It is one of the most common problems in the making of activated charcoal by chemical activation procedure. After washing, keep the charcoal in the tray for draining water. Following this, transfer charcoal into an oven, setting the temperature to about 215 – 230 degrees Fahrenheit and bake for about 3 hours.
→ After baking for the stipulated time, remove the charcoal from the oven and crush it with the help of a blender. You can also grind the charcoal into powder form by using a hammer. For future use, store the powdered charcoal into zipper bags or airtight containers.