mixed with an activator such as water vapor carbon dioxide air or a mixture thereof they are heated again this time between 850 u00b0 c to 1050 u00b0 c for at least 45 hours as before an inert gas such as nitrogen must be added into the kiln to balance air pressure at the end of the heating period they automatically move down to the next level where they are cooled to a temperature between 170 u00b0 c to 240 u00b0 c finally reaching the bottom of the kiln they are taken out and cooled to room temperature one of the advantages of this activation step is that it produces an increase in the volume of the material it also breaks some bonds of the turbostratic carbon structures that form surface functional groups and it removes non crystallized carbons from the bamboo charcoals as a result the bamboo adsorbents of the present invention have a high specific surface area and a high pore volume fig5 and fig6 this means that the present invention has greater adsorbency than most if not all other materials the following is an example of the process using a selected type of raw bamboo in this example specific details may.