**2.1 Production of AC through physical activation**

Physical activation is a commercially adopted two-step process that involves carbonization (pyrolysis) of carbon rich precursors in a neutral atmosphere followed by thermal treatment of the resultant mass in an atmosphere of oxidizing gases such as steam, CO2, CO2-N2 or CO2-air mixtures in the range of 800–1100°C. This method has the ability to produce AC powders of porous structure and hence physical activation is considered as an inexpensive and green because it is chemicalfree. Nevertheless, long activation time, low adsorption capacity of prepared AC and high energy requirements are the main disadvantages [6].
