Preparation and evaluation of activated carbons obtained by physical activation of polyethyleneterephthalate (PET) wastes

Polyethyleneterephthalate (PET), has become one of the major post-consumer plastic wastes. In this work, PET wastes were used to produce activated carbon by physical activation method, using carbon dioxide (CO2) for gasification. The effects of the production variables such as temperature, heating rate, flow rate and holding time of carbonization stage and activation stage on the adsorption capacity of activated carbon were investigated. Preparation tests for the effects of these factors were designed with Taguchi method. According to the Taguchi parameter design methodology, L16 orthogonal array was used. Analysis of experimental results showed that, the most effective factors on each experimental design response were activation temperature and holding time in both stage. The optimum conditions for activated carbons production from PET wastes were found to be as follows: carbonization temperature 800 °C, carbonization time 60 min, activation temperature 975 °C, activation time 240 min, heating rate of carbonization and activation 10 k/min, flow rate N2 200 ml/min and CO2 100 ml/min. The properties of prepared activated carbon at optimum operating conditions such as surface area 790 m2/g and iodine number 630 mg I2/g C, were comparable to commercial activated carbons.