Fuel Processing Technology, Vol.189, 74-79, 2019
De-intercalation of the intercalated potassium in the preparation of activated carbons by KOH activation
In this study, the potassium formed during the activation of petroleum coke with KOH as activation agent was quantified, and three de-intercalation reagents (acetic acid, water vapor, methanol) with different flow and at different temperature were used to de-intercalate the potassium. It is suggested that the activation process yields almost the same amount potassium in the free state as that in the potassium-graphite intercalation compounds. The results also indicated that the introduction of acetic acid (250 degrees C, 0.4ml/min), water vapor (200 degrees C, 0.4ml/min), methanol (150 degrees C, 0.4ml/min) could furthest improve the porosity and decrease the microcrystalline size as well as increase graphite layer spacing d(002.) Moreover, the de-intercalation reagents could accelerate the formation of oxygen-containing groups on the surface of the activated carbons. Based on these results, the deintercalation mechanism has been proposed.