De-intercalation Of The Intercalated Potassium In The Preparation Of Activated Carbons By KOH Activation

High specific surface area activated carbon (AC) prepared with KOH is widely used in fuel gas storage, gas separation, catalysis and various chemical processes due to its developed porosity and large adsorption ability. As a result, the safe and efficient production technology becomes a research focus. According to the reaction mechanism with KOH activation, K-intercalation plays an important role in the porosity development of the activated carbon. In the actual production process, the K will be easily oxidation and the combustion may occur if the activation products directly exposed in the air, which will be a security risk. Therefore, the study of the various de-intercalation reagents on the porosity development and surface functional groups of the activated carbon is significant, to select the suitable reagent.Activated carbon was prepared from a PC from SINOPEC Liaoyang Petrochemical Company as precursor with KOH as activating agent. The preparation is the ratio of KOH to coke2:1, the activation temperature780℃, the activation time60minutes. As the activation is finished and the reactor cooled to the appropriate temperature, methanol, ethanol, water vapor, acetic acid and ammonia was introduced into the reactor respectively to investigate the reactivity and their effect on the porosity development of the resultant activated carbons. The Boehm titration、IR analysis and elemental analysis were used to investigate the surface properties of the resultant activated carbons. The results showed that methanol, ethanol, water vapor, acetic acid and ammonia could react with potassium. Different de-intercalation reagents have different effect on the porosity development of the resultant activated carbons. In the appropriate temperature, the introduction of methanol (150℃), ethanol (200℃),water vapor(250℃) and ammonia (400℃) can promote the porosity development; But the introduction of acetic acid (200℃) would destroy the original pore structure. Different de-intercalation reagents also have different effect on the surface properties of the resultant activated carbons. The amount of surface groups like Hydroxyl groups and oxygen-containing groups were changed on the surface of the activated carbons as the methanol(150℃), water vapor(250℃) and acetic acid(200℃) were introduced into the reactor. And the-C=N group was generated on the surface of activated carbon as the ammonia (400℃) introduced into the reactor.