Activated carbon was prepared by using Liaohua petroleum coke as raw material and KOH as activator. The effects of alkali-coke mixing mode, particle size of raw material, carrier gas flow rate, different chlorophyll immersion, drying and heating rate on the properties of activated carbon were investigated.The experimental results show that Liaohua petroleum coke is a high quality raw material for the preparation of activated carbon with high specific surface area. The mixing mode of alkali coke, the particle size of raw material and the velocity of activated gas all affect the performance of the product.The specific surface area of activated carbon was obtained in the following order: water ~ glacial acetic acid >, ethanol >, methanol ~ tetrahydroaromatic >, ethylene glycol >, 30% hydrogen peroxide, which indicated that the removal of potassium compounds in activated carbon particles had a great influence on the formation of activated carbon pores and the adsorption performance.The microcrystalline structure and surface properties of the raw materials were changed by pre-carbonization, and the effect of these changes on the properties of the activated products was emphatically investigated.
At higher pre-carbonization temperature, with the increase of pre-carbonization temperature, the content of hydrogen and oxygen in petroleum coke decreases sharply, the content of surface functional groups also decreases, and the microcrystalline structure becomes more stable. As a result, activation is difficult, which leads to the reduction of specific surface area of activated carbon and the change of pore size distribution.yrd carbon
The mesopore content increased relatively.buy activated charcoal bulk
The specific surface area of activated carbon prepared by untreated petroleum coke plus three times the mass of alkali activation is 1997m2g, while the specific surface area of activated carbon prepared by petroleum coke carbonized at 1200℃ under the same activation condition is only 12m2g1.However, the heat treatment of petroleum coke at lower temperature has little effect on the specific surface area of the activated carbon prepared, but increases the DOO of graphite microcrystals in the raw material.
The pore size of the activated carbon is also increased.It is indicated that the surface functional groups of petroleum coke, such as C-O-C, C-O-H and the basic groups such as -CH, =CH and -CHCH3, play a very important role in the chemical activation process, and the microcrystalline structure of petroleum coke has an effect on the pore size in the activation process.Furthermore, the raw materials of petroleum coke were preoxidized with air, HNO, or HZOZ solution respectively to change the surface properties of the raw materials. It is proved that the oxygen-containing functional groups on the surface of the raw materials are the "active point" of the reaction in the activation process, which can promote the formation of activated carbon pores. Thus, the activation mechanism model of the preoxidized petroleum coke is proposed.
After the pre-oxidation treatment under appropriate conditions, the surface of petroleum coke contained by the basic functional groups significantly decreased, while the oxygen-containing functional groups significantly increased, indicating that the basic functional groups were oxidized into oxygen-containing functional groups, and due to the introduction of oxygen, the distance between the litho-ancient microcrystalline layer increased.At the same time, preoxidation treatment can also improve the reactivity of petroleum coke and reduce the activation temperature.