1. Raw material pretreatment. Pretreatment of activated carbon raw materials includes deliming and pre-oxidation. The raw materials for activated carbon production are natural products such as wood and coal, which contain a certain amount of impurities, such as Si, Al, Ca, Mg and other elements. These components have an extremely sensitive effect in preventing the formation of micropores during the preparation process of activated carbon by affecting the raw materials. Deliming pretreatment can significantly improve the performance of activated carbon. There are generally two methods for pre-oxidation treatment of raw materials: dry and wet. The dry method uses gases such as air and oxygen as oxidants under certain heating conditions. The wet method uses nitric acid, sulfuric acid, etc. as oxidants. Research shows that oxidation pretreatment can obtain the performance of coal-based activated carbon with a specific surface area of ??3 000 m2/g, an iodine adsorption value of 1 500 mg/g, a methylene blue adsorption value of 300 mg/g, and a phenol adsorption value of 250 m g/g. For wood-based activated carbon, the methylene blue adsorption value is The value can reach 760 mg/g.
2. Use catalytic activator. When physical activation method is used to prepare super activated carbon, adding a catalyst for catalytic activation can exponentially increase the reaction rate, lower the activation temperature, and concentrate the pore size distribution. For example, domestic patents use calcium catalyzed physical activation method, the C-H2O reaction activation energy is reduced from 185 kJ/mol to 164~169 kJ/mol, and the pore size is concentrated at 5~10 nm. The Japanese patent uses transition metal elements as catalysts, which not only reduces the reaction time, but also obtains super activated carbon with a specific surface area of ??2 500 ~ 3 000 m2/g. Representative transition metal compounds are Fe2(NO3)3.Fe(OH)3 , FePO4, FeBr3, Fe203, etc. However, too fast reaction speed may cause the micropore wall to be burned through and destroy the micropore structure.
3. Use templates. By introducing an organic polymer into a small space (nanoscale) in the inorganic template and carbonizing it, and then using strong acid to dissolve the template, a porous carbon material with a similar spatial structure to the inorganic template can be produced. This method can Mesoporous activated carbon with narrow pore size distribution and high selective adsorption is produced. The United States and Japan use silica gel particles (75 to 147um, specific surface area 470m2, pore diameter 4.7 nm) as templates to produce specific surface areas of 1 100 to 2 000 m2/g, pore diameters of 1 to 10 nm, and are concentrated at 2 nm. Activated carbon material with narrow pore size distribution. The advantage of using the template method to prepare activated carbon is that the pore distribution of the activated carbon can be controlled by changing the template. However, the disadvantage of this method is that the preparation process is complicated and requires the use of acid to remove the template, which increases the cost.