The physical activation method is generally carbonized at low temperature (600 ℃), and then activated at high temperature of 800 ℃. In the process, water vapor, CO2 and other gases are introduced for protection. The high-temperature gas reacts with the material to generate pore structure on the surface of the material. The process flow is shown in Figure 2. Generally, the process of activation of carbon group by gas as physical activator can be divided into the following five steps: the first step, the activator molecules in the gas phase diffuse to the surface of carbonated material; the second step, the activator diffuses from the particle surface through the pores to the inside of carbon matrix; the third step, the activator molecules react with carbon to generate gas; the fourth step, the gas generated by the reaction flows from the inside of matrix to particles In the fifth step, the gas generated by the reaction diffuses from the surface to the gas phase space. The production process of physical activation is simple and clean. There is no problem of equipment corrosion and environmental pollution. Active carbon products do not need to be cleaned and can be used directly. Therefore, this kind of activation method is usually used in the industrial production of active carbon. However, the gas activator used in physical activation is relatively weak, which makes it difficult to form a developed pore structure in the carbon precursor. Generally, the specific surface area of porous carbon material prepared by water vapor activation is 1000-1500m2 / g, and the pore volume is less than 1.0cm3/g.<br>
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