The preparation methods of activated carbon include physical method, chemical method, microwave radiation method, etc.(1) Physical method.
Physical method is to use carbon dioxide, water vapor or the mixture of both as activator, the carbonized carbon material and gas in the activation furnace at 500~1200℃ for carbon activation reaction, so that the pore size of the carbonized material to expand, the formation of activated carbon with porous microcrystalline structure.Gas activation method mainly includes carbonization and activation engineering.The so-called carbonization, refers to the low temperature (about 500℃) is small, the volatile coal tar molecules in the material and the thermal decomposition and curing process of asphalt, that is, to remove the volatile in advance, made suitable for the next step of activation with carbonization.
When the temperature is below 600℃, the specific surface area of carbonized material increases with the increase of temperature.When 600~900℃, the specific surface area reaches a certain value: 250~300 m2/g; when above1000℃, the specific surface area shrinks rapidly.
When the carbonization temperature is above 800℃, the reaction performance of carbonized compounds and activation gas gradually becomes weaker, so the carbonization temperature is generally below 1000℃. However, if the residual volatile content and thermal effect are taken into account, the most suitable temperature should be 600~700℃39].
The carbonized substance obtained from the carbonization process is placed in water vapor or a mixture of water vapor and combustion gas and heat treated at 800~1000℃, which is called the activation process.Microwave method, microwave method is not independent of the physical method and chemical method of the preparation of activated carbon, but on the basis of the physical method and Microwave method, microwave method is not independent of the physical method and chemical method of the preparation of activated carbon, but on the basis of the physical method and chemical method instead of the traditional heating method, but it has a very significant effect.https://www.granular-activated-carbon.com/
Microwave refers to the electromagnetic radiation located between far-infrared and radio waves in the electromagnetic spectrum, with a frequency range of 300MHz to 300GHz and a wavelength of 1m to 1mmMicrowave generates "internal friction heat" through high frequency reciprocating motion of dipole molecules in the heated body, which raises the temperature of the material. It does not require any heat conduction process, and has the characteristics of high efficiency, selectivity, non-contact, integrity, uniformity, quick start and stop, and easy operation Studies have shown that activated carbon can effectively absorb microwave energy and make the temperature rise to 110o℃5' within a few minutes.
Microwave heating can produce good effects in the preparation and modification of activated carbon (S2. Microwave modification, many backwater hole is opened, the distributed capacitance change obviously, promoting the improvement of the adsorption. The microwave power and irradiation time are key determinants of modified activated carbon adsorption performance. On the mechanism of microwave carbonization and activation, it is generally believed thatcoal based activated carbon factory
Microwave refers to the electromagnetic radiation located between far-infrared and radio waves in the electromagnetic spectrum, with a frequency range of 300MHz to 300GHz and a wavelength of 1m to 1mmMicrowave generates "internal friction heat" through high frequency reciprocating motion of dipole molecules in the heated body, which raises the temperature of the material. It does not require any heat conduction process, and has the characteristics of high efficiency, selectivity, non-contact, integrity, uniformity, quick start and stop, and easy operation Studies have shown that activated carbon can effectively absorb microwave energy and make the temperature rise to 110o℃5' within a few minutes.