The commonly used activation gases are carbon dioxide, water vapor, oxygen, etc., due to the oxidation reaction of these gases on the surface of the carbonized substance, eroding the carbonized substance, thus producing a rich porous structure.(2) Chemical method.
Chemical activation method is a method of preparing activated carbon by adding chemicals to the raw materials used or impregnation into the raw materials or carbonized materials, and then heating it at high temperature in inert gas.The chemicals used in chemical activation are generally dehydhttps://www.granular-activated-carbon.comrating.The more commonly used activator is: inorganic acid varieties have phosphoric acid, sulfuric acid and boric acid, salt varieties have zinc chloride, calcium carbonate and potassium sulfate, alkali varieties have sodium hydroxide, potassium hydroxide, etc.
The main principle of chemical activation method is the raw materials in 0.5~5 times the chemical activator impregnation for a certain time, in the process of heating, because of the dehydration of chemicals, the H and О elements in the raw materials in the form of water vapor released, the results produced a developed porous structure of activated carbon.The method requires the oxygen content in the raw material.25%, hydrogen content ≥5%[4], and most of the materials that can meet the requirements of this index are rice husk, wood and coalIn order to verify the accuracy of the simulation calculation, two 12g activated carbon bags thickness of activated carbon ~ 1.5cm) were put into the container containing uranium ore, and then taken out after radon adsorption for 30 min and 85 min. After continuous measurement, the change curve of total Y number of activated carbon over time could be obtained.
According to the adsorption duration used in the experiment and the appropriate value of n (in the calculation process, when the adsorption duration is 30 min, n=480
When the adsorption time is 85 min, take n-600), and the calculated theoretical curve is shown in FigureIt can be seen from the figure that the measured curve is in good agreement with the theoretical curve.Fig. 2 is the simulation result of the total number of Y taken out over time after activated carbon adsorbs 1 radon atom from the environment every second and continues to adsorb for 3 days.After the activated carbon was taken out, the total number of V reached the maximum after t time, and then the total number became smaller. After about 50 min, the total number of V decreased by a negative exponential function.
The curve can be divided into a stationary area and a measuring area. The width of the stationary area (i.e. the duration of the stationary area) is set at (t+50) min, followed by the measuring area.
There is no obvious rule of counting in the standing zone. Should be avoided during this period of time.Total number of;The measurement area is counted byActivated carbon, is black powder or block, granular, honeycomb amorphous carbon, but also a regular arrangement of crystalline carbon.In addition to carbon elements, activated carbon also contains two kinds of admixtures: one is the chemical combination of elements, mainly oxygen and hydrogen, these elements are due to incomplete carbonization and residual in the carbon, or in the activation process, foreign non-carbon elements and activated carbon surface chemical combination;Another kind of admixture is ash, which is the inorganic part of activated carbon, and ash in active carbon is easy to cause secondary pollution.Because of its strong adsorption, activated carbon is widely used in production,In the life.Activated carbon material is processed by the amorphous carbon, has a large specific surface area, the gas, solution of inorganic or organic matter and colloidal particles have good adsorption capacity.Activated Carbon materials mainly include Activated Carbon (AC) and Activated Carbon Fibers (ACF), etc.Activated carbon material as a kind of excellent adsorbent, mainly because of its unique adsorption surface structure and surface chemical properties.Activated carbon material has stable chemical properties and high mechanical strength.pellet based activated carbon