Study on modification of activated carbonChemical functional groups as the active center dominated the surface chemical properties of activated carbon and activated carbon number and variety of surface functional groups was mainly determined by the production of activated carbon raw materials, so in the process of the preparation of activated carbon material by physical and chemical methods to increase the specific surface area of activated carbon material, adjusting the aperture and its distribution, makes the adsorption of activated carbon material surface structure change, thereby increasing physical adsorption properties of activated carbon material, to improve the adsorption performance has important significance.
The structure characteristics determine the physical adsorption of activated carbon.dxd activated carbon
The structural characteristics mainly refer to the micropore volume, specific surface area and micropore structure, etc. Ordinary activated carbon has high ash content, small pore volume, wide distribution of micropores, small specific surface area and poor adsorption performance
The physical properties of activated carbon, such as specific surface area and pore size distribution, have great influence on its adsorption capacity.
At present, there are three methods to modify surface structural characteristics: physical method, chemical method and physical-chemical combination method, the latter two methods are more commonly used.The micro-structure of activated carbon can be achieved by microwave heating, neutron radiation and low temperature plasma technology.
Microwave modification is to control the surface chemical composition or element content of activated carbon by adjusting the microwave power and radiation time, so as to adjust the surface chemical properties of activated carbon and improve the adsorption performance of activated carbon. It is an effective method to change the adsorption performance of activated carbon.Some studies have found that after the activated carbon by microwave irradiation, the surface become rough, is in the shape of concave and convex, many backwater hole was opened and extends into, the pores attachments to be removed, the carbon skeleton to contract, different size of hole shrinkage, jung, entrance to drop, pore size distribution in the direction of microporous migration, thus effectively improve the adsorption ability of active carbon, enhance the adsorption ability of refractory organic matter
When the activated carbon is treated by ultrasonic wave, the ultrasonic cavitation will cause shock wave and microjet, and the different ultrasonic treatment time and physical parameters will have different effects on the properties of activated carbon.activated carbon supplier
Yu Fengwen et al. 1 found that the pore size of activated carbon was changed by ultrasonic modification, and the BET specific surface area and micropore specific surface area of activated carbon decreased slightly with the extension of ultrasonic treatment time.
In order to make the activated carbon material have more abundant void structure and more uniform pore size distribution, some activators are often added in the activation process.
The commonly used activators are alkali metals, hydroxides of alkali earth metals, inorganic salts and some acids. At present, the more widely used and more mature chemical activators are KOH, NaOH, ZnCH, CaCb and H.PO, etc."Different activators and their dosages make the preparation of activated carbon more flexible, among which the super activated carbon prepared by KOH as the activator has the best performance.