The modification method that combines the two methods of physical activation and chemical activation is called the combination of physical and chemical modification corundum suppliers
Generally speaking, activated carbon with very rich micropores can be successfully obtained by chemical activation followed by physical activation.It was found that after chemical activation with ZnCH and physical activation with carbon dioxide, walnut activated carbon could further open and expand pores.H The lignocellulosic activated carbon was activated by mixing H,PO and ICOZ to obtain super activated carbon with high specific surface areaThe chemical modification of the adsorption surface of activated carbon material is to improve the structure of the functional groups and surrounding atmosphere on the adsorption surface of activated carbon material by certain methods, so as to make it become the active point in the specific adsorption process, so as to control the hydrophilic or hydrophobic properties and the binding ability with metal or metal oxides.Surface chemical properties of activated carbon materials can be modified by oxidation modification, reduction modification, metal loading modification, acid base modification, heteroatom carrying and compound modification, graft polymerization, etc. Surface oxidation modification of activated carbonhslabrasive
Surface oxidation modification is mainly to oxidize the functional groups on the surface of activated carbon materials by using appropriate oxidants at appropriate temperatures, so as to improve the content of oxygen-containing groups on the surface of carbon materials, enhance the surface hydrophilicity and polarity, and enhance the adsorption capacity of polar substances.
The number and types of oxygen-containing functional groups are different after treatment with different oxidants.Oxidation treatment also changed the void structure of activated carbonThe commonly used modified oxidants mainly include HNO, HClO, HPO, H,SO4, HF, O and HO, etc.
Oxidant HNO;After the modified activated carbon was treated with proper amount of nitric acid, the mesopore increased, the ratio of carboxylic hydroxyl increased, the surface polarity of activated carbon increased, and the adsorption capacity of some solutes with certain polarity increased.However, excessive nitric acid modification treatment will increase the unstable groups on the surface of activated carbon and fail to achieve the predetermined effect 18-20].
After modified by HCIO with mild oxidation, the number of oxygen-containing groups on the surface of activated carbon increased, but the micropore structure and specific surface area did not change much.After ozonation treatment, the number of oxygen-containing acid functional groups on the surface of activated carbon and the surface acidity increased, and the adsorption rate and capacity of C** increased. P-Morwski et al. 2 used HNO to oxidize the carbon synthesized from phenols, and the adsorption performance of the treated activated carbon material to trihalomethane was greatly improved.Shan Xiaomei et al. 2 found that the surface area and pore volume of activated carbon decreasedafter high concentration of HNO treatment.
However, the surface and pore volume of activated carbon increased after low concentration HNO treatment.(NH4) S0.Oxidation changes the micropore size distribution of coal-based carbon, but has little effect on the micropore size distribution of coconut-shell carbon.
In addition, the number of carboxyl groups on the surface of activated carbon increased obviously after modification of HNO, (NH4)S
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