Microporous activated carbon fiber and preparation method thereof

Abstract

The invention provides a microporous activated carbon fiber and a preparation method thereof, and belongs to the field of activated carbon fibers. The ash content of the microporous activated carbon fiber is 1.1 wt%-2.0 wt%, the specific surface area is 1500 m < 2 >/g-2100 m < 2 >/g, the proportion of pores below 0.8 nm is 40-50%, the proportion of pores of 0.8-2 nm is 50-60%, no mesopores above 2nm exist, the O element content is 5%-15%, the C element content is 65%-90%, the H element content is 1%-2%, and the ignition point is 300-450 DEG C. The preparation method comprises the following steps: impregnating raw materials with a phosphoric acid aqueous solution, drying, carbonizing, washing with water, and carrying out high-temperature modification to obtain the activated carbon fiber. Wherein the raw materials are artificial fibers and/or natural fibers; the mass fraction of the phosphoric acid aqueous solution is 5%-15%. The microporous activated carbon fiber has the advantages ofno mesopore, high proportion of 0.8-2 nm micropores, large specific surface area, high strength and no sticking problem; meanwhile, the ignition point is high, the hydrophobicity is high, and the VOCsadsorption acting force is enhanced; the preparation method is low in cost and high in product yield.

Description

technical field [0001] The invention relates to the field of activated carbon fibers, in particular to a microporous activated carbon fiber and a preparation method thereof. Background technique [0002] The physical activation method is the preparation method of activated carbon fiber commonly used in industrial production at present. After pretreatment and carbonization of the activator, the carbon monoxide or carbon dioxide gas generated by the reaction with the physical activator (carbon dioxide, water vapor, etc.) Many micropores are produced. There are following problems in this activated carbon fiber preparation technology: (1) the physical activation method needs to use the oxidizing property of activated gas to erode the surface of activated carbon fiber at high temperature, remove tar and uncarbonized matter, and produce new pores, thereby causing huge The proportion of material ablation and the shrinkage rate of size will reduce the yield and increase the produc...

AI Technical Summary

Problems solved by technology

There are following problems in this activated carbon fiber preparation technology: (1) the physical activation method needs to use the oxidizing property of activated gas to erode the surface of activated carbon fiber at high temperature, remove tar and uncarbonized matter, and produce new pores, thereby causing huge Ratio of material ablation and dimensional shrinkage, reducing yield and increasing production cost

(2) The activation process inevitably causes the loss of carbon components and reduces the fiber strength

[0004] However, the existing phosphoric acid chemical activation method ACF products usually have the following problems: (1) the oxidation of phosphoric acid in the preparation process of the chemical activation method ACF will increase the content of oxygen-containing functional groups on the surface of the material

Oxygen-containing functional groups, acidic functional groups and other strong hydrophilic functional groups lead to poor hydrophobicity of the material, and it is easy to adsorb water molecules, so that the adsorption sites are occupied and the adsorption force on pollutants is reduced.

(2) The pore size of the ACF product prepared by the physical method is concentrated below 0.8nm, and the adsorption force on VOCs is much higher than that on water. Although the activated carbon fiber prepared by the chemical method has a large specific surface area and a wide range of pore size distribution, it is beneficial Desorption, but its adsorption force of VOCs is weaker than the physical method ACF, resulting in the material's adsorption performance on VOCs being greatly affected by the water content and the humidity of the exhaust gas

(3) The final carbonization temperature in the preparation process of chemical activation method ACF is low, resulting in incomplete removal of H and O elements, and its ignition point is lower than that of physical method ACF

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