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Recognition method of activated carbon adsorption value


Information summary: There are three ways to identify the high and low adsorption value of activated carbon: iodine value, look at bubbles, and look at the decolorization ability. Put activated carbon into colored water, the amount should reach half or more of the water, so that the effect will be more obvious. After standing for 10-20 minutes, compare it with the comparative water sample.

 Activated carbon is black powdered or granular amorphous carbon. In addition to carbon, the main component of activated carbon contains elements such as oxygen and hydrogen. In the structure of activated carbon, the microcrystalline carbon is irregularly arranged, and there are fine pores between the cross-connections, which will produce carbon structure defects during activation. Therefore, it is a porous carbon with low bulk density and large specific surface area. The correct selection of activated carbon can maximize the effect of activated carbon.

1. Iodine value:

Iodine value is a performance parameter of activated carbon. The iodine value of nut shells, bamboo charcoal, and coal are all in the hundreds. The iodine value of activated carbon raw materials ranges from 800, 850, 900, 950, 1000, 1100 mg/g, etc. (Iodine value is liquid Phase adsorption index, you can generally see whether the specific surface area and micropores of the activated carbon are developed. The gas phase adsorption index is important to look at: CTC adsorption value, benzene adsorption value. Good activated carbon CTC>100%, benzene adsorption>50%), adsorption The ability is also different! The cost price is also different! Activated carbon coconut shell with the same iodine value has a better adsorption effect on small fractions. Activated carbon of different materials is selected for different applications. Hand weighing: As mentioned above, if you want to improve the adsorption performance of activated carbon, you can only make as much pore structure on the activated carbon as possible. The more pores, the looser the activated carbon and the lighter the relative density. Activated carbon feels lighter. In the case of the same weight, activated carbon with good performance will be much larger than inferior activated carbon.

2. Look at the bubbles:

Put a small amount of activated carbon into the water. Due to the penetration of water, the water will gradually immerse into the pore structure of the activated carbon, forcing the air in the pores to expel, thereby generating a series of relatively small bubbles, and pulling out a thin bubble line in the water. At the same time, there will be a faint sound of bubbles, which is very interesting. The more intense this phenomenon occurs and the longer the duration, the better the adsorption of activated carbon.

3. Look at the decolorization ability:

Another manifestation of the adsorption capacity of activated carbon is its decolorization ability. Activated carbon has the magical ability to turn colored liquids into light or colorless. This is actually caused by activated carbon adsorbing pigment molecules in colored liquids. It is precisely because of this characteristic of activated carbon that it is widely used in the production process of brown sugar to white sugar in the sugar industry. Take two transparent cups, put pure water in one cup, and then drop a drop of red ink (here you can use any kind of pigment that is easy to observe but does not change the nature of the water, such as blue ink, printer color ink, But ink and carbon ink can not be used), after mixing evenly, pour half of the colored water into another cup for comparison. Put activated carbon into colored water, the amount should reach half or more of water, so that the effect will be more obvious. After standing for 10-20 minutes, compare with the comparative water sample. Under the same conditions, the stronger the decolorization effect indicates the adsorption of activated carbon. The better.