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Principle of Decolorized Activated Carbon

Jul. 27, 2019

Activated carbon for decolorization is made of high-quality sawdust and other raw materials, Zinc chloride process has developed mesoporous structure, large adsorption capacity, rapid filtration, and other characteristics.

It is mainly suitable for decolorization, purification, deodorization and impurity removal of high-pigment solutions such as refined sugar, monosodium glutamate, glucose, starch sugar, chemical additives, dye intermediates, food additives, and pharmaceutical preparations.


Decolorized activated carbon process:


The decolorized activated carbon produced by the phosphoric acid process has developed mesoporous structure and specific surface area, large adsorption capacity, fast filtration speed, and no zinc salt. It is widely used in decolorization, purification, deodorization and impurity removal of sugar, glutamic acid and salt, lactic acid and salt, citric acid and salt, wine, condiments, animal and plant proteins, biochemical products, pharmaceutical intermediates, vitamins, antibiotics, and other products in the food industry.


Detailed introduction of decolorized activated carbon:


Activated carbon has the magical ability to turn colored liquids into light or colorless, which is actually due to the adsorption of pigment molecules in colored liquids by activated carbon. Because of this characteristic of activated carbon, it is widely used in the sugar industry in the production process of brown sugar to white sugar.


Take two transparent cups, put pure water in one cup, then drop a drop of red ink (here you can use any color that is easy to observe but does not change the nature of the water, such as blue ink, printer color ink, but can not use ink and carbon ink). Stir evenly and pour half of the colored water into it. Save it in the other cup as a contrast. When activated carbon is put into colored water, the quantity of activated carbon should reach half or more of that of water.


This effect will be more obvious. After standing for 10 - 20 minutes, compared with the control water sample, under the same conditions, the stronger the decolorization effect, the better the adsorbability of activated carbon.


Activated carbon is a kind of black powder, granular or pellet amorphous carbon with porous, the main component is carbon, but also contains a small amount of oxygen, hydrogen, sulfur, nitrogen, chlorine. It also has the fine structure of graphite, but the grains are small and irregular accumulation between layers. It has a large surface area (500-1000 m2/g) and strong adsorption performance. It can adsorb gases, liquids or colloidal solids on its surface. For gases and liquids, the quality of adsorbed substances can be close to that of activated carbon itself.


Its adsorption is selective, and non-polar substances are easier to adsorb than polar substances. In the same series of substances, the higher the boiling point, the easier to adsorb, the higher the pressure, the higher the temperature and the lower the concentration, the greater the adsorption capacity. On the contrary, decompression and heating are beneficial to gas desorption. It is commonly used for gas adsorption, separation and purification, solvent recovery, decolorizer for sugar, grease, glycerin, and drugs, deodorant for drinking water and refrigerators, filter in a gas mask, and carrier of catalyst or metal salt catalyst.


The raw materials for the early production of activated carbon were wood, hard nutshell or animal bone. Later, coal was mainly used. After distillation and activation, activated carbon was produced by steam and gas activation methods. Carbon is activated by steam or carbon dioxide at 850-900 C. (2) Chemical activation method. Activated carbon can be obtained by using the gas released by an activator or impregnating raw materials with activator after high-temperature treatment.


Activated carbon has a microcrystalline structure, the microcrystalline arrangement is completely irregular. There are micro-holes (radius less than 20_A=10-10 meters), transition holes (radius 20-1000), and macro-holes (radius 1000-100000), which make it have a large inner surface with a specific surface area of 500-1700 m 2/g.


This determines that activated carbon has good absorptivity and can adsorb metal ions, harmful gases, organic pollutants, pigments and so on in wastewater and waste gas. Industrial application of activated carbon also requires high mechanical strength and good wear resistance.

Its structure strives to be stable, and the energy required for adsorption is small, so as to be conducive to regeneration. Activated carbon is used for decolorization and deodorization of oil, beverage, food and drinking water, gas separation, solvent recovery and air conditioning, as catalyst carrier and adsorbent for the gas mask. Activated carbon has the strongest decolorization effect in water and weaker decolorization effect in organic solvents.


Generally adding 0.1-3% (W/V) and stirring for 30-60 minutes, the particle size of activated carbon has an effect on decolorization time, and the decolorization effect of activated carbon produced by different manufacturers and processing methods is quite different. The decolorization temperature and PH should be determined by experiments according to the properties of your products.


Principle and procedure of decolorization of activated carbon:


1)Activated carbon is usually used at 75-80 degrees

2)The decolorization effect of activated carbon is the strongest in water, and it is also good in strong polar solvents, but poor in non-polar solvents.

3)Generally, it is better to use it under the condition of pH 3-6.

4) Generally, the dosage is one-thousandth to three (or five)

5) Decolorization time is generally 30-60 minutes.

6) There are many types of activated carbon, such as sugar carbon, oil carbon and so on. Choose a suitable activated carbon for your use.


Decolorized activated carbon is widely used in industry and plays an important role in the decolorization of glycerol.


The distilled 20 oil often fails to meet the requirements of higher quality products in terms of color and odor, such as reagent grade, medicinal grade, and special grade.


Therefore, the distilled crude oil should be decolorized by activated carbon with a dosage ratio of U.Z% to 10.3'} (mass). Decolorization temperature is 8} - - 90}', heat preservation and stirring for more than 1 hour, and vacuum should be pumped in the tank to help remove odor. Finally, essential glycerol products meeting all levels of quality requirements can be obtained by filtration.


In this process, the filter link is also very important. It needs a filter element which is not easy to clog, can be backwashed, pressure drop, and has strong corrosion resistance. Johnson screen is the best choice.



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