What is activated carbon and how to make it.

1. Chemical activation method.

The general process steps taken by this method are to first impregnate carbon-containing raw materials with chemical reagents, and then activate them under the protection of inert gas at a certain temperature to directly obtain activated carbon, and the process flow is shown in the figure below

Liu Haiyan et al. used fruit shell, anthracite and petroleum coke as raw materials, and activated activated carbon with KOH to obtain a specific surface area of about 3300m2 g. Some people use coal as raw material, first use chemical methods to remove the inorganic minerals by acid treatment, and then impregnate with chemical reagents such as phosphoric acid (such as zinc chloride, potassium hydroxide, sodium hydroxide, potassium carbonate, etc.), and then activate under nitrogen protection to prepare activated carbon with good quality, less ash, less volume shrinkage and low carbon volatilization loss tendency. Regarding the chemical activation mechanism, the author believes that the chemical reagent and carbon can achieve the dehydrogenation and cross-linking of tar, the catalytic gasification of carbon and the dissolution of silicon and aluminum at high temperatures.

At present, potassium hydroxide alkali melting method is the most effective method to improve the specific surface area of activated carbon. Especially for raw materials such as petroleum coke, petroleum asphalt, and coal asphalt, potassium hydroxide can be used as an activator to prepare activated carbon with a higher specific surface area - super activated carbon. The advantages of this method are:

Different activators and their dosages can be used to prepare activated carbon with different pore size distribution and surface chemical properties, and it is easier to control the pore size distribution of activated carbon.

2. Physical activation method.

The physical activation method is to react the carbonized material with oxidizing gases such as water vapor, carbon dioxide or air at high temperature to form a well-developed microporous structure inside the carbon material. The carbonization temperature is generally 600, and the activation temperature is generally between 800 and 900. The process of preparing microporous activated carbon by physical activation method has been relatively mature, especially for the preparation of low-cost coal-based activated carbon, and the effect is very significant.

However, in this process, the activity of raw materials is low, the activation time required is long, the pore size distribution of micropores is difficult to control, the quality of activated carbon is unstable, the specific surface is low, and the mesopores are not developed enough, which limits the application of activated carbon.

What is Activated Charcoal:

Activated carbon is a very excellent adsorbent, which is made of charcoal, bamboo charcoal, various fruit shells and high-quality coal as raw materials, and processed and manufactured by a series of processes such as crushing, sifting, catalyst activation, rinsing, drying and screening of raw materials through physical and chemical methods. It has the dual characteristics of physical adsorption and chemical adsorption, and can selectively adsorb various substances in the gas phase and liquid phase to achieve the purposes of decolorization and refining, disinfection and deodorization, decontamination and purification.

Preparation of activated carbon:

The preparation of activated carbon is to carbonize solid carbon (such as coal, wood, hard husks, kernels, sugar, resin, etc.) at high temperature under the condition of isolating air, and the temperature generally reaches 600-900 degrees, and then use air under the condition of 400-900 degrees. A porous substance formed by oxidation and activation of carbon dioxide, water vapor or their mixtures. Therefore, the preparation of activated carbon can be divided into two stages: carbonization and activation, the carbonization stage can be the volatilization of substances other than carbon, and the oxidation activation stage can burn off the residual volatile substances to generate new pores and expand the original pores, improve the micropore structure, and increase its attachment activity.

1. Raw material preparation: pre-treatment of carbon-containing raw materials, which may include one or more in the process of drying, impurity removal, crushing, milling, and even pre-oxidation treatment.

2. Raw material mixing: Carbon-containing raw materials and chemical agents (solid or solution) are mixed in proportion, and for some raw materials, a grinding process may be added after the mixing is made, so that the raw materials can be more fully connected to the potato cover to facilitate the chemical reaction of the subsequent process.

3. Heating and heating for hydrolysis or oxidation, dehydrogenation and other chemical reactions.

4. Extraction to remove the activator and its reaction products.

5. After the above-mentioned mixed products are cooled, they are repeatedly soaked in tap water to completely remove the activation agent and its reaction products to obtain wet activated carbon products.

Dear, glad to answer for you. The production method of activated carbon is as follows: The preparation process of activated carbon is roughly divided into:

It is refined by a series of processes such as carbonization, cooling, activation and washing. The shape of the finished product of activated carbon production is roughly divided into: granular, columnar, powdery, etc.

Use firewood to make charcoal, then knock it into a small piece of charcoal of about 1cm3, put the small piece of charcoal into a clean fine nylon mesh bag socks, tie it to the mouth of the bag, and then put it into a household pressure cooker or medical pressure cooker containing 5% sodium carbonate solution, and boil at high pressure for about 30 minutes to wash out the oil and dredge the micro holes in the charcoal. To prevent the charcoal from floating on the sodium carbonate solution, a clean stone can be tied to the outside of the nylon bag and fall down. After boiling, rinse the charcoal twice with water to remove the oil, then put it in a 5% sodium carbonate solution and boil it at high pressure for about 30 minutes, and rinse it three times with water of about 80 after taking it out to wash off the oil and a small amount of sodium carbonate.

Finally, boil with water at high pressure for about 30 minutes to further dredge the micropores in the charcoal; Remove and dry to obtain activated charcoal, and bake it before use for best results. The adsorption capacity of activated carbon prepared by this method far exceeds that of charcoal. Used activated carbon can also be regenerated using this method.

Activated carbon is an efficient adsorption material, and its manufacturing process generally includes the following steps:1Preparation of raw materials:

Select high-quality raw materials such as coal, wood, coconut shell, etc., and crush, screen and other treatments. 2.Drying charring:

The raw materials are placed in a high-temperature furnace and carbonized under the condition of no oxygen or less oxygen, and the carbonization temperature is generally between 600 -900. 3.Activation Treatment:

The carbonized material is activated, that is, heated to a high temperature, and then activated with gas (such as water vapor, carbon dioxide, air, etc.). The purpose of activation is to make the pore structure of the carbon material more developed, so as to improve the adsorption performance. 4.

Washing treatment: The activated material is washed to remove impurities and ash and improve the adsorption performance. 5.

Drying and simple packaging: The washed activated carbon is dried and then packaged. The whole manufacturing process involves multiple links, and the process flow and raw material quality need to be strictly controlled to ensure the performance and quality of the activated carbon.

Categories: Science & Engineering.

Analysis: The main component of activated carbon is carbon, and it also contains a small amount of oxygen, hydrogen, sulfur, nitrogen and chlorine.

Preparation of activated carbon:

Principle】 The walnut shell is distilled by strong heat to obtain crude activated carbon, and then after acid boiling and washing, better activated carbon can be obtained.

Supplies】 Rigid test tubes, single-hole rubber stoppers with bent catheters, 100ml beakers, funnels, filter paper, flask clamps, iron racks, iron rings, asbestos nets, evaporation dishes.

Walnut wide shell, copper sheet, concentrated nitric acid, 2mol l hydrochloric acid.

Operation] 1 Carbonization of walnut shells.

Put the walnut shell on a thick piece of paper, smash it with a hammer, take 5 10g of the broken powder and put it into a 30 200mm hard test tube, heat it with an alcohol blowtorch according to the device shown in the figure, and constantly rotate the test tube and move the blowtorch to make the walnut shell crushed evenly heated. Soon you can see that the pipe wall is attached to the water, when the amount is large, it flows to the cotton ball, a large amount of gas escapes from the nozzle and the black-brown wood tar stool digs and soaks the cotton ball, and the peach shell slag of the core of the tube is gradually carbonized until it no longer produces gas or the carbon particles are heated to red, and the alcohol lamp can be removed, and then the following steps are used to treat the test tube after cooling.

2 Acidification of carbon pellets.

Take out the carbon particles generated by dry distillation and put them into a beaker, pour in 50ml of 2mol l hydrochloric acid, heat and boil with an alcohol lamp for 15min, the solution is light yellow, discard the solution in the cup, and then pour 50ml of 2mol l hydrochloric acid and boil for 15min to remove the impurities in the carbon particles. After cooling, filter, wash three times with distilled water, then pour the carbon particles on the filter paper into another clean beaker containing 50ml of distilled water, boil for 15min, discard the solution in the cup, and then change to new distilled water and boil several times, test with pH test paper, the aqueous solution is acidic at first, and finally neutral. Filter the solution containing the carbon particles.

3 Drying of homemade activated carbon granules.

Put the wet charcoal particles filtered through the rough edge into the evaporation dish, use an alcohol blowtorch to increase the heat, and stir continuously with a glass rod until the charcoal particles are all dry, do not let the charcoal particles burn. Remove the alcohol blowtorch, cool, and take a small amount of activated carbon to carry out the following experiments to check whether it meets the experimental requirements. Collect the activated carbon that meets the requirements in a clean, dry bottle for storage.

4. Adsorption experiment of homemade activated carbon.

Take a test tube full of nitrogen dioxide, put in the newly made activated carbon particles, plug the mouth of the test tube with a rubber plug so that there is no air leakage, shake the test tube to make the carbon particles fully contact with the gas in the tube, and place the test tube for a period of time, the color of the reddish-brown gas in the test tube gradually changes to light yellow, which proves that the activated carbon made of walnut shell has an adsorption effect.