TWI658988B - Method for preparing active carbon - Google Patents

Abstract

An activated carbon preparation method is used to solve the problems that the conventional activated carbon preparation method is complicated in operation and consumes more energy. The system includes: preparing a raw material, the raw material is a carbonaceous material; and under a nitrogen environment, the raw material is subjected to a carbonization reaction at a temperature of 300 to 500 ° C for 1 to 3 hours, without further adding an activator to An activation reaction is performed to obtain activated carbon. The iodine value of the obtained activated carbon is between 436 and 1085 mg / g.

Description

Preparation method of activated carbon

The invention relates to a method for preparing activated carbon, in particular to a method for preparing activated carbon which eliminates the use of an activator.

According to this, activated carbon is a porous substance with good adsorption capacity. It is often used for gas adsorption, water treatment or as a support for chemical catalysts. When evaluating the adsorption capacity of activated carbon, the iodine value is often measured. The iodine value is about 400 ~ 1100mg / g. A conventional method for preparing activated carbon is to first perform a carbonization reaction at a temperature of 400 to 500 ° C for a raw material containing carbon atoms, hydrogen atoms and oxygen atoms to remove a hydrogen atom and an oxygen atom of the raw material to obtain a porous carbon structure. At this time, because the tar is attached to the porous carbon structure, an activation reaction (for example, water vapor or carbon dioxide, etc.) must be performed at a temperature of 700 to 1000 ° C to remove the porous carbon structure. On the tar, it is possible to obtain activated carbon.

The above conventional activated carbon preparation method requires additional activation of the activation reaction at a high temperature after the carbonization reaction to obtain activated carbon, and therefore consumes more energy, which is not in line with the current trend of developing green processes in the world.

In view of this, the conventional method for preparing activated carbon does still need to be improved.

In order to solve the above problems, an object of the present invention is to provide a method for preparing activated carbon, which can obtain activated carbon with less energy.

The activated carbon preparation method of the present invention comprises: preparing a raw material, the raw material is coffee grounds, Luo Han Guo, bagasse, coconut husk, green coffee beans, rice straw or orange peel; and a nitrogen atmosphere at 300-500 ° C At the temperature, the raw material is subjected to a carbonization reaction for 1 to 3 hours, without further adding an activator to perform an activation reaction, to obtain activated carbon, wherein the obtained activated carbon has an iodine value of 43.6 to 1085 mg / g. between.

Accordingly, the activated carbon preparation method of the present invention can eliminate the activation reaction performed at a high temperature (700-1000 ° C.) in the conventional activated carbon preparation method. Therefore, the activated carbon preparation method of the present invention can be performed at a relatively low temperature. In addition, the use of the activator is eliminated, so the energy consumed in the preparation of activated carbon can be reduced, and the effect of saving energy can be achieved.

Among them, the carbonization reaction is preferably performed at a temperature of 400 ° C. for 2 hours. In this way, it has the effect of improving the adsorption capacity of activated carbon.

Among them, the nitrogen flow rate of the nitrogen environment is 400-600c.c. min ^-1 . In this way, it has the effect of preventing the carbon atoms contained in the raw material from being oxidized to obtain activated carbon.

In order to make the above and other objects, features, and advantages of the present invention more comprehensible, the following describes the preferred embodiments of the present invention in detail as follows: The method for preparing activated carbon of the present invention includes: preparing a raw material; and The raw material undergoes a carbonization reaction, without further adding an activator to perform an activation reaction, to obtain activated carbon.

The raw material is a carbonaceous source material. In addition to carbon atoms, the carbonaceous material may include other atoms such as hydrogen atoms and oxygen atoms. Examples of such carbonaceous materials include raw coffee beans, coffee grounds, and Luo Han Guo. , Bagasse, coconut shell, tea leaves, beech, banana peel, pine wood, rice straw or orange peel, etc., are not particularly limited in the present invention.

The carbonization reaction is carried out in an environment where the oxygen content is not sufficient to initiate the oxidation reaction. The raw material is heated to thermally decompose the raw material, and further, hydrogen atoms and oxygen atoms contained in the raw material are separated from the raw material. Moreover, in the method for preparing activated carbon of the present invention, after the raw material undergoes the carbonization reaction, the hydrogen atom and oxygen atom are removed, and the carbon atom remains in the raw material in the form of activated carbon. In addition, when the raw material is subjected to the carbonization reaction, the raw material is subjected to the carbonization reaction at a temperature of 300 to 500 ° C for 1 to 3 hours, preferably the raw material is subjected to the carbonization reaction at a temperature of 400 ° C for 2 hours. In this way, activated carbon with a better iodine value (that is, activated carbon with a better adsorption capacity) can be obtained. In addition, the iodine value of the activated carbon obtained by the method for preparing an activated carbon of the present invention is between 436 and 1085 mg / g.

In the present invention, the raw material is subjected to the carbonization reaction under a nitrogen environment, and the nitrogen flow rate of the nitrogen environment may be 400-600 c.c. min ^-1 , thereby preventing the carbon atoms contained in the raw material from being oxidized and failing to obtain activated carbon.

In addition, in order to further improve the adsorption capacity of the obtained activated carbon, baking can be performed before the raw material is subjected to the carbonization reaction. The baking is preheating the raw material, and it can be baked at a temperature of 100 to 300 ° C. The raw material is baked for 55 to 225 minutes, preferably at 200 ° C. for 195 minutes. After baking the raw material, the raw material can be cooled to room temperature and then the carbonization reaction can be performed.

In order to confirm that the method for preparing activated carbon of the present invention can indeed prepare activated carbon, the following experiments were performed:

(A) Reaction temperature and reaction time

Coffee grounds were prepared as the raw material. Nitrogen was introduced into the reactor with a capacity of 1 L at a rate of 500 ml / min per minute. The pressure in the reactor was normal pressure, and the temperature was raised to 10 ° C / min. At each temperature shown in Table 1, activated carbon was obtained after the carbonization reaction was performed on the raw material at different temperatures after reaching each temperature, and the iodine value of the obtained activated carbon was measured and recorded in Table 1.

Table 1: Reaction temperature, reaction time and iodine value for preparing activated carbon

As can be seen from Table 1, under the condition that the carbonization reaction is performed at 400 ° C for 2 hours, the iodine value of the activated carbon obtained can reach 922 mg / g, in other words, the activated carbon obtained under this condition has a better quality. Adsorption capacity.

In addition, the raw materials shown in Table 2 were prepared, and according to the above experimental results, the carbonization reaction was performed at a temperature of 400 ° C for 2 hours under the nitrogen environment, and the iodine value of the obtained activated carbon was measured. Recorded in Table 2. As can be seen from Table 2, the activated carbon preparation method of the present invention can indeed obtain activated carbon from a variety of different raw materials.

(B) the effect of the presence of nitrogen environment on the iodine value

Coffee grounds were prepared in the same manner as in Experiment (A). Environment and an air environment (that is, in general air), the raw material was subjected to the carbonization reaction at a temperature of 400 ° C. for 2 hours, and the iodine value of the obtained activated carbon was measured. As a result, it was found that the activated carbon obtained by subjecting the raw material to the carbonization reaction under the nitrogen environment had an iodine value of 922 mg / g, compared with that of the raw material after the carbonizing reaction was performed in the air environment. The obtained activated carbon had an iodine value of 769 mg / g. Therefore, it can be known that the carbonization reaction of the raw material under the nitrogen environment can make the obtained activated carbon have better adsorption capacity.

(C) Selection of baking time

Raw coffee beans were prepared as the raw material, and the raw material was roasted at a roasting temperature of 200 ° C under the time conditions shown in Table 3, and then the roasted raw material was subjected to the carbonization reaction at a temperature of 400 ° C under the nitrogen environment 2 Hours, and the iodine value of the obtained activated carbon was measured and recorded in Table 3.

As can be seen from Table 3, when the baking time is 195 minutes, the activated carbon obtained from the raw material has a better iodine value, that is, a better adsorption capacity.

(D) The effect of the presence or absence of baking on the iodine value

Prepare the raw materials shown in Table 4 and bake at a baking temperature of 200 ° C for 195 minutes. The raw materials after baking are then carbonized at a temperature of 400 ° C under the nitrogen atmosphere. The reaction was performed for 2 hours, and the iodine value of the obtained activated carbon was measured and recorded in Table 4.

It can be seen from Table 4 that baking can be performed before the carbonization reaction, and activated carbon with better adsorption capacity can be obtained after the reaction.

In summary, the activated carbon preparation method of the present invention can obtain activated carbon by subjecting the raw material to the carbonization reaction at a temperature of 300 to 500 ° C for 1 to 3 hours, which can eliminate the need for the conventional activated carbon preparation method. The activation reaction is performed at a high temperature (700-1000 ° C). Therefore, the method for preparing activated carbon of the present invention can be performed at a relatively low temperature, and the use of the activator is eliminated, thereby reducing the energy consumption for the preparation of activated carbon and achieving Energy efficiency.

Although the present invention has been disclosed using the above-mentioned preferred embodiments, it is not intended to limit the present invention. Anyone skilled in the art can make various changes and modifications to the above embodiments without departing from the spirit and scope of the present invention. The technical scope protected by the invention, so the scope of protection of the present invention shall be determined by the scope of the appended patent application.

Claims (3)

An activated carbon preparation method, comprising: preparing a raw material, the raw material is coffee grounds, Luo Han Guo, bagasse, coconut husk, green coffee beans, rice straw or orange peel; and a temperature of 300 ~ 500 ° C under a nitrogen atmosphere Then, the raw material is subjected to a carbonization reaction for 1 to 3 hours without further adding an activator to perform an activation reaction to obtain activated carbon. The iodine value of the obtained activated carbon is between 436 to 1085 mg / g. The method for preparing activated carbon according to item 1 of the scope of patent application, wherein the carbonization reaction is performed on the raw material at a temperature of 400 ° C for 2 hours. The method for preparing activated carbon according to item 1 of the scope of patent application, wherein the nitrogen flow rate of the nitrogen environment is 400-600c.c. min ^-1 .