KR101927288B1 - Manufacturing method of surface modified activated carbon and the surface modified activated carbon manufacturing by the method - Google Patents

Abstract

The surface modified activated carbon according to the present invention and the surface modified activated carbon produced by the method can be used for modifying the surface of activated carbon only by a simple process that saves cost and time and to treat wastewater containing organic pollutants It is possible to remove the anionic contaminant which is difficult to remove in the process of removing the contaminant, and other contaminants can improve the removal efficiency.
In addition, the surface modification of the activated carbon improves the ability of the activated carbon to adsorb pollutants, thereby providing activated carbon having high pollutant removal efficiency.

Description

TECHNICAL FIELD [0001] The present invention relates to a method for producing a surface-modified activated carbon, and a surface-modified activated carbon produced by the method. BACKGROUND OF THE INVENTION 1. Field of the Invention < RTI ID =

The present invention relates to a method for producing activated carbon modified with a surface and to a surface-modified activated carbon produced by the method, and more particularly, to a method for modifying the surface of an activated carbon to remove anionic contamination The present invention relates to a method for producing a surface-modified activated carbon capable of not only removing a substance but also removing other pollutants, and to a surface-modified activated carbon produced by the method.

Recently, with the increase in population, industrial development, and living standard, emissions of sewage, industrial wastewater, animal wastewater and various organic wastewater have rapidly increased, and water pollution such as river, river, lake, Is coming. Among them, when nutrients such as nitrogen (N) are excessively discharged into the aquatic ecosystem of the natural world, eutrophication is caused and the water pollution due to the proliferation of algae is increased.

The chemical treatment method and the biological treatment method are used as a method for purifying the organic matter, nitrogen and phosphorus which is the main cause of the water pollution, but the chemical treatment method has a disadvantage that the initial facility cost and the operation cost are increased because the equipment and the drug cost are high There is a problem that secondary pollution occurs due to chemical agents. In addition, the biological treatment method is a method for decomposing organic matter and nutrients into microorganisms. Since the microorganisms take a considerably long residence time until decomposing organic matters and nutrients, there is a problem that the volume of the reaction tank becomes large. In addition, It is difficult to secure stable water quality due to poor sedimentation efficiency and difficult operation.

Techniques for removing contaminants by adsorption using activated carbon have been developed as means for solving the problems of such chemical and biological treatment methods and for satisfying the enhanced water quality standards.

Activated carbon is mainly used as an adsorbent. Contaminants are adsorbed on the surfaces of activated carbon when bacteria and microorganisms pass through activated carbon columns as well as contaminants such as various organic or inorganic substances. As such, activated carbon has a large specific surface area and a high adsorption capacity, and exhibits a high characteristic of removing contaminants due to its excellent adsorption ability and is advantageous in comparison with other treatment methods. However, since the surface is nonpolar, it is known that the boiling point such as ammonia is low and the adsorption efficiency is low for the polar component.

In this connection, Korean Patent No. 10-1407506 discloses a method for producing activated carbon in which an acid or an alkali is added to the pore surface in order to enhance the adsorption performance, and the adsorption performance is enhanced to selectively adsorb the specific component.

However, these chemical treatment methods require 1) a large amount of water is consumed to clean the chemical and the washed water needs to be treated again, which is costly and time consuming, and 2) the unique adsorption ability And the efficiency of removing contaminants is low. 3) There is a problem that the anionic contaminants can not be removed.

SUMMARY OF THE INVENTION It is an object of the present invention to solve the above problems and to solve the above problems. It is an object of the present invention to provide a method for removing carbonic anhydride, There is a need for a method for producing activated carbon having a high surface modification and a surface-modified activated carbon produced by the method.

In order to solve the above-described problems, the present invention provides a process for producing a modified activated carbon comprising (1) treating activated carbon with a flocculant containing an iron salt, and (2) irradiating the activated carbon with radiation.

According to another aspect of the present invention, there is provided a method of treating wastewater using activated carbon produced by any one of the above methods. Further, the surface of the activated carbon contains iron salt, and the iron salt is at least one of ferric sulfate (Fe ₂ (SO ₄ ) ₃ ) or ferric chloride (FeCl ₃ ).

In order to solve the above-mentioned problems, the present invention provides a surface-modified activated carbon produced by any one of the above-mentioned production methods.

The surface modified activated carbon according to the present invention and the surface modified activated carbon produced by the method can be used for modifying the surface of activated carbon only by a simple process that saves cost and time and to treat wastewater containing organic pollutants It is possible to remove the anionic contaminant which is difficult to remove in the process of removing the contaminant, and other contaminants can improve the removal efficiency.

In addition, the surface modification of the activated carbon improves the ability of the activated carbon to adsorb pollutants, thereby providing activated carbon having high pollutant removal efficiency.

FIG. 1 is a graph _{showing changes} in total organic carbon (TOC), chemical oxygen (H.sub.2), and the like depending on the concentration (mM) of flocculant of activated carbon prepared by using a flocculant containing ferric chloride (FeCl.sub.3) (COD), ammonia nitrogen (NH 3 -N), and nitrate nitrogen (NO ₃ ^- ).
FIG. 2 is a graph showing the relationship between total organic carbon (TOC), chemical (chemical), and the like, according to the irradiation dose (kGy) of the activated carbon surface modified by using the coagulant containing ferric chloride (FeCl ₃ ) The removal efficiency of oxygen demand (COD), ammonia nitrogen (NH ₃ -N) and nitrate nitrogen (NO ₃ ^- ).
FIG. 3 is a graph showing the relationship between the total irradiation dose (kGy) of a modified activated carbon surface prepared by using a flocculant containing ferric sulfate (Fe ₂ (SO ₄ ) ₃ ) according to an embodiment of the present invention, (TOC), chemical oxygen demand (COD), ammonia nitrogen (NH ₃ -N) and nitrate nitrogen (NO ₃ ^- ).

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings so that those skilled in the art can easily carry out the present invention. It should be understood, however, that the embodiments are not intended to limit the scope of the present invention, which should be construed to facilitate understanding of the present invention.

As described above, in the conventional method of producing activated carbon having a surface modified by the chemical treatment method, a large amount of water is consumed to wash the chemical substance and the washed water must be treated again, there was. In addition, due to the strong chemical reaction, the inherent adsorption ability of the activated carbon is destroyed, the removal efficiency of the contaminants is lowered, and the anionic contaminants can not be removed.

Accordingly, the present invention provides a process for producing a modified activated carbon comprising the steps of (1) treating activated carbon with a flocculant containing iron salts, and (2) irradiating the activated carbon with radiation, thereby solving the above-mentioned problems . The surface of the activated carbon can be effectively modified by increasing the number of iron ions bonded to the surface of the activated carbon by a simple process that saves cost and time.

In addition, when the surface of activated carbon is modified to treat wastewater containing organic pollutants, it is possible to remove anionic pollutants which are difficult to remove, and the removal efficiency of other pollutants can be improved. In addition, the surface modification of the activated carbon improves the ability of the activated carbon to adsorb pollutants, thereby providing activated carbon having a high pollutant removal efficiency.

First, (1) a step of treating activated carbon with a flocculant containing an iron salt will be described.

Activated carbon is an aggregate of amorphous carbon with well-developed micropores. It is an adsorbent that has a large internal surface area due to the fine pore size of the molecular size during the activation process. The activated carbon used in the present invention can be used in various industrial fields such as environment, water treatment and the like, but it can be manufactured using various materials as well as those made of coconut, wood, and lignite. It is also possible to use activated carbon produced by known water vapor or chemical activation method, or by treating the produced activated carbon with hydrochloric acid or sodium chloride to remove impurities and metals. In addition, activated carbon produced by various known methods may also be used .

Specifically, the activated carbon usually has a surface area of 1,000 m 2 or more per unit g, and the functional group of the carbon atom present on the surface adsorbs molecules of the adsorbate by applying an attractive force to the surrounding liquid or gas. That is, when such activated carbon is used, the surface area that can be modified by many pores is increased, so that the space for adsorbing and removing contaminants is increased. As a result, the pollutants contained in the wastewater can be removed more efficiently.

The activated carbon used in the present invention may be of a size that can easily remove contaminants contained in wastewater through adsorption, but preferably has a particle size of 100 to 400 mesh. More preferably 150 to 350 mesh, and more preferably 200 to 300 mesh. When the activated carbon having a particle diameter within the above range is used, the surface area per number of activated carbon can be appropriately maintained, thereby improving the removal efficiency of the pollutant.

If the particle diameter of the activated carbon is less than 100 mesh, the surface area of the activated carbon is too small, so that it is difficult for the pollutant to be adsorbed and the removal efficiency of the pollutant may be lowered. If the particle size of the activated carbon is larger than 400 mesh, the surface area of the activated carbon becomes excessively wide, so that the total surface area of the activated carbon is decreased to decrease the adsorption capacity of the pollutant. As a result, the efficiency of removing contaminants may be reduced.

The iron salt contained in the coagulant used in the present invention may be an iron salt that is usually bound to the surface of activated carbon and adsorbs contaminants. According to a preferred embodiment of the present invention, ferric sulfate (Fe ₂ (SO ₄ ) ₃ ) or ferric chloride (FeCl ₃ ). More preferably, it may be ferric chloride (FeCl ₃ ).

When the surface of the activated carbon is modified with the iron salt, the amount of anionic contaminants contained in the wastewater and other contaminants contained in the wastewater can be increased, thereby maximizing the effect of treating wastewater. In addition, since iron ions bind to the surface of activated carbon to reduce the amount of iron ions remaining and discharged, it is possible to prevent secondary water pollution by preventing generation of ammonia ion or nitrite ion due to iron ion discharge Can be obtained.

Further, when the above ferric sulfate (Fe ₂ (SO ₄ ) ₃ ) or ferric chloride (FeCl ₃ ) is used, the productivity is remarkably increased due to high treatment efficiency and lower cost than the case of using other iron salts .

Meanwhile, the concentration of the iron salt-containing flocculant used in the present invention may be preferably 15 to 25 mM, more preferably 17 to 23 mM. When the concentration of the flocculant is within the above range, the removal efficiency of total organic carbon (TOC), chemical oxygen demand (COD), ammonia nitrogen (NH ₃ -N) and nitrate nitrogen (NO ₃ ^- ) is increased, .

If the concentration of coagulant is less than 15 mM or more than 25 mM, the total organic carbon (TOC), chemical oxygen demand (COD), ammonia nitrogen (NH ₃ -N) and nitrate nitrogen (NO ₃ ^- The removal efficiency of the pollutants may be lowered during the treatment of wastewater.

The solvent used in the coagulant may be distilled water. When distilled water is used as a solvent, the solubility of the iron salt is high, which is easy to manufacture and can be produced without additional additives. Further, by using the distilled water as a solvent and proceeding to the step of irradiating the raw water, water molecules are decomposed by the irradiation of the radiation to form radicals, and the formed radicals react with a series of reforming mechanisms Can be made at once without any additional process.

Further, when the flocculant treatment step is performed, a flocculant containing 0.5 to 2.8 parts by weight of iron salt may be preferably used for 100 parts by weight of activated carbon. More preferably, a flocculant containing 0.7 to 2.6 parts by weight of iron salt may be used per 100 parts by weight of activated carbon, and more preferably, a flocculant containing 1.0 to 2.4 parts by weight of iron salt may be used. When the coagulant containing iron salt is used within the above range, the number of iron ions that can bind to the surface of the activated carbon is appropriately adjusted to the surface area of the activated carbon, so that the surface of the activated carbon can be more efficiently modified. In addition, ammonia ions or nitrite ions are not generated due to the release of iron ions that are not bonded to the surface of the activated carbon, so that secondary water contamination can be prevented in advance.

If a flocculant containing less than 0.5 part by weight of iron salt is used with respect to 100 parts by weight of activated carbon, modification of the surface of activated carbon may not occur completely because the number of iron ions that can be combined with the total surface area of activated carbon is small. Accordingly, the removal efficiency of the contaminants may be lowered.

Also, if a flocculant containing 2.8 parts by weight of iron salt is used for 100 parts by weight of activated carbon, the iron ion is excessively increased, so that the release of iron ions not bound to the activated carbon surface may increase. Accordingly, ammonia ion or nitrite ion may be generated due to the release of iron ions, which may cause secondary water pollution.

More specifically, FIG. 1 is a graph showing the relationship between total organic carbon (TOC), total organic carbon (TOC), and total organic carbon (TOC) according to the flocculant concentration (mM) of the surface modified activated carbon prepared using the coagulant containing ferric chloride (FeCl ₃ ) (COD), ammonia nitrogen (NH 3 -N), and nitrate nitrogen (NO ₃ ^- ).

As shown in the figure, when the surface-modified activated carbon is used, the concentration of total organic carbon (TOC) before and after the wastewater treatment varies by about 150 to 170 mg / L. On the other hand, when the wastewater is treated with the surface-modified activated carbon of the present invention, the removal efficiency of total organic carbon is remarkably improved due to the difference of about 150 to 30 mg / L. The concentration of chemical oxygen demand (COD) before and after wastewater treatment is 450 to 1310 mg / L and the concentration of nitrate nitrogen (NO ₃ ^- ) before and after wastewater treatment is 38 to 100 mg / L, indicating that the removal efficiency of anionic contaminants and other contaminants is significantly improved. In addition, when the concentration of the coagulant is 15 to 25 mM, the concentration difference between the pollutants before and after the wastewater treatment becomes larger. That is, it can be confirmed that the removal efficiency of contaminants is increased within the concentration range of the flocculant.

Next, (2) a step of irradiating the activated carbon with radiation will be described.

The radiation usable in the present invention is preferably gamma rays. In the case of irradiating the above-described radiation, the number of iron ions bonded to the surface of the activated carbon can be increased, thereby improving the surface modification effect of the activated carbon. That is, since the surface activated carbon can be sufficiently produced through the irradiation of the radiation, the adsorbing ability of the pollutant can be improved and the effluent treatment effect can be enhanced.

If the radiation is not irradiated, the number of iron ions bonded to the surface of the activated carbon decreases, so that the surface modification of the activated carbon may not be sufficiently performed. Accordingly, the removal efficiency of the contaminants may be lowered.

In addition, the dose of radiation may preferably be 0.7 to 8 kGy, more preferably 0.8 to 7 kGy, and still more preferably 0.9 to 6 kGy / h. When the radiation is irradiated within the above range, the removal efficiency of total organic carbon (TOC), chemical oxygen demand (COD), ammonia nitrogen (NH ₃ -N) and nitrate nitrogen (NO ₃ ^- ) is increased, do.

The total organic carbon (TOC), chemical oxygen demand (COD), ammonia nitrogen (NH ₃ -N) and nitrate nitrogen (NO ₃ ^- ) removal efficiencies, if the dose of radiation is less than 0.7 kGy or exceeds 8 kGy And the ability to remove contaminants may be lowered during wastewater treatment.

Specifically, FIG. 2 is a graph showing the total organic carbon (TOC) according to the irradiation dose (kGy) of the surface-modified activated carbon prepared using the coagulant containing ferric chloride (FeCl ₃ ) according to an embodiment of the present invention. , Chemical oxygen demand (COD), ammonia nitrogen (NH ₃ -N), and nitrate nitrogen (NO ₃ ^- ). FIG. 3 is a graph showing the relationship between the irradiation dose (kGy) of a surface-modified activated carbon prepared using a flocculant containing ferric sulfate (Fe ₂ (SO ₄ ) ₃ ) according to an embodiment of the present invention (TOC), chemical oxygen demand (COD), ammonia nitrogen (NH ₃ -N), and nitrate nitrogen (NO ₃ ^- ).

(TOC), chemical oxygen demand (COD), ammonia nitrogen (NH ₃ -N), and nitrate nitrogen (NO ₃ ^- ) in the case of using surface modified activated carbon irradiated with radiation. And the concentration before and after the wastewater treatment is significantly different. That is, it can be confirmed that when the radiation is irradiated, the removal efficiency of the pollutants is remarkably improved as compared with the surface activated carbon without irradiating the radiation. In this case, regardless of which ferric chloride (FeCl ₃ ) or ferric sulfate (Fe ₂ (SO ₄ ) ₃ ) is used as the iron salt, the removal efficiency of the contaminant is high. As a result, it can be confirmed that the surface modification of the activated carbon can be effectively performed when the radiation is irradiated, and the wastewater treatment capability is increased.

On the other hand, when the radiation dose is 0.7 to 8 kGy, the concentration difference between the pollutants before and after the wastewater treatment is larger. That is, it can be confirmed that the removal efficiency of the pollutants is increased within the range of the radiation dose.

Meanwhile, the step (2) may further include a step of firing the surface-modified activated carbon to bind the iron ions and the activated carbon more strongly. The calcination may be performed preferably by drying the activated carbon at 80 to 120 DEG C for 8 to 30 hours.

Furthermore, the present invention provides activated carbon produced by any one of the above-mentioned methods and a method of treating wastewater using the activated carbon. Thus, when the wastewater containing organic pollutants is treated, it is possible not only to remove the anionic pollutants but also to efficiently remove the other pollutants, thereby enhancing the wastewater treatment capacity.

Hereinafter, the present invention will be described in detail except for the contents overlapping with the above description.

The method of treating wastewater using the surface-modified activated carbon of the present invention is applicable not only to wastewater but also to treatment of sewage and other polluted water. The activated carbon of the present invention not only maintains its own adsorption capacity, but also has a relatively large surface binding to iron ions due to the above-mentioned production method, so that its adsorption capacity is increased. Therefore, when treating the wastewater using activated carbon, it is possible to remove anionic contaminants and to remove other contaminants.

Further, the present invention provides activated carbon having a surface modified with at least one of ferric sulfate (Fe ₂ (SO ₄ ) ₃ ) or ferric chloride (FeCl ₃ ) do. As a result, it is possible to remove the anionic contaminants which are difficult to remove when the wastewater containing organic contaminants is treated, and the removal efficiency of other contaminants can be improved.

As a result, when the surface of the activated carbon is modified through the present invention, the number of iron ions bonded to the surface of the activated carbon can be increased, so that the surface activated carbon can be obtained more completely. When the activated carbon is used to treat wastewater containing pollutants, not only an anionic pollutant but also other pollutants can be efficiently removed.

In addition, the above-described process can be carried out only by a simple process with reduced time and cost, and the adsorption ability inherent to activated carbon can be maintained, so that organic wastewater can be efficiently treated.

Example

Hereinafter, embodiments of the present invention will be described. However, the scope of the present invention is not limited by these examples.

Table 1

Table 1 shows the specifications of the reagents and instruments used in this embodiment.

Example  One

50 g of activated carbon was washed with distilled water and dried overnight at 105 ° C. 20 mM coagulant was prepared (FeCl _{3 ,} solvent: distilled water). 50 g of activated carbon was immersed in 150 ml of the flocculant at 70 캜 for 18 hours. The activated carbon was irradiated with a dose of 1 kGy with gamma rays at an irradiation dose rate of 5 kGy / hr. After the irradiation, the activated carbon was dried at 105 ° C. overnight, and firing was carried out to prepare the surface-modified activated carbon.

Example  2 to 14

Activated carbon having a surface modified in the same manner as in Example 1 was produced according to the conditions shown in Table 2 below.

Table 2

Comparative Example  One

The procedure of Example 1 was repeated except that no coagulant was used.

Comparative Example  2

The procedure of Example 1 was repeated except that no radiation was applied.

Comparative Example  3

The same procedure was followed as in Example 10, except that no radiation was applied.

Experimental Example  - Measurement of pollutant concentration and removal efficiency before and after wastewater treatment

The concentration and removal efficiency of the pollutants included in the target polluted water were measured using the activated carbon obtained from the examples and the comparative examples. The leachate diluted to 1/100 of the target pollution water was used and NO ₃ ^- was not included in the leachate. Therefore, NO ₃ ^- 100 mg / L was added to the activated carbon pollutant removal efficiency of the modified activated carbon. Removal efficiency of total organic carbon (TOC), chemical oxygen demand (COD), ammonia nitrogen (NH ₃ -N) removal efficiency and nitrate nitrogen (NO ₃ ^- ) removal efficiency were measured, .

Table 3

First, comparing Example 1 with Example 10, ferric chloride (FeCl ₃ ) was used as the iron salt in Example 1, ferric sulfate (Fe ₂ (SO ₄ ) ₃ ) was used as Example 10, Respectively. In the case of Example 1 and Example 10, the pollutant removal efficiency was high, but the case of Example 1 has higher pollutant removal efficiency. Particularly, the removal efficiency of nitrate nitrogen (NO ₃ ^- ), which is an anionic contaminant which is difficult to remove, is 88.30%, which is significantly higher than that of Example 10 (44.79).

In comparison between Example 1 and Examples 2 to 5, the removal efficiency of most pollutants in Example 1 exceeds 80%. On the contrary, in Examples 2 to 5, all the contaminant removal efficiencies were less than 80%, and it was confirmed that the wastewater treatment capacity using the activated carbon prepared in Example 1 with the coagulant concentration of 20 mM was the greatest.

In comparison between Example 1 and Examples 6 to 9, the removal efficiency of most pollutants in Example 1 exceeds 80%. On the contrary, in Examples 6 to 9, all pollutants were found to be less than 80%, and it was confirmed that the wastewater treatment capacity using the activated carbon prepared in Example 1 with the radiation dose of 1 kGy was the greatest.

On the other hand, in the case of treating wastewater using activated carbon which has not been surface-modified with the coagulant containing the iron salt of Comparative Example 1, the pollutant removal efficiency is all lower than 52%. On the other hand, in the case of Examples 1 and 10 in which the surface was modified with the coagulant containing iron salts, most of the pollutant removal efficiency was remarkably higher than 60%. It can be seen that the efficiency of removing pollutants and the wastewater treatment capacity of activated carbon surface modified with iron salts are remarkably high.

In addition, in Comparative Examples 2 and 3, most of the pollutant removal efficiency is significantly lower than in Examples 1 and 10. As a result, the surface modification of the activated carbon can be performed more easily than the irradiation of the radiation, so that the pollutant removal efficiency is improved and the wastewater treatment capacity is increased.

Claims (9)

(1) treating activated carbon with a flocculant containing at least one iron salt selected from ferric sulfate (Fe ₂ (SO ₄ ) ₃ ) and ferric chloride (FeCl ₃ ) at a concentration of 15 to 25 mM; And
(2) irradiating the activated carbon with 0.7 to 8 kGy of radiation.
The method according to claim 1,
Wherein the activated carbon in step (1) has a particle diameter of 100 to 400 mesh.
delete The method according to claim 1,
Wherein the coagulant is used in an amount of 0.5 to 2.8 parts by weight based on 100 parts by weight of activated carbon in the step (1).
The method according to claim 1,
Wherein the radiation of step (2) is gamma ray.
delete A method for treating wastewater using activated carbon produced by the method of any one of claims 1, 2, 4, and 5.
delete 6. A process for the preparation of a compound according to any one of claims 1, 2, 4 and 5,
A surface-modified activated carbon comprising at least one iron salt selected from ferric sulfate (Fe ₂ (SO ₄ ) ₃ ) and ferric chloride (FeCl ₃ ) bonded to the surface of activated carbon.

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