KR100889037B1 - A Method for Preparing Zeolite Molded Object and Method for Water Treating Using the Zeolite Molded Object Prepared Thereby - Google Patents

Abstract

The present invention relates to a method for producing a natural zeolite molded body having excellent adsorption rate, strength and durability against ammonia nitrogen (NH ₃ -N) using a natural zeolite and a binder, and a water treatment method using the natural zeolite molded body produced accordingly. According to the present invention, after mixing a natural zeolite powder and a methyl cellulose binder in a 4: 1-3: 2 weight ratio to prepare a mixture of zeolite powder and a binder, a method for producing a natural zeolite molded body which is molded, fired and dried, and accordingly Provided is a water treatment method for adsorbing and removing ammonia nitrogen in wastewater by using the prepared natural zeolite molded body before the activated sludge process, specifically after the screening process. The natural zeolite molded body produced in the present invention exhibits excellent adsorption rate, strength and durability against ammonia nitrogen (NH ₃ -N). In addition, by adsorbing and removing ammonia nitrogen in the waste water by using the zeolite molded body of the present invention, it is possible to denitrate without using a separate external carbon source during waste water treatment, and the waste water treatment efficiency is increased.

Zeolite, Methyl Cellulose Binder, Fiber, Ammonia Nitrogen, Strength, Durability, Adsorption Rate

Description

A method for preparing zeolite molded object and method for water treating using the zeolite molded object prepared thereby}

1 is a photograph showing the cylindrical zeolite pellets prepared in the method according to the present invention,

2 is a view showing a tiled zeolite molded body produced by the method according to the present invention,

3 is a view showing a water treatment process using a zeolite molded body according to one embodiment of the present invention.

The present invention relates to a method for producing a zeolite molded body and a water treatment method using the zeolite molded body produced accordingly. More specifically, the present invention provides a method for producing a natural zeolite molded article having excellent adsorption rate, strength, and durability against ammonia nitrogen (NH ₃ -N) using a natural zeolite and a binder and a natural zeolite molded article prepared accordingly. It relates to a water treatment method.

Zeolite is a mineral produced by the volcanic ashes of the 3rd Era of Volcanoes under the action of hot water, and is a hydrous alumina silicate mineral in which water molecules exist in the form of crystal water. Zeolite has physical adsorption, hygroscopic action, and chemical ion exchange characteristics, and due to these properties, it is possible to remove harmful constituents of exhaust gas, automobile wastewater purification, marine pollution prevention agent, red tide phenomenon prevention agent, wastewater treatment agent, heavy metal ion removal agent, and decolorizing agent. It is used for various purposes.

However, natural zeolites inevitably contain impurities compared to synthetic zeolites, which are somewhat heterogeneous, have low adsorption efficiency, and limit the available species. Synthetic zeolites, on the other hand, are superior to natural zeolites but are expensive. In addition, the conventional zeolite molded body has a problem in that the body is not detached and the mold is not retained upon immersion.

Therefore, there is a need for a natural zeolite molded article having excellent adsorption rate, strength and durability against ammoniacal nitrogen.

Accordingly, an object of the present invention is to provide a method for producing a natural zeolite molded article having excellent adsorption to ammonia nitrogen (NH ₃ -N).

Another object of the present invention is to provide a method for producing a natural zeolite molded article having excellent strength and durability.

Still another object of the present invention is to provide an effective water treatment method for adsorbing and removing ammonia nitrogen in wastewater by activated sludge method using the zeolite molded body produced in the present invention.

According to one aspect of the invention,

Preparing a mixture of zeolite powder and binder by mixing natural zeolite powder and methyl cellulose binder in a 4: 1 to 3: 2 weight ratio;

Shaping the mixture;

Firing the molded zeolite molding; And

Drying;

There is provided a natural zeolite molded body production method comprising a.

According to another aspect of the present invention,

Provided is a water treatment method comprising adsorbing and removing ammonia nitrogen from waste water by contacting the waste water and the zeolite molded body produced in the method according to the present invention in the previous step of the water treatment process by the active sludge process.

EMBODIMENT OF THE INVENTION Hereinafter, this invention is demonstrated in detail.

Zeolite is used for waste water treatment because of its large specific surface area and strong adsorption power, especially for adsorption removal of ammonia nitrogen. However, natural zeolites have lower adsorption and removal efficiency of ammonia-nitrogen nitrogen than synthetic zeolites, and have a problem in that they are desorbed upon immersion due to insufficient strength and durability when manufactured into a molded article.

Accordingly, the present invention is characterized by producing a zeolite molded article having excellent ammonia nitrogen adsorption removal rate, strength and durability by mixing and molding natural zeolite powder with a specific binder and firing.

The natural zeolite molded product manufacturing method of the present invention comprises mixing the natural zeolite powder with a binder to prepare a mixture of natural zeolite powder and a binder, and then forming, calcining and drying the same.

First, the zeolite powder is obtained by crushing and screening the natural zeolite so as to increase the specific surface area of the zeolite to increase the adsorption power to the ammonia nitrogen and to knead evenly with the binder. The zeolite can be ground by any milling method commonly known. Although not limited to this, the natural zeolite is crushed using a pulverizer, and then the crushed zeolite is filtered through a 106 µm sieve and the powder that has passed through the sieve is selected and used. The zeolite passed through the selected 106㎛ sieve has a diameter of about 106㎛ or less, the zeolite having a particle size of more than 106㎛ has a large particle size does not uniformly mixed with the binder and the like, the strength is weakened and shows a relatively small surface area .

The natural zeolite powder is mixed with a binder and kneaded. As the binder, a methyl cellulose binder is used. Methyl cellulose binder firmly binds the fine zeolite powder and maintains adhesion even upon firing and immersion. Accordingly, the molded article produced has excellent strength and durability, and when applied to wastewater treatment, the shape of the molded article is maintained. Zeolite powder and methylcellulose binder may be blended in a 4: 1-3: 2 weight ratio. When the mixing ratio of the zeolite powder exceeds 4: 1 weight ratio, the amount of binder is insufficient to prevent the dough, and when the mixing ratio of the zeolite powder is less than 3: 2, the dough becomes vaginal when compressed. Strength is weakened.

If necessary, an inorganic binder and / or a curing agent may be further used together with the methylcellulose binder. By further using an inorganic binder and / or a curing agent, the strength and durability of the molded body are further increased, and the form of the zeolite molded body is more firmly maintained. Silica sol, alumina sol, etc. may be used as the inorganic binder, but is not limited thereto, and SL-750, which is a ceramic coating agent of Fine Chem, may be used. The curing agent is not limited thereto, but a curing agent of Fine Chem may be used.

In addition, if necessary, fibers may be further mixed with the mixture of the natural zeolite powder and the binder. Fiber has excellent weather resistance, chemical resistance and heat resistance (especially high temperature heat resistance), and it is environmentally friendly and does not generate byproducts. Fibers are generally used to stabilize the structure and reinforce its bearing capacity. By combining these fibers in the production of the zeolite of the present invention, the tensile strength and durability of the zeolite molded body can be further increased. When fiber is added, the fiber may be added at most 0.33 parts by weight, preferably 0.06 to 0.33 parts by weight per 100 parts by weight of the zeolite powder. If it is less than 0.06 parts by weight, the effect of increasing the tensile strength and durability at the time of mixing with the zeolite is not sufficient, and if it is more than 0.33 parts by weight, it is difficult to knead smoothly due to less moisture due to excessive addition of fibers. Polyester fibers may be used as the fibers.

As described above, the natural zeolite powder and the methyl cellulose binder are evenly mixed or, if necessary, the natural zeolite powder and the methyl cellulose binder are further uniformly mixed with fibers, an inorganic binder and / or a curing agent, and then kneaded to a desired shape. Mold. Molding can be done by any method generally known in the art. Although it does not restrict | limit by this, For example, compression molding or it can shape | mold using a depilator.

In the case of compression molding, for example, a zeolite powder and a binder mixture are filled in a container of a desired shape, and then put into a compression mold and 3 kg / cm ² to 15 kg / cm ² Compress for 5-10 minutes under pressure. If the pressure is less than 3kg / cm ² or the compression time is less than 5 minutes, it will not be compressed to sufficient strength and density, and if it exceeds 15kg / cm ² or if the compression time is more than 10 minutes, the mold and press will be strained and deformed. It is undesirable because it can be caused and inefficient. When the contents are compressed during compression, the pressure gauge drops, and the pressure must be kept constant by using the lever of the compressor.

In the case of using a cyclone, for example, a mixture of zeolite powder and a binder can be filled into a cyclone frame and the cyclone can be operated to form a ring.

The zeolite molded body can be produced in any form that can exhibit a large specific surface area, and is not limited thereto, and can be produced, for example, in the form of a cylinder, a ring or a tile. The cylindrical zeolite pellets finally obtained in the present invention are shown in FIG. 1 and the zeolite in tile form (200 mm × 200 mm) is shown in FIG. 2. The zeolite in the form of a tile of FIG. 2 may form holes as shown in FIG. 2 during molding to increase the contact surface with water when applied to water treatment.

The molded zeolite molded body is fired. Firing can be performed, for example, in a microwave oven. In the microwave, electric energy is transmitted as a radio wave, which is a high-energy electromagnetic wave with a frequency of about 2.4 GHz and an output of 1000 watts. Therefore, the zeolite powder is firmly bonded by a binder and removes only the moisture of the zeolite compact within a short time by using the microwave oven. The zeolite molded body of the present invention can be effectively fired so as to be effective. The firing time is variable depending on the size of the molded article and the like, but is not particularly limited. For example, the firing time may be fired for 50 seconds to 12 minutes. If the zeolite molded body is less than 50 seconds, the zeolite molded body is not sufficiently fired, and if it exceeds 12 minutes, it is inefficient because it is already sufficiently fired. In the case of firing in a microwave oven, it is preferable not to continuously bake for the total firing time, but to bake by dividing the total firing time by about three times. This is because the molded zeolite may burst when continuously fired.

Since only moisture in the zeolite molded body is removed and the binder remains by firing in a microwave oven, the fired zeolite molded body exhibits excellent strength and durability, and the moldability of the zeolite molded body is maintained. Therefore, when applied to wastewater treatment, the molded body is strong even under impact load and hardly occurs desorption in water.

After firing, the calcined zeolite shaped body is naturally dried in a desiccator at room temperature for at least 6 hours, specifically 6-48 hours. The longer the natural drying is, the better the upper drying time is not specifically defined. If the drying time is less than 6 hours, it is not preferable in that it does not naturally dry and the strength of the molded body is lowered. When the zeolite molded body is dried in an ambient environment, it is preferable to dry it in a desiccator because it can absorb water again.

The natural zeolite molded body produced by the method of the present invention has a very high surface area per unit mass and shows excellent adsorptivity, in particular, excellent adsorptivity to ammonia nitrogen. Specifically, the zeolite shaped body according to the present invention exhibits ammonia nitrogen adsorption capacity of up to 10.12 mg NH ₃ -N / g. In addition, since the zeolite powder is firmly bonded by methyl cellulose, and exhibits excellent durability and strength, it is also resistant to impact load and does not desorb due to moisture when immersed.

The zeolite molded body prepared in the present invention can be used to adsorb and remove ammonia nitrogen in the water treatment process by the active sledge method. The water treatment process by the activated sludge process generally includes screen (step of removing suspended matter from waste water), flow adjusting tank (step of adjusting waste water uniformly), aeration tank, primary sedimentation tank (step of first sinking waste water), oxygen free Aerobic tank (decomposition of organic matter in wastewater by microorganisms), secondary settling tank (step of submerging again to obtain clear water) and effluent of the treated water.

The zeolite molded body produced by the method according to the present invention in the wastewater treatment process by the activated sludge process can be used to adsorb and remove ammonia nitrogen in the wastewater in the previous step of wastewater treatment by the activated sludge process. Specifically, the zeolite molded article prepared in the present invention is contacted with the zeolite molded article prepared in the present invention and the wastewater from which the suspended matter is removed in the screening process after the screening step in the activated sludge process, and the ammonia nitrogen in the wastewater is It can be used to adsorb and remove by zeolite molded body. More specifically, the ammonia nitrogen adsorption removal in the wastewater using the zeolite molded body according to the present invention is carried out after the screening process and before the aeration tank process, and more specifically, between the screening process and the flow adjusting process, the flow rate adjusting process and the aeration tank process. This can be done at the same time or at the same time during the flow adjustment process step. An example of a water treatment process by adsorption removal of ammonia nitrogen in wastewater using a zeolite molded body according to one embodiment of the present invention is shown in FIG. 3, which is merely illustrative of the present invention and thus does not limit the present invention. .

In this way, when the water treatment by the activated sludge process, the ammonia nitrogen in the waste water by adsorption and removal of the ammonia nitrogen in the waste water by using the zeolite molded body according to the present invention 40% or more, specifically 40-60% Is reduced. Therefore, in the process after the aeration tank in the activated slurry process, not only can be denitrated without using a separate external carbon source, but also the wastewater treatment efficiency is remarkably improved.

Hereinafter, the present invention will be described in detail through examples. The following examples illustrate the invention but do not limit the invention.

Example 1

After the natural zeolite was crushed using a crusher, the natural zeolite powder was passed through a sieve by filtration through a 106 μm sieve.

360 g of the selected natural zeolite powder and 180 g of methyl cellulose binder were stirred and kneaded for 1 hour using a magnetic stirrer to prepare a mixture of zeolite powder and binder. The mixture was filled in an open container having a diameter of 7 mm and a height of 7 mm, and then placed in a compression mold. The compression mold was placed in a compressor and molded by applying a pressure of 10 kg / cm ² to 13 kg / cm ² for 5 minutes.

After completion of compression molding, the molded zeolite was taken, placed in a microwave oven, and fired for 50 seconds. During firing, since the zeolite molded body may burst when continuously fired for 50 seconds in a microwave oven, 50 seconds were divided into three sections of 20 seconds / 20 seconds / 10 seconds and fired. At the time of split firing, the zeolite was taken out of the microwave oven, allowed to cool for 5 seconds, and then placed in the microwave oven and fired. After firing, the resultant was dried at room temperature for 6 hours in a desiccator to obtain a natural zeolite shaped body having a cylindrical shape having a diameter of 7 mm and a height of 7 mm as shown in the photograph of FIG. 1.

Example 2

After mixing the zeolite powder and the methyl cellulose binder as in Example 1, it was filled in a container having an upper and lower portions of 15 mm in diameter and 10 mm in height, and then placed in a compression mold. The compression mold was placed in a compressor and a pressure of 10 kg / cm ² to 13 kg / cm ² was applied for 10 minutes.

After compression molding was completed, the molded zeolite was taken into a microwave oven and fired for 60 seconds. At the time of firing, since the zeolite molded body may burst when 60 seconds were continuously fired in a microwave oven, 60 seconds were divided into three times of 20 seconds / 20 seconds / 20 seconds and fired. At the time of split firing, the zeolite was taken out of the microwave oven, allowed to cool for 5 seconds, and then put again in the microwave oven to be fired. After firing, the resultant was dried at room temperature for 6 hours in a desiccator to obtain a cylindrical zeolite shaped body having a diameter of 15 mm and a height of 10 mm.

Example 3

After mixing the zeolite powder and the methyl cellulose binder as in Example 1, the mixture was filled in the mold of the recirculator to prepare a pill (ring) having a diameter of 7 mm and 15 mm, respectively. Thereafter, it was baked in a microwave oven and dried to a room temperature in a desiccator to prepare a zeolite molded body in the form of a pill (ring) having a diameter of 7 mm and a diameter of 15 mm, respectively. Zeolite molded bodies having a diameter of 7 mm were fired and dried under the same conditions as in Example 1, and zeolite molded bodies having a diameter of 15 mm were subjected to the same conditions as in Example 2.

Example 4

After the natural zeolite was crushed using a crusher, the natural zeolite powder was passed through a sieve by filtration through a 106 μm sieve. 360 g of the selected natural zeolite powder, 180 g of methyl cellulose binder and 0.54 g of polyester fiber were kneaded while stirring with a magnetic stirrer for 1 hour to prepare a mixture of zeolite powder, binder and fiber. The mixture was filled into an open container of 20 cm wide, 20 cm high and 2 cm high, and then placed in a compression mold. The compression frame was placed in a compressor and a pressure of 10 kg / cm ² to 13 kg / cm ² was applied for 7 minutes. Was added to form the shape of FIG. Thereafter, 12 minutes was divided into three portions of 4 minutes / 4 minutes / 4 minutes in an electronic range, followed by divided baking. Thereafter, the resultant was dried at room temperature for 40 hours in a desiccator to obtain a tile having holes having a width of 20 cm, a height of 20 cm, and a height of 2 cm in FIG. 2.

Example 5

In this example, the ammonia nitrogen adsorption rate of the zeolite molded bodies was evaluated using the zeolite molded bodies prepared in Examples 1 and 2.

The zeolite shaped bodies prepared in Examples 1 and 2 were added to 100 ml of artificial wastewater having ammonia nitrogen content of 10.2 mg / l, respectively, in the amounts shown in Table 1 and left for 10 minutes to measure the adsorption rate of ammonia nitrogen. The results are shown in Table 1 below.

TABLE 1

Zeolite molded body input Concentration of Ammonia Nitrogen in Wastewater after Adsorption (mg / L) Removal rate Example 1 5.2 g 3.2 mg / L 68.6% Example 2 6.5g 2.4 mg / L 76.47%

In addition, the zeolite shaped bodies prepared in Examples 1 and 2 did not unwind while being immersed in the ammonia-containing nitrogen wastewater and maintained their form.

Example 6

In this embodiment, 300 g of natural zeolite and the zeolite molded body prepared in Example 1 were added to 1 L of wastewater having an ammonia nitrogen (NH ₃ -N) concentration of 38.15 mg / L, respectively, and after 5 minutes, the ammonia nitrogen adsorption removal rate was It was measured and shown in Table 2 below.

TABLE 2

Zeolite Concentration of Ammonia Nitrogen in Wastewater after Adsorption (mg / L) Removal rate Natural zeolite 34.15 10.48% Example 1 21.2 44.42%

As can be seen from Table 2, it was found that the adsorption removal rate of ammonia nitrogen was excellent when the natural zeolite molded body according to the present invention was used as compared with the case of using natural zeolite.

Example 7

As shown in Fig. 3, after the screening process of wastewater having an ammonia nitrogen content of 30 to 40 mg / L, the zeolite formed body prepared in Example 2 was filled with a raw water storage tank (not shown). Adsorbed ammonia nitrogen in the waste water to the zeolite carrier for 5-10 minutes of residence time by introducing wastewater with a pH of 6.8-7.4 at room temperature into an ammonia nitrogen treatment tank containing 20 cm and 1400 cm high zeolite carrier tanks (four). To remove. This reduced the ammonia nitrogen in the wastewater to about 15-18 mg / L.

The zeolite molded body produced by the method according to the present invention is manufactured in an ideal form with a very large surface area per unit mass, so that the adsorption rate to ammonia nitrogen (NH ₃ -N) is excellent (for example, up to 10.12 mg NH ₃ -N / Not only g) but also excellent in strength and durability, it is resistant to impact load and hardly desorbs from moisture. In addition, by adsorbing and removing ammonia nitrogen in the waste water using the zeolite of the present invention, the waste water treatment can be denitrified without using a separate external carbon source, and the waste water treatment efficiency is increased.

Claims (4)

Preparing a mixture by mixing natural zeolite powder and methyl cellulose binder in a weight ratio of 4: 1 to 3: 2, and blending up to 0.33 parts by weight of fiber per 100 parts by weight of the natural zeolite powder; Shaping the mixture; Firing the molded zeolite molding; And Drying; Natural zeolite molded body production method comprising a. The method of claim 1, wherein an inorganic binder, a curing agent or a mixture thereof is blended with the mixture. delete A method for treating water comprising adsorbing and removing ammonia nitrogen in waste water by contacting the waste water and the zeolite molded body prepared by the method of any one of claims 1 or 2 in the previous step of the water treatment process by the active sludge process.

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