KR100670872B1 - Zeolite Combined Magnetic Beads for Removal of Ammonium Ion from Water and Preparation Method Thereof - Google Patents

Abstract

The present invention is a zeolite bond that can be continuously reused by adsorbing ammonia dissolved in the water in a short time to easily remove the ammonia from the water and also to quickly regenerate the adsorption force by ammonia is desorbed in a short time Provide a magnetic adsorbent. The present invention also provides a zeolite for removing ammonium ions in water, comprising the steps of adding and mixing a binding agent to the zeolite, and adding magnetic material powder to the mixture to bind the magnetic material and the zeolite and to refine the bond. Provided is a method of preparing a bonded magnetic adsorbent. By using the zeolite-coupled magnetic adsorbent provided in the present invention, it is possible to remove ammonium ions dissolved in water in a very simple manner, thereby facilitating treatment of process water or wastewater that is difficult to purify due to the presence of high concentrations of ammonium ions. In addition, the purification cost can be greatly reduced by reusing the zeolite binding magnetic adsorbent after proper treatment.

Ammonia Removal, Ammonium Removal, Magnetic Adsorbent, Ion Exchange, Adsorption, Livestock Wastewater, Desorbent

Description

Zeolite Combined Magnetic Beads for Removal of Ammonium Ion from Water and Preparation Method Thereof}

1 is a schematic view showing a process of the present invention for removing ammonium ions in water using a magnetic adsorbent combined with a zeolite.

FIG. 2A shows a discontinuous process for removing ammonium ions in water using a magnetic adsorbent bound to zeolites. FIG.

FIG. 2b shows a continuous process for removing ammonium ions in water using a magnetic adsorbent combined with zeolites. FIG.

An object of the present invention is to attach zeolite to a magnetic body to quickly and economically remove ammonium ions dissolved in water.

The present invention provides a magnetic adsorbent for removing ammonium ions (hereinafter referred to as “zeolite-bound magnetic adsorbent”) in which ammonium ions and a zeolite having ion exchange ability are combined with a magnetic material to remove ammonium ions dissolved in water, and their preparation and It is about how to use.

As a method of removing ammonium ions in water, a biological treatment method of purifying through ammonium ionization and denitrification from ammonium ions by using microbial activity in water is preferred. In this process, ammonium ions are oxidized to nitrate ions in the nitrification process by adding oxygen in the presence of microorganisms, such as activated sludge method, and these nitrate ions are converted into molecular nitrogen in the anaerobic denitrification process and disappear into the air. However, since the nitrate ion is converted to nitrogen in the biological denitrification process, a carbon source is required, so that a part of the nitrogen component remains as nitrate ion if there is not enough carbon source in the water.

On the other hand, the biological nitrification process is carried out only after most of the carbon source is removed. Therefore, the removal of the nitrogen source by the biological method is limited, and there is an excess of ammonium in the desorption solution generated from the livestock wastewater, some leachate or the dehydration filtrate of the digested sludge. In this case, ammonia disturbances may cause problems in the removal of the carbon source, and even if the carbon source is removed to some extent, a huge amount of air is required to convert high concentrations of ammonium ions into nitrate ions, There is a problem that the external carbon source such as alcohol should be input in excess.

Therefore, to remove ammonium ions dissolved in water when a high concentration of ammonium ions is present in water such as livestock wastewater or sludge desorption liquid, or when there is almost no carbon source as the industrial wastewater or the concentration of nitrogen is higher than the carbon source. Physical degassing may be used for this purpose. This process uses ammonium ions in water as ammonia at high temperature and high pH to operate at a temperature above about 70 ° C and a pH above about 9.0 and ammonia by blowing air or water into the water. Is separated from water along these media in gaseous form. The ammonia gas separated from the water may be condensed through a condenser or combined with reactants such as sulfuric acid to be recovered as oil (ammonium sulfate). However, this process has been very limited until now because of the excessive cost of energy to maintain a high temperature, the cost of chemicals to raise the pH, and also the cost of condensation.

When ammonium ions combine with magnesium and phosphate ions in a ratio of 1: 1: 1, there is a method of chemically removing ammonium ions in water by using a principle of forming a poorly soluble compound called Struvite. However, this method has a very high cost of chemicals to be introduced, especially at high concentrations of ammonium ions. In addition, the amount of chemicals to be added to remove the ammonium ions inevitably be excessively added, there is a high possibility that secondary pollution may occur due to the excessive input of phosphate, an eutrophic material. In addition, this reaction has a big disadvantage that interference may occur when a substance having properties similar to ammonium ions such as potassium ions is dissolved. In addition to these chemical problems, in order to proceed with the crystallization process, the pH must be raised to about 9.0, and the crystallized struvite is present in the water as very fine particles. There is also a problem of leakage. Therefore, this process remains at the academic level.

It is well known that zeolite is widely used in detergents because of its excellent cation exchange ability and adsorbs ammonium ions in water by ion exchange. In addition, it is also well known that after the adsorption of the cation can be easily recycled by alternative ions such as brine. However, there are some limitations to the method of removing ammonium ions using zeolite from wastewater. First of all, in order to easily recover the zeolite after use, if the particle size is several millimeters in size, the surface area is small, so that the adsorption performance is very low, and therefore, it takes a very long time to remove the ammonium ion. Therefore, the use of finely ground zeolites can greatly improve this problem. However, in this case, due to the low specific gravity of the zeolite, the state becomes similar to that of releasing the water-based paint in water, which makes it very difficult to recover after use, and this problem also appears in the recovery process after recovery. Membrane separation methods have been tried to overcome this problem, but are still in the development stage due to the aforementioned problems.

Therefore, in order to use a zeolite for the purpose of removing ammonium ions in water, it is necessary to develop a fine zeolite in a form that can be easily separated from water.

Accordingly, an object of the present invention is to remove the ammonium salt in the water by a simple method at room temperature by making the fine zeolite in a form that can be easily separated from water, and can be reused by a simple method after using the zeolite wastewater due to ammonium salt Another aspect of the present invention is to provide an economical ammonium salt removing material and a method of manufacturing and using the same, which can greatly reduce the processing cost of process water.

The present inventors have conducted a number of studies to achieve the above object, by physically mixing the zeolite and the magnetic material and by using a binding agent to combine the zeolite and the magnetic material can solve the problems occurring when using the zeolite conventionally alone It has been found that the present invention has been completed.

Accordingly, the present invention provides a zeolite-bound magnetic adsorbent for ammonium ion removal in which a zeolite having an affinity for ammonium ions is combined with a magnetic material to remove ammonium ions from water containing ammonium ions.

The present invention also provides a zeolite-bound magnetic adsorbent for removing ammonium ions in water, comprising mixing zeolite with a magnetic substance, adding and mixing a solvent, a binding agent and a dispersant to the mixture, and miniaturizing the mixture. It provides a manufacturing method.

Further, the present invention comprises mixing the zeolite binding magnetic material according to the present invention with water contaminated with ammonium ions to combine ammonium ions with the zeolite-containing magnetic material and then separating the zeolite binding magnetic material from water by external magnetic force. Provided is a method for separating ammonium ions from.

According to the present invention, as a basic material for the synthesis of the zeolite-bound magnetic material, a fine magnetic powder of about 100 microns and a fine zeolite of about 100 microns are used depending on the purpose in a ratio of 1: 1 to 1:10 by weight, The weight ratio used is about 1: 1 to 1: 5. As used herein, the term "fine zeolite and micromagnetic material" refers to zeolites and magnetic materials having a diameter of 10 mm or less, and preferably a diameter of 100 microns or less. In addition, a binding agent for binding them and a solvent for dissolving the same are used. The mixing ratio of the binding agent is 10% to 50% based on the combined amount of the magnetic material and the zeolite, but the mixing ratio that is commonly used is about 20 to 30%. As for the solvent, it is preferable to use the minimum amount which a binding agent can fully melt | dissolve. When the mixing ratio of the binding agent is less than 10%, the binding strength of the zeolite and the magnetic body is very weak, so that the zeolite may be desorbed when used, and if it exceeds 50%, the content of the zeolite contained in the finished zeolite binding magnetic body is too low. It becomes difficult to manufacture to the following sizes.

Zeolites have affinity for ammonium ions and have the ability to adsorb or bind ammonium ions through ion exchange.

Magnetic materials include, but are not limited to, magnetite or iron powder, for example.

The solvent used to prepare the zeolite-bound magnetic material may include a polar solvent such as water, toluene or hexane, or a nonpolar solvent depending on the binding agent, and the binding agent may include a water-soluble or oil-soluble urethane as a synthetic resin, and may be used to disperse particles. Dispersants may also be used, in which case nonionic surfactants are included, but are not limited to these.

The mixture consisting of a mixture of fine zeolite and magnetic material powder, a binder, a solvent and a dispersant is first formed into a plate or particle shape so that the solvent can be easily pulverized in a subsequent grinding process before the solvent is volatilized and solidified. The primary moldings are again ground to fine powder of 100 microns or less in the mill, and water may be added in the process to absorb frictional heat.

When the zeolite-bound magnetic adsorbent of the present invention is mixed with water containing ammonium ions to be treated, the ammonium ions are bonded to the zeolite within a few minutes. And then regenerated. It is very preferable to use the brine most commonly used for the regeneration method. If the zeolite-bound magnetic adsorbent used is in contact with brine during regeneration, ammonium ions are separated from the zeolite-bound magnetic adsorbent within minutes and discharged, and the regeneration of the magnetic adsorbent is completed.

A method of removing ammonium ions in water by using a zeolite-bound magnetic adsorbent is a method of directly recovering and reusing and reusing the magnet by injecting it directly into water such as the wastewater to be treated and mixing for an appropriate time (see FIG. 2A), It is also possible to circulate through the regeneration tank after a fixed time in the waste water tank to be fixed to the magnet (see Fig. 2b).

As exemplified above, the ammonium ion removal method in water using the zeolite-bound magnetic adsorbent according to the present invention combines a magnetic material with a zeolite having high affinity for ammonium ions, and then mixes it with water contaminated with ammonium ions. By transferring ammonium ions from the water to the zeolite-bound magnetic adsorbent, and then recovering the zeolite-bound magnetic adsorbent enriched with ammonium ions to an external magnetic field and regenerating it for use. Therefore, the ammonium ion removal method in water using a zeolite-bound magnetic adsorbent enables the removal of ammonium ions without separate chemicals, pH adjustment, and thermal energy input. The process is very simple and the processing cost is much lower than other methods. Can be.

Hereinafter, the present invention will be described in more detail with reference to the following examples, but it should be understood that the scope of the present invention is not limited thereto.

<Example>

In order to confirm the effect on the method of the present invention, a particulate zeolite having an apparent diameter distribution of 1.4 to 2.3 millimeters, a fine zeolite having an apparent diameter of about 75 micrometers, and a zeolite-bound magnetic adsorbent prepared by the method of the present invention were used. Ammonium ion removal experiments were performed in aqueous solution.

Zeolite bonded magnetic adsorbent was prepared as follows. The particle size of the zeolite used was 75 microns, and the magnetic material used magnetite having a particle size of about 1 micron. As binding agent, water-soluble polyurethane (RS 835) was used, and the mixing ratio of zeolite, magnetic material and binding agent was 1: 1: 1, 1: 1: 2, 1 to confirm proper mixing ratio of binding agent. : 1: 3, 2: 1: 1, 2: 2: 1, 5: 1: 1, 5: 3: 1, 5: 5: 1 and uniformly mixed with water as a solvent, followed by drying and grinding It was used after the process. After grinding, the size of the zeolite-bound magnetic adsorbent was confirmed by electron microscopy, and the apparent diameter was distributed between about 80 microns and 1 millimeter. Water was added only to the extent that the binding agent could be uniformly mixed with the zeolite and the magnetic body. In the zeolite-bound magnetic adsorbent prepared as described above, when the mixing ratio was 1: 1: 2, it took much time for grinding, and when the mixing ratio was 5: 5: 1, the attached zeolite and the magnetic substance were detached. On the other hand, the zeolite-bound magnetic adsorbent prepared at a 5: 1: 1 mixing ratio, which has the lowest mixing ratio of the magnetic material, has no problem in separating into a magnet.

In the following ammonium ion adsorption experiment, a zeolite-bound magnetic adsorbent prepared by using a mixing ratio of 1: 1: 1 was used.

<Example 1>

After ammonium chloride was dissolved in distilled water so that the nitrogen concentration in ammonium ions was 90 mg / l, adsorption and desorption experiments were performed by mixing granular zeolite and zeolite-bound magnetic adsorbent at a concentration of 2 g per liter, respectively.

As a result, in the case of the granular zeolite, the time required for the 50% reduction in the nitrogen concentration in the ammonium ion was 2 hours, whereas in the case of the zeolite-coupled magnetic adsorbent, it took about 30 seconds. In addition, as a result of using 30% brine in the desorption experiment for regeneration, the granular zeolite took 4 hours from room temperature to complete desorption, but in the case of zeolite-bound magnetic adsorbent, complete desorption was achieved in about 3 minutes at room temperature.

<Example 2>

As a result of the adsorption and desorption experiments performed for 10 minutes by injecting a granular zeolite and a zeolite-bound magnetic adsorbent at a concentration of 100 g per liter into a leachate having a nitrogen concentration of 550 mg / l in ammonium ions, In the case of zeolite-bound magnetic adsorbents, adsorption proceeded about 85% at 10 minutes and desorption proceeded completely.

<Example 3>

After 10 minutes of mixing a desorbent having a nitrogen concentration of 550 mg / l and a zeolite-bound magnetic adsorbent and regenerating it for 10 minutes with 30% brine, the zeolite-bound magnetic regenerated during this period was repeated 15 times. The performance of the adsorbent did not change.

<Example 4>

1 liter of water and 50 g of fine zeolite and zeolite-bound magnetic adsorbent were added to each of the two Erlenmeyer flasks, and the mixture was sufficiently mixed, and the standing state of the fine zeolite was observed. Did.

In contrast, the zeolite-coupled magnetic adsorbent could be quickly separated from the water by attaching it directly to the magnet in the container and then taking it out or by installing a magnet on the outer wall of the container to collect on the inner wall of the container, and the remaining filtrate was kept clear. It has been shown that the whey bonded magnetic adsorbent can be recovered quickly and very easily.

As described in detail above, since the removal process of ammonium ions in water using the zeolite-bound magnetic adsorbent of the present invention and the regeneration process of the zeolite-bound magnetic adsorbent used are performed within a few minutes, the circulation cycle is short, so that a large amount of wastewater can be treated. In addition, it is very economical to remove ammonium ions in water because it is unnecessary to add oxygen, supply carbon source, and adjust pH and temperature required by other methods. This effect can also be applied to the removal of other cations contained in water due to the cation exchange capacity, which is a general property of zeolites.

Claims (9)

An adsorbent for removing ammonium ions in water having a particle size of 100 microns or less in which zeolite is physically bonded to a magnetic material using a binding agent. The adsorbent of claim 1 wherein the zeolite and magnetic material have a size of 100 microns or less. The adsorbent according to claim 1, wherein the mixing ratio of the magnetic material and the zeolite is 1: 1 to 10: 1. The adsorbent according to claim 1, wherein the magnetic material is magnetite or iron oxide. Adding a solvent, a binding agent and a dispersant to the mixture of zeolite and magnetic material and mixing to prepare a mixture in which the magnetic material is physically bound to the zeolite; and After drying the mixture, grinding the particle size of the mixture to 100 microns or less Method for producing a zeolite bonded magnetic adsorbent comprising a. The method of claim 5 wherein the binding agent is 10% to 50% mixed based on the amount of the zeolite mixed with the magnetic material. The method of claim 6, wherein the surfactant is further mixed with the mixture of zeolite and magnetic material. Mixing the zeolite-bound magnetic adsorbent of claim 1 with water contaminated with ammonium ions to bind ammonium ions with the zeolite-bound magnetic adsorbent, and then separating the zeolite-bound magnetic adsorbent from water using magnetic force; Method for removing ammonium ions from The method of claim 8, further comprising a workup step of separating ammonium ions from the adsorbent.

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