KR101653382B1 - Manufacuring method of complex adsorbent for ammonia removal - Google Patents

Abstract

The present invention relates to a manufacturing method of a complex adsorbent with excellent ammonia adsorbability for ammonia removal, which generates iron oxyhydroxide (FeOOH) via a neutralization reaction between an iron-based compound and an ammonia-based neutralizing agent by titrating the iron-based compound with the ammonia-based neutralizing agent in the presence of powdered active carbon, and which uniformly distributes the iron oxyhydroxide (FeOOH) on the surface and pores of the powdered active carbon. According to the present invention, the manufacturing method of a complex adsorbent for ammonia removal comprises the following steps: mixing an iron-based compound and distilled water in a weight ratio of 3:1 to generate an iron-based compound solution, adding powdered active carbon to the iron-based compound solution, and performing an agitation process to uniformly infiltrating the iron-based compound solution into the surface and pores of the powdered active carbon; performing titration with an ammonia-based neutralizing agent so that the pH of the iron-based compound solution mixed with the powdered active carbon becomes 4.5-7, thereby generating iron oxyhydroxide (FeOOH) into the pores of the powdered active carbon via a neutralization reaction between the iron-based compound and the ammonia-based neutralizing agent; and removing a residual solution in the case of completing the neutralization reaction between the iron-based compound and the ammonia-based neutralizing agent, and performing washing and drying processes. The ammonia-based neutralizing agent is ammonium carbonate ((NH4)2CO3) or ammonia bicarbonate.

Description

[0001] The present invention relates to a method for producing a complex adsorbent for ammonia removal,

The present invention relates to a process for producing iron oxide, which is obtained by titrating an iron-based compound with an ammonia-based neutralizing agent in the presence of powdered activated carbon to uniformly distribute oxyhydroxide (FeOOH) produced by the neutralization reaction between an iron-based compound and an ammonia- And a method for producing a composite adsorbent for removing ammonia having an ammonia adsorption capability.

Fertilizer raw materials, petrochemical, electronic industry, textile industry and so on. With the development of industry, domestic consumption of ammonia is continuously increasing. In addition to fertilizers, ammonia is widely used in chemical industries such as synthetic fibers such as caprolactam and acrylonitrile monomer, refrigeration, soda industry, and ammonium bicarbonate manufacture, as well as fertilizer, in addition to sulfuric acid and phosphoric acid.

On the other hand, anaerobic digestion of solid organic wastes is increasing as a problem of landfill shortage, atmospheric release of landfill gas, saturation of landfill, etc. Anaerobic digestion liquor is generally subjected to a biological treatment process using nitrification denitrification , Huge amount of ammonia was required to remove microorganisms, and huge wind power was needed to prevent the self-sufficiency of the sewage treatment plant.

Ammonia, like hydrogen, is an eco-friendly feature that does not emit greenhouse gases. It is easier to store and transport than hydrogen because of its ease of liquefaction at low pressures. It also has a high energy density comparable to that of methanol . By utilizing the characteristic of ammonia, ammonia discharged into the atmosphere is recovered and applied to the nitrogen oxide removal process, thereby separating the wastewater containing high concentration ammonia into ammonia and liquid wastewater, thereby reducing the ammonia contained in the wastewater in the liquid phase .

Generally, ammonia is stripped without pretreatment of solid matter such as livestock wastewater or nitrate-containing digestion liquor from biogasification process, and ammonia gas of high purity is recovered through absorption-desorption reaction.

Accordingly, although activated carbon or zeolite is usually used to recover ammonia by adsorption / desorption, there is a problem that the use time is shortened due to the limit of the adsorption capacity, so that development of another vapor adsorbent capable of compensating for this is required

A problem to be solved by the present invention is to titrate an iron-based compound with an ammonia-based neutralizing agent in the presence of powdered activated carbon, thereby producing iron oxyhydroxide (FeOOH) generated by the neutralization reaction between the iron-based compound and the ammonia- And uniformly distributing the ammonia adsorbed on the adsorbent.

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A method for producing a composite adsorbent for removing ammonia according to the present invention is characterized in that powdery activated carbon is added to a solution of an iron compound produced by mixing an iron compound and distilled water at a weight ratio of 3: Uniformly impregnating the compound solution; (FeOOH) is produced by neutralizing an iron-based compound with an ammonia-based neutralizing agent in pores of powdered activated carbon by titrating an ammonia-based neutralizing agent so that the pH of the iron-based compound solution mixed with powdered activated carbon becomes 4.5 to 7; (NH ₄ ) ₂ CO ₃ ) or ammonia bicarbonate, after the neutralization reaction of the iron-based compound and the ammonia-based neutralizing agent is completed.

Preferably, the iron-based compound is at least one selected from Fe (NO ₃ ) ₃ .9H ₂ O, FeCl ₃ .6H ₂ O, FeCl ₂ .6H ₂ O and FeSO ₄ .7H ₂ O.

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The complex adsorbent produced by the present invention is used as powdered activated carbon alone with powdered activated carbon because oxy iron hydroxide (FeOOH) produced by neutralization reaction of an iron-based compound with an ammonia-based neutralizing agent is evenly distributed on the surface and pores of powdered activated carbon The ammonia adsorption performance is remarkably improved.

1 is a graph showing particle size distribution and size of an adsorbent for removing ammonia according to the present invention.
2 is a graph of a nitrogen adsorption / desorption isotherm of an embodiment according to the present invention.
FIG. 3A is a graph of ammonia temperature desorption (NH ₃ -TPD) analysis of an embodiment according to the present invention. FIG.
FIG. 3B is a graph showing the ammonia temperature desorption (NH ₃ -TPD) analysis of the comparative example.
FIG. 4 is a photograph of a reactor in an ammonia breakdown experiment. FIG.
5 is a graph of exhaust gas concentration / time for an embodiment according to the present invention.

The method for producing a composite adsorbent for removing ammonia according to the present invention comprises an iron-based compound dissolution step, a powdered activated carbon mixing step, an ammonia-based neutralization step, and a washing step.

≪ Iron-based compound dissolution step &

The iron-based compound is added to distilled water and stirred to be dissolved evenly. The iron-based compound is preferably Fe (NO ₃ ) ₃ .9H ₂ O, FeCl ₃ .6H ₂ O, FeCl ₂ .6H ₂ O, FeSO ₄ .7H ₂ O and the like. Further, it is preferable to mix the iron-based compound and distilled water at about 3: 1. When a large amount of distilled water is used, there is a problem that a large amount of ammonia-based neutralizing agent and a solution to be removed after the reaction are generated. On the other hand, the iron-based compound can also be used directly as a solution of an iron-based compound in a solution state.

≪ Powder Activated Carbon Mixing Process >

Powdered activated carbon is added to a solution in which the iron-based compound is dissolved and stirred to uniformly penetrate the iron-based compound solution into the pores of the powdered activated carbon. Preferably, the powdered activated carbon is 75 microns or less. Such powder activated carbon can distribute oxyhydroxide produced by the reaction of the iron-based compound with the ammonia-based neutralizing agent on the porous surface.

≪ Ammonia-based neutralization step &

(FeOOH) for use as an adsorbent by neutralization reaction of an iron-based compound with an ammonia-based neutralizing agent by titrating an ammonia-based neutralizing agent to a solution of an iron-based compound mixed with powdered activated carbon at a pH of about 4.5 to 7. At this time, the generated oxy iron hydroxide is uniformly formed in the pore of the powdered activated carbon, and the intergranular particles are spread by the powder activated carbon, so that it is formed as a composite adsorbent for removing ammonia together with powdered activated carbon. At this time, the particle size of the composite adsorbent produced increases as the pH of the ammonia-based neutralizer is optimized.

Ammonia-based neutralizing agent is preferably used in an ammonium carbonate _{((NH 4) 2 CO 3} ), bicarbonate, ammonia, aqueous ammonia or the like.

<Cleaning Process>

When the neutralization reaction between the iron-based compound and the ammonia-based neutralizing agent is completed, the solution is removed, washed with distilled water and dried to prepare a composite adsorbent.

Hereinafter, the present invention will be described in more detail with reference to Examples and Test Examples. However, the scope of the present invention is not limited by these examples and test examples.

<Examples>

90 g of Fe (NO ₃ ) ₃ 9H ₂ O (98%) as an iron-based compound was added to 30 g of distilled water and dissolved by stirring for 3 hours. 10 g of powdered activated carbon (iodine adsorption capacity 1,600 mg / g, 75 microns) And stirred evenly. Thereafter, the solution was titrated to pH 7 using a 1 M solution of ammonium carbonate ((NH ₄ ) ₂ CO ₃ ) (30%) as a neutralizing agent. After completion of titration, the remaining solids were separated using a centrifuge, washed several times with distilled water, and dried at 110 ° C to prepare a composite adsorbent.

<Physical and chemical characterization of composite adsorbent>

The specific surface area, pore size, and pore volume were measured in order to examine the physical and chemical properties of the composite adsorbent prepared in the examples. The particle size was shown in FIG. 1, and the nitrogen adsorption / desorption isotherm was shown in FIG. 2 Respectively.

Specific surface area (m ² / g) Average pore size
Pore Size (nm) Pore volume
V _total (cm ³ / g) Medieval Study P V _meso (cm ³ / g) Microcircuit
V _Micro (cm ³ / g) 724.75 28.1423 0.509 0.228 0.281

Example composite adsorbent also carried out as shown in Fig. 1 it can be seen that having a small particle of 20.95㎛ at D _50. As shown in FIG. 2, the adsorption isotherms of type I and intermediate type I and II are shown in the results of nitrogen adsorption isotherms. The isothermal adsorption curves of type I and type II intermediates are shown in Fig.

<Ammonia Temperature Deposition (NH ₃ -TPD) Analysis>

Ammonia temperature desorption (NH ₃ -TPD) analysis was performed to confirm the ammonia adsorption performance of the composite adsorbent prepared in the examples, and the results are shown in the graphs of Table 2 and FIG. As a comparative example, NH ₃ -TPD analysis of the powdered activated carbon used as the components of the examples was carried out and shown in the graphs of Table 3 and FIG. 3B. The temperature elevation desorption experiments were carried out in the range of 0 ~ 600 ℃, and the total peak area shows the acidity of the adsorbent.

Example Start time
(sec) End time
(sec) Time width
(sec) Peak position
(sec) Area
(count) Output
mmol / g Primary peak 943 3,146 2,203 2,044 7.76E + 08 2.286 Secondary peak 3,185 5,080 1,895 4,132 1.6E + 08 0.472

Comparative Example Start time
(sec) End time
(sec) Time width
(sec) Peak position
(sec) Area
(count) Output
mmol / g Primary peak 3,097 5,393 2,296 4,245 2.25E + 07 0.077

As shown in Table 2 and FIG. 3A, the composite adsorbent of the example had ammonia measured at 943 seconds (about 120 DEG C) and gradually increased to about 1,150,000 (uV) while forming a first peak point at 2044 seconds And then decreased. Thereafter, it rapidly decreased again after about 300,000 (uV) while forming 2 peak points at 4,132 seconds (about 570 ° C). It was confirmed that the total amount of acid in the examples was 2.758 mmol / g.

On the other hand, the adsorbent of the comparative example decreased after detecting about 48,000 (uV) while forming a peak point at 4,245 seconds (about 580 DEG C) as shown in Table 3 and FIG. 3B. The total amount of acid in the comparative example was 0.077 mmol / g.

As described above, it can be confirmed that the complex adsorbent of the present invention has a remarkably excellent acid amount as compared with the case of using powdered activated carbon singly, and is superior as an ammonia adsorbent.

<Ammonia Breakout Experiment>

4, the composite adsorbent prepared in Example 4 was filled in a cylindrical reactor as shown in FIG. 4, 5% ammonia gas was injected at 200 ml / min at the lower end, and gas discharged to the upper end was measured every 3.5 minutes through gas chromatography. The measured exhaust gas values are shown in the concentration / time graph of FIG. 5 in terms of concentration, and the breakthrough point, end point, and ammonia gas adsorption amount are shown in Table 4.

Breakthrough point Adsorption (g) Breakthrough point - end point adsorption amount (g) Total adsorption (g) 0.0796875 0.257819 0.337507 Breakthrough point adsorption (wt%) Breakthrough point - end point adsorption amount (wt%) Total adsorption (wt%) 1.593750 5.156387 6.750137

As shown in FIG. 5, the composite adsorbent of the example adsorbed all the ammonia gas for 10.5 minutes, and ammonia gas was not detected in the exhaust gas. After 94.5 minutes, 5% ammonia gas was discharged. That is, the breakthrough point, which is the initial point at which ammonia gas was detected in the exhaust gas, was 10.5 minutes, and the end point, at which all the ammonia gas was discharged, was 94.5 minutes.

The amount of ammonia gas adsorption up to the breakthrough point (10.5 minutes) and the amount of ammonia gas adsorption up to the end point (94.5 minutes) after the breakthrough point were calculated and found to be slightly higher than the total adsorption rate similar to NH ₃ -TPD analysis I could.

Claims (8)

delete delete delete Mixing the iron-based compound and distilled water at a weight ratio of 3: 1, adding powdered activated carbon to the resulting solution of the iron-based compound, and stirring the solution to uniformly penetrate the iron-based compound solution into the surface and pores of the powdered activated carbon;
(FeOOH) is produced by neutralizing an iron-based compound and an ammonia-based neutralizing agent in the pores of the powdered activated carbon by titrating an ammonia-based neutralizing agent so that the pH of the iron-based compound solution mixed with the powdered activated carbon becomes 4.5 to 7;
And removing the solution, washing and drying after completion of the neutralization reaction of the iron-based compound and the ammonia-based neutralizing agent,
Ammonia-based neutralizing agent is ammonium carbonate _{((NH 4) 2 CO 3} ) or a method of producing a composite sorbent for ammonia removal, characterized in that ammonium bicarbonate.
The method according to claim 4, the iron compound is _{Fe (NO 3) 3 · 9H} 2 O, FeCl 3 · 6H 2 O, FeCl 2 · 6H 2 O, FeSO 4 · remove ammonia, characterized in that at least one selected from among 7H ₂ O for A method for producing a composite adsorbent. delete delete delete

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