KR102255659B1 - Nanoparticles containing iron-manganese oxide, composition for adsortioning heavy metal comprising the same, and method for manufacturing the same - Google Patents

Abstract

The present specification discloses iron-manganese oxide-containing nanoparticles, a composition for adsorbing heavy metals including the same, and a method of preparing the nanoparticles. The iron-manganese oxide-containing nanoparticles, which are an aspect of the present invention, have excellent heavy metal adsorption efficiency and excellent oxidizing power, so that a large amount of heavy metals present in the soil can be removed even if only a small amount is used. In addition, the method of manufacturing the nanoparticles, which is an aspect of the present invention, can manufacture the nanoparticles with a high yield, and can manufacture nanoparticles having uniform performance in large quantities.

Description

Iron-manganese oxide-containing nanoparticles, a composition for adsorbing heavy metals containing the same, and a method of manufacturing nanoparticles {NANOPARTICLES CONTAINING IRON-MANGANESE OXIDE, COMPOSITION FOR ADSORTIONING HEAVY METAL COMPRISING THE SAME, AND METHOD FOR MANUFACTURING THE SAME}

The present specification discloses iron-manganese oxide-containing nanoparticles, a composition for adsorbing heavy metals including the same, and a method of preparing the nanoparticles.

Heavy metal refers to a heavy metal element having a specific gravity of 4 or more, such as arsenic, antimony, lead, mercury, cadmium, chromium, tin, zinc, barium, bismuth, and nickel. Most of heavy metals are introduced into the soil through human activities such as resource development and disposal, urbanization and industrialization, and are exposed to humans through paths such as animals, plants and groundwater. When heavy metals enter the body, they accumulate and are not well discharged, and even a small amount damages the central nervous system, cardiovascular system, reproductive organs, and hematological systems, causing serious diseases in the human body.

As a method of restoring soil contaminated with heavy metals, a soil washing method using acid to wash the soil, a purification treatment method using subcritical water, and the like are used.

The soil washing method is a method of extracting and separating heavy metals by washing the soil with a strong acidic solution such as hydrochloric acid. Due to the advantage of reducing the volume of contaminated soil and being able to reuse the soil after treatment, it is evaluated as a relatively common purification method. However, this method is expensive and requires a large-scale water treatment facility such as neutralization and coagulation and precipitation at the rear stage, so it is not only uneconomical but also non-environmental.

The purification treatment method using subcritical water refers to a method of extracting and separating heavy metals from contaminated soil by heating the inside of a reaction vessel into which contaminated soil is put into a state of subcritical water by heating the inside of the reaction vessel into a state of subcritical water. This method has the advantage of being applicable even in cases where it is difficult to purify with a general pickling method because heavy metals and soil particles are strongly combined, such as an organic material-coupled type and a mineral grid-coupled type, among the combined types of heavy metals and soil. However, since it is necessary to maintain a state of high temperature and high pressure, not only the treatment unit cost is high, but also the continuous treatment of contaminated soil is not possible, and since only batch type is possible, large-scale contaminated soil cannot be quickly processed.

In addition, Korean Patent No. 10-1586686 proposes a water treatment method using iron hydroxide substituted with manganese, but it is pointed out that the effect is insignificant compared to the existing heavy metal treatment method, and it is difficult to apply it to the soil environment.

Therefore, there is an urgent need for a simple and effective method of removing heavy metals from soil.

KR 10-1586686 B1

In one aspect, the object of the present invention is to remove heavy metals in soil simply and efficiently.

In one aspect, an object of the present invention is to provide nanoparticles having excellent heavy metal adsorption and oxidation power.

In one aspect, an object of the present invention is to prepare iron-manganese oxide-containing nanoparticles within a short time.

In one aspect, an object of the present invention is to prepare iron-manganese oxide-containing nanoparticles in high yield.

In order to achieve the above object, the present invention in one aspect, i) a specific surface area of ^{130 ~ 150m 2 /g,}

ii) an average pore diameter of 18 to 26 nm, and iii) ^{an average porosity of 0.001 to 0.01 cm 3} /g to provide iron-manganese oxide-containing nanoparticles.

In addition, the present invention provides a method for producing iron-manganese oxide-containing nanoparticles, including the step of mixing iron hydrate and manganese hydrate in the same aspect as described above.

The iron-manganese oxide-containing nanoparticles, which are an aspect of the present invention, have excellent heavy metal adsorption efficiency and excellent oxidizing power, so that a large amount of heavy metals present in the soil can be removed even if only a small amount is used. In addition, the method of manufacturing the nanoparticles, which is an aspect of the present invention, can manufacture the nanoparticles with a high yield, and can manufacture nanoparticles having uniform performance in large quantities.

1 is a diagram showing the results of X-ray diffraction analysis.
2 is a diagram showing the results of X-ray fluorescence analysis.
3 is a BET analysis result based on the US ASTM test method D3663.
4 is a diagram showing the results of TEM-EDS analysis (4a:100nm, 4b:50nm, 4c:20nm, 4d:10nm).
5 is a diagram showing a result of a heavy metal adsorption force test.

Hereinafter, each configuration will be described in more detail, but this is only an example, and the scope of the present invention is not limited by the following content.

In one aspect, the present invention is a manganese hydrate containing nanoparticles, wherein the iron-manganese oxide containing nanoparticles are iron-manganese oxide containing nanoparticles comprising the following characteristics:

i) a specific surface area of ^{130-150 m 2 /g;} ii) an average pore diameter of 18-26 nm; And iii) an average porosity of ^{0.001-0.01 cm 3 /g.}

In one aspect. The specific surface area may include a specific surface area measured by a Brunauer, Emmet, Teller (BET) method.

The specific surface area may be 130 to 150 m ² /g, preferably 135 to 140 m ² /g, more preferably 135 to 145 m ² /g, or more preferably 138 to 145 m ² /g.

In addition, the average pore diameter of the particles may be 18 ~ 26nm. The average pore diameter may mean an average value of diameters measured at two arbitrary points, excluding the shortest axis and the longest axis of an arbitrary pore present in an arbitrary particle. The average pore diameter of the particles may be 18 to 26 nm, or 19 to 24 nm, or 20 to 24 nm or 21 to 23 nm.

In addition, the average porosity may be 0.001 to 0.01cm ³ /g, or 0.003 to 0.01cm ³ /g, or 0.004 to 0.08cm ³ /g, and in one embodiment may be 0.006cm ³ /g.

In addition, the average diameter of the nanoparticles may be 25 to 50 nm. The average diameter may mean an average value of diameters measured at two arbitrary points, excluding the shortest axis and the longest axis of any nanoparticles. For example, the average diameter of the nanoparticles may be 25 to 50 nm, or 30 to 50 nm, or 30 to 50 nm, or 35 to 50 nm, or 38 to 50 nm, or 38 to 45 nm.

When the nanoparticles satisfy the above conditions, the most maximized heavy metal adsorption power and heavy metal oxidation power may be exhibited.

The iron-manganese oxide-containing nanoparticles may contain manganese oxide (MnO) and iron oxide III (Fe ₂ O ₃ ) in a molar ratio of 18 to 25: 82 to 75, preferably 18 to 23: 82 to 77, more preferably 20 to 23: 80 to 77, more preferably 20 to 22: may be included in a molar ratio of 80 to 78, and in one embodiment may be included in a ratio of 21.7: 77.3.

The molecular formula of the iron-manganese oxide-containing nanoparticles may be _{MnFe 2} O _4.

In one aspect, the present invention is a heavy metal adsorption composition comprising the iron-manganese oxide-containing nanoparticles.

In one embodiment, the composition may be for adsorption in a medium pole in the soil.

The heavy metal may include one or more of arsenic, lead, chromium, and copper, but is not limited thereto.

In addition, in one aspect, the present invention is a method of manufacturing iron-manganese oxide-containing nanoparticles, the method comprising mixing iron hydrate and manganese hydrate, iron-manganese oxide-containing nanoparticles.

In the above aspect, the mixing may include a first mixing step of mixing iron hydrate and metal hydroxide; And a second mixing step of mixing manganese hydrate with the mixture of iron hydrate and metal hydroxide. And a third mixing step of mixing hydrogen peroxide and metal hydroxide with the mixture of iron hydrate, metal hydroxide and manganese hydrate.

In the mixing step, in the iron hydrate and manganese hydrate used, the molar ratio of the iron of the iron hydrate and the metal of the manganese hydrate may be about 1:4-7, preferably 1:4-6.

In addition, the volume ratio of the iron hydrate and manganese hydrate may be 1:0.3-7, preferably, 1:0.4 ~ 0.6.

In addition, the pH of the mixture of the iron hydrate and the metal hydroxide may be 10 to 13.

The metal hydroxide may include at least one selected from the group consisting of sodium hydroxide, potassium hydroxide, calcium hydroxide, magnesium hydroxide, and iron hydroxide, but is not limited thereto.

In one embodiment, the metal hydroxide may be sodium hydroxide.

In one embodiment, the manufacturing method is as follows:

To 1 L of iron hydrate FeCl ₂ 4H ₂ O, add about 5 to 8 mL of a 1M NaOH solution to adjust the pH of the solution to 10 to 13, stir magnetically for about 20 to 40 minutes, and then add manganese hydrate MnCl ₂ 4H ₂ O can be magnetically stirred for about 15-25 minutes by adding 0.4~0.6L. After that, after _{adding 0.4 to 0.6 L of a 6% H 2} O ₂ and NaOH mixed solution, magnetic stirring may be performed for about 5 to 15 minutes. Thereafter, the supernatant may be separated, and the remaining precipitate may be washed with distilled water and then freeze-dried to obtain.

Hereinafter, the present invention will be described in more detail based on Preparation Examples, Examples and Experimental Examples, but the scope of the present invention is not limited thereto.

[Preparation Example] Preparation of iron-manganese-containing nanoparticles

_{FeCl 2} ·4H ₂ O was used as an iron oxide reagent _{, and MnCl 2} ·4H ₂ O was used as a manganese hydrate reagent. The molar ratio of iron and manganese was set to 1: 5 (the molar concentration of iron was prepared as 0.02 M and the molar concentration of manganese was set to 0.1 M), and 1 L of iron and manganese hydrate synthesis solution was prepared and used in the experiment. I did. Specifically, about 6.5 mL of a 1 M NaOH solution was added to 1 L of an iron oxide solution, and the pH of the solution was adjusted to a range of 10 to 13, and the reaction was performed by magnetic stirring for 30 minutes. Then, 500 mL of a manganese hydrate solution was added to the solution, followed by magnetic stirring for 20 minutes. After that, _{500 mL of a 6% H 2} O ₂ and NaOH solution was further added and magnetically stirred for 10 minutes, the supernatant of the solution was separated, and the remaining precipitate was washed 3 times with distilled water and freeze-dried. , To obtain nanoparticles.

The obtained nanoparticles were subjected to X-ray diffraction analysis (XRD). X-ray diffraction analysis was performed using a Rigaku Miniflex II under the conditions of Cu target, scan section 2~60˚, scan speed 2˚/min, 0.02˚/step, and 1 second per step. As a result, the nanoparticles were analyzed as ferrite-based iron-manganese oxide called _{MnFe 2} O _{4 (FIG. 1 ).}

In addition, as a result of X-ray fluorescence analysis (XRF) using ZSX Primus ± manufactured by Rigaku, it was found that 21.7% of MnO _{and 77.3% of Fe 2} O ₃ were contained in the particles (FIG. 2 ).

In addition, as a result of BET analysis with BELSORP's MINI-±, based on the US ASTM test method D3663, the BET surface area of the particles is 142.20 m 2 /g, the average pore size is 22 nm, the average porosity is 0.006 cm 3 /g, The average size of the particles was 42 nm (Fig. 3).

In addition, as a result of TEM-EDS analysis on the particles, it was possible to confirm the shape of an angular polygonal or spherical particle (Fig. 4).

[Experimental Example 1] Heavy metal adsorption test

The experiment on the adsorption capacity of nanomaterials to heavy metals was carried out using a nanomaterial turbid solution prior to lyophilization. After mixing the nanomaterial turbid solution and contaminated water in a 50 mL Palcon Tube, the mixture was stirred for 1 hour. Then, after separating the precipitate and the supernatant using a centrifuge, the supernatant was taken and pretreated, followed by ICP analysis. Cases 1 and 5 were used for the QA/QC of the device as a control group, and for Cases 2, 3, and 4, the amount of heavy metal adsorption before/after application of nanomaterials compared to the contamination concentration of each experimental group was confirmed.

Case 1
(Control) Case 2 Case 3 Case 4 Case 5
(Control) Pollution concentration
(mg/L) 0 5 10 15 20 Nano substance input amount (mL) 50 37.5 25 12.5 0 Artificial contaminated water input amount (mL) 0 12.5 25 37.5 50

As a result, it showed excellent adsorption power for lead, arsenic, chromium, and copper, but low adsorption power for zinc and nickel (FIG. 5).

Claims (10)

As iron-manganese oxide-containing nanoparticles,
The iron-manganese oxide-containing nanoparticles are for adsorption of heavy metals,
The iron-manganese oxide-containing nanoparticles, including the following features, iron-manganese oxide-containing nanoparticles:
i) a specific surface area of ^{135-150 m 2 /g;}
ii) an average pore diameter of 19-26 nm; And
iii) Average porosity of ^{0.003-0.01cm 3 /g.} The method of claim 1,
The iron-manganese oxide-containing nanoparticles have an average diameter of 35 to 50 nm, iron-manganese oxide-containing nanoparticles. The method of claim 1.
The iron-manganese oxide-containing nanoparticles,
Iron-manganese oxide-containing nanoparticles containing manganese oxide (MnO) and iron oxide III (Fe ₂ O _{3) in a molar ratio of 18-25: 82-75.} Claims 1 to 3, comprising the iron-manganese oxide-containing nanoparticles of any one of, heavy metal adsorption composition. The method of claim 4,
The composition is for adsorption of heavy metals in soil, a composition for adsorption of heavy metals. The method of claim 4,
The heavy metal, containing at least one of arsenic, lead, chromium and copper, heavy metal adsorption composition. The method for producing iron-manganese oxide-containing nanoparticles of any one of claims 1 to 3,
The above method,
A method for producing iron-manganese oxide-containing nanoparticles comprising the step of mixing iron hydrate and manganese hydrate. The method of claim 7,
The mixing step,
A first mixing step of mixing iron hydrate and metal hydroxide; And
A second mixing step of mixing manganese hydrate with the mixture of iron hydrate and metal hydroxide; And
A method for producing iron-manganese oxide-containing nanoparticles comprising a third mixing step of mixing hydrogen peroxide and metal hydroxide in the mixture of iron hydrate, metal hydroxide and manganese hydrate. The method of claim 8,
The pH of the mixture of the iron hydrate and the metal hydroxide is 10 to 13, the method for producing iron-manganese oxide-containing nanoparticles. The method of claim 8,
The metal hydroxide,
A method for producing iron-manganese oxide-containing nanoparticles comprising at least one selected from the group consisting of sodium hydroxide, potassium hydroxide, calcium hydroxide, magnesium hydroxide and iron hydroxide.

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