KR102206636B1 - metal oxide catalyst with Sulphur doping for removal of Sulphur mustard and preparation method thereof - Google Patents

Abstract

The present invention is a blister comprising the step of applying a catalyst for oxidation and removal of a blistering agent consisting of a sulfur-doped metal oxide, a method of preparing a catalyst for oxidation and removal of a blistering agent, and a catalyst for removing the oxidation of the blistering agent to the blistering agent The present invention relates to a method for removing oxidation of an agent, and to provide a catalyst with improved oxidation and removal efficiency of a blistering agent.

Description

Metal oxide catalyst with sulfur doping for removal of sulfur mustard and preparation method thereof

The present invention is a blister comprising the step of applying a catalyst for oxidation and removal of a blistering agent consisting of a sulfur-doped metal oxide, a method of preparing a catalyst for oxidation and removal of a blistering agent, and a catalyst for removing the oxidation of the blistering agent to the blistering agent It relates to a method for removing oxidation of an agent.

Chemical Warfare Agents refer to chemical substances in a gaseous, liquid, or solid state used to exert a direct toxic effect on humans, animals and plants. Chemical agents can be broadly classified into blister agents and nerve agents. The most representative of the blistering agents is the mustard-based gas (Sulphur mustard; Bis(2-chloroethyl)sulfide).

Sulfur contained in sulfur mustard separates chlorine gas, becomes a very reactive reactive group, and directly attacks proteins or DNA to show toxicity (FIG. 1).

Since the actual catalytic performance test cannot handle the actual agonist, the blister agonist, most studies measure the catalytic performance of CEES (2-Chloroethyl ethyl sulfide) as a similar agonist, a kind of pesticide that can be handled in a general laboratory. CEES has a molecular structure similar to that of mustard gas, but has a difference in that a methyl group (-CH ₃ ) is attached to one end, not a chlorine group (-Cl).

There are largely adsorption removal and decomposition removal as methods of removing mustard gas, and hydrolysis and oxidative decomposition using a catalyst are used for decomposition removal. Activated carbon is mainly used for adsorption and removal. Specifically, the hydrolysis method during decomposition and removal proceeds by spraying water on the contaminated area with a blister agent. Both methods have been well known since ancient times.

On the other hand, the oxidative decomposition method is a field that has been studied relatively recently, and various metal oxide catalysts for the purpose of oxidative decomposition and removal are being studied. Specifically, the oxidative decomposition method uses oxygen in the air or uses reduced oxygen species including peroxo species to bind oxygen atoms to the sulfur (S) element located in the center of the CEES molecular structure, sulfone).

Adsorption removal has a disadvantage in that materials that have been adsorbed can be easily desorbed under high temperature and high humidity conditions and a short lifespan. In addition, the existing oxidation removal catalysts have low performance as catalysts for chemical agent removal reactions, so they have not yet been used for decomposing and removing blistering agents in the actual field. In addition, as a method of removing the chemical agent, there is a method of removing it by chemical reaction using a catalyst for combustion reaction (Patent Document KR 10-1997-0010497 B1), but the chemical agent may exist in an untreated state due to incomplete combustion. , Toxic substances may be released to the outside in the form of gases during incineration, and when a hydrolyzate-generated decomposition substance is embedded, the decomposition substance contains halogen or acidic substances and a large amount of salt, which can be the main cause of environmental pollution. There is a problem.

Accordingly, the present inventors have studied to improve the performance of the metal oxide catalyst for oxidation and removal of CEES, which is a similar agent of mustard gas, and as a result, the present invention has been completed.

KR 10-1997-0010497 B1

One object of the present invention is to provide a catalyst for oxidation and removal of a blistering agent comprising a sulfur-doped metal oxide.

Another object of the present invention is a first step of providing a solution containing a metal precursor solution and sulfur ions; A second step of stirring after adding a reducing agent to the solution; A third step of drying the solution to obtain a precipitate; And a fourth step of sintering the precipitate to provide a method of preparing a catalyst for oxidation and removal of a blistering agent.

Another object of the present invention is to provide a method for deoxidation of a blistering agent comprising the step of applying a catalyst for oxidation removal of a blistering agent comprising a sulfur-doped metal oxide to the blistering agent.

The inventors of the present invention have studied to improve the problem of low performance of the existing catalyst for removing blistering agents. Therefore, based on the fact that the catalytic performance increases when sulfur element is added to the oxide by facilitating electron transfer, a metal oxide catalyst in which sulfur is supported on metal oxides known to be capable of oxidative decomposition of a blister agent was devised. , It was confirmed that the oxidative decomposition effect of the blistering agent was increased using the successfully synthesized catalysts.

This will be described in detail as follows. Meanwhile, each description and embodiment disclosed in the present invention can be applied to each other description and embodiment. That is, all combinations of various elements disclosed in the present invention belong to the scope of the present invention. In addition, it cannot be seen that the scope of the present invention is limited by the specific description described below.

As an aspect of the present invention for solving the above problems, the present invention provides a catalyst for oxidation and removal of a blistering agent comprising a sulfur-doped metal oxide.

The term "blistering agent" used in the present invention is an agent that is absorbed through the respiratory tract, digestive tract, or through the skin to induce severe pain, inflammation and blisters in the skin, eyes, and mucous membranes, thereby destroying body tissues, typically, mustard (mustard) It can be a series. In the present application, the blistering agent of the "must series" may be represented by the following formula, specifically, sulfur mustard (bis(2-chloroethyl) sulfide) or nitrogen mustard, and CEES (2-Chloroethyl ethyl sulfide). have.

A[(CH ₂ ) _n X] _a [(CH ₂ ) _n CH ₃ ] _b

At this time, A may be any one selected from N, O, S, X is a halogen element, n is an integer of 1 to 6, a is an integer of 1 to 3, b may be an integer of 0 to 2. .

In the catalyst for oxidation and removal of the blistering agent constituting the doped metal oxide of the present invention, the metal oxide may be specifically selected from the group including Fe, Ti, Cu, Zn, Zr, and Al, but is limited thereto. no.

The molar ratio of the metal atom and the sulfur atom in the catalyst for oxidation and removal of the blister agent of the present invention may be 4: 1 to 1: 4, specifically 3: 1 to 1: 3 or 2: 1 to 1: 2 May be, more specifically 1:1, and the moles of sulfur atoms may be less than the moles of metal atoms, but are not limited thereto.

The reaction in which the blistering agent is removed in the catalyst of the present invention may be by adsorption removal or oxidation removal. Specifically, the oxidation-removal reaction may be due to the mechanism of FIG. 2.

At this time, the adsorption removal has the disadvantage that the adsorbed materials can be easily desorbed under high temperature and humid conditions, and the lifespan is short, and the removal by combustion reaction may exist in a state where the chemical agent is not treated by incomplete combustion. However, there is a problem in that toxic substances can be released to the outside in the form of gases during incineration, which can become the main cause of environmental pollution, whereas the reaction in which the blistering agent is removed by oxidation and removal in the catalyst of the present invention is the toxicity of the blistering agent. It has the advantage of being able to semi-permanently and eco-friendly removal.

Specifically, it is possible to prevent the sulfur atom in the molecular center from being oxidized to separate chlorine gas. At this time, the process of primary oxidation to CEESO in the CEES oxidation reaction is a difficult step due to high activation energy, and the process of oxidation from CEESO to CEESO ₂ is known as an easy step due to low activation energy. That is, CEES oxidation removal reaction is an irreversible reaction in which CEES is oxidized to CEESO as soon as it is secondary oxidized to CEESO ₂ .

GC analysis can be used to measure the CEES removal rate of the catalyst of the present invention, but the degree of oxidation of S in the middle of the molecule, that is, the CEESO ₂ signal, can be measured using NMR to measure the CEES removal rate by oxidation removal. In this case, in the case of preparing a CEES solution to measure the CEES removal rate, a polar solution or a non-polar solution may be used, but under a polar solution, the Cl at the CEES terminal may be substituted by a nucleophilic substitution, so a non-polar solution It could be more clearly confirmed that the oxidation removal efficiency of the present invention was increased through the CEES removal rate of the sulfur-doped catalyst measured higher under.

It was confirmed that the sulfur-doped catalyst of the present invention has a significantly higher oxidation removal rate of CEES compared to other catalysts not doped with sulfur, which gives the effect of increasing catalytic performance when sulfur is added to the oxide, and facilitates electron transfer. This suggests that it is due to the properties of the sulfur element.

In the present invention, a method of doping sulfur on a metal oxide may be prepared by a precipitation method, an impregnation method, or a mixing method, but is not limited thereto. Specifically, it can be prepared by sufficiently mixing a metal precursor solution and a solution containing sulfur ions.

As another aspect of the present invention for solving the above problems, the present invention is a first step of providing a solution containing a metal precursor solution and sulfur ions; A second step of stirring after adding a reducing agent to the solution; A third step of drying the solution to obtain a precipitate; And it provides a method for producing a catalyst for oxidation and removal of the blister agent comprising a fourth step of sintering the precipitate.

The metal in the first step of providing the metal precursor solution according to the present invention may be selected from the group including Fe, Ti, Cu, Zn, Zr, and Al, but is not limited thereto.

The reducing agent used in the second step of the manufacturing method of the present invention includes formic acid (HCOOH), oxalic acid (C ₂ H ₂ O ₄ ), and lithium aluminum hydride (LiAlH ₄ ). It may be selected from the group, but is not limited thereto.

In the present invention, a metal oxide having a porosity can be obtained by appropriately adjusting the reduction rate, and the specific surface area of the metal oxide after reduction of the present invention may be 30 m ² /g to 200 m ² /g, specifically 35 m ^{It may be 2} / g to 180 m ² /g, more specifically 40 m ² /g to 150 m ² /g, but is not limited thereto. At this time, specifically, when the specific surface area of the metal oxide after reduction is measured using the BET method, the specific surface area must be 30 m ² /g to 200 m ² /g to increase the active point, so that the oxidation decomposition reaction occurs easily. A metal oxide having porosity can be obtained, and when it exceeds 200 m ² /g, it is difficult to obtain a metal oxide having porosity by a practical method due to a difference in synthesis method.

In the third step of the manufacturing method of the present invention, the solution may be vacuum-dried to obtain a precipitate, and in this case, the temperature may be 50°C to 90°C, specifically, 60°C to 80°C, and more specifically May be 70 °C.

In the fourth step of the manufacturing method of the present invention, the dried sample may be subjected to a sintering process to control the size and dispersion of the active metal through heat treatment. At this time, if the temperature of the sintering process is too high, there may be a disadvantage of reducing the specific surface area of the metal oxide, so the sintering process is a gas atmosphere containing nitrogen and oxygen when considering the conversion rate and energy efficiency for nitrogen oxide. At 200 ℃ to 400 ℃ can be performed for 1 hour to 5 hours, specifically 250 ℃ to 350 ℃ can be performed, more specifically, the sintering process can be performed at 300 ℃, but is limited thereto no.

The present invention may include a catalyst prepared by the method for preparing a catalyst for oxidation removal of a blister agent of the present invention.

As yet another aspect of the present invention for solving the above problems, the present invention is to remove the oxidation of the blister agent comprising the step of applying a catalyst for oxidation removal of the blister agent comprising a sulfur-doped metal oxide to the blister agent. Provides a way.

In the method for removing oxidation of the blistering agent of the present invention, descriptions of "a blistering agent", "metal oxide", and "catalyst for removing the oxidation of blistering agent" are as described above.

The method for removing oxidation of the blister agent of the present invention may be applied in the presence of a polar solvent or in air, but is not limited thereto.

The catalyst of the present invention exhibits the effect of increasing the removal rate of the blister agent compared to the existing catalyst for removing blister agents that are not doped with sulfur. In particular, it is possible to provide a catalyst that effectively oxidizes and removes the blister agent by activating the oxidation decomposition reaction of CEES. I can.

1 is a schematic diagram of a mechanism in which sulfur contained in sulfur mustard separates chlorine gas, becomes a reactive reactive group, and directly attacks proteins or DNA.
Figure 2 is a schematic diagram of the mechanism of the reaction by oxidation and removal of CEES.
3 shows the synthesized metal oxides.
Figure 4 shows an overall experimental schematic diagram of the CEES removal performance test method in a solution.
5 is a result of comparing the removal rate of CEES methanol solution using FID-GC.
6 is a result of comparing the oxidation decomposition rate of a CEES methanol solution using ¹ H NMR.
7 is a result of comparing the removal rate of CEES decane solution using FID-GC.
8 shows a schematic diagram of an experiment and comparison results for measuring the removal rate and oxidative decomposition rate of a CEES stock solution using GC and NMR.

Example: Synthesis of Metal Oxide

Example 1: Synthesis of sulfur-containing zinc oxide (MS-Zn)

0.02 mol (5.751 g) of ZnSO ₄ .7H ₂ O and 0.01 mol (2.489 g) of Na ₂ S ₂ O ₄ .5H ₂ O were prepared, and then added to distilled water to prepare a 50 mL solution.

After preparing 0.02 mol (2.5227 g) of C ₂ H ₂ O ₄ .2H ₂ O (oxalic acid), it was added to distilled water to prepare a 50 mL solution.

The prepared two solutions were mixed and stirred in a stirrer for 1 hour, and then vacuum-dried at 70°C. At this time, a greenish white precipitate was formed, and the precipitate was sintered at 300°C for 1 hour to synthesize a white powdery zinc oxide containing sulfur (hereinafter referred to as MS-Zn). The specific surface area of the synthesized zinc oxide was 43 m ² /g.

Comparative Example 1: Synthesis of zinc oxide (M-Zn)

After preparing 0.02 mol (5.751 g) of ZnSO ₄ .7H ₂ O, it was added to distilled water to prepare a 50 mL solution.

After preparing 0.02 mol (2.5227 g) of C ₂ H ₂ O ₄ .2H ₂ O (oxalic acid), it was added to distilled water to prepare a 50 mL solution.

The prepared two solutions were stirred in a stirrer for 1 hour and then vacuum-dried at 70°C. At this time, a white precipitate was formed, and the precipitate was sintered at 300° C. for 1 hour to synthesize a white powder of zinc oxide (hereinafter referred to as M-Zn).

Comparative Example 2: Synthesis of copper oxide (M-Cu)

After preparing 0.02 mol (4.832 g) of Cu(NO ₃ ) ₄ .3H ₂ O, it was added to distilled water to prepare a 50 mL solution.

C ₂ H ₂ O ₄ .2H ₂ O (oxalic acid) 0.02 mole (2.5227 gram) was prepared, and then added to distilled water to prepare a 50 mL solution.

The prepared two solutions were mixed and stirred in a stirrer for 1 hour, and then vacuum-dried at 70°C. At this time, a blue precipitate was formed, and the precipitate was sintered at 300° C. for 1 hour to synthesize a black powdery copper oxide (hereinafter referred to as M-Cu).

Comparative Example 3: Synthesis of copper oxide containing sulfur

0.02 mol (4.832 g) of Cu(NO ₃ ) ₄ .3H ₂ O and 0.01 mol (2.489 g) of Na ₂ S ₂ O ₄ .5H ₂ O were prepared, and then added to distilled water to prepare a 50 mL solution. At this time, copper ions and thiosulfate (thiosulfate: S ₂ O ₃ ^2- ) ions were combined to form a precipitate.

After preparing 0.02 mol (2.5227 g) of C ₂ H ₂ O ₄ .2H ₂ O (oxalic acid), it was added to distilled water to prepare a 50 mL solution.

When the copper-sulfur bond is present in an ionic form, the desired compound can be obtained by mixing with oxalic acid thereafter, but the two prepared solutions could not be mixed due to the formed precipitate, so that the desired compound could not be obtained.

A photograph of the metal oxide powder synthesized by the above method is shown in FIG. 3.

Comparative Example 4: Titanium Oxide (TiO ₂ , Preparation of titania)

A commercially available titanium oxide (TiO ₂ , titania) with known activity was prepared. As a commercial titania, DT-51 powder from Cristal was used.

Experimental example: CEES removal rate comparison

Experimental Example 1: Comparison of CEES removal rates of metal oxides in the presence of a polar solvent

Among the metal oxides synthesized in the above example, the CEES removal rate was compared using Example 1 and Comparative Examples 1 to 4 except for Comparative Example 3 in which synthesis was not performed.

Since CEES is a non-polar molecule, hydrolysis occurs when it comes into contact with water, but CEES itself is not soluble in water. Therefore, since an aqueous solution of CEES cannot be made, a solution of CEES was prepared using methanol, which is a relatively less polar solvent . The concentration of the solution was 0.122 M. Several vials containing 1 mL of CEES methanol solution were prepared, and 20 mg of a metal oxide catalyst was added to each vial, and the vials were sealed using a lid. While stirring the metal oxide and solution in the solution using a stirrer, open the vial at 1, 3, 6, and 24 hours, take out a very small sample of about several uL with a syringe and pass it through the filter, and then use FID-GC for 24 hours. The degree of decrease in CEES during was measured (FIG. 4).

Figure 5 shows the CEES removal performance results using GC. Through this, it can be seen that zinc oxides (M-Zn, MS-Zn) are superior to copper oxide or commercial titanium oxide in CEES removal rate. CEES removal using metal oxides is generally applied at the same time as adsorption removal and oxidation removal. By GC analysis, only the degree to which CEES decreases is known, and it is unclear how much of it is adsorption removal and what is oxidation removal. Therefore, in order to compare only the degree of oxidation removal, the degree of oxidation of S in the middle of the molecule, that is, the CEESO ₂ signal, should be compared using NMR. Accordingly, the same experiment was repeated using ¹ H NMR. For the NMR sample retake, CEES and CEESO ₂ were collected in the solution using CD ₃ OD at each time (FIG. 6).

Referring to FIG. 6, a tendency similar to that of the CEES removal rate of FIG. 5 is shown in general. In the case of zinc oxide, it was confirmed that the oxidative decomposition rate of MS-Zn mixed with sulfur was much higher than that of M-Zn not mixed with sulfur.

Experimental Example 2: Comparison of CEES removal rates of metal oxides in the presence of a non-polar solvent

Since methanol itself used as a solvent is slightly polar, CEES in methanol solution may be modified by replacing Cl at the end of the molecule through nucleophilic substitution. In addition, there is a possibility of hydrolysis by reacting with water molecules dissolved in methanol. To block this effect, a CEES solution was prepared using decane, a non-polar solvent having a lower polarity than methanol. A 0.122 M concentration of CEES solution was prepared using decane, and the CEES removal rate was compared in the same manner as the methanol solution. Fig. 7 shows the comparison result of CEES removal rate using FID-GC for the decane solution. 0.2M of dodecane was used as an internal reference material for the GC measurement of the decane solution.

It was confirmed through FIG. 7 that the overall CEES removal rate was lower in the methanol solution. This is interpreted as a phenomenon that appeared because the nucleophilic substitution reaction and hydrolysis reaction of the methanol solution mentioned above were removed. When comparing the removal rate between each metal oxide, the removal rate of zinc oxide was still higher than that of other metal oxides. In the comparison between zinc oxides, the removal rate of MS-Zn mixed with sulfur was higher than that of M-Zn, which is believed to be due to the excellent oxidation removal ability of MS-Zn.

Experimental Example 3: Measurement of CEES removal rate and oxidative decomposition rate in the absence of a solvent

After confirming that zinc oxide exhibits excellent CEES removal performance, experiments using CEES stock solutions for two types of metal oxides M-Zn and MS-Zn were performed as follows in order to completely exclude the effect of the solvent. First, 8 aluminum substrates with a size of 2 cm x 2 cm are prepared, and then 20 mg of each zinc oxide is coated on the substrate in a slurry form. Then, it is baked in an oven at 80 degrees Celsius for 5 hours to remove moisture. Each of the prepared aluminum substrates is placed on a saale, and 0.2 g of CEES undiluted solution is dropped, and then each saale is sealed using a plastic wrap. Thereafter, every 1, 3, 6, and 24 hours elapsed, open the prepared chalet, immerse the substrate in 1 mL methanol, and shake to extract the remaining CEES and oxidative decomposition products. This extract was measured by GC and NMR in the same manner as above, and the removal rate and oxidative decomposition rate were compared. 8 shows the experimental method and measurement results.

As can be seen in Figure 8, the stock solution removal rate was much faster than when in the solution. It is believed that this was due to simultaneous hydrolysis due to moisture in the air. When removing the effect of the common hydrolysis and looking at the removal rate and the oxidation decomposition rate by the catalyst, the removal rates were similar for the two metal oxides (Fig. 8 left). However, the oxidation removal rate was generally higher in the case of MS-Zn than that of M-Zn (Fig. 8 right). As a result, it was found that when sulfur is mixed, the ability of metal oxides to oxidatively decompose CEES increases.

Claims (11)

Containing a sulfur-doped metal oxide,
The molar ratio of the metal atom and the sulfur atom is 4:1 to 1:4, thereby forming an oxygen species reduced by electron transfer by the sulfur atom,
The reduced oxygen species reacts with nitrogen or sulfur atoms in the blistering agent to bind at least one oxygen to the nitrogen or sulfur atom in the blistering agent, catalyst for oxidation and removal of the blistering agent.
The catalyst according to claim 1, wherein the metal oxide is selected from the group containing Fe, Ti, Cu, Zn, Zr and Al.
The catalyst according to claim 1, wherein the blistering agent is a mustard-based agent.
The catalyst according to claim 2, wherein the metal oxide is zinc oxide (MS-Zn) containing sulfur.
The catalyst according to claim 1, wherein the specific surface area of the metal oxide is 30 to 200 m ² /g.
A first step of providing a solution containing a metal precursor solution and sulfur ions;
A second step of stirring after adding a reducing agent to the solution;
A third step of drying the solution to obtain a precipitate; And
A method for producing a catalyst for oxidation and removal of a blistering agent comprising a fourth step of sintering the precipitate.
The method of claim 6, wherein the metal is selected from the group comprising Fe, Ti, Cu, Zn, Zr and Al.
The method of claim 6, wherein the sintering in the fourth step is performed at 200°C to 400°C.
The method of claim 6, wherein the reducing agent in the second step comprises oxalic acid (C ₂ H ₂ O ₄ ), formic acid (HCOOH), and lithium aluminum hydride (LiAlH ₄ ). That is selected from the group, the manufacturing method.
A method for removing oxidation of a blistering agent, comprising the step of applying the catalyst for oxidation removal of the blistering agent according to any one of claims 1 to 9 to the blistering agent.
11. The method of claim 10, wherein the blistering agent is applied in the presence of a polar solvent or in air.

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