KR20220001235A - Adsorbent based on metal-carbon to remove gaseous hydrogen chloride and manufacturing method for the same - Google Patents

Abstract

The present invention relates to a metal-carbon composite adsorbent for hydrogen chloride gas removal, comprising: transition metal sulfides; and a metal-carbon composite adsorbent for removing hydrogen chloride gas including carbon nitride having a polymer structure. The present invention has an excellent adsorption effect despite the relatively low surface area and pore volume through the chemical reaction between the transition metal and the acid gas.

Description

Metal-carbon composite adsorbent for removing hydrogen chloride gas and manufacturing method thereof

The present invention relates to a metal-carbon composite adsorbent for removing hydrogen chloride gas and a method for manufacturing the same, and more particularly, to a metal-carbon composite for removing hydrogen chloride gas having excellent chemical adsorption effect through a composite structure in which a transition metal sulfide and carbon nitride are combined. It relates to a composite adsorbent and a method for manufacturing the same.

Adsorption techniques are widely used to remove gases such as hydrogen chloride. For example, Korean Patent Registration No. 10-1521247 discloses a technology for adsorbing hydrogen chloride with a carrier containing sodium carbonate.

Such adsorbents generally require a large specific surface area in order to increase the contact area with the gas containing hydrogen chloride.

For example, Korean Patent Registration No. 10-2000389 discloses a cadmium adsorbent with azinate bead bonded to a disulfide polymer. In this case, an adsorbent with a specific surface area above a certain level is manufactured in the form of beads using a thiocyaturic acid solution. However, an adsorbent that effectively enhances the adsorption effect by strengthening the chemical reaction between the actual adsorbent surface and hydrogen chloride and a method for manufacturing the same have not yet been developed. situation is not

Accordingly, the problem to be solved by the present invention relates to an adsorbent having improved adsorption and removal efficiency by increasing a chemical reaction with a gas to be removed, and a method for manufacturing the same.

In order to solve the above problems, the present invention provides a metal-carbon composite adsorbent for removing hydrogen chloride gas, a transition metal sulfide; And it provides a metal-carbon composite adsorbent for removing hydrogen chloride gas containing carbon nitride having a polymer structure.

In one embodiment of the present invention, the carbon nitride includes a thiol group, and the transition metal sulfide is formed according to a covalent bond between the transition metal and the thiol group of the carbon nitride.

In an embodiment of the present invention, the covalent bond between the thiol group between the transition metal and the carbon nitride is formed by simultaneously sintering the transition metal and the carbon nitride.

In one embodiment of the present invention, the carbon nitride has a polymerized triazine structure.

In an embodiment of the present invention, the carbon nitride is trithiocyanuric acid (TCA), and the transition metal is copper or silver.

In one embodiment of the present invention, when the transition metal is copper, _{a transition metal compound having a formula of Cu x} S (1≤x≤3) is dominant, and when the transition metal is silver, the formula of _{Ag 2 S is} Transition metal compounds with

The present invention also provides a method for producing the above-described metal-carbon composite adsorbent for removing hydrogen chloride gas, the method comprising: mixing a transition metal precursor and a carbon nitride containing a thiol group with water; and sintering the mixed transition metal precursor and the carbon nitride at a high temperature, wherein in the sintering, the transition metal and the thiol group form a covalent bond to form a transition metal sulfide.

In one embodiment of the present invention, the carbon nitride has a polymerized triazine structure.

In an embodiment of the present invention, the carbon nitride is trithiocyanuric acid (TCA), and the transition metal is copper or silver.

In one embodiment of the present invention, when the transition metal is copper, a transition metal compound having a formula of _{Cu x S (1≤x≤3) is dominant.}

In an embodiment of the present invention, when the transition metal is silver, a transition metal compound having a chemical formula of _{Ag 2 S is dominant.}

The adsorbent according to the present invention has a structure in which a transition metal is stably bound to the adsorbent even in the high-temperature calcination process, and has significantly higher adsorption capacity (1.72 to 5.47 mmol hydrogen chloride/g adsorbent) than activated carbon (0.1 to 0.33 mmol hydrogen chloride/g adsorbent), which is a general-purpose adsorbent. has In particular, through the chemical reaction between the transition metal and the acid gas, the adsorption effect is excellent despite the relatively low surface area and pore volume.

1 is a schematic diagram of the molecular structure of a transition metal sulfide of an adsorbent according to an embodiment of the present invention.
2 and 3 are SEM images of the compounds prepared according to the above examples using copper and silver as transition metals, respectively. In FIGS. 2 and 3, X=0 means TCA-H ₂ O crystals to which a transition metal is not added.
4 is an XRD pattern of a TCA-Cu (or Ag)-x (x=0, 0.1, 1, 3) transition metal compound.
5 is an FT-IR spectrum of a TCA-Cu (or Ag)-x (x=0, 0.1, 1, 3) transition metal compound.
6 is a predicted structure of transition metal sulfide-carbon nitride TCA-Cu (or Ag)-x-550 (x=0, 0.1, 1, 3), and FIG. 7 is TCA-Cu (or Ag)-x-550 (x=0, 0.1, 1, 3) It is a photograph comparing the color of the powder before and after firing the transition metal compound.
8 is an XPS survey scan and high-resolution Cu 2p spectrum of transition metal sulfide carbon nitride TCA-Cu (or Ag)-x-550 (x=0, 0.1, 1, 3).
9 and 10 are XRD patterns and FT-IR spectra of transition metal sulfide-carbon nitride TCA-Cu (or Ag)-x-550 (x=0, 0.1, 1, 3).
11 and 12 are SEM images of TCA-Ag-x (x=0, 0.1, 1, 3) transition metal compound before firing, respectively, transition metal sulfide-carbon nitride TCA-Cu (or Ag)-x-550 after firing SEM image of (x=0, 0.1, 1, 3).
13 is a thermal analysis result of TCA-M (M=Cu, Ag) transition metal compound.
14 and 15 are results of a breakthrough experiment _{of Cl 2 and HCl gas.}

Hereinafter, a preferred embodiment of a metal-carbon composite adsorbent for removing hydrogen chloride gas and a method for manufacturing the same according to the present invention will be described in detail with reference to the accompanying drawings. For reference, the terms and words used in the present specification and claims are not to be construed as being limited to conventional or dictionary meanings, and the inventor must properly understand the concept of the term in order to best describe his invention. Based on the principle that it can be defined, it should be interpreted as meaning and concept consistent with the technical idea of the present invention. In addition, the configurations shown in the embodiments and drawings described in this specification are only the most preferred embodiment of the present invention, and do not represent all of the technical spirit of the present invention, so at the time of the present application, various It should be understood that there may be equivalents and variations.

In order to solve the above problems, the present invention provides a metal-carbon composite adsorbent for removing hydrogen chloride gas including a transition metal sulfide-carbon nitride composite.

1 is a schematic diagram of the molecular structure of a transition metal sulfide in an adsorbent according to an embodiment of the present invention.

Referring to FIG. 1 , copper, which is a transition metal according to an embodiment of the present invention, has a strong covalent bond with a thiol group of trithiocyanuric acid (TCA). That is, the present invention mixes a carbon nitride having a triazine structure containing a transition metal and a thiol group, and strongly bonds the thiol group of the carbon nitride with the transition metal so that the transition metal is stably covalently bonded to the thiol group of TCA even after high-temperature sintering. Implementation of an adsorbent having a transition metal sulfide-carbon nitride composite structure.

The present invention will be described in more detail through the following Examples and Experimental Examples.

Example

After completely dissolving TCA (0.7 g) in DMSO (dimethyl sulfoxide, 10 ml), the transition metal precursor (copper nitrate, silver nitrate) is dissolved in water (20 ml) as shown in the table below to form a bond between TCA and the transition metal. A TCA-transition metal self-assembled structure was obtained.

_{As a comparative example, TCA-H 2} O crystals were prepared under the same conditions without adding a transition metal.

Then, an adsorbent was prepared by heating the prepared crystals to 550 degrees Celsius while flowing nitrogen gas using a tube furnace.

Experimental example

TCA-transition metal compound (TCA-M) analysis

2 and 3 are SEM images of the compounds prepared according to the above examples using copper and silver as transition metals, respectively. In FIGS. 2 and 3, X=0 means TCA-H ₂ O crystals to which a transition metal is not added.

_{2 and 3, TCA-H 2} O organic crystals labeled as TCA-Cu (or Ag)-0 are polygonal micro-particles having a size of about 1 to 10 μm. In this case, TCA molecules are aligned with a certain arrangement through hydrogen bonding with water molecules to form organic crystals.

^{When Cu 2+} or Ag ⁺ is present in water (in practice) upon addition of water, which causes precipitation of organic crystals, it competes with hydrogen bonds between thiol groups and water molecules to change the arrangement of _{TCA-H 2 O crystals.} At this time, when a strong covalent bond is formed between a metal ion and a thiol, a long range order does not occur, and as a result, Cu ²⁺ or Ag ⁺ As the content increases, the particle size continues to decrease to about 10 nm, which can be confirmed through the size change in FIGS. 2 and 3 .

4 is an XRD pattern of a TCA-Cu (or Ag)-x (x=0, 0.1, 1, 3) transition metal compound.

Referring to FIG. 4 , as the nanocrystals are formed by the transition metal, the peaks of the XRD pattern spread widely and the intensity decreases. In ^{the case of Cu 2+} , when TCA:Cu ²⁺ is 1:1, and in the case of Ag+, when TCA:Ag ⁺ is 1:3, it can be observed that the crystallinity rapidly decreases in the XRD pattern, Through this, ^{it can be expected that Cu 2+ forms about two covalent bonds and Ag +} forms about one covalent bond.

5 is an FT-IR spectrum of a TCA-Cu (or Ag)-x (x=0, 0.1, 1, 3) transition metal compound.

5, the case of Cu ²⁺ TCA: 1, the case of Ag ⁺ TCA:: The Cu ²⁺ Ag ⁺ 1

It can be seen that a peak of ^{1723 cm -1} occurs from 1:3, _{which can be matched to a metal ion complex (Cu 2} S or AgS), and Cu ²⁺ or Ag ⁺ in the complex compound TCA through coordination bonds. It means that it is well fixed to the surface. In addition, it can be seen that the aromatic thiol structure is well maintained from the peaks of ^{1215 cm -1} and 1450 cm- ¹ seen when TCA:Cu ²⁺ is 1:1 and when TCA:Ag ⁺ is 1:3. This suggests that, in the end, the transition metal ions strongly bond with the thiol group of carbon nitride, which has aromatic properties in a two-dimensional plane, to maintain the trithiol structure of TCA well.

Transition Metal Sulfide-Carbon Nitride Analysis

When TCA-H ₂ O organic crystals (x=0) are heated to 550 degrees Celsius for polycondensation, tri- s- triazine-based carbon nitride (or polymeric melon, CN) is formed. When transition metal ions coexist in the polycondensation process, thiols decomposed from TCA cause transition metal sulfide formation as a sulfur source. In the range of x=0 to 0.1, the formation of carbon nitride is not affected by the presence of a transition metal, but at this time, it is expected to form a transition metal compound-carbon nitride complex as shown in FIG. 6 .

6 is a predicted structure of transition metal sulfide-carbon nitride TCA-Cu (or Ag)-x-550 (x=0, 0.1, 1, 3), and FIG. 7 is TCA-Cu (or Ag)-x-550 (x=0, 0.1, 1, 3) It is a photograph comparing the color of the powder before and after firing the transition metal compound. Here, 550 means a firing temperature.

In particular, it can be seen in FIG. 7 that even with a trace amount of transition metal sulfide, the color of the composite powder is darkened due to the semiconductor properties of the transition metal compound having a lower band gap compared to carbon nitride, and this is because the transition metal sulfide is present in the carbon nitride. Forming a composite as shown in FIG. 6 is well described.

8 is an XPS survey scan and high-resolution Cu 2p spectrum of transition metal sulfide carbon nitride TCA-Cu (or Ag)-x-550 (x=0, 0.1, 1, 3).

^{Referring to FIG. 8 , the presence of Cu 2+} is all observed except for the case where x = 0, which means that the transition metal sulfide forms a complex with the carbon nitride as shown in FIG. 6 even if it is a trace metal. do.

However, when the content of the transition metal is more than the reference value, for example, when x≥1 or more, a different aspect is observed.

9 and 10 are XRD patterns and FT-IR spectra of transition metal sulfide-carbon nitride TCA-Cu (or Ag)-x-550 (x=0, 0.1, 1, 3).

Referring to FIG. 9, the peak due to graphitic stacking of the two-dimensional tri-s- triazine, seen at 27 degrees, is not observed, and instead, several strong peaks start to appear in the range of 5 to 60 degrees. Also, referring to FIG. 10, stretching vibration peaks due to the CN hetero ring are not observed in the range of ^{1100 to 1600 cm -1 .} It is expected that when x≥1, CN is no longer a mainstream material, and instead, the content of the transition metal compound becomes high, thereby preventing the polycondensation of carbon nitride.

11 and 12 are SEM images of TCA-Ag-x (x=0, 0.1, 1, 3) transition metal compound before firing, respectively, transition metal sulfide-carbon nitride TCA-Cu (or Ag)-x-550 after firing SEM image of (x=0, 0.1, 1, 3).

11 and 12, the formation of a crystalline material other than carbon nitride, which is an amorphous material, can be confirmed through an increase in the content of round nanoparticles (about <1 μm) than in the SEM image, which is also confirmed in FIG. 8 It is possible.

In addition, as the content of transition metal ions in the transition metal compound increased, it was confirmed that the mass of the material remaining after high-temperature sintering increased in proportion (refer to FIG. 13), through which the transition metal ions were heated through strong covalent bonding. It can be confirmed that it is not lost during the calcination process and is converted into a transition metal compound by participating in the reaction.

In addition, it was confirmed by the XRD result that when x=3, Cu _7.2 S ₄ (or Ag ₂ S) was formed (see FIG. 9 ). In the ^{case of Cu 2+} , copper sulfide having various compositions is formed at 1≤x≤3, and in the case of ^{Ag +} _{, Ag 2} S is mainly formed. Therefore, in the adsorbent according to the present invention, when the transition metal is copper, Cu _x S (1≤x≤3) is a dominant transition metal sulfur compound, and when the transition metal is silver, Ag ₂ S is a dominant sulfur compound. Herein, the term "dominant" means at least 70% or more of the compound of the corresponding formula among all the compounds.

adsorption effect

_{The breakthrough experiment of Cl 2} and HCl gas was conducted using the adsorbent transition metal sulfide-carbon nitride TCA-Cu (or Ag)-x-550 (x=0, 0.1, 1, 3) obtained after the calcination process according to the present invention. In the process, FIGS. 14 and 15 are results of breakthrough experiments _{of Cl 2 and HCl gas.}

14 and 15, as the transition metal sulfide content or the transition metal ion content in the transition metal compound increased, it was confirmed that a larger amount of HCl adsorption was possible, which was confirmed that HCl was converted to transition metal sulfide CuS _{y through the following reaction.} It can be explained in that it is possible to react with

aCuS _y + bHCl + cO ₂ <-> dCuCl ₂ + eH ₂ O + fS

Furthermore, since the carbon nitride in the complex has a lot of basic -NH _x - (x=1 or 2) on the surface, HCl can be adsorbed through an acid-base reaction.

15, when no transition metal is included (TCA-H ₂ 2-550), the adsorption amount of HCl was 1.72 mmol/g adsorbent level, but it can be seen that the adsorption amount increases as Cu increases to 0.1 and 1 mol. have. In particular, when the specific surface area is low (x=1), it can be seen that the surface area is low but the HCl adsorption amount is greatly increased (5.47 mmol HCl/g adsorbent). Considering that activated carbon, a commercial adsorbent, exhibits an adsorption capacity of about 0.1 to 0.5 mmol HCl/g adsorbent even when the performance is increased by a basic salt (NaOH, KOH), this means a very good value.

Claims (12)

A metal-carbon composite adsorbent for hydrogen chloride gas removal,
transition metal sulfides; and
A metal-carbon composite adsorbent for hydrogen chloride gas removal containing carbon nitride having a polymer structure. The method of claim 1,
The carbon nitride includes a thiol group,
A metal-carbon composite adsorbent for removing hydrogen chloride gas, characterized in that the transition metal sulfide is formed according to a covalent bond between the transition metal and the thiol group of the carbon nitride. 3. The method of claim 2,
A metal-carbon composite adsorbent for removing hydrogen chloride gas, characterized in that the covalent bond between the thiol group between the transition metal and the carbon nitride is formed by simultaneously sintering the transition metal and the carbon nitride. 3. The method of claim 2,
The carbon nitride is a metal-carbon composite adsorbent for removing hydrogen chloride gas, characterized in that it has a polymerized triazine structure. 5. The method of claim 4,
The carbon nitride is trithiocyanuric acid (TCA), and the transition metal is a metal-carbon composite adsorbent for removing hydrogen chloride gas, characterized in that copper or silver. 6. The method of claim 5,
When the transition metal is copper, a metal-carbon composite adsorbent for removing hydrogen chloride gas, characterized in that the transition metal compound having the formula of CuxS (1≤x≤3) is dominant. 6. The method of claim 5,
When the transition metal is silver, a metal-carbon composite adsorbent for removing hydrogen chloride gas, characterized in that the transition metal compound having a chemical formula of _{Ag 2 S is dominant.} The method for manufacturing a metal-carbon composite adsorbent for removing hydrogen chloride gas according to any one of claims 1 to 7,
mixing a transition metal precursor and a carbon nitride containing a thiol group with water; and
and sintering the mixed transition metal precursor and carbon nitride at a high temperature, wherein in the sintering step, the transition metal and the thiol group form a covalent bond to form a transition metal sulfide. Metal for removing hydrogen chloride gas - Manufacturing method of carbon composite adsorbent. 9. The method of claim 8,
The carbon nitride is a metal-carbon composite adsorbent manufacturing method for hydrogen chloride gas removal, characterized in that it has a polymerized triazine structure. 10. The method of claim 9,
The carbon nitride is trithiocyanuric acid (TCA), and the transition metal is copper or silver. 11. The method of claim 10,
When the transition metal is copper, a method for producing a metal-carbon composite adsorbent for hydrogen chloride gas removal, characterized in that the transition metal compound having the formula of _{Cu x S (1≤x≤3) is dominant.} 11. The method of claim 10,
When the transition metal is silver, a method for producing a metal-carbon composite adsorbent for removing hydrogen chloride gas, characterized in that the transition metal compound having a chemical formula of _{Ag 2 S is dominant.}

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