KR102270006B1 - Adsorbent for separation of carbon monoxide and preparation method thereof - Google Patents

Abstract

The present invention provides a method for preparing a carbon monoxide adsorbent, which comprises the steps of: preparing an aqueous solution containing a copper precursor; injecting an aqueous solution containing the copper precursor into a support; preparing an adsorbent precursor by drying the support in which the aqueous solution containing the copper precursor is injected; and heat-treating the adsorbent precursor. According to the present invention, there is provided a method for preparing an adsorbent having a simple synthesis method, excellent selectivity for carbon monoxide, and high performance for adsorbing carbon monoxide. In addition, there is provided a method for preparing an adsorbent having a high performance for absorbing carbon monoxide at a low preparation cost and without using harmful substances such as ammonia water or hydrochloric acid, as well as a carbon monoxide adsorbent according thereto.

Description

ADSORBENT FOR SEPARATION OF CARBON MONOXIDE AND PREPARATION METHOD THEREOF

The present invention relates to an adsorbent for separating carbon monoxide and a method for preparing the same.

Gases such as carbon monoxide (CO), carbon dioxide (CO ₂ ), and nitrogen (N ₂ ) are mixed in the by-product gas generated from steel mills and chemical plants, and to utilize this gas, through pressure swing adsorption (PSA), Carbon monoxide adsorbents are used in the process of separating carbon monoxide.

In general, in order to selectively separate and purify carbon monoxide, the adsorption performance of the adsorbent and the gas are different. Specifically, since the adsorption amount of carbon monoxide is high and the adsorption amount of other gases is low, carbon monoxide is adsorbed in the adsorbent and other gases are removed. In order to realize these characteristics well in the pressure swing adsorption process, it is important to synthesize an adsorbent having a relatively high carbon monoxide adsorption performance.

The conventionally known method for synthesizing an adsorbent for carbon monoxide separation is complicated and uses various chemicals. In addition, it is difficult to control synthesis parameters due to a complicated synthesis method, and thus, it is somewhat difficult to secure reproducibility for preparing an adsorbent having the same adsorption performance.

More specifically, in the prior art, a CuCl-based adsorbent has been used to separate carbon monoxide from a mixed gas. To synthesize CuCl-based adsorbent, CuCl chemicals are used, and since CuCl has low solubility in water, ammonia water or hydrochloric acid must be used. Also, after loading CuCl on a support, ammonia water or hydrochloric acid must be separated and removed. . At this time, wastewater is generated, and the treatment cost for this is also increased. On the other hand, when CuCl is mixed with ammonia water, there is a problem in that heat is generated and CuCl reagent is lost due to a very violent reaction, so there was a difficulty in preparing an adsorbent by well controlling synthesis parameters and conditions.

The present invention was devised in view of the above circumstances, and it is intended to provide a method for producing an adsorbent with a simple synthesis method, excellent selectivity to carbon monoxide, and high carbon monoxide adsorption performance, and an adsorbent produced by the method.

According to one aspect of the present invention, preparing an aqueous solution containing a copper precursor; injecting an aqueous solution containing the copper precursor into a support; preparing an adsorbent precursor by drying the support in which the aqueous solution containing the copper precursor is injected; And there is provided a method for producing a carbon monoxide adsorbent comprising the step of heat-treating the adsorbent precursor.

The solubility of the copper precursor in water at 0 to 100° C. may be 700 to 1,100 g/l.

The copper precursor may be copper chloride dihydrate.

The support may be at least one selected from alumina, zeolite, and silica.

The drying may be performed at a temperature range of 80 to 150° C. at normal pressure.

The heat treatment may be performed in a reducing atmosphere in a temperature range of 350 to 600 °C.

An atomic ratio of Cl to Cu on the surface of the adsorbent precursor (Cl/Cu) may be 1.2 to 2.5.

An atomic ratio of Cl to Cu on the surface of the carbon monoxide adsorbent (Cl/Cu) may be 0.8 to 1.2.

According to another aspect of the present invention, there is provided a carbon monoxide adsorbent prepared according to the manufacturing method.

The adsorbent precursor _{may be formed of CuCl 2} and a support.

The carbon monoxide adsorbent _{may be made of CuCl, CuCl 2} and a support or CuCl and a support.

According to the present invention, there is provided a method for producing an adsorbent having a simple synthesis method, excellent carbon monoxide selectivity, and high carbon monoxide adsorption performance. In addition, there is provided a method for producing an adsorbent having high carbon monoxide adsorption performance at a low manufacturing cost and without using harmful substances such as ammonia water or hydrochloric acid, and a carbon monoxide adsorbent according thereto.

1 is a photograph of a carbon monoxide adsorbent precursor (a) and a carbon monoxide adsorbent (b) according to an embodiment of the present invention.
Figure 2 shows the X-ray diffraction (XRD) analysis results of the carbon monoxide adsorbent precursor according to an embodiment of the present invention.
3 shows the results of thermogravimetric analysis (TGA) of the carbon monoxide adsorbent precursor according to an embodiment of the present invention.
4 shows the results of XRD analysis of the carbon monoxide adsorbent according to Examples 1 and 2 and Comparative Example 1 of the present invention.
5 shows the results of temperature-programmed reduction (TPR) analysis of the carbon monoxide adsorbent according to Example 1 (a), Example 2 (b) and Comparative Example 1 (c) of the present invention.
6 shows the results of an isothermal adsorption experiment of the carbon monoxide adsorbent according to Example 1 and Comparative Example 1 of the present invention.

Hereinafter, preferred embodiments of the present invention will be described with reference to various examples. However, the embodiment of the present invention may be modified in various other forms, and the scope of the present invention is not limited to the embodiments described below.

The present invention relates to an adsorbent for separating carbon monoxide and a method for preparing the same.

According to one aspect of the present invention, preparing an aqueous solution containing a copper precursor; injecting an aqueous solution containing the copper precursor into a support; preparing an adsorbent precursor by drying the support in which the aqueous solution containing the copper precursor is injected; And there is provided a method for producing a carbon monoxide adsorbent comprising the step of heat-treating the adsorbent precursor.

First, using water as a solvent, an aqueous solution containing a copper precursor is prepared. The copper precursor preferably has a solubility in water of 700 to 1,100 g/l at 0 to 100°C, and more preferably 706 to 1.079 g/l. Since solubility means the maximum amount of solute that can be dissolved in a certain amount of solvent at a constant temperature, the concentration of the copper precursor can be, for example, less than 1 g/l, but in this case, a large amount of water must be used and the synthesis As the equipment becomes large, the cost of synthesizing the adsorbent increases. If the solubility is more than 1,100 g/l, temperature and pressure conditions must be changed in order to further dissolve, which also requires additional equipment, which may increase the cost. Since the CuCl-based carbon monoxide adsorbent used in the prior art has a very low solubility of CuCl in water of 0.047 g/L, ammonia water or hydrochloric acid must be used. there was. In the present invention, a carbon monoxide adsorbent can be prepared by using water as a solvent and using a copper precursor having high solubility in water.

_{Copper chloride dihydrate (CuCl 2} ·2H ₂ O) can be used as such a copper precursor, and the copper chloride dihydrate is three times cheaper than CuCl, which is used as a raw material for conventional carbon monoxide adsorbents. There is an advantage that

Next, by impregnating the support in the aqueous solution containing the copper precursor, the step of impregnating the copper precursor on the support is performed. This step is not particularly limited, but is preferably performed by dry impregnation, that is, by injecting an aqueous solution containing a copper precursor into the support.

Meanwhile, the support may be, for example, at _{least one selected from alumina (Al 2} O ₃ ), zeolite, and silica. In addition, for the selective adsorption of carbon monoxide, ^{it is preferable to use a support having a specific surface area of 10 to 50 m 2} /g, and it is more preferable to use alumina.

Next, the step of preparing an adsorbent precursor by drying the support injected with the aqueous solution is performed. As described above, in the present invention, a dry impregnation method is used, and accordingly, since the amount of water is not large, a precursor may be synthesized using an atmospheric drying method instead of a vacuum drying method.

On the other hand, the drying is preferably performed in a temperature range of 80 to 150 ℃. If it is less than 80 ℃, the drying time may be long, and if it is more than 150 ℃, it may not be easy to control the Cl/Cu ratio when high heat is applied in the air.

In addition, it is preferable that the atomic ratio of Cl to Cu on the surface of the adsorbent precursor (Cl/Cu) is 1.2 to 2.5. If it is less than 1.2, CuCl should be used as a precursor, but the concentration is low and it is difficult to apply the manufacturing method proposed in the present invention. If it is more than 2.5, the Cl/Cu ratio is high and the Cl/Cu atomic ratio is not controlled close to 1 through heat treatment. There is a problem.

Furthermore, the adsorbent precursor _{may be made of CuCl 2} and a support, and the carbon monoxide adsorbent prepared by heat treatment to be described later may be made of CuCl, CuCl ₂ and a support or CuCl and a support.

Finally, the adsorbent precursor is heat-treated to prepare a carbon monoxide adsorbent. The heat treatment is preferably performed in a reducing atmosphere, and for this purpose, it is preferable to create a reducing atmosphere by introducing at least one reducing gas selected from nitrogen, argon, helium, hydrogen and carbon monoxide in the heat treatment apparatus.

The heat treatment is preferably performed in a temperature range of 350 to 600 ℃. When the temperature is less than 350°C, the Cl/Cu ratio is high and thus the desired CuCl structure is not synthesized. When the temperature exceeds 600°C, the overall adsorption amount decreases due to a decrease in specific surface area due to excessive heat treatment, and the adsorbent performance may be deteriorated.

Meanwhile, the atomic ratio of Cl to Cu on the surface of the carbon monoxide adsorbent (Cl/Cu) may be 0.8 to 1.2, preferably 0.9 to 1.1. If it is less than 0.8, carbon monoxide may not be selectively adsorbed because the Cl ratio is small, and even if it is more than 1.2, it may not be synthesized into a CuCl structure in which carbon monoxide can be adsorbed well, so selective carbon monoxide adsorption may not be made.

As described above, the manufacturing method of the present invention has a simple synthesis step compared to the conventional synthesis method of carbon monoxide adsorbent, can significantly reduce the amount of waste liquid generated, and reduces the cost of synthesizing the adsorbent by using a low-cost copper precursor. You can save a lot.

Hereinafter, the present invention will be described in more detail through specific examples. The following examples are merely examples to help the understanding of the present invention, and the scope of the present invention is not limited thereto.

Example

Example 1

After preparing an aqueous solution by injecting _{CuCl 2} ·2H ₂ Og into 350 mL of distilled water _{, heat-treated Al 2} O ₃ balls are prepared as a support, and the aqueous solution is _{injected into Al 2} O ₃ balls little by little to be absorbed into the support. , impregnated.

After all aqueous solutions were injected, the precursor was synthesized by drying in an oven at normal pressure and 120° C., and heat treatment was performed at 500° C. in an _{N 2 atmosphere to synthesize a carbon monoxide adsorbent.}

Example 2

A carbon monoxide adsorbent was synthesized in the same manner as in Example 1 except for heat treatment at 350°C.

Comparative Example 1

A solution in which 18.72 g of glucose as a reducing agent was injected into 300 mL of aqueous ammonia was prepared. The solution was mounted on a rotary distillation concentrator and rotated at 30° C. for 1 hour to dissolve, then 76.73 g of CuCl capable of adsorbing CO was injected, and the same was installed in a distillation concentrator and rotated at 30° C. for 2 hours to dissolve. .

Thereafter, heat-treated Al ₂ O ₃ balls were injected into the support, and the Al ₂ O ₃ balls were rotated for 2 hours so that CuCl could be sufficiently impregnated. Thereafter, a vacuum atmosphere was formed using a pump to remove ammonia water, and the adsorbent was dried in an oven at 120°C. Finally, a carbon monoxide adsorbent was synthesized by heat treatment at 350° C. in an _{N 2 atmosphere.}

One. adsorbent precursor XRD analysis

In order to confirm the crystal structure of the carbon monoxide adsorbent precursor according to Example 1, XRD analysis was performed, and is shown in FIG. 2 . Referring to FIG. 2 , it can be confirmed that there is no other crystal structure except for _{Al 2} O ₃ and impregnated CuCl _{2 as a support.}

2. adsorbent Thermogravimetric analysis of precursors

To evaluate the thermal stability of the carbon monoxide adsorbent precursor according to Example 1, thermogravimetric analysis was performed in a nitrogen atmosphere, and is shown in FIG. 3 . Referring to FIG. 3 , the weight reduction occurs twice, and in the range of 100 to 400° C., it is considered that moisture or OH groups and some Cl groups contained in the precursor are decomposed. After that, it is considered that the Cl group, which is a little more strongly bound, is decomposed, since about 20% weight loss occurs similarly to the low temperature at 500~600°C.

3. adsorbent Cl to Cu on precursor and adsorbent surfaces atomic ratio analysis

The adsorbent precursors according to Examples 1 and 2 and X-ray photoelectron spectroscopy (XPS) analysis were performed to confirm the surface atomic ratio of the adsorbent synthesized by heat treatment of the precursor, and are shown in Table 1 below.

Surface Atomic Ratio Cl(2p) O(1s) C(1s) Cu(2p3) Cl/Cu Example 1 8.57 67.4 14.7 9.33 0.92 Example 2 13.01 66.92 7.72 12.35 1.05 Precursors of Examples 1 and 2 15.17 67.83 7.83 9.17 1.65

Referring to Table 1, it can be seen that the surface Cl/Cu atomic ratio of the precursor is 1.65, which is close to the atomic ratio of the _{CuCl 2 reagent.} The Cl/Cu atomic ratios of the adsorbents of Examples 1 and 2 heat treated at 500° C. and Examples 1 and 2 heat treated at 300° C. are respectively 1.05 and 0.92, which are lower than the ratio of the precursor, which means that Cl is decomposed and removed by heat treatment. it means. In addition, the Cl/Cu ratio of the adsorbent close to 1 after heat treatment means that the same structure as that of preparing the adsorbent using CuCl can be impregnated on the support.

4. Carbon Monoxide adsorbent XRD analysis

Although it was confirmed through XPS analysis that the Cl/Cu ratio on the surface of the carbon monoxide adsorbent according to the embodiment of the present invention was close to 1, this corresponds to the surface properties of the adsorbent. indicated.

Referring to FIG. 4 , in Comparative Example 1, which is a CuCl-based adsorbent, _{only CuCl and Al 2} O ₃ as a support were shown, but in _{Examples 1 and 2 using CuCl 2} , different crystal structures were confirmed depending on the heat treatment temperature. In more detail, when heat treatment at a low temperature of 350 ° C., CuCl _{2 as} a precursor structure is mostly and CuCl is partially found, which is when the heat treatment is performed at a low temperature, Cl is removed only from the surface to synthesize CuCl form and inside the particles It means that it does not change to _{CuCl 2 structure.} On the other hand, in Example 1, which was heat treated at 500° C., no CuCl ₂ structure was found but only a CuCl structure was found, and it was confirmed that an adsorbent having a CuCl structure could be synthesized by heat treatment at a high temperature.

5. Carbon Monoxide adsorbent TPR (temperature-programmed reduction) analysis

In order for CO to adsorb on the CuCl adsorption point, the reduction property must also be evaluated, so a temperature-programmed reduction (TPR) analysis was performed using _{H 2 , and is shown in FIG. 5 .} FIG. 5(a) is Example 1, FIG. 5(b) is Example 2, and FIG. 5(c) is Comparative Example 1.

Referring to FIG. 5(c), in the case of the conventional CuCl-based adsorbent, two peaks appear at about 280 and 400° C., and the ratio of the peaks appearing at a high temperature is high. On the other hand, in Example 1 heat-treated at 350 ° C., two peaks appeared, but the temperature appeared at 350 and 450 ° C., and the reduction temperature was about 50 ° C higher than the conventional CuCl-based adsorbent. On the other hand, it was confirmed that Example 2 heat-treated at 500 ° C. was reduced at the same temperature as Comparative Example 1, and it was observed that the reduction rate at a high temperature was higher than before.

6. Isothermal adsorption experiment of carbon monoxide adsorbent

In order to confirm whether or not it can be used as an adsorbent, an isothermal adsorption experiment for each gas was performed at 30° C. using the adsorbents according to Example 1 and Comparative Example 1, and is shown in FIG. 6 . The condition of the adsorbent for CO separation is that it adsorbs a lot of CO, but _{the adsorption amount of CO 2} and N ₂ , which are other gases, should be low.

Both of the adsorbents according to Example 1 and Comparative Example 1 _{had very low adsorption amounts of CO 2} and N ₂ , and it was confirmed that when the adsorbent was 8 bar, it was lower than 1 mmol/g. The amount of CO adsorption of the adsorbent according to Comparative Example 1 was _{higher than that of CO 2} and N ₂ , which was equally high in the adsorbent of Example 1. In particular, when it is 8bar, it can be confirmed that the CO adsorption amount is 2.7mmol/g. This means that CO selectively adsorbs to the adsorbent at high pressure.

On the other hand, at a low pressure, the amount of CO adsorption of the adsorbent of Example 1 is lower than that of the adsorbent of Comparative Example 1, but it is _{about 2 times higher than that of CO 2} , N ₂ , and it can be confirmed that CO selectively adsorbs even at a low pressure. That is, according to the present invention, there is provided a method for producing a carbon monoxide adsorbent that is simple in synthesis, does not generate a waste solution such as ammonia water or hydrochloric acid, and has a low manufacturing cost. can confirm that it is possible.

Although the embodiments of the present invention have been described in detail above, the scope of the present invention is not limited thereto, and various modifications and variations are possible within the scope without departing from the technical spirit of the present invention described in the claims. It will be apparent to those of ordinary skill in the art.

Claims (11)

preparing an aqueous solution containing a copper precursor;
injecting an aqueous solution containing the copper precursor into a support;
preparing an adsorbent precursor by drying the support in which the aqueous solution containing the copper precursor is injected; and
heat-treating the adsorbent precursor;
The copper precursor is copper chloride dihydrate (CuCl ₂ ·2H ₂ O),
Method for producing a carbon monoxide adsorbent, characterized in that the atomic ratio of Cl to Cu on the surface of the carbon monoxide adsorbent (Cl/Cu) is 0.8 to 1.2
According to claim 1,
The method for producing a carbon monoxide adsorbent, characterized in that the solubility of the copper precursor in water at 0 to 100 ℃ is 700 to 1,100 g / l.
delete According to claim 1,
The method for producing a carbon monoxide adsorbent, characterized in that the support is at least one selected from alumina, zeolite, and silica.
According to claim 1,
The method for producing a carbon monoxide adsorbent, characterized in that the drying is carried out in a temperature range of 80 to 150 ℃ at atmospheric pressure.
According to claim 1,
The method for producing a carbon monoxide adsorbent, characterized in that the heat treatment is performed in a temperature range of 350 to 600 ℃ in a reducing atmosphere.
According to claim 1,
A method for producing a carbon monoxide adsorbent, characterized in that the atomic ratio of Cl to Cu on the surface of the adsorbent precursor (Cl/Cu) is 1.2 to 2.5.
delete delete delete delete

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