Transition metal-doped base bifunctional co2 adsorbents, methods of making, and uses thereof

Abstract

The application discloses a transition metal doped alkali base bifunctional CO2 adsorbent, a preparation method and application thereof, and comprises an alkali base bifunctional material and a transition metal. The preparation comprises the following steps: weighing transition metal, Ni, Na and Zr sources, dissolving the transition metal, Ni, Na and Zr sources in deionized water, stirring to form a uniform solution, weighing a precipitant, dissolving the precipitant in deionized water, adding the mixed system into the precipitant after complete dissolution, stirring and precipitating the mixed system in a constant-temperature water bath, drying the precipitate, calcining the obtained solid powder, and grinding the calcined solid powder into powder to obtain the transition metal doped alkali base bifunctional CO2 adsorbent. The preparation method of the transition metal doped alkali base bifunctional CO2 adsorbent material is simple, the transition metal is doped into Ni-Na2ZrO3 by using a coprecipitation method, the formation of in-situ pores and channels is promoted, the exposure area of active sites of the adsorbent is increased, the formation of lattice defects in the crystal cell is promoted, the surface energy of the crystal face of the material is changed from the dimension of solid physics, and the CO2 adsorption capacity and cycle stability are improved.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of gas purification, and particularly relates to a transition metal doped alkali base bifunctional CO2 adsorbent, a preparation method and application thereof. BACKGROUND

[0002] CO2 emitted by fossil fuel combustion is the main cause of global warming, and its contribution rate has exceeded 60%. Adding a decarbonization device after a flue gas desulfurization and denitrification system to capture and separate CO2 in flue gas is widely considered as one of the most effective methods to achieve CO2 emission reduction in the short term. Compared with the absorption method flue gas decarbonization technology, the adsorption method technology can significantly reduce the regeneration energy consumption, and can also avoid equipment corrosion and other problems. However, the actual flue gas flow is large, the CO2 concentration is low, and the composition is complex, which poses great challenges to the specific surface area, adsorption capacity, adsorption rate, selectivity, and chemical stability of the CO2 capture material.

[0003] The selection of the adsorbent material is a key factor for high-temperature solid adsorption method, and the currently reported high-temperature solid adsorbents mainly include Ca-based adsorbents, Li-based adsorbents, and Na-based adsorbents. Although the calcium-based adsorbent represented by CaO has a relatively high CO2 capture adsorption capacity, the sintering of CaO is serious under high-temperature conditions, which greatly reduces the high-temperature carbon adsorption performance, and in the long run, it cannot meet the application requirements of sustainable development. Although the Li-based adsorbent has high cycle stability and adsorption capacity, the high cost of Li source makes its application cost too high, and it is not suitable for large-scale application at present. In comparison, the Na-based adsorbent can overcome the application bottlenecks of the above two, and it has relatively low raw material cost and excellent cycle carbon adsorption stability, and is a kind of adsorbent material with good application prospect. Therefore, it has far-reaching practical significance to develop an efficient Na-based CO2 adsorbent.

[0004] Chinese patent CN118267966A discloses a preparation method of a performance-enhanced Na2ZrO3-based CO2 adsorbent. The CO2 adsorbent prepared according to the application can only maintain the cycle CO2 adsorption performance under a low-concentration CO2 atmosphere, and the CO2 adsorption capacity decreases obviously after 4 cycles.

[0005] Therefore, in order to solve the technical problems in the above background art, the application provides a preparation method of a transition metal doped alkali base bifunctional CO2 adsorbent material, which can effectively improve the CO2 adsorption capacity and cycle stability. SUMMARY

[0006] The purpose of the application is to provide a transition metal doped alkali base bifunctional CO2 adsorbent, a preparation method and application thereof, to solve the problems raised in the above background art.

[0007] To achieve the above object, the present application provides the following technical solutions: a transition metal doped alkali base bifunctional CO2 adsorbent, comprising an alkali base bifunctional material and a transition metal.

[0008] Preferably, the alkali base bifunctional material is Ni@Na2ZrO3.

[0009] Preferably in any of the above solutions, the transition metal accounts for 8-12% of the total weight of the material.

[0010] Preferably in any of the above solutions, the mass ratio of the transition metal to Ni is 1:(0.8-1.2).

[0011] Preferably in any of the above solutions, the Na2ZrO3 accounts for 88-92% of the total weight of the material, and the molar ratio of Na to Zr is 1:(0.3-0.5).

[0012] A preparation method of a transition metal doped alkali base bifunctional CO2 adsorbent, comprising the following steps:

[0013] S1: weigh a certain amount of transition metal, Ni, Na, and Zr source, mix and dissolve in deionized water, and magnetically stir to form a uniform solution;

[0014] S2: weigh a certain amount of precipitant and dissolve in deionized water, add to the above-mentioned mixed system after complete dissolution, and stir and precipitate in a constant temperature water bath for 6-8 hours;

[0015] S3: dry the precipitate in a drying oven for 12-14 hours to remove the water;

[0016] S4: place the obtained solid powder in a muffle furnace, calcine, and grind into powder to obtain a transition metal doped alkali base bifunctional CO2 adsorbent.

[0017] Preferably in any of the above solutions, in step S1, the transition metal comprises one or a combination of Co, Fe, Mn, Cu, and Zn.

[0018] Preferably in any of the above solutions, in step S1, the stirring speed is 1000-1500 rpm / min.

[0019] Preferably in any of the above solutions, in step S2, the precipitant is one or a combination of urea, sodium hydroxide, or sodium carbonate.

[0020] Preferably in any of the above solutions, in step S2, the ratio of the total amount of the precipitant to the metal elements is 6-10.

[0021] Preferably in any of the above solutions, the temperature in the water bath in step S2 is 60-80 DEG C.

[0022] Preferably in any of the above solutions, the drying temperature in step S3 is 100-120 DEG C.

[0023] Preferably in any of the above solutions, the calcination process in step S4 is first heating to 350-450 DEG C for 2h, and then heating to 630-680 DEG C for 6h.

[0024] Application of a transition metal doped base bifunctional CO2 adsorbent in flue gas CO2 capture and conversion process.

[0025] Technical effects and advantages of the present application:

[0026] 1. The adsorbent preparation process of the present application is simple, low cost, and the modification effect is remarkable. By co-precipitation method, transition metal is doped into Ni@Na2ZrO3, which promotes the formation of in-situ pores and channels, so that the microstructure of the final obtained adsorbent is more complex, the exposure area of the active sites of the adsorbent is increased, and the CO2 adsorption performance of the adsorbent is improved.

[0027] 2. By using the transition metal doping method, the formation of crystal lattice defects in the unit cell is promoted, the surface energy of the crystal plane is changed from the dimension of solid physics, and then the adsorption energy and charge density difference of CO2 adsorption are changed, and the adsorption capacity and cycle stability of CO2 are obviously improved. BRIEF DESCRIPTION OF DRAWINGS

[0028] Figure 1 is the SEM graph of the adsorbent of example 1 of the present application.

[0029] Figure 2 is the CO2 cycle adsorption graph of the adsorbent of example 1 of the present application.

[0030] Figure 3 is the CO2 adsorption amount comparison graph of the adsorbent of example 1 of the present application and comparative examples 1, 2 and 3.

[0031] Figure 4 is the SEM graph of the adsorbent of comparative example 2 of the present application.

[0032] Figure 5 is the SEM graph of the adsorbent of comparative example 3 of the present application. DETAILED DESCRIPTION

[0033] The specific embodiments of the present application will be further described with reference to the drawings. It should be noted that the description of these embodiments is intended for the purpose of illustration and is not intended to limit the present application. Furthermore, the technical features involved in the various embodiments of the present application described below can be combined with each other as long as they do not conflict with each other.

[0034] Example 1:

[0035] 40 g of cobalt acetate, 39.95 g of nickel acetate, 300 g of sodium nitrate and 326.48 g of zirconyl nitrate were weighed out, mixed and dissolved in deionized water, and magnetic stirring was performed to form a uniform solution;

[0036] 2480 g of urea was dissolved in deionized water, and after complete dissolution, it was added to the above-mentioned mixed system. The mixed system was stirred and precipitated at 70°C in a constant temperature water bath for 6 h;

[0037] The precipitate was placed in a drying oven and dried at 120°C for 12 h to dry the moisture therein;

[0038] The obtained solid powder was placed in a muffle furnace, first heated to 400°C for 2 h, and then heated to 650°C for calcination for 6 h. After calcination, the powder was ground to obtain a transition metal-doped alkali-based bifunctional adsorption material S1.

[0039] Example 2:

[0040] 43.8 g of iron acetate, 39.95 g of nickel acetate, 300 g of sodium nitrate and 326.48 g of zirconyl nitrate were weighed out, mixed and dissolved in deionized water, and magnetic stirring was performed to form a uniform solution;

[0041] 2480 g of urea was dissolved in deionized water, and after complete dissolution, it was added to the above-mentioned mixed system. The mixed system was stirred and precipitated at 70°C in a constant temperature water bath for 6 h;

[0042] The precipitate was placed in a drying oven and dried at 120°C for 12 h to dry the moisture therein;

[0043] The obtained solid powder was placed in a muffle furnace, first heated to 400°C for 2 h, and then heated to 650°C for calcination for 6 h. After calcination, the powder was ground to obtain a transition metal-doped alkali-based bifunctional adsorption material S2.

[0044] Example 3:

[0045] 39.1 g of manganese acetate, 39.95 g of nickel acetate, 300 g of sodium nitrate and 326.48 g of zirconyl nitrate were weighed out, mixed and dissolved in deionized water, and magnetic stirring was performed to form a uniform solution;

[0046] Take 2480g of urea dissolved in deionized water, after complete dissolution, add the above mixed system, the mixed system is stirred in constant temperature water bath pot at 70℃ for 6h;

[0047] Put the precipitate in the drying oven at 120℃ for 12h to dry the water in it;

[0048] Put the obtained solid powder in the muffle furnace, first heat to 400℃ for 2h, then heat to 650℃ for 6h, after calcination, grind into powder to obtain the transition metal doped alkali base bifunctional adsorption material S3.

[0049] Example 4:

[0050] Take 45.12g of copper acetate, 39.95g of nickel acetate, 300g of sodium nitrate and 326.48g of zirconium oxynitrate, mix and dissolve in deionized water, magnetically stir to form a uniform solution;

[0051] Take 2480g of urea dissolved in deionized water, after complete dissolution, add the above mixed system, the mixed system is stirred in constant temperature water bath pot at 70℃ for 6h;

[0052] Put the precipitate in the drying oven at 120℃ for 12h to dry the water in it;

[0053] Put the obtained solid powder in the muffle furnace, first heat to 400℃ for 2h, then heat to 650℃ for 6h, after calcination, grind into powder to obtain the transition metal doped alkali base bifunctional adsorption material S4.

[0054] Example 5:

[0055] Take 39.1g of manganese acetate, 39.95g of nickel acetate, 300g of sodium nitrate and 326.48g of zirconium oxynitrate, mix and dissolve in deionized water, magnetically stir to form a uniform solution;

[0056] Take 1632g of sodium hydroxide dissolved in deionized water, after complete dissolution, add the above mixed system, the mixed system is stirred in constant temperature water bath pot at 70℃ for 6h;

[0057] Put the precipitate in the drying oven at 120℃ for 12h to dry the water in it;

[0058] Put the obtained solid powder in the muffle furnace, first heat to 400℃ for 2h, then heat to 650℃ for 6h, after calcination, grind into powder to obtain the transition metal doped alkali base bifunctional adsorption material S5.

[0059] Comparative Example 1:

[0060] The same as example 1, the only difference is that cobalt acetate is not added in the preparation process of the adsorbent, and finally the adsorbent D1 is obtained.

[0061] Comparative example 2:

[0062] The same as example 1, the only difference is that the adsorbent is not calcined in stages, but directly calcined at 650℃ for 6h, and finally the adsorbent D2 is obtained.

[0063] Comparative example 3:

[0064] The same as example 1, the only difference is that the adsorbent is not calcined in stages, but directly calcined at 650℃ for 6h, and finally the adsorbent D2 is obtained.

[0065] Performance evaluation of base adsorbent

[0066] The CO2 adsorbents prepared in examples 1-S and comparative examples 1-3 are tested for CO2 adsorption performance in cycles. The adsorption conditions are: adsorption temperature 700℃, adsorption time 25min, and atmosphere 30vol.% CO2 and 70vol.% N2. The specific evaluation data are shown in Table 1 below:

[0067] Table 1

[0068] Adsorbent CO2adsorption capacity (g adsorbent / g CO2) S1 0.31 S2 0.26 S3 0.25 S4 0.18 S5 0.26 D1 0.11 D2 0.19 D3 0.21

[0069] As can be seen from the data in Table 1, the CO2 adsorbent prepared by the method can exhibit good adsorption performance under the conditions of adsorption temperature 700℃, adsorption time 25min, and atmosphere 30vol.% CO2 and 70vol.% N2, especially the adsorption capacity and cycle stability of example 1 are better.

[0070] Comparative example 1 does not add transition metal Co, and the CO2 adsorption capacity is found to be significantly lower during use; comparative example 2 uses the same transition metal as example 1, but because the calcination process does not use the step-by-step calcination method, the surface microstructure of the adsorbent is destroyed, resulting in a significant decrease in CO2 adsorption capacity.

[0071] In addition, comparative example 3 does not add Ni component, and the structure of the adsorbent is quite different from that of the examples, so the CO2 adsorption capacity is relatively low.

[0072] At the same time, the adsorbent S1 prepared by the method is found by SEM test to have a large number of mesopores and a small amount of macropores combined in a thin layer structure on the surface, and the surface is rough; the S1 adsorbent is found to have stable CO2 adsorption capacity after 10 cycles, without a downward trend. The adsorbents prepared in example 1 and comparative examples are compared in terms of 25min adsorption capacity, and it is found that the CO2 of example 1 is significantly higher than that of the comparative examples.

[0073] As can be seen from the above, the embodiment of the present application not only has a simple preparation process, but also promotes the formation of in-situ pores and channels by doping transition metals into Ni@Na2ZrO3, so that the microstructure of the obtained adsorbent is more complex, the exposure area of the active sites of the adsorbent is increased, and the CO2 adsorption performance and the service life of the adsorbent are improved.

[0074] The above is only the preferred embodiment of the present application, and does not limit the present application in any form. Although the present application has been disclosed as above with the preferred embodiment, it is not intended to limit the present application. Any person skilled in the art can make some changes or modifications to the above disclosed methods and technical contents to obtain equivalent embodiments with equivalent changes, without departing from the technical solution of the present application. Any simple modification, equivalent change and modification made to the above embodiments according to the technical essence of the present application are still within the scope of the technical solution of the present application.

Claims

1. A transition metal-doped base bifunctional CO2 adsorbent, characterized by: include Base bifunctional materials and transition metals; The base bifunctional material is Ni-Na2ZrO3; The transition metal includes one or more combinations of Co, Fe, Mn, Cu, and Zn.

2. The transition metal-doped base bifunctional CO2 adsorbent according to claim 1, characterized in that: The transition metal and Ni account for 8-12% of the total weight of the material.

3. The transition metal-doped base bifunctional CO2 adsorbent according to claim 2, characterized in that: The mass ratio of the transition metal to Ni is 1:(0.8~1.2).

4. The transition metal-doped base bifunctional CO2 adsorbent according to claim 1, characterized in that: The Na2ZrO3 accounts for 88-92% of the total weight of the material, wherein the molar ratio of Na to Zr is 1:(0.3-0.5).

5. A method for preparing a transition metal-doped base bifunctional CO2 adsorbent according to any one of claims 1 to 4, characterized in that: The following steps are involved: S1: Weigh a certain amount of transition metal, Ni, Na, and Zr sources, mix them, dissolve them in deionized water, and stir them magnetically to form a homogeneous solution; S2: Weigh a certain amount of precipitant and dissolve it in deionized water. After it is completely dissolved, add it to the above mixed system. Stir and precipitate the mixed system in a constant temperature water bath for 6 to 8 hours; S3: Place the sediment in a drying oven and dry it for 12 to 14 hours to remove the moisture. S4: placing the obtained solid powder in a muffle furnace, calcining it, and then grinding it into powder to obtain a transition metal-doped base bifunctional CO2 adsorbent.

6. The method for preparing a transition metal-doped base bifunctional CO2 adsorbent according to claim 5, characterized in that: In step S1 , the transition metal includes one or more combinations of Co, Fe, Mn, Cu, and Zn.

7. The method for preparing a transition metal-doped base bifunctional CO2 adsorbent according to claim 5, characterized in that: In step S1, the stirring speed is 1000-1500 rpm / min.

8. The method for preparing a transition metal-doped base bifunctional CO2 adsorbent according to claim 5, characterized in that: In step S2, the precipitant is a combination of one or more of urea, sodium hydroxide or sodium carbonate.

9. The method for preparing a transition metal-doped base bifunctional CO2 adsorbent according to claim 5, characterized in that: In step S2, the ratio of the precipitant to the total molar amount of the metal element is 6-10.

10. The method for preparing a transition metal-doped base bifunctional CO2 adsorbent according to claim 5, characterized in that: In step S2, the temperature in the water bath is 60-80°C.

11. The method for preparing a transition metal-doped base bifunctional CO2 adsorbent according to claim 5, characterized in that: In step S3, the drying temperature is 100-120°C.

12. The method for preparing a transition metal-doped base bifunctional CO2 adsorbent according to claim 5, characterized in that: In step S4, the calcination process is to first raise the temperature to 350-450°C and maintain it for 2 hours, and then raise the temperature to 630-680°C and calcine it for 6 hours.

13. Use of the transition metal-doped base bifunctional CO2 adsorbent according to any one of claims 1 to 4 in a process of capturing and converting CO2 from flue gas.

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