Calcium oxide / alumina / lanthanum oxide-based CO2 adsorbent and preparation method thereof

Abstract

The invention belongs to the technical field of preparation of environmental energy materials, and particularly relates to a calcium oxide / aluminum oxide / lanthanum oxide-based CO2 trapping material and a preparation method thereof. The calcium oxide / aluminum oxide / lanthanum oxide adsorbent comprises CaO, aluminum oxide and lanthanum oxide, the CaO is used as an active material for capturing CO2, and Al2O3 and La2O3 are used as precursors of a structure supporting material of the CaO, so that the material stability of the CaO in the repeated CO2 capturing process is further improved. The problems of poor cycle performance, high requirements on raw materials and the like of a calcium-aluminum material in the CO2 trapping process in the prior art are solved. The preparation method disclosed by the invention is simple and controllable, low in equipment requirement, low in energy consumption and simple in steps, and the obtained product is excellent in performance and easy for industrial production and application.

Description

Technical Field

[0001] The present invention belongs to the technical field of preparation of environmental energy materials, and in particular relates to a calcium oxide / aluminum oxide / lanthanum oxide-based CO2 adsorbent and a preparation method thereof. Background Art

[0002] Carbon capture, utilization, and storage (CCUS) is an important technology for addressing climate change, primarily in response to increasing anthropogenic CO2 emissions. As an alternative to traditional amine scrubbing, solid CO2 adsorbents such as calcium oxide (CaO) are considered a promising solution, especially in the calcium cycle. CaO is effectively used as a high-temperature CO2 adsorbent, with a reaction mechanism of CaO(s) +CO2(g) CaCO3(s) has a theoretical capture capacity of up to 0.786 g-CO2 / g-CaO. In addition, the capture and release reaction rate of CaO with CO2 is relatively fast, significantly improving the efficiency of the overall process. The cost-effectiveness, wide availability, and environmentally friendly raw material advantages of CaO from limestone and dolomite further enhance its appeal, while the potential for its waste recycling in the cement industry is also noteworthy. However, the main disadvantage of CaO is its limited cyclic stability due to microstructural deterioration caused by sintering. The Tammann temperature of CaCO3 is approximately 530 °C, which is lower than the operating temperature of the calcium cycle process (600-700 °C for carbonization and 900 °C for calcination), which poses a challenge to the long-term effectiveness of CaO in practical applications.

[0003] In order to address the problem of capacity loss of CaO-based CO2 adsorbents due to sintering, researchers have explored the addition of high-temperature stabilizers, such as Al2O3, SiO2, MgO, Y2O3, etc. Although these stabilizers do not directly participate in the CO2 capture process, they play a key role in enhancing the cyclic stability of the adsorbent. In particular, Al2O3 is particularly important as an inert support structure. It reacts with CaO to form a variety of calcium aluminates, such as Ca3Al2O6, CaAl2O4 and Ca 12 Al 14 O 33 , thereby significantly improving the adsorbent's resistance to sintering. By stabilizing the adsorbent's structure and reducing the harmful effects of sintering, these compounds can achieve more efficient and sustainable CO2 capture over longer cycles. However, studies have shown that during multiple CO2 capture cycles, Ca3Al2O6 will gradually decompose into Al2O3 - the process first dissociates into Ca 12 Al 14 O 33, ultimately converting to Al2O3. This decomposition causes Al2O3 to segregate on the adsorbent surface, weakening its inherent anti-sintering properties. This in turn affects the adsorbent's structural stability, leading to a decrease in CO2 capture performance with increasing cycle number. Addressing this issue is crucial for extending the service life of CaO / Al2O3 adsorbents or developing novel synergistic calcium aluminate phases.

[0004] This study innovatively introduced La2O3 into the CaO / Al2O3 system and discovered that its core mechanism is: 1) effectively disrupting the reaction equilibrium of the CaO-Al2O3 binary system; 2) inducing the formation of a new stable phase; and 3) significantly improving the CO2 capture performance of the composite adsorbent (by over 40%). Given the dual demands for long-term adsorbent stability and economic viability in industrial applications, systematically studying the effect of regulating the Al2O3 / La2O3 ratio on the structural stability and cyclic performance of CaO-based adsorbents is of great scientific and engineering significance.

[0005] The innovation of this invention is that it is the first to explore the CO2 capture performance, especially the long-cycle CO2 capture performance, when Al2O3, La2O3 and CaO precursors are combined. It also explores the influence of the introduction method of La2O3 on the long-cycle CO2 capture performance of the product. Summary of the Invention

[0006] In order to solve the problem of material deactivation of calcium-aluminum-based adsorbents in the CO2 capture cycle in the existing technology, the present invention adopts Al2O3 mixed with La2O3 and CaO to prepare a calcium-aluminum-based CO2 adsorbent with excellent CO2 capture cycle performance through sintering.

[0007] The present invention provides a calcium oxide / aluminum oxide / lanthanum oxide-based adsorbent, comprising at least one of the following three schemes;

[0008] Option 1: The adsorbent includes Al2O3 / La2O3 and CaO; the adsorbent is obtained by mixing a CaO precursor with Al2O3 / La2O3 and calcining the mixture; the mass ratio of CaO to Al2O3 / La2O3 in the prepared calcium oxide / aluminum oxide / lanthanum oxide-based adsorbent is 7-9:3-1; the calcination temperature is greater than the decomposition temperature of the precursor,

[0009] In the second scheme, the adsorbent is prepared by mixing a CaO precursor with an aqueous lanthanum salt solution, which is then uniformly mixed with Al2O3, and then calcined to obtain a calcium oxide / aluminum oxide / lanthanum oxide-based adsorbent; the calcination temperature is greater than the decomposition temperature of the precursor; and the mass ratio of CaO to (Al2O3 + La2O3) in the obtained calcium oxide / aluminum oxide / lanthanum oxide-based adsorbent is 7-9:3-1.

[0010] Option 3: The adsorbent is a mixture of a CaO precursor and a water-soluble lanthanum salt solution, which is then mixed with Al2O 3、 The mixture is uniformly mixed with La2O3, and then calcined using a calcination process to obtain a calcium oxide / aluminum oxide / lanthanum oxide-based adsorbent; the calcination temperature is greater than the decomposition temperature of the precursor; in the obtained calcium oxide / aluminum oxide / lanthanum oxide-based adsorbent, the mass ratio of CaO to (Al2O3+La2O3) is 7-9:3-1, preferably 7.5-8.5:1.5-2.5.

[0011] Preferably, in the obtained calcium oxide / aluminum oxide / lanthanum oxide-based adsorbent, the mass ratio of CaO to (Al2O3+La2O3) is 8:2.

[0012] Preferably, in the obtained calcium oxide / aluminum oxide / lanthanum oxide-based adsorbent, the mass ratio of La2O3 to (CaO+Al2O3+La2O3) is 1-10:100, preferably 2-6:100.

[0013] If the selection is based on the overall adsorption capacity of the cycle, the mass ratio of La2O3 to (CaO+Al2O3+La2O3) in the obtained calcium oxide / aluminum oxide / lanthanum oxide-based adsorbent is 6:100.

[0014] If we look at it from the perspective of multiple cycle efficiency, the mass ratio of La2O3 to (CaO+Al2O3+La2O3) in the obtained calcium oxide / aluminum oxide / lanthanum oxide-based adsorbent is 3.8~4.2:100.

[0015] The present invention discloses a calcium oxide / aluminum oxide / lanthanum oxide-based adsorbent, wherein the precursor used is at least one selected from calcium acetate, calcium carbonate, calcium nitrate and calcium citrate.

[0016] The calcium oxide / aluminum oxide / lanthanum oxide-based adsorbent of the present invention has a calcination temperature preferably of 700-950°C, more preferably of 820-900°C.

[0017] The invention discloses a calcium oxide / aluminum oxide / lanthanum oxide-based adsorbent, and the calcination time is 1-3 hours.

[0018] In the present invention, the calcination temperature cannot be too high and the calcination time cannot be too long, otherwise the composite material will be over-sintered and deactivated; the calcination temperature cannot be too low and the calcination time cannot be too short, otherwise the CaO precursor will not be decomposed or will be completely decomposed.

[0019] The present invention provides a method for preparing a calcium oxide / aluminum oxide / lanthanum oxide-based adsorbent, comprising the following steps:

[0020] Raw materials are taken according to the designed composition ratio, and then mixed evenly. After mixing evenly, they are calcined at 700-950°C, preferably 850-900°C, to obtain a product. The raw materials include a CaO precursor and Al2O3 / La2O3.

[0021] The present invention uses Al2O3 / La2O3 to prepare the adsorbent. After sintering, Al2O3 reacts with CaO to generate Ca3Al2O6, Al2O3 / La2O3 reacts with CaO to generate CaLaAl3O7, and Al2O3 reacts with La2O3 to generate LaAlO3.

[0022] The invention discloses a preparation method of a calcium oxide / aluminum oxide / lanthanum oxide-based adsorbent, which comprises the steps of uniformly mixing the materials through ball milling, wherein the rotation speed is controlled to be 400-800 r / min, the ball milling time is 4-8 h, and the ball-to-material mass ratio is 8:1.

[0023] The invention discloses a preparation method of a calcium oxide / aluminum oxide / lanthanum oxide-based adsorbent, wherein the calcination time is 1-3 hours.

[0024] The present invention provides a method for preparing a calcium oxide / aluminum oxide / lanthanum oxide-based adsorbent, wherein the Al2O3 used is commercial Al2O3 having a particle size of less than or equal to 1 μm and a gamma phase.

[0025] As a preferred embodiment, the present invention mixes Al2O3 / La2O3 with a calcium acetate precursor by ball milling and sintering at high temperature to obtain a CaO@Al2O3 / La2O3-10~30% adsorbent; wherein,

[0026] The ball milling conditions were 800 r / min, the ball milling time was 6 h, and the ball-to-material mass ratio was 8:1;

[0027] The high-temperature sintering temperature was 900°C, and the sintering schedule was 0-900°C at 5°C / min, with a 2-h hold. After high-temperature sintering, the mass ratio of CaO to Al₂O₃ / La₂O₃ was 8:2. Under this scheme, the product's cyclic performance and total CO₂ absorption over 20 cycles were both higher than those of other schemes. This achieved unexpected results.

[0028] The calcium oxide / aluminum oxide / lanthanum oxide-based adsorbent designed and prepared by the present invention has the best performance after optimization. Its initial CO2 capture capacity is 0.63 g CO2 / g adsorbent. After 20 cycles, the CO2 capture capacity can still be 0.47 g CO2 / g adsorbent, and the cycle retention rate is 82.46%; after 70 cycles, the CO2 capture capacity can still be 0.37 g CO2 / g adsorbent, and the cycle retention rate is 64.91%.

[0029] Beneficial effects of the embodiments of the present invention

[0030] 1. The present invention designed and prepared a calcium oxide / aluminum oxide / lanthanum oxide-based adsorbent, explored the physical effects of different lanthanum oxides on the calcium oxide / aluminum oxide-based adsorbent, and obtained an adsorbent with the best CO2 capture performance after optimization. Its initial CO2 capture capacity was 0.57 g CO2 / g adsorbent. After 20 cycles, the CO2 capture capacity could still be 0.47 g CO2 / g adsorbent, with a cycle retention rate of 82.46%; after 50 cycles, the CO2 capture capacity could still be 0.37 g CO2 / g adsorbent, with a cycle retention rate of 64.91%.

[0031] 2. The present invention has low requirements on equipment, low energy consumption, simple steps, high controllability, and is easy for industrial production. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 This is the XRD pattern of the CaO@Al2O3 / La2O3-10~30% adsorbent prepared in Example 1.

[0033] Figure 2 This is the SEM image of the CaO@Al2O3 / La2O3-10% adsorbent prepared in Example 1.

[0034] Figure 3 This is the SEM image of the CaO@Al2O3 / La2O3-20% adsorbent prepared in Example 1.

[0035] Figure 4 This is the SEM image of the CaO@Al2O3 / La2O3-30% adsorbent prepared in Example 1.

[0036] Figure 5 This is the XRD pattern of the CaO@Al2O3 adsorbent prepared in Example 2.

[0037] Figure 6 This is the SEM image of the CaO@Al2O3 adsorbent prepared in Example 2.

[0038] Figure 7 This is the CO2 capture performance diagram (20 times) of the CaO@Al2O3 / La2O3-10% adsorbent prepared in Example 1.

[0039] Figure 8 This is the CO2 capture performance diagram (20 times) of the CaO@Al2O3 / La2O3-20% adsorbent prepared in Example 1.

[0040] Figure 9 This is the CO2 capture performance diagram (20 times) of the CaO@Al2O3 / La2O3-30% adsorbent prepared in Example 1.

[0041] Figure 10 This is the SEM image of the CaO@Al2O3 / La2O3-10~30% adsorbent prepared in Example 1 after 20 CO2 capture cycles.

[0042] Figure 11 This is the CO2 capture performance diagram of the CaO@Al2O3 adsorbent prepared in Example 2 (20 times).

[0043] Figure 12 This is the SEM image of the CaO@Al2O3 adsorbent prepared in Example 2 after 20 CO2 capture cycles.

[0044] Figure 13 This is the CO2 capture performance diagram (70 times) of the CaO@Al2O3 / La2O3-30% adsorbent prepared in Example 1.

[0045] Figure 14 This is the SEM image of the CaO@Al2O3 / La2O3-30% adsorbent prepared in Example 1 after 70 CO2 capture cycles. DETAILED DESCRIPTION

[0046] In one aspect, embodiments of the present invention provide a calcium oxide / alumina / lanthanum oxide-based adsorbent. This calcium oxide / alumina / lanthanum oxide-based adsorbent includes CaO, Al2O3, and La2O3 as structural support materials for the CaO, further enhancing the stability of the CaO during repeated CO2 capture processes. In another aspect, embodiments of the present invention also provide a method for preparing the aforementioned calcium oxide / alumina / lanthanum oxide-based adsorbent.

[0047] In order to better understand the above technical solution, the above technical solution will be described in detail below in conjunction with specific embodiments.

[0048] Example 1

[0049] This embodiment provides a method for preparing a calcium oxide / aluminum oxide / lanthanum oxide-based adsorbent:

[0050] S1: ball milling Al2O3, La2O3 and calcium source precursor calcium acetate;

[0051] S2: CaO precursor is mixed with Al2O3 / La2O3 and then calcined; the mass ratio of CaO to Al2O3 / La2O3 is 8:2;

[0052] Specifically, the uniformly mixed precursors are placed in a tubular furnace and sintered at 900°C to obtain CaO@Al2O3 / La2O3-10%, CaO@Al2O3 / La2O3-20%, and CaO@Al2O3 / La2O3-30% adsorbents, respectively; (In the embodiment of the present invention, the physical meaning of CaO@Al2O3 / La2O3-10% is that the mass ratio of CaO to Al2O3 / La2O3 is 8:2, and La2O3 accounts for 10% of the total mass of (Al2O3+La2O3), that is, La2O3 accounts for 2% of the total mass of (CaO+Al2O3+La2O3)); the physical meanings of other CaO@Al2O3 / La2O3-20% and CaO@Al2O3 / La2O3-30% are similar.

[0053] from Figure 1 It can be seen that the XRD patterns of the prepared adsorbents are three groups: Figure 2 This is the SEM image of CaO@Al2O3 / La2O3-10% adsorbent. Figure 3 This is the SEM image of CaO@Al2O3 / La2O3-20% adsorbent. Figure 4 This is the SEM image of CaO@Al2O3 / La2O3-30% adsorbent.

[0054] The ball milling conditions described in S1 are 800 r / min, ball milling time is 6 h, and ball-to-material mass ratio is 8:1;

[0055] The sintering program of the sintering temperature of 900°C in S2 is 0-900°C, 5°C / min, and holding temperature for 2 hours.

[0056] Example 2

[0057] This example provides a method for preparing a calcium oxide / aluminum oxide adsorbent, comprising the following steps:

[0058] S1: ball milling Al2O3 and calcium source precursor calcium acetate;

[0059] S2: CaO precursor is mixed with Al2O3 and then calcined to obtain CaO@Al2O3 adsorbent; the mass ratio of CaO and Al2O3 is 8:2;

[0060] S3: The sintering temperature is 900 °C, the sintering program is 0-900 °C, and the temperature is kept for 2 h.

[0061] from Figure 5 It can be seen from the XRD pattern of the prepared CaO@Al2O3 adsorbent, Figure 6 It is the SEM image of CaO@Al2O3 adsorbent.

[0062] Example 3

[0063] This example provides a method for preparing a calcium oxide / lanthanum oxide adsorbent, comprising the following steps:

[0064] S1: lanthanum oxide and calcium source precursor calcium acetate are ball-milled together;

[0065] S2: CaO precursor and lanthanum oxide are mixed and calcined to obtain CaO@La2O3 adsorbent; the mass ratio of CaO and La2O3 is 8:2;

[0066] S3: The sintering temperature is 900 °C, the sintering program is 0-900 °C, and the temperature is kept for 2 h.

[0067] Example 4

[0068] This example provides a method for testing the CO2 capture performance of calcium oxide / alumina and calcium oxide / alumina / lanthanum oxide based adsorbents, the steps of which include:

[0069] S1: Take about 10 mg of each of the CaO@Al2O3 / La2O3-10%, CaO@Al2O3 / La2O3-20%, CaO@Al2O3 / La2O3-30%, CaO@Al2O3, and CaO@La2O3 adsorbents in Examples 1-3, steps S2, and S3, and place them in a platinum crucible.

[0070] S2: The test procedure is designed to heat the sample from room temperature to 900°C, keep the temperature for 5 minutes, and use argon as the gas.

[0071] S3: After the end of the heat preservation, the temperature is reduced from 900 ℃ to 700 ℃ and kept at 700 ℃ for 30 minutes, and the gas introduced is (15% plus 85% N2) CO2;

[0072] S4: Raise the temperature from 700 ℃ to 900 ℃ and keep it at 900 ℃ for 10 min, and the gas introduced is CO2.

[0073] S5: Repeat steps S3-S5 20 times.

[0074] Performance test example 1

[0075] Testing CaO / Alumina-based adsorbents for CO2 capture:

[0076] The CaO@Al2O3 / La2O3-10%, CaO@Al2O3 / La2O3-20%, and CaO@Al2O3 / La2O3-30% adsorbents prepared in Example 1 were weighed 6.31, 6.09, and 6.53 mg, respectively, and placed in a platinum crucible compatible with a thermogravimetric analyzer to test the CO2 capture performance of the adsorbent.

[0077] The CO2 capture performance and cycle performance of the calcium oxide / aluminum oxide / lanthanum oxide based adsorbent of this example are shown in FIG. Figure 7-9 As shown, from Figure 7 It can be seen that the initial CO2 capture capacity of CaO@Al2O3 / La2O3-10% adsorbent is 0.49 g CO2 / g adsorbent. After 20 cycles, the CO2 capture capacity is 0.44 g CO2 / g adsorbent, and the cycle retention rate is 89.80%;

[0078] Figure 8 The CO2 capture performance of the CaO@Al2O3 / La2O3-20% adsorbent is shown in Figure 2. Its initial CO2 capture capacity is 0.50 gCO2 / g adsorbent. After 20 cycles, the CO2 capture capacity is 0.45 gCO2 / g adsorbent, with a cycle retention rate of 90.0%.

[0079] Figure 9 The CO2 capture performance of the CaO@Al2O3 / La2O3-30% adsorbent is shown in Figure 2. Its initial CO2 capture capacity is 0.57 gCO2 / g adsorbent. After 20 cycles, the CO2 capture capacity reaches 0.47 gCO2 / g adsorbent, with a cycle retention rate of 82.46%.

[0080] Figure 10 SEM images of CaO@Al2O3 / La2O3-10%, CaO@Al2O3 / La2O3-20%, and CaO@Al2O3 / La2O3-30% adsorbents after 20 CO2 capture cycles. It can be seen that the particle size of the CaO@Al2O3 / La2O3-30% adsorbent remains uniform after 20 cycles.

[0081] It can be seen that the CaO@Al2O3 / La2O3-30% adsorbent prepared by ball milling and sintering in this embodiment of the present invention has improved CO2 capture performance (capacity) compared to the CaO@Al2O3 / La2O3-10% and CaO@Al2O3 / La2O3-20% adsorbents. However, in terms of cyclic stability, the CaO@Al2O3 / La2O3-20% obtained in Example 1 has better cyclic performance than the other solutions, but the CaO@Al2O3 / La2O3-30% has a higher CO2 capture capacity.

[0082] Performance test example 2

[0083] Weigh Example 2 and 6.34 mg of the CaO@Al2O3 adsorbent prepared in step S1, place them in a platinum crucible compatible with a thermogravimetric analyzer, and test the CO2 capture performance of the CaO@Al2O3 adsorbent.

[0084] like Figure 11 As shown in the figure, the initial CO2 capture capacity of CaO@Al2O3 adsorbent is 0.48 g CO2 / g adsorbent, and after 20 cycles, the CO2 capture capacity is 0.40 g CO2 / g adsorbent.

[0085] Figure 12 This is a SEM image of the CaO@Al2O3 adsorbent after 20 cycles of CO2 capture. It can be seen that after 20 cycles, the material sintering of the CaO@Al2O3 adsorbent is more serious than that of the CaO@Al2O3 / La2O3-30% adsorbent.

[0086] It can be seen that the CO2 capture performance of the CaO@Al2O3 adsorbent prepared by ball milling and sintering in the embodiment of the present invention is poorer than that of the CaO@Al2O3 / La2O3-10% and CaO@Al2O3 / La2O3-20% adsorbents (capacity).

[0087] Performance test example 3

[0088] Weigh 6.53 mg of the CaO@Al2O3 / La2O3-30% adsorbent prepared in Example 1 (the adsorbent with the largest adsorption capacity after 20 CO2 capture cycles) prepared in step S2, place it in a platinum crucible compatible with a thermogravimetric analyzer, and test the CO2 capture performance of the adsorbent.

[0089] The CO2 capture performance and cycle performance of the calcium oxide / aluminum oxide / lanthanum oxide based adsorbent of this example are shown in FIG. Figure 13 As shown, from Figure 13 As can be seen from the graph, the initial CO2 capture capacity of the CaO@Al2O3 / La2O3-30% adsorbent was 0.57 g CO2 / g adsorbent. After 20 cycles, the CO2 capture capacity reached 0.47 g CO2 / g adsorbent, with a cycle retention rate of 82.46%. After 70 cycles, the CO2 capture capacity reached 0.37 g CO2 / g adsorbent, with a cycle retention rate of 64.91%.

[0090] Figure 14 This is a SEM image of the CaO@Al2O3 / La2O3-30% adsorbent after 70 CO2 capture cycles. It can be seen that after 70 cycles, the CaO@Al2O3 adsorbent has a uniform particle size.

[0091] After 20 cycles, the CO2 capture capacity of the CaO@La2O3 adsorbent was 0.36 g CO2 / g adsorbent, and the cycle retention rate was 61.02%.

[0092] The above description is only a preferred embodiment of the present invention and does not limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A calcium oxide / aluminum oxide / lanthanum oxide based adsorbent, characterized in that: Include at least one of the following three options; Option 1: The adsorbent includes Al2O3 / La2O3 and CaO; the adsorbent is obtained by mixing a CaO precursor with Al2O3 / La2O3 and calcining the mixture; the mass ratio of CaO to Al2O3 / La2O3 in the prepared calcium oxide / aluminum oxide / lanthanum oxide-based adsorbent is 7-9:3-1; the calcination temperature is greater than the decomposition temperature of the precursor, In the second scheme, the adsorbent is prepared by mixing a CaO precursor with an aqueous lanthanum salt solution, which is then uniformly mixed with Al2O3, and then calcined to obtain a calcium oxide / aluminum oxide / lanthanum oxide-based adsorbent; the calcination temperature is greater than the decomposition temperature of the precursor; and the mass ratio of CaO to (Al2O3 + La2O3) in the obtained calcium oxide / aluminum oxide / lanthanum oxide-based adsorbent is 7-9:3-1. Option 3: The adsorbent is a mixture of a CaO precursor and a water-soluble lanthanum salt solution, which is then mixed with Al2O 3、 The mixture is uniformly mixed with La2O3, and then calcined using a calcination process to obtain a calcium oxide / aluminum oxide / lanthanum oxide-based adsorbent; the calcination temperature is greater than the decomposition temperature of the precursor; in the obtained calcium oxide / aluminum oxide / lanthanum oxide-based adsorbent, the mass ratio of CaO to (Al2O3+La2O3) is 7-9:3-1, preferably 7.5-8.5:1.5-2.

5.

2. A calcium oxide / aluminum oxide / lanthanum oxide based adsorbent according to claim 1, characterized in that: In the obtained calcium oxide / aluminum oxide / lanthanum oxide-based adsorbent, the mass ratio of CaO to (Al2O3+La2O3) is 8:

2.

3. A calcium oxide / aluminum oxide / lanthanum oxide based adsorbent according to claim 1, characterized in that: In the obtained calcium oxide / aluminum oxide / lanthanum oxide-based adsorbent, the mass ratio of La2O3 to (CaO+Al2O3+La2O3) is 1-10:100, preferably 2-6:

100.

4. A calcium oxide / aluminum oxide / lanthanum oxide based adsorbent according to claim 3, characterized in that: In the obtained calcium oxide / alumina / lanthanum oxide-based adsorbent, the mass ratio of La2O3 to (CaO+Al2O3+La2O3) is 6:100; or in the obtained calcium oxide / alumina / lanthanum oxide-based adsorbent, the mass ratio of La2O3 to (CaO+Al2O3+La2O3) is 3.8~4.2:

100.

5. The calcium oxide / aluminum oxide / lanthanum oxide based adsorbent according to claim 1, characterized in that: The precursor used is at least one selected from calcium acetate, calcium carbonate, calcium nitrate, and calcium citrate.

6. The calcium oxide / aluminum oxide / lanthanum oxide based adsorbent according to claim 1, characterized in that: The calcination temperature is preferably 700-950°C, more preferably 820-900°C.

7. The calcium oxide / aluminum oxide / lanthanum oxide based adsorbent according to claim 1, characterized in that: The calcination time is 1-3h.

8. The calcium oxide / aluminum oxide / lanthanum oxide based adsorbent according to claim 1, characterized in that: After sintering, Al2O3 reacts with CaO to produce Ca3Al2O6, Al2O3 / La2O3 reacts with CaO to produce CaLaAl3O7, and Al2O3 reacts with La2O3 to produce LaAlO3.

9. The calcium oxide / aluminum oxide / lanthanum oxide based adsorbent according to claim 1, characterized in that: The mixture was uniformly mixed by ball milling, the speed was controlled at 400-800 r / min, the ball milling time was 4-8 h, and the ball-to-material mass ratio was 8:

1.

10. The calcium oxide / aluminum oxide / lanthanum oxide-based adsorbent according to claim 1, characterized in that: The Al2O3 used is commercial Al2O3; its particle size is less than or equal to 1 μm, and the Al2O3 phase is a gamma phase.

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