River sand loaded zirconium oxide solid acid catalyst, its preparation method and application

Abstract

The present application belongs to the field of solid acid catalysts, and relates to a river sand loaded zirconium oxide solid acid catalyst and a preparation method and application thereof. The present application uses river sand loaded zirconium oxide and adopts flour biomass charcoal for bonding. The prepared river sand / C / zirconium oxide solid acid catalyst can accelerate the rupture of carbamate C-N bonds in the process of desorption of CO2 from a CO2-rich alcohol amine solution, and realizes the rapid separation of CO2 from the alcohol amine solution. In the process of desorption and separation of CO2 from the CO2-rich alcohol amine solution, compared with no catalyst under the same conditions, the desorption rate is increased by 17-24%, and the desorption energy consumption is reduced by 15-22%. The stability and cyclic catalytic effect are good, and after 5 cycles, the catalytic activity still remains 98.5%. The river sand is cheap and easy to obtain, the prepared powder catalyst is easy to recover, and can be reused after solid-liquid separation. Compared with porous ceramic, zeolite and other carrier materials, the catalyst disclosed by the present application has the advantages of low cost, simple preparation method and good catalytic desorption effect.

Description

Technical Field

[0001] This invention belongs to the field of solid acid catalysts, specifically, it relates to a zirconium oxide solid acid catalyst supported on river sand, its preparation method, and its application. Background Technology

[0002] Fossil fuels (coal, oil, and natural gas) are the primary energy source for both developed and developing countries, and their core position is unlikely to change in the short term. The combustion of fossil fuels is a major source of carbon dioxide (CO2) emissions. CO2 emissions contribute to global warming, leading to rising sea levels and extreme weather events; therefore, reducing CO2 emissions is of paramount importance. Currently, most industrial applications use organic amine solutions to absorb CO2 from factory flue gas emissions. However, the CO2 desorption stage (alcoholic amine solvent regeneration) is energy-intensive and costly, hindering its widespread application. Therefore, finding a catalyst material with promising industrial applications to improve CO2 desorption efficiency and reduce energy input is essential.

[0003] In the field of acid catalysis, solid acid catalysts offer advantages over traditional liquid acids, including being non-corrosive, non-polluting, easily separable, and recyclable. The catalytic function of solid acid catalysts primarily depends on the acid sites on the solid acid surface, including Brønsted acid (BAS) and Lewis acid (LAS) sites. Exploring a solid acid catalyst with low raw material costs and the ability to be applied to large-scale production is of great significance. Summary of the Invention

[0004] To overcome the problems existing in the background technology, this invention proposes a river sand-supported zirconia solid acid catalyst. Using river sand as a substrate, zirconia is supported by flour bonding. The prepared catalyst has no effect on CO2 absorption after the regeneration of the alkanolamine solution and has excellent stability for repeated use. The preparation method of this invention is simple and easy to implement, and the raw materials are inexpensive and readily available, making it more practical and feasible for large-scale factory applications.

[0005] To achieve the above objectives, the present invention is implemented through the following technical solution:

[0006] A river sand-supported zirconia solid acid catalyst is a river sand / C / zirconia composite prepared by bonding river sand and zirconium salt together with flour and biochar.

[0007] The preparation method of the aforementioned river sand-supported zirconium oxide solid acid catalyst includes the following specific steps:

[0008] 1) Pretreatment of river sand:

[0009] a. Take river sand, pass it through a 20-30 mesh sieve, wash it with water, and dry it for later use;

[0010] b. After the treatment in step a, ball milling is performed using a planetary ball mill.

[0011] 2) Zirconia loading onto river sand:

[0012] a. River sand is processed and then mixed with zirconium salts and flour;

[0013] b. After processing in step a, place the mixture in deionized water and stir.

[0014] c. The stirred material is dried and then ground to obtain a mixed material;

[0015] d. The mixed material is transferred to a tube furnace for high-temperature heat treatment to obtain the river sand / C / zirconium oxide solid acid catalyst.

[0016] Further, in step 1), the drying temperature is 100-120℃, the rotation speed of the planetary ball mill is 300-500 r / min, and the ball milling time is 30-60 min.

[0017] Further, in step 2), the zirconium salt is any one of zirconium oxychloride, zirconium tetrachloride, and zirconium acetate.

[0018] Further, in step 2), the mass ratio of flour to river sand is 1:6-10, and the mass ratio of river sand to zirconium salt is 1-6:1.

[0019] Furthermore, in step 2), the zirconium salt, river sand, and flour are mixed at a stirring speed of 300-400 rpm for 4-8 hours at room temperature.

[0020] Furthermore, in step 2), the drying temperature after stirring is 100-120℃, and the drying time is 10-18h.

[0021] Furthermore, in step 2), the high-temperature heat treatment is carried out in an inert gas atmosphere, the heat treatment temperature is 500-700℃, the heating rate is 2-6℃ / min, and the heat treatment time is 1-4h.

[0022] The river sand-supported zirconium oxide solid acid catalyst prepared in this invention is applied to the regeneration treatment of CO2-rich alcoholamine solutions.

[0023] The beneficial effects of this invention are:

[0024] 1. The raw material of this invention, river sand, is readily available, the process is simple and easy to operate, and the prepared powder catalyst has no effect on the absorption of CO2 after the regeneration of the amine solution. Moreover, it has excellent stability for repeated use, thus realizing the reuse of resources.

[0025] 2. The flour used as the raw material in this invention not only serves as a binder, but also possesses certain acidic sites after high-temperature carbonization. This has positive implications for the synthesis of solid acid catalysts in terms of both cost and chemical properties.

[0026] 3. The catalyst prepared by this invention has a good effect on reducing energy input when used in the catalytic regeneration (CO2 desorption) of CO2-rich alcoholamine solutions. Compared with desorption without a catalyst, the regeneration energy input can be reduced by 15-22% using this catalyst. Moreover, the raw materials are relatively inexpensive and readily available, making it more practical and feasible for large-scale factory applications. Attached Figure Description

[0027] Figure 1 The XRD pattern of the river sand-supported zirconium oxide solid acid catalyst prepared in Example 1;

[0028] Figure 2 shows SEM images of different river sand catalysts, where, Figure 2a Comparative Example 2: River sand catalyst; Figure 2b Comparative Example 1: River sand / C catalyst; Figure 2c , Figure 2d , Figure 2e Examples 1-3 are respectively river sand / C / zirconium oxide;

[0029] Figure 3 Raman plot of the river sand-supported zirconium oxide solid acid catalyst prepared in Example 1;

[0030] Figure 4 The image shows the pyridine infrared spectroscopy of the zirconium oxide solid acid catalyst supported on river sand prepared in Example 1.

[0031] Figure 5 The graphs show the CO2 desorption effect analysis of the river sand-supported zirconium oxide solid acid catalysts prepared in Examples 1-3.

[0032] Figure 6 The graph shows the recycling performance of the river sand-supported zirconium oxide solid acid catalyst prepared in Example 1.

[0033] Figure 7 The graph shows the effect of the river sand-supported zirconium oxide solid acid catalyst prepared in Example 1 on the reabsorption of CO2 from an alcohol amine solution. Detailed Implementation Plan

[0034] The present invention will be further described below through specific embodiments, but is not limited to the best mode used in the following embodiments. The present invention can also be implemented or applied through other different specific embodiments, and various details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of the present invention.

[0035] Example 1

[0036] A zirconium oxide solid acid catalyst supported on river sand, the specific steps of its preparation method include:

[0037] 1) Pretreatment of river sand:

[0038] River sand needs to be screened to a certain particle size, passed through a 30-mesh sieve, and then repeatedly washed before being dried in a constant temperature forced-air drying oven at 110℃. The dried river sand is then ball-milled in a planetary ball mill at a speed of 400 r / min for 40 min.

[0039] 2) Zirconia loading onto river sand:

[0040] Weigh 3g of pretreated river sand, 0.5g of flour, and 3g of zirconium oxychloride (the mass ratio of river sand to zirconium oxychloride is 1:1), and add them to 50ml of deionized water for mixing. The mass ratio of river sand to flour is fixed at 6:1. The mixing speed is 300rpm and the mixing time is 6h.

[0041] After stirring, the mixture was dried in a constant temperature forced-air drying oven at 110℃ for 12 hours. After drying, it was placed in an agate mortar for grinding, and then transferred to a tube furnace for sintering in an inert nitrogen atmosphere. After sintering at 650℃ for 2 hours, a solid acid catalyst (river sand / C / zirconia) supported on zirconium oxide was prepared.

[0042] Example 2

[0043] A zirconium oxide solid acid catalyst supported on river sand, the specific steps of its preparation method include:

[0044] 1) Pretreatment of river sand:

[0045] River sand needs to be screened to a certain particle size, passed through a 30-mesh sieve, and then repeatedly washed before being dried in a constant temperature forced-air drying oven at 110℃. The dried river sand is then ball-milled in a planetary ball mill at a speed of 400 r / min for 40 min.

[0046] 2) Zirconia loading onto river sand:

[0047] Weigh 3g of pretreated river sand, 0.5g of flour, and 1.5g of zirconium oxychloride (the mass ratio of river sand to zirconium oxychloride is 2:1), and add them to 50ml of deionized water for mixing. The mass ratio of river sand to flour is fixed at 6:1. The mixing speed is 300rpm and the mixing time is 6h.

[0048] After stirring, the mixture was dried in a constant temperature forced-air drying oven at 110℃ for 12 hours. After drying, it was placed in an agate mortar for grinding, and then transferred to a tube furnace for sintering in an inert nitrogen atmosphere. After sintering at 650℃ for 2 hours, a solid acid catalyst (river sand / C / zirconia) supported on zirconium oxide was prepared.

[0049] Example 3

[0050] A zirconium oxide solid acid catalyst supported on river sand, the specific steps of its preparation method include:

[0051] 1) Pretreatment of river sand:

[0052] River sand needs to be screened to a certain particle size, passed through a 30-mesh sieve, and then repeatedly washed before being dried in a constant temperature forced-air drying oven at 110℃. The dried river sand is then ball-milled in a planetary ball mill at a speed of 400 r / min for 40 min.

[0053] 2) Zirconia loading onto river sand:

[0054] Weigh 3g of pretreated river sand, 0.5g of flour, and 0.5g of zirconium oxychloride (the mass ratio of river sand to zirconium oxychloride is 6:1), and add them to 50ml of deionized water for mixing. The mass ratio of river sand to flour is fixed at 6:1. The mixing speed is 300rpm and the mixing time is 6h.

[0055] After stirring, the mixture was dried in a constant temperature forced-air drying oven at 110℃ for 12 hours. After drying, it was placed in an agate mortar for grinding, and then transferred to a tube furnace for sintering in an inert nitrogen atmosphere. After sintering at 650℃ for 2 hours, a solid acid catalyst (river sand / C / zirconia) supported on zirconium oxide was prepared.

[0056] Comparative Example 1

[0057] The river sand pretreatment is the same as step 1) in Example 1.

[0058] Weigh 3g of pretreated river sand and 0.5g of flour, add them to 50ml of deionized water and stir at 300rpm for 6 hours. After stirring, dry in a constant temperature forced-air drying oven at 110℃ for 12 hours. After drying, grind the mixture in an agate mortar, then transfer it to a tube furnace for high-temperature sintering in an inert nitrogen atmosphere at 650℃ for 2 hours to obtain a mixture of river sand and carbonized flour (river sand / C).

[0059] Comparative Example 2

[0060] The river sand pretreatment is the same as step 1) in Example 1.

[0061] Weigh 3g of pretreated river sand and add it to 50ml of deionized water. Stir at 300rpm for 6 hours. After stirring, dry in a constant temperature forced-air drying oven at 110℃ for 12 hours. After drying, grind the sand in an agate mortar. Then, transfer the sand to a tube furnace for high-temperature sintering in an inert nitrogen atmosphere at 650℃ for 2 hours to obtain sintered river sand.

[0062] Experimental Analysis

[0063] I. Characterization of the river sand catalysts prepared in Examples 1-3 and Comparative Examples 1-2

[0064] The river sand / C / zirconium oxide prepared in Example 1 was tested, as follows: Figure 1 As shown in the XRD pattern, zirconium oxide is doped into river sand. The main component of river sand is SiO2. After loading, a peak of ZrO2 appears, proving that river sand / C / zirconium oxide has been synthesized.

[0065] Figure 2 shows the SEM images of the river sand catalysts prepared in Examples 1-3 and Comparative Examples 1-2. It can be seen that small particles appeared on the surface of the river sand loaded with zirconium oxide, and they were relatively uniformly distributed under certain proportions. Among them, the particle distribution in Figure 2(c) was the most uniform, indicating that the distribution of river sand / C / zirconia was also different depending on the ratio of river sand to zirconium oxide.

[0066] The five river sand catalysts prepared in Examples 1-3 and Comparative Examples 1-2 were subjected to BET tests, and the test results are shown in Table 1.

[0067] Table 1 BET test results for each catalyst

[0068]

[0069] As shown in Table 1, the river sand / C / zirconium oxide (2:1) prepared under sintering conditions of 650℃ has the highest specific surface area. Combining the results of BET and SEM, the amount of zirconium salt added also needs to be appropriate; too little will easily lead to uneven loading and a decrease in specific surface area.

[0070] The river sand / C / zirconium oxide sample prepared in Example 1 was subjected to Raman spectroscopy, as shown below. Figure 3 As shown, the degree of carburization and defect degree of river sand / C / zirconia, when sintered at 650℃, its I D / I G The value reached 0.96, indicating that the proportion of disordered carbon and the degree of defect in river sand / C / zirconia are relatively high, which is conducive to the generation and utilization of defective active sites.

[0071] The relative contents of Brønsted acid and Lewis acid in the three river sand catalysts prepared in Example 1 and Comparative Examples 1-2, and the catalyst prepared in Example 1 after recycling are shown in Table 2.

[0072] Table 2. Statistical table of Brønsted acid, Lewis acid, and B / L ratio for each catalyst.

[0073]

[0074] Table 2 shows that the river sand / C / zirconia catalyst has high levels of both Brønsted acid and Lewis acid, and the values ​​of Brønsted acid and Lewis acid change little after cycling, indicating good cycling stability. The high total acidity of the river sand / C / zirconia catalyst allows it to release more Brønsted and Lewis acids during the regeneration of CO2-rich alcoholamine solutions to attack the CN bonds in carbamates, accelerating CO2 separation from the solution, reducing external energy input, and saving desorption costs.

[0075] The catalysts prepared in Example 1 and Comparative Examples 1-2, and the catalyst prepared in Example 1 after recycling, were subjected to pyridine infrared spectroscopy. The test results are as follows: Figure 4 As shown in the figure, it appears at 1450cm. -1 The peak at 1540 cm⁻¹ is attributed to the Lewis acidic site (LAS); the peak at 1540 cm⁻¹ is also attributed to the Lewis acidic site (LAS). -1 The peak is attributed to the Brønsted acid site (BAS); located at 1570-1620 cm⁻¹. -1 The peaks around the left and right are attributed to weak and strong Lewis acidic sites; located at 1490 cm⁻¹. -1 The nearby peaks are attributed to the synergistic reaction band between LAS and BAS.

[0076] II. Performance Test of Catalytic CO2 Desorption

[0077] (1) The performance of the five river sand catalysts prepared in Examples 1-3 and Comparative Examples 1-2 in catalytic desorption of CO2 in CO2-rich alcoholamine solutions was tested. The test results are as follows: Figure 5 As shown, the river sand / C / zirconia mixtures in Examples 1-3 all improved the desorption rate and reduced desorption energy consumption to varying degrees. Among them, the river sand / C / zirconia (2:1) mixture in Example 1 exhibited the fastest desorption rate, and compared with the uncatalyst-free system, the relative energy consumption was reduced by 15-22% at the same temperature (90℃). In 100 mL of CO2-rich alkanolamine solution at 90℃, the CO2 catalytic desorption amount reached 42.08 mmol within 10 min, with a maximum desorption rate of 6.82 mmol / min, representing an increase of approximately 20% compared to the uncatalyst-free system.

[0078] (2) Cyclic stability studies were conducted using the river sand / C / zirconium oxide (2:1) mixture prepared in Example 1. The test results are as follows: Figure 6 As shown, it exhibits good cycle stability. After five cycles, the desorption amount and energy consumption are basically the same as those of fresh material, and it still maintains 98.5% of the catalytic activity, with a still high catalytic effect.

[0079] (3) A CO2-deficient amine solution containing river sand / C / zirconium oxide, obtained after desorption in Example 1, was used for CO2 reabsorption to investigate the effect of this catalyst on CO2 reabsorption. The test results are as follows: Figure 7 As shown, at 40℃, both the CO2-deficient alcoholamine solution in the river sand / C / zirconia system and the CO2-deficient alcoholamine solution in the catalyst-free system reached absorption saturation in about 100 min, and the absorption curves were basically the same, indicating that the presence of the solid acid catalyst of zirconium oxide supported on river sand has no negative impact on CO2 reabsorption.

[0080] The solid acid catalyst of zirconium oxide supported on river sand prepared in this invention has a high acidity site, enabling efficient desorption of CO2 from CO2-rich amino acid solutions at 90°C, reducing energy input and significantly lowering desorption energy consumption by 15%-22%. This catalyst is used for the first time in the catalytic regeneration of CO2-rich MEA solutions, and the raw materials, flour and river sand, are inexpensive and readily available, making it more practical and feasible for large-scale catalytic regeneration of CO2-rich MEA solutions in factories.

Claims

1. A river sand supported zirconia solid acid catalyst, characterized by: The river sand loaded zirconium oxide solid acid catalyst is a river sand / C / zirconium oxide composite prepared by using river sand and zirconium salt as raw materials and through the binding of flour biomass charcoal, and the specific preparation steps include: 1) Pretreatment of river sand: a. Take river sand through 20-30 mesh sieve, wash with water, and dry for standby; b. After step a treatment, use a planetary ball mill for ball milling; 2) Zirconium oxide is loaded to river sand: a. After the treatment of river sand, zirconium salt and flour are added; b. After step a treatment, put into deionized water and stir; c. After stirring, the material is dried and then ground to obtain a mixed material; d. Transfer the mixed material to a tube furnace for high temperature heat treatment, and obtain the river sand / C / zirconium oxide solid acid catalyst.

2. A river sand supported zirconia solid acid catalyst according to claim 1, wherein: In step 1), the drying temperature is 100-120℃, the rotation speed of the planetary ball mill is 300-500 r / min, and the ball milling time is 30-60 min.

3. A river sand supported zirconia solid acid catalyst according to claim 1, wherein: In step 2), the zirconium salt is any one of zirconium oxychloride, zirconium tetrachloride and zirconium acetate.

4. A river sand supported zirconia solid acid catalyst according to claim 1, wherein: In step 2), the mass ratio of river sand to flour is 6-10:1, and the mass ratio of river sand to zirconium salt is 1-6:

1.

5. A river sand supported zirconia solid acid catalyst according to claim 1, wherein: In step 2), the stirring speed of the mixture of zirconium salt, river sand and flour is 300-400 rpm, and the stirring time is 4-8 h at room temperature.

6. A river sand supported zirconia solid acid catalyst according to claim 1, wherein: In step 2), the drying temperature after stirring is 100-120℃, and the drying time is 10-18 h.

7. A river sand supported zirconia solid acid catalyst as claimed in claim 1, wherein: In step 2), the high temperature heat treatment is carried out in an inert gas atmosphere, the heat treatment temperature is 500-700℃, the heating rate is 2-6℃ / min, and the heat treatment time is 1-4 h.

8. The river sand loaded zirconium oxide solid acid catalyst of claim 1 is applied in the regeneration treatment of CO2-rich alcohol amine solution.

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