Oxygen-containing porous carbon supported copper-based adsorbents, methods of making and using the same

Abstract

The application discloses a kind of oxygen-containing porous carbon supported copper-based adsorbent and its preparation method and application, belong to inorganic functional material field.CuCl2 2H2O is loaded in high specific surface area oxygen-containing micro-mesoporous porous carbon carrier ZPC in the application, and copper loading is regulated by solid heat dispersion method, and copper-based adsorbent with high CO working capacity is prepared;The oxygen-containing micro-mesoporous porous carbon carrier is prepared by carbonization and activation after using ZIF-8 as precursor;Oxygen element content in oxygen-containing micro-mesoporous porous carbon carrier ZPC is 5.6%-8.5%, pore size is 10-30 angstrom, BET surface area is 2714-3416 m 2 / g, pore volume is 1.52-2.01 cm 3 / g.The CuCl2 2H2O in the application forms new unsaturated Cu (I) active adsorption site with oxygen-containing group on the surface of carrier;Copper-based adsorption material prepared by regulating copper loading has high CO adsorption capacity and working capacity and excellent CO / N2 separation performance.

Description

Technical Field

[0001] This invention relates to an oxygen-containing porous carbon-supported copper-based adsorbent, its preparation method, and its application, belonging to the field of inorganic functional materials. Background Technology

[0002] Carbon monoxide (CO) is an important raw material for the synthesis of basic organic chemical products and intermediates. CO mainly originates from syngas obtained from the conversion of coal, petroleum, and natural gas. However, other industrial by-product gases, such as blast furnace gas, converter gas, calcium carbide furnace tail gas, yellow phosphorus tail gas, and water gas, are also increasingly becoming sources for CO extraction. Enriching, separating, and utilizing CO from by-product gases in the steel industry not only yields important CO raw materials but also reduces CO2 emissions.

[0003] After pretreatment such as dust removal, desulfurization, deoxygenation, and decarburization, the by-product gas from the iron and steel industry yields a mixture mainly composed of CO (30%-60%) and N2. However, CO and N2 have extremely similar properties, differing in boiling point by only 4.3 °C, dipole moment by only 0.11 D, and polarizability by only 0.21 × 10⁻⁶. −40 C·m 2 ·V −1 The diameter difference is only 0.12 Å. Therefore, the efficient separation of CO from a CO and N2 mixture is a key step in its resource utilization.

[0004] Currently, CO and N2 separation methods include cryogenic separation, solution absorption, membrane separation, and adsorption separation. Cryogenic separation involves multiple distillations within a low-temperature range based on the different boiling points of the gases, requiring complex refrigeration and heat recovery systems, resulting in high investment and costs; it also consumes a lot of energy due to the high pressure and low temperature; furthermore, because CO and N2 have similar boiling points, it is difficult to achieve complete separation between the two. Solution absorption is a chemical absorption technology that utilizes the selective absorption of CO by the absorbent to separate it from other components. However, this method requires frequent replacement of expensive solvents, and the treatment of waste solvents is complex. Membrane separation has advantages such as room temperature operation, low energy consumption, and simple process; however, research on CO separation membranes mainly focuses on separating and purifying CO from CO / H2, while CO / N2 separation is more difficult, and membrane preparation costs are high, stability is poor, and there is still a long way to go before industrial application. Adsorption separation, with its low energy consumption, large adsorption capacity, high selectivity, and simple process operation, is considered one of the most promising methods for CO / N2 separation. Based on the differences in electron distribution and molecular orbitals between CO and N2 molecules, CO can form π-complexes with transition metal ions. Therefore, π-complex adsorption is the most suitable method for separating CO and N2.

[0005] π-complex adsorbents consist of porous materials loaded with transition metal ions. These transition metal ions mainly include Cu(I), Ag(I), and Pd(II), but Cu(I) is the most widely used. Porous material supports mainly include molecular sieves, activated alumina, activated carbon, and metal-organic frameworks (MOFs). Due to differences in elemental composition and pore structure distribution, they exhibit varying formation and distribution of Cu(I) active sites, resulting in different CO adsorption performances. Currently, the π-complex adsorbent used in industrial applications is CuCl-supported molecular sieve adsorbent (Chinese Patent CN86102838A; Xie Youchang, Zhang Jiaping, Tong Xianzong, et al., High-efficiency carbon monoxide adsorbent CuCl / molecular sieve [J], Journal of Chemical Research in Chinese Universities, 1997, 7, 1159-1165). Although it has shown good application potential, the strong π-complexation between CO and the adsorbent makes desorption difficult, requiring operation at higher temperatures or lower vacuum desorption pressures. This results in low CO working capacity and relatively high energy consumption during the adsorption-desorption continuous cycle. Therefore, developing π-complex adsorbents with high CO working capacity under room temperature and mild desorption conditions is a highly challenging task. Summary of the Invention

[0006] This invention aims to provide an oxygen-containing porous carbon-supported copper-based adsorbent, its preparation method, and its application. The method involves loading CuCl2·2H2O onto a unique oxygen-containing microporous porous carbon support (ZPC) via solid thermal dispersion to prepare two adsorbents, Cu(Ⅰ) / ZPC-Ⅰ and Cu(Ⅰ) / ZPC-Ⅱ, which are then used for CO / N2 adsorption and separation.

[0007] The Cu(I) active sites in the two adsorbents prepared in this invention can selectively bind CO through moderate-strength Cu-CO π-complexation, thereby achieving high CO working capacity and excellent CO / N2 separation performance under mild vacuum pressure swing adsorption conditions. Specifically, the Cu(I) / ZPC-I adsorbent exhibits a CO working capacity as high as 3.21 mmol / g at 1 bar–0.1 bar (adsorption-desorption pressure); the Cu(I) / ZPC-II adsorbent exhibits a CO working capacity as high as 5.65 mmol / g at 3 bar–0.1 bar (adsorption-desorption pressure).

[0008] This invention provides an oxygen-containing porous carbon-supported copper-based adsorbent. CuCl2·2H2O is loaded onto a high specific surface area oxygen-containing microporous porous carbon support (ZPC), and the copper loading is controlled by a solid-state thermal dispersion method to obtain a copper-based adsorbent with high CO working capacity. The oxygen-containing microporous porous carbon support is prepared by carbonization and activation using ZIF-8 as a precursor. The oxygen content of the oxygen-containing microporous porous carbon support ZPC is 5.6%-8.5%, the pore size is 10-30 Å, and the BET surface area is 2714-3416 m². 2 / g, pore volume 1.52-2.01 cm³ 3 / g.

[0009] Depending on the copper loading, two types of adsorbents, Cu(Ⅰ) / ZPC-Ⅰ and Cu(Ⅰ) / ZPC-Ⅱ, can be prepared. The active structural unit of Cu(Ⅰ) / ZPC-Ⅰ adsorbent is (CO)CuCl, with a CO working capacity of 2.73~3.21 mmol / g and an adsorption-desorption pressure of 1 bar to 0.1 bar. In Cu(Ⅰ) / ZPC-Ⅱ adsorbent, CuCl2·2H2O reacts with oxygen-containing microporous carbon with high specific surface area to form two independent unsaturated Cu(Ⅰ) active adsorption sites: reactive intercalation type dicoordinate (CO)CuCl and tricoordinate (CO)CuCl2 units, and filled intercalation type tricoordinate CuCl3 units, with a CO working capacity of 4.80~5.65 mmol / g and an adsorption-desorption pressure of 3 bar to 0.1 bar.

[0010] This invention provides a method for preparing the above-mentioned oxygen-containing porous carbon-supported copper-based adsorbent, specifically including the following steps:

[0011] (1) Preparation of ZIF-8, a precursor of oxygen-containing micro-mesoporous porous carbon: Zinc nitrate dihydrate: 2-methylimidazolium = 1:3 was dissolved in anhydrous methanol and added to a reaction vessel lined with polytetrafluoroethylene. After sealing, the mixture was placed in an oven at 90-110 °C for 2-3 days. After the reaction was completed and cooled to room temperature, the mixture was washed with anhydrous ethanol, filtered and dried to obtain ZIF-8.

[0012] (2) Preparation of oxygen-containing micro-mesoporous porous carbon with high specific surface area: The ZIF-8 precursor obtained in step (1) was placed in a tube furnace and carbonized at high temperature for 3 h under Ar atmosphere. After cooling at room temperature, it was soaked in 1-1.5 mol / L hydrochloric acid for 12-24 h, washed with distilled water, and dried at room temperature to obtain carbonized porous carbon material. The carbonization temperature was 950-1000 °C and the heating rate was 2.5-5 °C / min. Then, the carbonized porous carbon material was thoroughly mixed and ground with potassium hydroxide at a mass ratio of 1:3.5-1:4.5. The mixed sample was placed in a tube furnace and activated at high temperature for 1 h under Ar atmosphere. After cooling at room temperature, it was soaked in 2-2.5 mol / L hydrochloric acid solution for 12-24 h, washed with distilled water until neutral, and dried at room temperature to obtain oxygen-containing micro-mesoporous porous carbon. The activation temperature was 750-850 °C and the heating rate was 2.5-5 °C / min.

[0013] (3) Preparation of copper-based adsorbents: CuCl2·2H2O and oxygen-containing microporous porous carbon obtained in step (2) were mixed and ground in different proportions of 1.71~5.65 g / g, and then placed in a tube furnace and calcined at 350 °C for 4-6 h under Ar atmosphere. After cooling to room temperature, copper-based adsorbents with different copper loadings were obtained.

[0014] In step (3) above, when the mass ratio of CuCl2·2H2O to porous carbon is 1.71~2.56 g / g, Cu(Ⅰ) / ZPC-Ⅰ adsorbent is prepared; the CO working capacity of Cu(Ⅰ) / ZPC-Ⅰ adsorbent at 1-0.1 bar (adsorption-desorption pressure) is 2.73~3.21 mmol / g. When the mass ratio of CuCl2·2H2O to oxygen-containing microporous porous carbon is 3.41~6.82 g / g, Cu(Ⅰ) / ZPC-Ⅱ adsorbent is prepared; the CO working capacity of Cu(Ⅰ) / ZPC-Ⅱ adsorbent at 3-0.1 bar (adsorption-desorption pressure) is 4.80-5.65 mmol / g.

[0015] This invention provides the application of the above-mentioned oxygen-containing porous carbon-supported copper-based adsorbent in the adsorption and separation of CO / N2. The adsorption and separation performance is tested by single-component static adsorption and two-component dynamic breakthrough experiments.

[0016] The single-component static adsorption experiment was conducted using Cu(Ⅰ) / ZPC-Ⅰ and Cu(Ⅰ) / ZPC-Ⅱ materials as adsorbents. The adsorption capacities of CO and N2 were measured using a gravimetric adsorption analyzer at 25 °C. The gas adsorption capacities at different pressures were recorded to obtain gas adsorption isotherms. Before adsorption measurement, the samples needed to be vacuum activated at 150-180 °C for 2-5 h.

[0017] The described two-component dynamic breakthrough method includes breakthrough tests under adsorption capacity conditions and breakthrough tests under working capacity conditions. The method is as follows: Cu(Ⅰ) / ZPC-Ⅰ and Cu(Ⅰ) / ZPC-Ⅱ are used as adsorbents and packed into stainless steel breakthrough columns. The breakthrough columns are 12 cm high and 0.4 cm in inner diameter. The desorption pressure of the adsorption capacity is the limit pressure of the vacuum pump. Therefore, before the breakthrough experiment, the breakthrough column containing the sample is evacuated to the limit pressure of the vacuum pump, and then heated to 150-180 °C for activation for 3-5 h. After cooling, at a test temperature of 25 °C, a CO / N2 mixed gas with a volume ratio of 1:1 is introduced into the breakthrough column at a rate of 10 mL / min. The inlet gas flow rate is controlled by a mass flow meter, the test pressure is adjusted by a back pressure valve, and the outlet gas is analyzed by a mass spectrometer to obtain the adsorption capacity breakthrough curve. The working capacity desorption pressure is 0.2 bar. Therefore, after the two-component gas adsorption capacity breakthrough experiment, the sample was desorbed at 0.2 bar for 0.5-1 h. Then, at a test temperature of 25 °C, a CO / N2 mixed gas with a volume ratio of 1:1 was passed through the breakthrough column again at a rate of 10 mL / min to obtain the working capacity breakthrough curve.

[0018] The obtained adsorbents exhibit high CO working capacity and excellent CO / N2 separation performance. Their CO / N2 separation performance was investigated through static adsorption and dynamic breakthrough experiments. Specifically, the Cu(Ⅰ) / ZPC-Ⅰ adsorbent showed a CO adsorption capacity of 3.50–4.63 mmol / g at 1 bar, and a CO working capacity of 2.73–3.21 mmol / g at 298 K and 1 bar–0.1 bar (adsorption-desorption pressure). The Cu(Ⅰ) / ZPC-Ⅱ adsorbent showed a CO adsorption capacity of 5.5–6.82 mmol / g at 3 bar, and a CO working capacity of 4.80–5.65 mmol / g at 298 K and 3 bar–0.1 bar (adsorption-desorption pressure).

[0019] The beneficial effects of this invention are:

[0020] This invention uses unique large specific surface area oxygen-containing microporous porous carbon (ZPC) as a support, and loads CuCl2·2H2O in the support to form new unsaturated Cu(Ⅰ) active adsorption sites with oxygen-containing groups on the support surface; the copper-based adsorbent material prepared by controlling the copper loading has high CO adsorption capacity and working capacity. Attached Figure Description

[0021] Figure 1 PXRD patterns of 10Cu(Ⅰ) / ZPC-Ⅰ, 13Cu(Ⅰ) / ZPC-Ⅰ and 15Cu(Ⅰ) / ZPC-Ⅰ prepared in Example 1;

[0022] Figure 2 The N2 adsorption-desorption isotherms and pore size distribution curves of 10Cu(Ⅰ) / ZPC-Ⅰ, 13Cu(Ⅰ) / ZPC-Ⅰ and 15Cu(Ⅰ) / ZPC-Ⅰ prepared in Example 1 at 77 K;

[0023] Figure 3 The PXRD patterns of 20Cu(Ⅰ) / ZPC-Ⅱ, 30Cu(Ⅰ) / ZPC-Ⅱ and 40Cu(Ⅰ) / ZPC-Ⅱ in Example 2;

[0024] Figure 4 The N2 adsorption-desorption isotherms and pore size distribution curves of 20Cu(Ⅰ) / ZPC-Ⅱ, 30Cu(Ⅰ) / ZPC-Ⅱ and 40Cu(Ⅰ) / ZPC-Ⅱ at 77 K are shown in Example 2.

[0025] Figure 5 The static adsorption isotherms of CO and N2 for 10Cu(Ⅰ) / ZPC-Ⅰ, 13Cu(Ⅰ) / ZPC-Ⅰ and 15Cu(Ⅰ) / ZPC-Ⅰ at 25 °C are shown in Example 3.

[0026] Figure 6 The static adsorption isotherms of CO and N2 for 20Cu(Ⅰ) / ZPC-Ⅱ, 30Cu(Ⅰ) / ZPC-Ⅱ and 40Cu(Ⅰ) / ZPC-Ⅱ at 25 °C are shown in Example 4.

[0027] Figure 7 The dynamic breakthrough curve of 15Cu(Ⅰ) / ZPC-Ⅰ against CO / N2 at 25 °C in Example 5;

[0028] Figure 8 The dynamic penetration curve of 30Cu(Ⅰ) / ZPC-Ⅱ against CO / N2 at 25 °C is shown in Example 6. Detailed Implementation

[0029] The present invention will be further illustrated by the following embodiments, but is not limited to the following embodiments.

[0030] Example 1: Cu(Ⅰ) / ZPC-Ⅰ copper-based adsorbents include 10Cu(Ⅰ) / ZPC-Ⅰ, 13Cu(Ⅰ) / ZPC-Ⅰ and 15Cu(Ⅰ) / ZPC-Ⅰ, and the preparation method is as follows:

[0031] (1) Preparation of ZIF-8, a precursor of oxygen-containing micro-mesoporous porous carbon: Zinc nitrate dihydrate: 2-methylimidazolium = 1:3 was dissolved in anhydrous methanol and added to a reaction vessel lined with polytetrafluoroethylene. After sealing, the mixture was placed in an oven at 100 °C for 3 days. After the reaction was completed and cooled to room temperature, the mixture was washed with anhydrous ethanol, filtered and dried to obtain ZIF-8.

[0032] (2) Preparation of oxygen-containing micro-mesoporous porous carbon with high specific surface area: The ZIF-8 precursor obtained in step (1) was placed in a tube furnace and carbonized at high temperature for 3 h under Ar atmosphere. After cooling to room temperature, it was soaked in 1 mol / L hydrochloric acid for 24 h, then washed with distilled water and dried at room temperature to obtain carbonized porous carbon material. The carbonization temperature was 1000 °C and the heating rate was 5 °C / min. Then, the carbonized porous carbon material was thoroughly mixed and ground with potassium hydroxide at a mass ratio of 1:4. The mixed sample was placed in a tube furnace and activated at high temperature for 1 h under Ar atmosphere. After cooling to room temperature, it was soaked in 2 mol / L hydrochloric acid solution for 24 h, washed with distilled water until neutral, and dried at room temperature to obtain oxygen-containing micro-mesoporous porous carbon. The activation temperature was 800 °C and the heating rate was 5 °C / min.

[0033] Table 1 shows the pore structure and surface C, O, N, and H element content of the porous carbon support prepared in this embodiment. As can be seen from Table 1, the porous carbon support has a high specific surface area (3415 m²). 2 (g) and large pore volume (2.01 cm³) 3 The pore size is mainly distributed in the range of 10-30 Å, with an O content of 7.58 wt.%.

[0034] Table 1: Pore structure and surface C, O, N, and H content of porous carbon support ZPC

[0035]

[0036] (3) Preparation of Cu(Ⅰ) / ZPC-Ⅰ copper-based adsorbent: CuCl2·2H2O and oxygen-containing micro-mesoporous porous carbon obtained in step (2) were mixed and ground in proportions of copper loading of 10, 13 and 15 mmol / g porous carbon (mass ratio of 1.71~2.56 g / g), and then placed in a tube furnace and calcined at 350 °C for 4 h under Ar atmosphere. After cooling to room temperature, 10Cu(Ⅰ) / ZPC-Ⅰ, 13Cu(Ⅰ) / ZPC-Ⅰ and 15Cu(Ⅰ) / ZPC-Ⅰ were obtained.

[0037] Figure 1 The PXRD patterns of the support ZPC and adsorbents 10Cu(Ⅰ) / ZPC-Ⅰ, 13Cu(Ⅰ) / ZPC-Ⅰ and 15Cu(Ⅰ) / ZPC-Ⅰ are shown. It can be seen from the figure that almost no diffraction peaks related to Cu species are observed in the adsorbent, which indicates that Cu species are highly dispersed in ZPC. The highly dispersed Cu species are too small to be detected by XRD. Figure 2The figures show the N2 adsorption-desorption equilibrium isotherms and pore size distributions for the ZPC support and adsorbents 10Cu(I) / ZPC-I, 13Cu(I) / ZPC-I, and 15Cu(I) / ZPC-I at 77 K. As can be seen from the figures, all samples exhibit type I isotherm characteristics of a microporous structure, with pore sizes mainly distributed in the range of 10–30 Å.

[0038] Example 2: Cu(Ⅰ) / ZPC-Ⅱ copper-based adsorbents include 20Cu(Ⅰ) / ZPC-Ⅱ, 30Cu(Ⅰ) / ZPC-Ⅱ and 40Cu(Ⅰ) / ZPC-Ⅱ, and the preparation method is as follows:

[0039] CuCl2·2H2O was mixed and ground with oxygen-containing microporous carbon with high specific surface area obtained in step (2) of Example 1 at copper loading ratios of 20, 30, and 40 mmol / g porous carbon (mass ratio of 3.41~6.82 g / g). The mixture was then placed in a tube furnace and calcined at 350 °C for 4 h under an Ar atmosphere. After cooling to room temperature, 20Cu(Ⅰ) / ZPC-Ⅱ, 30Cu(Ⅰ) / ZPC-Ⅱ and 40Cu(Ⅰ) / ZPC-Ⅱ were obtained.

[0040] Figure 3 The PXRD patterns of the support ZPC and the adsorbents 20Cu(Ⅰ) / ZPC-Ⅱ, 30Cu(Ⅰ) / ZPC-Ⅱ and 40Cu(Ⅰ) / ZPC-Ⅱ are shown. Diffraction peaks at 28.5°, 47.4° and 56.3° can be seen from the figure. These peaks are attributed to the (111), (220) and (311) crystal planes of CuCl, respectively. Figure 4 The figures show the N2 adsorption-desorption equilibrium isotherms and pore size distributions at 77 K for the ZPC support and adsorbents 20Cu(Ⅰ) / ZPC-Ⅱ, 30Cu(Ⅰ) / ZPC-Ⅱ, and 40Cu(Ⅰ) / ZPC-Ⅱ. As can be seen from the figures, the porous carbon support ZPC exhibits typical Type I isotherm characteristics, with pore sizes mainly distributed in the 10-30 Å range. After loading Cu(Ⅰ), the N2 adsorption capacity and pore volume decrease sharply, which is due to the dispersion of Cu(Ⅰ) species into the pores of the porous carbon during the preparation process.

[0041] Example 3: Static adsorption of CO and N2 by a single component using Cu(Ⅰ) / ZPC-Ⅰ

[0042] Static adsorption experiments of CO and N2 were conducted using the 10Cu(Ⅰ) / ZPC-Ⅰ, 13Cu(Ⅰ) / ZPC-Ⅰ, and 15Cu(Ⅰ) / ZPC-Ⅰ materials prepared in Example 1. Gravimetric adsorption analysis was used for the tests. Before adsorption measurements, the samples were vacuum activated at 150-180 °C for 2-5 h. The test temperature was 25 °C, and the gas adsorption amounts at different pressures were recorded to obtain gas adsorption isotherms, as shown below. Figure 5 As shown in the table. The static CO working capacity was calculated from the CO adsorption isotherm. Table 2 lists the CO adsorption capacity of these Cu(Ⅰ) / ZPC-Ⅰ materials at 25 °C and different pressures, as well as the CO working capacity at different adsorption-desorption pressure ranges.

[0043] Figure 5 The results in Table 2 show that the CO adsorption capacities of 10Cu(Ⅰ) / ZPC-Ⅰ, 13Cu(Ⅰ) / ZPC-Ⅰ and 15Cu(Ⅰ) / ZPC-Ⅰ materials at 25°C and 1 bar are 4.17, 4.36 and 4.63 mmol / g, respectively, and the CO working capacities at 25 °C and 1-0.1 bar are 2.73, 2.97 and 3.21 mmol / g, respectively.

[0044] Table 2: Static CO adsorption capacity and working capacity of 10Cu(Ⅰ) / ZPC-Ⅰ, 13Cu(Ⅰ) / ZPC-Ⅰ and 15Cu(Ⅰ) / ZPC-Ⅰ at 25 °C and different pressures

[0045] .

[0046] Example 4: Static adsorption of CO and N2 by a single component using Cu(Ⅰ) / ZPC-Ⅱ

[0047] Static adsorption experiments of CO and N2 were conducted using the 20Cu(Ⅰ) / ZPC-Ⅱ, 30Cu(Ⅰ) / ZPC-Ⅱ, and 40Cu(Ⅰ) / ZPC-Ⅱ materials prepared in Example 2, respectively. Gravimetric adsorption analysis was used for the tests. Before adsorption measurements, the samples were vacuum activated at 150-180 °C for 2-5 h. The test temperature was 25 °C, and the gas adsorption amounts at different pressures were recorded to obtain gas adsorption isotherms, as shown below. Figure 6 As shown in the table. The static CO working capacity was calculated from the CO adsorption isotherm. Table 3 lists the CO adsorption capacity of these Cu(Ⅰ) / ZPC-Ⅱ materials at 25 °C and different pressures, as well as the CO working capacity at different adsorption-desorption pressure ranges.

[0048] Figure 6 The results in Table 3 show that the CO adsorption capacities of 20Cu(Ⅰ) / ZPC-Ⅱ, 30Cu(Ⅰ) / ZPC-Ⅱ and 40Cu(Ⅰ) / ZPC-Ⅱ materials at 25 °C and 3 bar are 6.15, 6.82 and 5.51 mmol / g, respectively, and the CO working capacities at 25 °C and 1-0.1 bar are 4.94, 5.65 and 4.80 mmol / g, respectively.

[0049] Table 3: Static CO adsorption capacity and working capacity of 20Cu(Ⅰ) / ZPC-Ⅱ, 30Cu(Ⅰ) / ZPC-Ⅱ and 40Cu(Ⅰ) / ZPC-Ⅱ at 25 °C and different pressures

[0050] .

[0051] Example 5: Dynamic penetration of CO and N2 binary components by Cu(Ⅰ) / ZPC-Ⅰ

[0052] Dynamic breakthrough experiments of CO / N2 were conducted using the 15Cu(Ⅰ) / ZPC-Ⅰ material prepared in Example 1. The 15Cu(Ⅰ) / ZPC-Ⅰ adsorbent was loaded into a stainless steel breakthrough column, with both ends of the column filled with quartz wool to support the sample. Before the breakthrough experiment, the sample was activated under vacuum and at 150-180 °C for 2-5 h. After cooling, the dynamic breakthrough experiment began. At a test temperature of 25 °C, a CO / N2 mixed gas with a volume ratio of 1:1 was introduced into the breakthrough column at a rate of 10 mL / min. The inlet gas flow rate was controlled by a mass flow meter, and the test pressure was controlled to 2 bar by a back pressure valve. The outlet gas was analyzed using a mass spectrometer to obtain the adsorption capacity breakthrough curve. After the gas adsorption capacity breakthrough experiment, the sample was desorbed at 0.2 bar for 0.5-1 h. Then, at a test temperature of 25 °C, a CO / N2 mixed gas with a volume ratio of 1:1 was passed through the breakthrough column again at a rate of 10 mL / min. The inlet gas flow rate was controlled by a mass flow meter, and the test pressure was controlled to 2 bar by a back pressure valve. The outlet gas was analyzed by a mass spectrometer to obtain the working capacity breakthrough curve.

[0053] Figure 7 The figure shows the breakthrough curves of 15Cu(Ⅰ) / ZPC-Ⅰ for a CO / N2 mixture with a volume ratio of 1:1 at 25 °C and a total pressure of 2 bar (CO partial pressure of 1 bar). The figure shows a significant difference in breakthrough times between CO and N2 in both the adsorption capacity curve (adsorption-desorption: 2.0–0.0 bar) and the working capacity curve (adsorption-desorption: 2.0–0.2 bar). N2 breaks through first, while CO is retained for a longer period. This is because the interaction force of 15Cu(Ⅰ) / ZPC-Ⅰ on CO is stronger than that on N2, thus enabling complete separation of the CO and N2 components by 15Cu(Ⅰ) / ZPC-Ⅰ. The dynamic adsorption capacity and working capacity of CO were calculated from the breakthrough curve. The results showed that at 25 °C and 2 bar total adsorption pressure, the CO adsorption capacity and working capacity of 15Cu(Ⅰ) / ZPC-Ⅰ for a CO / N2 mixture with a volume ratio of 1:1 were 4.17 and 3.10 mmol / g, respectively. Under the operating conditions of the adsorption capacity curve and the working capacity curve, the CO / N2 separation factors were 3.07 and 2.95, respectively, showing excellent CO / N2 separation effect.

[0054] Example 6: Dynamic penetration of CO and N2 binary components by Cu(Ⅰ) / ZPC-Ⅱ

[0055] Dynamic breakthrough experiments of CO / N2 were conducted using the 30Cu(Ⅰ) / ZPC-Ⅱ material prepared in Example 2. The 30Cu(Ⅰ) / ZPC-Ⅱ adsorbent was loaded into a stainless steel breakthrough column, with both ends of the column filled with quartz wool to support the sample. Before the breakthrough experiment, the sample was activated under vacuum and at 150-180 °C for 2-5 h. After cooling, the dynamic breakthrough experiment began. At a test temperature of 25 °C, a CO / N2 mixed gas with a volume ratio of 1:1 was introduced into the breakthrough column at a rate of 10 mL / min. The inlet gas flow rate was controlled by a mass flow meter, and the test pressure was controlled to 6 bar by a back pressure valve. The outlet gas was analyzed using a mass spectrometer to obtain the adsorption capacity breakthrough curve. After the gas adsorption capacity breakthrough experiment, the sample was desorbed at 0.2 bar for 0.5-1 h. Then, at 25 °C, a CO / N2 mixed gas with a volume ratio of 1:1 was passed through the breakthrough column again at a rate of 10 mL / min. The inlet gas flow rate was controlled by a mass flow meter, and the test pressure was controlled to 6 bar by a back pressure valve. The outlet gas was analyzed by a mass spectrometer to obtain the working capacity breakthrough curve.

[0056] Figure 8 The breakthrough curves of 30Cu(Ⅰ) / ZPC-Ⅱ for a CO / N2 mixture with a volume ratio of 1:1 at 25 °C and a total pressure of 6 bar (3 bar partial pressure of CO). The figure shows a significant difference in breakthrough times between CO and N2 in both the adsorption capacity curve (adsorption-desorption: 6.0–0.0 bar) and the working capacity curve (adsorption-desorption: 6.0–0.2 bar). N2 breaks through first, while CO is retained for a longer period. This is because the attraction of 30Cu(Ⅰ) / ZPC-Ⅱ for CO is stronger than that for N2, thus enabling complete separation of CO / N2 by 30Cu(Ⅰ) / ZPC-Ⅱ. The dynamic adsorption capacity and working capacity of CO were calculated from the breakthrough curve. The results showed that at 25 °C and 6 bar total adsorption pressure, the CO adsorption capacity and working capacity of 30Cu(Ⅰ) / ZPC-Ⅱ for a CO / N2 mixture with a volume ratio of 1:1 were 4.59 and 3.34 mmol / g, respectively. Under the operating conditions of the adsorption capacity curve and the working capacity curve, the CO / N2 separation factors were 2.22 and 1.84, respectively, showing excellent CO / N2 separation effect.

[0057] Table 4: Comparison of static CO adsorption capacity and working capacity between Cu(Ⅰ) / ZPC-Ⅰ and copper-based adsorbents in the literature

[0058]

[0059] Table Notes: a Corrected at 0.1-1 bar. b, c Values ​​recorded at 0.7 bar pressure; Table 4, references [1] to

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[0069]

[10] Vo T K, Le V N, Quang D T, et al. Facile synthesis of spraypyrolysis-derived CuCl / γ-Al2O3 microspheres and their properties for COadsorption and CO / CO2 separation[J]. Microporous and Mesoporous Materials,2021, 321: 111132.

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[11] Cho K, Kim J, Park J ho, et al. High CO adsorption capacity, andCO selectivity to CO2, N2, H2, and CH4 of CuCl / bayerite adsorbent[J].Microporous and Mesoporous Materials, 2019, 277: 142-148.

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[14] Peng J, Xian S, Xiao J, et al. A supported Cu(I)@MIL-100(Fe)adsorbent with high CO adsorption capacity and CO / N2 selectivity[J]. ChemicalEngineering Journal, 2015, 270: 282-289.

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[15] Wang Y, Li C, Meng F, et al. CuAlCl4 doped MIL-101 as a highcapacity CO adsorbent with selectivity over N2[J]. Frontiers of ChemicalScience and Engineering, 2014, 8(3): 340-345.

[0075] Table 4 lists the comparison of the static CO adsorption capacity at 1 bar and the CO working capacity at 0.1-1 bar between Cu(Ⅰ) / ZPC-Ⅰ prepared in Example 3 and typical copper-based adsorbents in existing literature. As can be seen from the table, the CO adsorption capacity and working capacity of Cu(Ⅰ) / ZPC-Ⅰ in this Example 3 are as high as 4.63 and 3.21 mmol / g, respectively, which are significantly higher than those of copper-based adsorbents reported in the literature.

[0076] Table 5: Comparison of static CO adsorption capacity and working capacity between Cu(Ⅰ) / ZPC-Ⅱ and copper-based adsorbents in the literature

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[0078] Table Notes: a Corrected at 0.1-3 bar; in Table 5, references [2] and [7] are consistent with those in Table 4, and reference

[16] is as follows:

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[16] Cho K, Kim J, Beum HT, et al. Synthesis of CuCl / Boehmiteadsorbents that exhibit high CO selectivity in CO / CO2 separation[J]. Journal of Hazardous Materials, 2018, 344: 857-864.

[0080] Table 5 lists the static CO adsorption capacity and working capacity of Cu(Ⅰ) / ZPC-Ⅱ prepared in Example 4 and copper-based adsorbents in existing literature at 3 bar and 0.1-3 bar. As can be seen from the table, the CO adsorption capacity and working capacity of Cu(Ⅰ) / ZPC-Ⅱ in this Example 4 are as high as 6.82 and 5.65 mmol / g, respectively, which far exceeds the copper-based adsorbents reported in the literature.

[0081] Table 6 shows the EXAFS fitting results of the 15Cu(Ⅰ) / ZPC-Ⅰ sample in Example 1, the 30Cu(Ⅰ) / ZPC-Ⅱ sample in Example 2, and the reference sample on the CuK-edge.

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[0083] Table 6 shows the Cu K-edge EXAFS spectral fitting results of Sample 15Cu(I) / ZPC-I and the reference sample in Example 1. The coordination numbers of Cu-O and Cu-Cl bonds are 1.1 and 1.4, respectively. It can be inferred that the configuration of Cu sites in 15Cu(I) / ZPC-I is an unsaturated dicoordinate (CO)CuCl unit. In Sample 30Cu(I) / ZPC-II of Example 2, the Cu K-edge EXAFS spectral fitting results of the reference sample show that the coordination numbers of Cu-O and Cu-Cl bonds are 0.6 and 2.4, respectively. It can be inferred that the configuration of Cu sites in 30Cu(I) / ZPC-II is: reactive intercalated dicoordinate (CO)CuCl units and tricoordinate (CO)CuCl2 units, as well as filled intercalated tricoordinate CuCl3 units.

Claims

1. A method of preparing an oxygen-containing porous carbon supported copper-based adsorbent, characterized by: The oxygen-containing porous carbon-supported copper-based adsorbent is prepared by loading CuCl2·2H2O onto a high specific surface area oxygen-containing microporous porous carbon support ZPC, and controlling the copper loading through a solid thermal dispersion method to obtain a copper-based adsorbent with high CO working capacity. The oxygen-containing microporous porous carbon support is prepared by using ZIF-8 as a precursor, followed by carbonization and activation. The oxygen content in the oxygen-containing microporous porous carbon support ZPC is 5.6%-8.5%, the pore size is 10-30 Å, and the BET surface area is 2714-3416 m². 2 / g, pore volume 1.52-2.01 cm³ 3 / g; A method for preparing an oxygen-containing porous carbon-supported copper-based adsorbent includes the following steps: (1) Preparation of ZIF-8, a precursor of oxygen-containing micro-mesoporous porous carbon: Zinc nitrate dihydrate: 2-methylimidazolium = 1:3 was dissolved in anhydrous methanol and added to a reaction vessel lined with polytetrafluoroethylene. After sealing, the mixture was placed in an oven at 90-110 °C for 2-3 days. After the reaction was completed and cooled to room temperature, the mixture was washed with anhydrous ethanol, filtered and dried to obtain ZIF-8. (2) Preparation of oxygen-containing micro-mesoporous porous carbon with high specific surface area: The ZIF-8 precursor obtained in step (1) was placed in a tube furnace and carbonized at high temperature for 3 h under Ar atmosphere. After cooling at room temperature, it was soaked in 1-1.5 mol / L hydrochloric acid for 12-24 h, washed with distilled water, and dried at room temperature to obtain carbonized porous carbon material. The carbonization temperature was 950-1000 °C and the heating rate was 2.5-5 °C / min. Then, the carbonized porous carbon material was thoroughly mixed and ground with potassium hydroxide at a mass ratio of 1:3.5-1:4.

5. The mixed sample was placed in a tube furnace and activated at high temperature for 1 h under Ar atmosphere. After cooling at room temperature, it was soaked in 2-2.5 mol / L hydrochloric acid solution for 12-24 h, washed with distilled water until neutral, and dried at room temperature to obtain oxygen-containing micro-mesoporous porous carbon. The activation temperature was 750-850 °C and the heating rate was 2.5-5 °C / min. (3) Preparation of copper-based adsorbents: CuCl2·2H2O and oxygen-containing microporous porous carbon obtained in step (2) were mixed and ground in different proportions of 1.71~5.65 g / g, and then placed in a tube furnace and calcined at 350 °C for 4-6 h under Ar atmosphere. After cooling to room temperature, copper-based adsorbents with different copper loadings were obtained.

2. The method of claim 1, wherein: Based on different copper loadings, two types of adsorbents, Cu(Ⅰ) / ZPC-Ⅰ and Cu(Ⅰ) / ZPC-Ⅱ, were prepared. The active structural unit of Cu(Ⅰ) / ZPC-Ⅰ adsorbent is (CO)CuCl, with a CO working capacity of 2.73~3.21 mmol / g and an adsorption-desorption pressure of 1 bar to 0.1 bar. In Cu(Ⅰ) / ZPC-Ⅱ adsorbent, CuCl2·2H2O reacts with oxygen-containing microporous carbon with high specific surface area to form two independent unsaturated Cu(Ⅰ) active adsorption sites: reactive intercalation type dicoordinate (CO)CuCl and tricoordinate (CO)CuCl2 units, and filled intercalation type tricoordinate CuCl3 units, with a CO working capacity of 4.80~5.65 mmol / g and an adsorption-desorption pressure of 3 bar to 0.1 bar.

3. The method of claim 1, wherein: In step (3), when the mass ratio of CuCl2·2H2O to porous carbon is 1.71~2.56 g / g, Cu(Ⅰ) / ZPC-Ⅰ adsorbent is prepared; the CO working capacity of Cu(Ⅰ) / ZPC-Ⅰ adsorbent at an adsorption-desorption pressure of 1-0.1 bar is 2.73~3.21 mmol / g; when the mass ratio of CuCl2·2H2O to oxygen-containing microporous porous carbon is 3.41~6.82 g / g, Cu(Ⅰ) / ZPC-Ⅱ adsorbent is prepared; the CO working capacity of Cu(Ⅰ) / ZPC-Ⅱ adsorbent at an adsorption-desorption pressure of 3-0.1 bar is 4.80-5.65 mmol / g.

4. The application of an oxygen-containing porous carbon-supported copper-based adsorbent prepared by the preparation method according to any one of claims 1 to 3 in the adsorption and separation of CO / N2.

5. Use according to claim 4, characterized in that: The adsorption separation performance test method is single-component static adsorption. The single-component static adsorption experiment is as follows: using the oxygen-containing porous carbon-supported copper-based adsorbent, the adsorbent is first activated under vacuum at 150-180 °C for 2-5 h; then, the adsorption capacity of CO and N2 is tested separately by a gravimetric adsorption analyzer at a test temperature of 25 °C, and the corresponding gas adsorption capacity is recorded under different pressures to obtain gas adsorption isotherms.

6. Use according to claim 4, characterized in that: The adsorption separation performance test method is a two-component dynamic breakthrough method. This method includes breakthrough tests under adsorption capacity conditions and breakthrough tests under working capacity conditions. Specifically, the oxygen-containing porous carbon-supported copper-based adsorbent is loaded into a stainless steel breakthrough column. The column is 12 cm high and has an inner diameter of 0.4 cm. The desorption pressure for adsorption capacity is the ultimate pressure of the vacuum pump. Before the breakthrough experiment, the breakthrough column containing the sample is evacuated to the ultimate pressure of the vacuum pump, and then heated to 150-180 °C for 3-5 h for activation. After cooling, at a test temperature of 25 °C, a CO / N2 mixed gas with a volume ratio of 1:1 is introduced into the breakthrough column at a rate of 10 mL / min. The inlet gas flow rate is controlled by a mass flow meter, the test pressure is adjusted by a back pressure valve, and the outlet gas is analyzed using a mass spectrometer to obtain the adsorption capacity breakthrough curve. The desorption pressure for working capacity is 0.2 bar. After the two-component gas adsorption capacity breakthrough experiment, the sample is desorbed at 0.2 bar for 0.5-1 h, and then at 25 °C... At a test temperature of ℃, a CO / N2 mixed gas with a volume ratio of 1:1 was passed through the penetration column again at a rate of 10 mL / min to obtain the working capacity breakthrough curve.

7. Use according to claim 5 or 6, characterized in that: The Cu(Ⅰ) / ZPC-Ⅰ adsorbent exhibits a CO adsorption capacity of 3.50–4.63 mmol / g at 1 bar, and a CO working capacity of 2.73–3.21 mmol / g at 298 K and an adsorption-desorption pressure of 1 bar–0.1 bar. The Cu(Ⅰ) / ZPC-Ⅱ adsorbent exhibits a CO adsorption capacity of 5.5–6.82 mmol / g at 3 bar, and a CO working capacity of 4.80–5.65 mmol / g at 298 K and an adsorption-desorption pressure of 3 bar–0.1 bar.

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