A nanosheet zeolite for CO2 adsorption, its preparation method and application

Abstract

This invention discloses a nanosheet zeolite for CO2 adsorption, its preparation method, and its application. The HZSM-5 nanosheet zeolite for CO2 adsorption has a b-axis thickness of <60 nm. This nanosheet zeolite combines the advantages of layered zeolites and nano-zeolites, reducing defects in the nanosheet framework, significantly shortening the axial thickness along the b-axis orientation, and clearly defining the crystal planes along the other two directions, resulting in better diffusion efficiency and improved surface accessibility. This further enhances the mass transfer rate during CO2 adsorption, thereby increasing the adsorption rate and reducing the risk of material pore blockage. The preparation method of HZSM-5 nanosheets includes (1) synthesis of a nanocrystal seed suspension; and (2) synthesis of HZSM-5 nanosheets. The HZSM-5 nanosheets provided by this invention can be applied in the field of carbon capture.

Description

Technical Field

[0001] This invention belongs to the field of CO2 adsorption materials, specifically relating to a nanosheet zeolite for CO2 adsorption and its preparation method. Background Technology

[0002] Climate change caused by CO2 has become a major global issue of widespread international concern. Reducing carbon emissions and utilizing carbon capture technology to enrich, recover, or store CO2 generated by industries such as coal-fired power plants is a crucial means to achieve carbon neutrality, ensure energy security, and promote sustainable development. For carbon capture of flue gas emitted from stationary CO2 emission sources such as coal-fired power plants, chemical absorption using monoethanolamine as the absorbent is the most widely used and mature carbon capture technology. However, bottlenecks such as high regeneration energy consumption and high corrosivity hinder the further promotion and application of this technology. Domestic and international scholars have conducted extensive research to develop new flue gas carbon capture technologies. Among these, highly efficient and stable zeolite solid adsorbents have received considerable attention. Their advantages lie in eliminating the sensible heat of solution heating and latent heat of vaporization during the regeneration process, significantly reducing energy consumption; furthermore, the adsorbent and reactor are in solid-solid contact, effectively avoiding equipment corrosion problems.

[0003] Zeolites are an important class of porous inorganic crystalline materials, mainly including silicates (germanium) (such as ZSM-5), phosphates (arsenates) (such as AIPO4-5), or silicate phosphates (such as SAPO-34). Due to their rich framework topologies and elemental compositions, zeolite molecular sieves have been widely used in ion exchange, adsorption separation, and catalysis since their synthesis. In the past decade, although zeolites have made some progress in CO2 adsorption, the space utilization and mass transfer limitations caused by the long microporous channels in traditional HZSM-5 (a three-dimensional zeolite material) remain unresolved issues. This not only results in low utilization efficiency of the zeolite's active volume but also limits the mass transfer efficiency during gas adsorption. The longer channels lead to CO2 enrichment, easily causing pore blockage and deactivation of the material. Summary of the Invention

[0004] The purpose of this invention is to address the shortcomings of existing technologies by providing a nanosheet zeolite for CO2 adsorption, its preparation method, and its application. By controlling the synthesis of nanosheet zeolite as a CO2 adsorbent, the adsorption rate and adsorption capacity can be improved, while reducing the risk of material pore blockage.

[0005] The present invention provides HZSM-5 nanosheet zeolite for CO2 adsorption, with a b-axis thickness of <60 nm. This nanosheet zeolite combines the advantages of layered zeolites and nano-zeolites, reducing defects in the nanosheet framework, significantly shortening the b-axis thickness, and clearly defining the crystal planes in the other two directions, resulting in better diffusion efficiency and improved surface accessibility. This further enhances the mass transfer rate during CO2 adsorption, thereby increasing the adsorption rate and capacity while reducing the risk of pore blockage.

[0006] The b-axis thickness of the aforementioned HZSM-5 nanosheet zeolite used for CO2 adsorption is preferably 20 nm < b-axis thickness < 60 nm.

[0007] The preparation method of the above-mentioned HZSM-5 nanosheet zeolite nanosheets for CO2 adsorption provided by the present invention includes the following steps:

[0008] (1) Synthesis of nanocrystal seed suspension

[0009] The nanocrystalline seed suspension was prepared under hydrothermal treatment. 10–60 parts by mass of tetraethyl orthosilicate (TEOS) were mixed with 50–80 parts by mass of tetrapropylammonium hydroxide and stirred at 20–40°C for 4–6 hours to obtain a clear hydrolyzed solution. The resulting solution was heated to 40–60°C to remove the ethanol produced by the hydrolysis of TEOS. The solution was then transferred to a stainless steel autoclave lined with polytetrafluoroethylene and hydrothermally treated at 50–90°C under static conditions for 24–72 hours to obtain a nanocrystalline seed suspension with a size of 20 nm.

[0010] (2) Synthesis of HZSM-5 nanosheets

[0011] A solution A is prepared by mixing a silicon source, an organic base, a template agent, deionized water, and a nanocrystal seed suspension. An aluminum source and NH4F are dissolved in deionized water to prepare solutions B and C, respectively. After stirring solution A at 30–40°C for 4–6 hours, solutions B and C are added dropwise sequentially to obtain a mixed solution. The mixed solution is then vigorously stirred for 1–2 hours to obtain a precursor gel. The resulting gel is transferred to a stainless steel autoclave lined with polytetrafluoroethylene (PTFE) and crystallized at 150–170°C for 1 day. The solid product is centrifuged 2–3 times, rinsed with deionized water until neutral, dried at 80–100°C for 12–24 hours, and then calcined in air at 500–600°C for 4–6 hours to obtain HZSM-5 nanosheets.

[0012] The molar ratio of the total amount of silicon source, aluminum source, organic base, template agent, NH4F, and deionized water used is SiO2:Al2O3:organic base:template agent:NH4F:H2O as 1:(0.001~0.1):(0.01~0.8):(0.01~0.5):(0.01~1):(100~200). That is, the amount of silicon source is calculated based on the proportion of SiO2, the amount of aluminum source is calculated based on the proportion of aluminum oxide Al2O3, and the deionized water is the total amount of deionized water used in this step. The amount of nanocrystal seed suspension added accounts for 1~100% of the mass percentage of SiO2.

[0013] In the above method, the amount of the added nanocrystalline seed suspension is 20-50% of the mass percentage of SiO2.

[0014] In the above method, the molar ratio of the total amount of silicon source, aluminum source, organic base, template agent, NH4F, and deionized water used is preferably 1:0.0025:0.04:0.1:0.8:180, according to the formula SiO2:Al2O3:organic base:template agent:NH4F:H2O.

[0015] In the above method, the silicon source is further selected from at least one of tetraethyl orthosilicate and silica sol.

[0016] In the above method, the organic base is further selected from at least one of tetramethylammonium hydroxide, tetraethylammonium hydroxide, tetrapropylammonium hydroxide, or tetrabutylammonium hydroxide.

[0017] In the above method, the template agent is further selected from at least one of tetramethylammonium bromide, tetraethylammonium bromide, tetrapropylammonium bromide, and tetrabutylammonium bromide.

[0018] In the above method, the aluminum source is further selected from at least one of aluminum nitrate, aluminum trichloride, and aluminum isopropoxide.

[0019] The present invention also provides the application of the above-mentioned HZSM-5 nanosheets in the field of carbon capture. Preferably, the application is as a CO2 adsorbent.

[0020] Compared with the prior art, the present invention has the following beneficial effects:

[0021] The HZSM-5 nanosheet zeolite described in this invention has a b-axis thickness of <60 nm. This nanosheet zeolite combines the advantages of layered zeolites and nano-zeolites, reducing defects in the nanosheet framework and significantly shortening the thickness along the b-axis orientation, while maintaining well-defined crystal planes in the other two directions. This effectively improves the diffusion mass transfer rate during CO2 adsorption, thereby increasing CO2 adsorption capacity and reducing the risk of material pore blockage. As a result, the HZSM-5 nanosheet zeolite is expected to maintain stable adsorption performance during multiple CO2 adsorption-desorption cycles. Attached Figure Description

[0022] Figure 1 SEM images (including b-axis thickness distribution maps) of nanosheets with different b-axis thicknesses: (a) N-25; (b) N-35; (c) N-40; (d) N-60; (e) N-90; (f) N-250;

[0023] Figure 2 XRD patterns of nanosheet zeolites with different b-axis thicknesses;

[0024] Figure 3 The N2 physical adsorption isotherms (Fig. a) and pore size distribution (Fig. b) are shown for nanosheets with different b-axis thicknesses. Detailed Implementation

[0025] The present invention will be further illustrated below through embodiments. It should be noted that the following embodiments are only used to further illustrate the present invention and should not be construed as limiting the scope of protection of the present invention. Those skilled in the art can make some non-essential improvements and adjustments to the present invention based on the above-described invention, and these improvements and adjustments still fall within the scope of protection of the invention.

[0026] In the following examples, the prepared HZSM-5 nanosheets are denoted as Nx, where x is the b-axis thickness of the HZSM-5 nanosheets.

[0027] Example 1

[0028] (1) Synthesis of nanocrystal seed suspension

[0029] The nanocrystalline seed suspension was prepared under hydrothermal treatment. 40 g of tetraethyl orthosilicate (TEOS) was mixed with 60 g of tetrapropylammonium hydroxide and stirred at 35 °C for 6 hours to obtain a clear hydrolyzed solution. Then, the mixture was heated to 60 °C to remove the ethanol produced by the hydrolysis of TEOS. Finally, the solution was transferred to a stainless steel autoclave lined with polytetrafluoroethylene and hydrothermally treated at 70 °C under static conditions for 72 hours to obtain the nanocrystalline seed suspension.

[0030] (2) Synthesis of HZSM-5 nanosheets

[0031] Solution A was prepared by dissolving tetraethyl orthosilicate, tetrapropylammonium hydroxide, tetrabutylammonium bromide, and a suspension of nanocrystals in a certain amount of water. Solutions B and C were prepared by dissolving aluminum nitrate and NH4F in deionized water, respectively. After stirring solution A at 35°C for 6 hours, solutions B and C were added dropwise sequentially. The mixture was stirred vigorously for another 2 hours to obtain a precursor gel, which was then transferred to a stainless steel autoclave lined with polytetrafluoroethylene. After crystallization at 170°C for 1 day, the solid product was repeatedly centrifuged, rinsed with deionized water until neutral, and dried overnight at 80°C. Subsequently, the product was calcined in an air atmosphere in a muffle furnace at 550°C for 6 hours to obtain HZSM-5 nanosheets, labeled N-25. The molar ratio of each component is 1:0.0025:0.04:0.1:0.8:180 for SiO2:Al2O3:organic base:template agent:NH4F:H2O, and the amount of nanocrystal seed suspension added is 50wt% of the mass of SiO2.

[0032] Experimental process

[0033] 1. Adsorption experiment

[0034] The CO2 adsorption capacity of HZSM-5 adsorbent over time was determined using a MetTLER thermogravimetric analyzer. Approximately 10 mg of adsorbent was placed in an alumina sample dish before each adsorption experiment. Initial activation was performed at 120 °C in an Ar (99.999%) atmosphere for 1 hour to remove impurities and moisture from the sample. Adsorption was then performed at 80 °C in a high-purity CO2 (99.999%) atmosphere for 1 hour, followed by desorption in Ar at 120 °C for 30 minutes. All gas flow rates were maintained at 30 mL / min at atmospheric pressure throughout the experiment, and the gas type was controlled by a switch valve.

[0035] 2. Adsorption capacity calculation

[0036] The amount of adsorbent adsorbed is calculated based on the change in weight of the adsorbent over time during the adsorption process.

[0037]

[0038] In the formula, q is the equilibrium CO2 adsorption capacity of the zeolite (mmol / g), m0 is the initial mass percentage (%) of the zeolite sample at the start of CO2 adsorption, and m c The percentage of the sample mass after adsorption equilibrium is %, and M is the relative molecular mass of CO2 (M = 44 g / mol).

[0039] Example 2

[0040] The method for synthesizing the nanocrystal seed suspension is the same as in Example 1.

[0041] Solution A was prepared by dissolving silica sol, tetrapropylammonium hydroxide, tetramethylammonium bromide, and a suspension of nanocrystals in a certain amount of water. Solutions B and C were prepared by dissolving aluminum trichloride and NH4F in deionized water, respectively. After stirring solution A at 35°C for 6 hours, solutions B and C were added dropwise sequentially. The mixture was stirred vigorously for another 2 hours to obtain a precursor gel, which was then transferred to a stainless steel autoclave lined with polytetrafluoroethylene. After crystallization at 170°C for 1 day, the solid product was repeatedly centrifuged, rinsed with deionized water until neutral, and dried overnight at 80°C. Subsequently, the product was calcined in a muffle furnace at 550°C for 6 hours under air atmosphere to obtain HZSM-5 nanosheets, labeled N-35. The molar ratio of each component is 1:0.0025:0.04:0.1:0.8:180 for SiO2:Al2O3:organic base:template agent:NH4F:H2O, and the amount of nanocrystal seed suspension added is 20wt% of the mass of SiO2.

[0042] The adsorption experiment and the method for calculating the adsorption amount are the same as in Example 1.

[0043] Example 3

[0044] The method for synthesizing the nanocrystal seed suspension is the same as in Example 1.

[0045] Solution A was prepared by dissolving silica sol, tetraethylammonium bromide, tetrabutylammonium bromide, and a suspension of nanocrystals in a certain amount of water. Solutions B and C were prepared by dissolving aluminum isopropoxide and NH4F in deionized water, respectively. After stirring solution A at 35°C for 6 hours, solutions B and C were added dropwise sequentially. The mixture was stirred vigorously for another 2 hours to obtain a precursor gel, which was then transferred to a stainless steel autoclave lined with polytetrafluoroethylene. After crystallization at 170°C for 1 day, the solid product was repeatedly centrifuged, rinsed with deionized water until neutral, and dried overnight at 80°C. Subsequently, the product was calcined in a muffle furnace at 550°C for 6 hours under air atmosphere to obtain HZSM-5 nanosheets, labeled N-40. The molar ratio of each component is 1:0.0025:0.04:0.1:0.8:180 for SiO2:Al2O3:organic base:template agent:NH4F:H2O, and the amount of nanocrystal seed suspension added is 5wt% of the mass of SiO2.

[0046] The adsorption experiment and the method for calculating the adsorption amount are the same as in Example 1.

[0047] Example 4

[0048] The method for synthesizing the nanocrystal seed suspension is the same as in Example 1.

[0049] Solution A was prepared by dissolving tetraethyl orthosilicate, tetrapropylammonium bromide, tetraethylammonium bromide, and a suspension of nanocrystal seeds in a certain amount of water. Solutions B and C were prepared by dissolving aluminum isopropoxide and NH4F in deionized water, respectively. After stirring solution A at 35°C for 6 hours, solutions B and C were added dropwise sequentially. The mixture was stirred vigorously for another 2 hours to obtain a precursor gel, which was then transferred to a stainless steel autoclave lined with polytetrafluoroethylene. After crystallization at 170°C for 1 day, the solid product was repeatedly centrifuged, rinsed with deionized water until neutral, and dried overnight at 80°C. Subsequently, the product was calcined in an air atmosphere at 550°C for 6 hours to obtain HZSM-5 nanosheets, labeled N-60. The molar ratio of each component was 1SiO2:0.01Al2O3:0.1 organic base:0.05 template agent:0.8NH4F:120H2O, and the amount of nanocrystal seed suspension added was 1 wt% of the mass of SiO2.

[0050] The adsorption experiment and the method for calculating the adsorption amount are the same as in Example 1.

[0051] Comparative Example 1

[0052] The method for synthesizing the nanocrystal seed suspension is the same as in Example 1.

[0053] Solution A was prepared by dissolving tetraethyl orthosilicate, tetrabutylammonium bromide, tetramethylammonium bromide, and a suspension of nanocrystal seeds in a certain amount of water. Solutions B and C were prepared by dissolving aluminum nitrate and NH4F in deionized water, respectively. After stirring solution A at 35°C for 6 hours, solutions B and C were added dropwise sequentially. The mixture was stirred vigorously for another 2 hours to obtain a precursor gel, which was then transferred to a stainless steel autoclave lined with polytetrafluoroethylene. After crystallization at 170°C for 1 day, the solid product was repeatedly centrifuged, rinsed with deionized water until neutral, and dried overnight at 80°C. Subsequently, the product was calcined in a muffle furnace at 550°C for 6 hours under air atmosphere to obtain HZSM-5 nanosheets, labeled N-90. The molar ratio of each component was 1SiO2:0.01Al2O3:0.1 organic base:0.05 template agent:0.8NH4F:120H2O, and the amount of nanocrystal seed suspension added was 0.1 wt% of the mass of SiO2.

[0054] The adsorption experiment and the method for calculating the adsorption amount are the same as in Example 1.

[0055] Comparative Example 2

[0056] The method for synthesizing the nanocrystal seed suspension is the same as in Example 1.

[0057] Solution A was prepared by dissolving silica sol, tetraethylammonium hydroxide, tetrabutylammonium bromide, and a suspension of nanocrystals in a certain amount of water. Aluminum trichloride and NH4F were dissolved in deionized water, respectively, to prepare solutions B and C. After stirring solution A at 35°C for 6 hours, solutions B and C were added dropwise sequentially. The mixed solution was stirred vigorously for another 2 hours to obtain a precursor gel, which was then transferred to a stainless steel autoclave lined with polytetrafluoroethylene. After crystallization at 170°C for 1 day, the solid product was repeatedly centrifuged, rinsed with deionized water until neutral, and dried overnight at 80°C. Subsequently, the product was calcined in a muffle furnace at 550°C for 6 hours under air atmosphere to obtain HZSM-5 nanosheets, labeled N-250. The molar ratio of each component was 1SiO2:0.01Al2O3:0.1 organic base:0.05 template agent:0.8NH4F:120H2O, and the amount of nanocrystal suspension added was 0.01 wt% of the mass of SiO2.

[0058] The adsorption experiment and the method for calculating the adsorption amount are the same as in Example 1.

[0059] Comparative Example 3

[0060] The adsorption experiment and the method for calculating the adsorption amount were the same as in Example 1. Commercially available Nankai University HZSM-5 zeolite was purchased as a comparison, denoted as NK-Z5 (b-axis thickness of 700 nm).

[0061] Nanosheet zeolites with different b-axis thicknesses were synthesized by adjusting the amount of nanocrystal seeds. SEM images ( Figure 1 The successful synthesis of nanosheets was confirmed, with average b-axis thicknesses of 25, 35, 40, 60, 90, and 250 nanometers. Further research... Figure 2 It can be seen that the synthesized nanosheet zeolite samples with different b-axis thicknesses all showed diffraction peaks at 7.9°, 8.8°, 23.1°, 23.9° and 24.3°, showing the typical MFI topology of HZSM-5, indicating that adjusting the nanosheet thickness did not change its structural characteristics.

[0062] N2 physical adsorption isotherm ( Figure 3 a) The results show that nanosheets of different b-axis thicknesses exhibit typical type I adsorption, indicating that HZSM-5 nanosheets all possess a microporous structure. The adsorption capacity increases sharply at very low P / P0 ratios because the interaction between the adsorbent and adsorbate is enhanced within the narrow micropores, leading to micropore filling at extremely low relative pressures; however, when the saturation pressure is reached, adsorbate aggregation occurs, causing the curve to rise. Pore size distribution curve ( Figure 3 b) shows that as the thickness of the b-axis decreases, the pore size in the HZSM-5 nanosheets gradually increases, and the larger pore size is conducive to the diffusion and adsorption of CO2.

[0063] Table 1 shows that for HZSM-5 nanosheet zeolite adsorbents, the CO2 adsorption capacity first increases and then decreases with decreasing b-axis thickness (700 nm → 25 nm). Adsorbents with a thickness less than 60 nm exhibit CO2 adsorption capacities exceeding 0.5 mmol / g, superior to HZSM-5 nanosheet zeolite adsorbents with b-axis thicknesses greater than 60 nm and commercial zeolite (NK-Z5). Among these, the N-35 adsorbent with a thickness of 35 nm demonstrates the best adsorption capacity, reaching 0.77 mmol / g, confirming that reducing the b-axis thickness of the zeolite crystals effectively reduces the CO2 diffusion path length, thereby improving the CO2 adsorption capacity.

[0064] Table 2 shows that as the thickness of the nanosheet zeolite decreases, the specific surface area first increases and then decreases, while the pore volume consistently increases. Adsorbents with a thickness less than 60 nm have superior pore volumes compared to adsorbents with a b-axis thickness greater than 60 nm and commercial zeolites. The pore structure and specific surface area of ​​zeolite are the main factors affecting its adsorption performance. Micropores and mesopores in zeolite have different functions for CO2 adsorption. Micropores provide active sites for CO2 adsorption, but their narrow channels significantly restrict the diffusion of gas molecules, prolonging the reaction time and causing gas molecules to become trapped in the pore channels, leading to adsorbent blockage and deactivation. Mesopores, on the other hand, allow gas molecules to diffuse out of the pores immediately, greatly reducing diffusion resistance and increasing the adsorption rate. Therefore, to maximize the function of zeolite, the synergistic effect between mesopores, which facilitate efficient mass transfer, and micropores, which provide active sites, is necessary. Regarding specific surface area, a larger specific surface area provides more active sites for CO2 adsorption, thereby increasing the adsorbent's CO2 adsorption capacity. Based on the above factors, adsorbents with a thickness of less than 60 nm exhibit better CO2 adsorption performance. Furthermore, although the thickness of N-35 nano-zeolite is slightly greater than that of N-25, the combined effect of its specific surface area and mesoporous ratio results in a greater number of active sites within its pores capable of adsorbing CO2, making adsorption easier to occur.

[0065] Table 1 Comparison of adsorbent thickness and CO2 adsorption capacity in the examples

[0066]

[0067] Table 2 Comparison of specific surface area and pore volume of adsorbents in the examples

[0068]

Claims

1. An application of HZSM-5 nanosheet zeolite nanosheets for CO2 adsorption as a CO2 adsorbent, characterized in that, The HZSM-5 nanosheets b Shaft thickness ≤ 25nm b The shaft thickness is <60 nm, and it is prepared by the following method: (1) Synthesis of nanocrystal seed suspension The nanocrystalline seed suspension was prepared under hydrothermal treatment by mixing 10-60 parts by mass of tetraethyl orthosilicate with 50-80 parts by mass of tetrapropylammonium hydroxide and stirring at 20-40°C for 4-6 hours to obtain a clear hydrolyzed solution. The resulting clear solution was heated to 40-60°C to remove the ethanol produced by the hydrolysis of TEOS; The solution was then transferred to a stainless steel autoclave lined with polytetrafluoroethylene and hydrothermally treated at 50–90°C under static conditions for 24–72 hours to obtain a suspension of nanocrystal seeds with a size of 20 nm. (2) Synthesis of HZSM-5 nanosheets A solution A is prepared by mixing a silicon source, an organic base, a template agent, deionized water, and a nanocrystal seed suspension. An aluminum source and NH4F are dissolved in deionized water to prepare solutions B and C, respectively. After stirring solution A at 30–40°C for 4–6 hours, solutions B and C are added dropwise sequentially to obtain a mixed solution. The mixed solution is then vigorously stirred for 1–2 hours to obtain a precursor gel. The obtained precursor gel is transferred to a stainless steel autoclave lined with polytetrafluoroethylene (PTFE) and crystallized at 150–170°C for 1 day. The solid product is centrifuged 2–3 times, rinsed with deionized water until neutral, dried at 80–100°C for 12–24 hours, and then calcined in air at 500–600°C for 4–6 hours to obtain HZSM-5 nanosheets. The molar ratio of the total amount of silicon source, aluminum source, organic base, template agent, NH4F, and deionized water used is SiO2:Al2O3:organic base:template agent:NH4F:H2O = 1:(0.001~0.1):(0.01~0.8):(0.01~0.5):(0.01~1):(100~200). That is, the amount of silicon source is calculated based on the proportion of SiO2, the amount of aluminum source is calculated based on the proportion of aluminum oxide (Al2O3), and the amount of deionized water is the total amount of deionized water used in this step. The amount of nanocrystalline seed suspension added accounts for 20~50% of the mass percentage of SiO2. The silicon source is at least one of tetraethyl orthosilicate and silica sol; The organic base is at least one of tetramethylammonium hydroxide, tetraethylammonium hydroxide, tetrapropylammonium hydroxide, or tetrabutylammonium hydroxide; The template agent is at least one of tetramethylammonium bromide, tetraethylammonium bromide, tetrapropylammonium bromide, and tetrabutylammonium bromide; The aluminum source is at least one of aluminum nitrate, aluminum trichloride, and aluminum isopropoxide.

2. The application according to claim 1, characterized in that, The molar ratio of the total amount of silicon source, aluminum source, organic base, template agent, NH4F, and deionized water used is SiO2: Al2O3: organic base: template agent: NH4F: H2O as 1: 0.0025: 0.04: 0.1: 0.8: 180.

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