Molecular sieve adsorbent for adsorbing ethylene as well as preparation method and application of molecular sieve adsorbent
Patent Information
- Application Number
- CN202510539837.1
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-04-27
- Publication Date
- 2025-08-15
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Abstract
Description
Technical Field
[0001] The present invention relates to the technical field of food preservation, and in particular to a molecular sieve adsorbent for adsorption, a preparation method thereof and an application thereof. Background Art
[0002] During the post-harvest storage and transportation of fruits and vegetables, ethylene is a key plant hormone that promotes ripening and aging, and its concentration control directly affects the physiological activity and quality retention of the products.
[0003] To effectively adsorb ethylene from food packaging, current mainstream technologies include two categories: adsorption (such as MOF materials and zeolite molecular sieves) and oxidation (such as KMnO4-loaded systems). However, with the increasing demand for food safety and diverse packaging, there is an urgent need for safer adsorbents with enhanced ethylene adsorption capabilities. Summary of the Invention
[0004] The present invention provides a metal adsorbent for adsorbing ethylene, a preparation method thereof, and an application thereof. During the preparation process of the adsorbent, copper nitrate is added to react after a silicon source and a titanium source are mixed but before a skeleton is fully formed, thereby significantly improving the adsorption capacity of the resulting adsorbent for ethylene. This method is also more conducive to the adsorption of ethylene by copper ions (in a non-reduced state). In addition, the molecular sieve adsorbent prepared by the present invention has excellent ethylene adsorption capabilities, can effectively reduce the ethylene concentration in food packaging, and extend the shelf life of food.
[0005] In the first aspect, the present invention provides a method for preparing a molecular sieve adsorbent for adsorbing ethylene, comprising: mixing a gel-like substance containing a silicon source, a titanium source and a first template with a mixture containing Cu 2+ Mixing with a solution of a second template and performing a hydrothermal reaction to obtain a colloid; The colloid is pretreated and then calcined to obtain the molecular sieve adsorbent.
[0006] According to the method for preparing the molecular sieve adsorbent for adsorbing ethylene provided by the present invention, the mass ratio of the titanium source to the silicon source is 0.5-1.5:15-25; According to the preparation method of the molecular sieve adsorbent for adsorbing ethylene provided by the present invention, the silicon source is selected from one or a combination of two or more of tetraethyl orthosilicate, tetramethyl orthosilicate, tetrapropyl orthosilicate, tetraisopropoxysilane and trifluoropropyltriethoxysilane; preferably tetraethyl orthosilicate.
[0007] According to the preparation method of the molecular sieve adsorbent for adsorbing ethylene provided by the present invention, the titanium source is selected from one or a combination of two or more of tetrabutyl titanate, tetraisopropyl titanate, tetraethyl titanate, bis(acetylacetonato) diisopropoxy titanate, polybutyl titanate and diisopropyl acetylacetonate titanate; preferably tetrabutyl titanate.
[0008] According to the method for preparing the molecular sieve adsorbent for adsorbing ethylene provided by the present invention, the first template is tetrapropylammonium hydroxide.
[0009] According to the method for preparing the molecular sieve adsorbent for adsorbing ethylene provided by the present invention, the second template is tetraethylenepentamine.
[0010] According to the method for preparing the molecular sieve adsorbent for adsorbing ethylene provided by the present invention, a silicon source, tetrapropylammonium hydroxide and water are mixed to obtain a first solution; mixing a titanium source with an alcohol to obtain a second solution; mixing the first solution and the second solution to obtain a third solution; heating the third solution to obtain a gel-like substance; Copper nitrate, tetraethylenepentamine and water are mixed to prepare a Cu-TEPA solution; mixing the gel-like substance and the Cu-TEPA solution to obtain a mixture; subjecting the mixture to a hydrothermal reaction to obtain a colloid; The colloid is centrifuged, washed, dried and calcined to obtain the molecular sieve adsorbent.
[0011] According to the method for preparing the molecular sieve adsorbent for adsorbing ethylene provided by the present invention, the mass ratio of the silicon source to tetrapropylammonium hydroxide is 15-25:5-10.
[0012] According to the method for preparing the molecular sieve adsorbent for adsorbing ethylene provided by the present invention, the mass concentration of the silicon source in the first solution is 25-35%.
[0013] According to the method for preparing the molecular sieve adsorbent for adsorbing ethylene provided by the present invention, the mass concentration of the titanium source in the second solution is 5-10%.
[0014] According to the method for preparing the molecular sieve adsorbent for adsorbing ethylene provided by the present invention, the mass ratio of copper nitrate to tetraethylenepentamine is 3-5:3-4.
[0015] According to the method for preparing the molecular sieve adsorbent for adsorbing ethylene provided by the present invention, the mass concentration of copper nitrate trihydrate in the Cu-TEPA solution is 2-6%.
[0016] According to the method for preparing the molecular sieve adsorbent for adsorbing ethylene provided by the present invention, the mass ratio of the amount of copper nitrate trihydrate added to the mixture to the tetraethyl orthosilicate used to form the gel-like substance is 0.3-0.5:15-25.
[0017] The method for preparing the molecular sieve adsorbent for adsorbing ethylene provided by the present invention comprises: Mixing tetraethyl orthosilicate and tetrapropylammonium hydroxide aqueous solution, then adding deionized water and stirring until a first solution is formed; dissolving tetrabutyl titanate in isopropyl alcohol to obtain a second solution; mixing the second solution and the first solution to obtain a third solution; Heating the third solution to 50-70° C. and stirring at a stirring speed of 300-400 rpm for 2-4 hours to form a gel-like substance; Dissolve copper nitrate trihydrate in water and mix with tetraethylenepentamine to obtain Cu-TEPA solution; The Cu-TEPA solution was added to the gel-like substance and stirred at a stirring speed of 300-400 rpm for 2-4 hours to obtain a mixture; The mixture is reacted under hydrothermal conditions at a reaction temperature of 150-180°C for more than 36 hours to obtain a colloid; The colloidal mixture is centrifuged to collect solid powder, which is then washed with water, dried, and finally calcined in air at a calcination temperature of 500-600° C. for 5-8 hours, followed by cooling to obtain the molecular sieve adsorbent; In order to prepare an adsorbent with excellent performance, it is necessary to fully stir the silicon source and titanium source during the water bath heating process and add the Cu 2+ The solution of the second template also needs to be fully stirred to ensure uniform dispersion.
[0018] In a second aspect, the present invention also provides a molecular sieve adsorbent for adsorbing ethylene prepared by the preparation method described above.
[0019] The molecular sieve adsorbent comprises: silicon, copper and titanium; Among them, silicon, copper and titanium are all part of the molecular sieve adsorbent skeleton; the silicon element mainly exists in the form of tetrahedral coordination, which serves as the main structure of the molecular sieve adsorbent skeleton; Copper is mainly Cu 2+ The titanium element exists in the form of oxidation state and coordination state, and serves as the secondary active component of the molecular sieve adsorbent framework.
[0020] According to the molecular sieve adsorbent for adsorbing ethylene provided by the present invention, the specific surface area of the molecular sieve adsorbent is greater than 400.
[0021] In a third aspect, the present invention further provides the use of the molecular sieve adsorbent as described above, or the molecular sieve adsorbent prepared by the preparation method as described above, in the adsorption of ethylene in the food field.
[0022] The present invention provides a metal adsorbent for adsorbing ethylene, a preparation method thereof, and an application thereof. By adding copper nitrate to the mixture after a silicon source and a titanium source are mixed but before a skeleton is fully formed, the adsorption capacity of the resulting adsorbent for ethylene can be significantly improved, with the ethylene adsorption amount reaching 0.045 mmol / g. The adsorbent has good cyclic adsorption stability at 0°C and can maintain relatively stable adsorption performance over multiple adsorption-desorption cycles. Furthermore, this method is more conducive to the adsorption of ethylene by copper ions (in a non-reduced state). In addition, the molecular sieve adsorbent prepared by the present invention has an excellent catalytic elimination function for ethylene, can effectively reduce the ethylene concentration in food packaging, and extend the shelf life of food. BRIEF DESCRIPTION OF THE DRAWINGS
[0023] In order to more clearly illustrate the technical solutions in the present invention or the prior art, a brief introduction is given below to the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.
[0024] Figure 1 This is the XPS spectrum of Cu@TS-1 of Example 1 provided by the present invention, wherein (a) is the full spectrum, (b) is the fine spectrum of the 2p orbital of the Cu element, (c) is the fine spectrum of the 2p orbital of the Si element, and (d) is the fine spectrum of the 2p orbital of the Ti element.
[0025] Figure 2 1 is the Fourier transform infrared (FT-IR) spectrum of Cu@TS-1 of Example 1 provided by the present invention. The black line represents the Fourier transform infrared (FT-IR) spectrum of Cu@TS-1 before ethylene adsorption, and the red line represents the Fourier transform infrared (FT-IR) spectrum of Cu@TS-1 after ethylene adsorption.
[0026] Figure 3 This is a graph of the ethylene adsorption capacity of Cu@TS-1 of Example 1, Comparative Example 1, and Comparative Example 2 provided by the present invention, wherein 2% corresponds to Example 1, 2.17% rotary evaporation corresponds to Comparative Example 2, and 1.815% reduction corresponds to Comparative Example 1.
[0027] Figure 4This is a penetration curve diagram of Cu@TS-1 of Example 1 provided by the present invention, wherein 2% corresponds to Example 1, 2.17% rotary evaporation corresponds to Example 2, and 1.815% reduction corresponds to Example 1.
[0028] Figure 5 This is a graph showing the adsorption-desorption cycle test results of Cu@TS-1 according to Example 1 of the present invention. DETAILED DESCRIPTION
[0029] To make the objectives, technical solutions, and advantages of the present invention more clear, the technical solutions of the present invention will be clearly and completely described below in conjunction with the accompanying drawings. Obviously, the embodiments described are only some of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts shall fall within the scope of protection of the present invention.
[0030] The following combination Figures 1 to 5 The present invention describes a metal adsorbent for adsorbing and eliminating ethylene, a preparation method thereof and an application thereof.
[0031] If no specific techniques or conditions are specified in the examples, the experiments were carried out according to the techniques or conditions described in the literature in the field or according to the product instructions. If no manufacturer is specified for the reagents or instruments used, they are all conventional products that can be purchased through regular channels.
[0032] Example 1 A method for preparing a molecular sieve adsorbent for adsorbing and eliminating ethylene comprises the following steps: (1) Tetraethyl orthosilicate (TEOS, 20.35 g, 98%) and tetrapropylammonium hydroxide aqueous solution (TPAOH, 7.13 g, 40 wt%) were mixed, and then deionized water (31 mL) was added and stirred until a clear solution was formed.
[0033] (2) Tetrabutyl titanate (TBOT, 1.08 g, 99%) was dissolved in isopropyl alcohol (13.04 g, 99.5%) and then added to the clear solution. The resulting mixed solution was then heated in a water bath at 333 K (60°C) and stirred at 350 rpm for 3 h to form a gel-like substance, which was designated as TS-1 starting gel.
[0034] (3) Copper nitrate trihydrate (Cu(NO3)2·3H2O, 0.43 g, 99.99%) was dissolved in deionized water (10 mL) and mixed with tetraethylenepentamine (TEPA, 0.37 g, 95%) to produce a Cu-TEPA solution with a dark blue color.
[0035] (4) The Cu-TEPA solution was added to the TS-1 starting gel and stirred at a stirring speed of 350 rpm for 3 h to obtain a mixture; the mixture was then placed in a Teflon-lined stainless steel autoclave and then placed in an oven under hydrothermal conditions at 170 °C for 48 h. The colloidal mixture was taken out and stirred thoroughly, and the resulting solid powder was collected by centrifuge, then washed three times with deionized water and dried overnight in an electric constant temperature drying oven at 100 °C. Finally, the obtained solid adsorbent was calcined at 550 °C in air for 6 h, and then rapidly cooled to room temperature to obtain a molecular sieve adsorbent, which was recorded as 2%Cu@TS-1.
[0036] Comparative Example 1 A method for preparing an adsorbent, the process is as follows: 1 g of 2-Cu@TS-1 prepared in Example 1 was immersed in 10 ml of deionized water for dissolution, and stirred at 300 rpm for 2 h to obtain a 2-Cu@TS-1 mixture.
[0037] 0.1176 g of NaBH4 was added to 10 ml of deionized water to dissolve, and then transferred to a fume hood for operation. It was added dropwise to the above 2-Cu@TS-1 mixture and vigorously stirred at 25 °C for 1 hour. The solution was observed to turn from white to black. Then it was washed with deionized water 5 times in a centrifuge to make the pH value of the solution neutral. The solid powder was collected and dried in a vacuum oven at 100 °C overnight. Finally, the obtained solid adsorbent was calcined in air at 550 °C for 6 hours, and then rapidly cooled to room temperature to finally obtain reduced 1.815% Cu@TS-1.
[0038] Comparative Example 2 Weigh 2.5 g of TS-1, then dissolve 0.1937 g of copper nitrate trihydrate in deionized water and stir thoroughly to dissolve it. Add TS-1 to the distillation flask of the rotary evaporator, and then slowly add the copper nitrate mixture. Set the temperature of the water bath to 35°C and the speed to 60 rpm. After fully reacting for about 30 minutes, only solid powder remains in the distillation flask. Turn off the rotary evaporator and take out the powder, which is 2.17% Cu / TS-1 synthesized by rotary evaporation.
[0039] Test Example 1 The 2%Cu@TS-1 prepared in Example 1 was characterized and analyzed by XPS. The results are as follows: Figure 1 Figure (a) shows the characteristic peaks of all elements in the adsorbent. Clear peaks such as Cu 2p, Si 2p, and Ti 2p are visible, indicating the presence of copper, silicon, and titanium. Additionally, peaks such as O 1s indicate the presence of oxygen. The presence of these peaks confirms the primary elemental composition of the adsorbent.
[0040] The refined spectrum of the Cu 2p orbital, shown in Figure (b), shows two major peaks at approximately 933.8 eV and 952.45 eV, corresponding to the binding energies of Cu 2p3 / 2 and Cu 2p1 / 2, respectively. This indicates that the copper in the adsorbent exists as Cu²⁺. The shape and position of the peaks can be used to further analyze the chemical environment and coordination state of the copper species, contributing to understanding the active sites and mechanism of copper in catalytic reactions.
[0041] In the fine spectrum of the Si element 2p orbital shown in Figure (c), the characteristic peak of Si 2p is located at about 103.3 eV, which is the common binding energy position of silicon in the molecular sieve framework. It shows that silicon exists in the TS-1 molecular sieve in a typical tetrahedral coordination form, maintaining the framework structure of the molecular sieve.
[0042] In the fine spectrum of the Ti element 2p orbital shown in Figure (d), the characteristic peaks of Ti 2p3 / 2 and Ti 2p1 / 2 are located at approximately 458.7eV and 464.19eV, respectively, which is consistent with the oxidation state and chemical environment of titanium in TS-1 zeolite, indicating that titanium also exists in a specific oxidation state and coordination form in the adsorbent, participating in the framework construction of the zeolite and catalytic activity-related processes.
[0043] Test Example 2 The Cu@TS-1 prepared in Example 1 was subjected to ethylene adsorption, and the process was as follows: Before measuring the adsorbed ethylene, the sample was pretreated at 300 °C under vacuum (0.03 mmHg) for 8 h to remove pre-adsorbed impurities. Then, ethylene was introduced for the adsorption test.
[0044] Furthermore, the Cu@TS-1 before and after ethylene adsorption was subjected to Fourier transform infrared (FT-IR) spectroscopy test, and the test results are as follows: Figure 2 shown.
[0045] It can be observed that after the adsorption of ethylene, the absorption peak position and intensity at certain wavenumbers in the spectrum change. This indicates that ethylene interacts with the Cu@TS-1 surface, causing changes in the chemical bond vibration characteristics of the Cu@TS-1 surface.
[0046] After adsorption of ethylene, at about 2980 cm -1 , 2927cm -1 and 2853cm -1 The absorption peaks at 1456 cm-1 are attributed to the stretching vibration of -CH. The appearance of these peaks and the changes in their intensity and position indicate that Cu@TS-1 has some kind of interaction with ethylene, or that the adsorption of ethylene has affected the chemical environment around Cu@TS-1, causing the stretching vibration of -CH. Similarly, after the adsorption of ethylene, a peak at 1456 cm-1 appears.-1 and 1386cm -1 The absorption peaks at 100 nm and 100 nm, which are related to the bending vibration of -CH3, reflect the changes in the surface chemical environment of Cu@TS-1 due to the adsorption of ethylene.
[0047] The changes in the spectrum after ethylene adsorption indicate that ethylene molecules are adsorbed onto the active sites on the surface of the 2% Cu@TS-1 catalyst, causing changes in the vibration frequency and intensity of the chemical bonds on the catalyst surface, which in turn show differences in the FT-IR spectrum.
[0048] Test Example 3 The porosity and specific surface area of the adsorbents prepared in the above examples and comparative examples were tested, and the results were as follows:
[0049] Judging from the test results of specific surface area, different Cu loading methods have a significant impact on the structural properties of the catalyst, such as the BET specific surface area. These differences may further affect the adsorption and catalytic performance of the catalyst.
[0050] Test Example 4 The products obtained in Example 1, Comparative Example 1 and Comparative Example 2 were subjected to ethylene adsorption to test their ethylene adsorption capacity, and the process was as follows: 1. Pretreatment: 1.0 g of sample was heated from room temperature to 300°C at a rate of 5°C / min in a N2 (20 ml / min) atmosphere and maintained at 300°C for 1 h.
[0051] 2. Breakthrough curve test: 200ppm C2H4 / 20%O2 / N2, 0℃, atmospheric pressure (inside the reactor); WHSV=6000cm 3 / (gh); mixed gas feed volume flow rate: 100 ml / min, normal temperature and pressure. Breakthrough curve test time: 120 min.
[0052] The test results of ethylene adsorption are as follows: Figures 3 and 4 As shown, from Figure 3 It can be seen that the ethylene adsorption amounts of Example 1, Comparative Example 1 and Comparative Example 2 are 0.045 mmol / g, 0.004 mmol / g and 0.04 mmol / g, respectively.
[0053] from Figure 4It can be seen that the outlet concentration of the adsorbent of Comparative Example 1 reaches a state close to the inlet concentration in a relatively short time, indicating that the adsorbent reaches penetration quickly and its adsorption capacity or adsorption amount for related substances is relatively low. The adsorbents of Example 1 and Comparative Example 2 take significantly longer to reach penetration, indicating that these two adsorbents have stronger adsorption capacity for ethylene and can prevent substances from penetrating for a longer time. In particular, the curve of Example 1 shows that the adsorbent has the strongest adsorption capacity for ethylene, which shows that the adsorbent structure of the present invention is more conducive to Cu 2+ Achieve better ethylene adsorption effect.
[0054] Test Example 5 The Cu@TS-1 prepared in Example 1 was subjected to an ethylene adsorption-desorption cycle test to test the stability of its ethylene adsorption capacity. The test process is as follows: Using conventional C₂H₄ adsorption, ethylene adsorption was tested at 0°C. Before the second ethylene adsorption, the sample was thoroughly desorbed. The desorption process involved pre-treating the sample at 300°C under vacuum (0.03 mmHg) for 8 hours to remove any pre-adsorbed C₂H₄. After sufficient desorption, ethylene was introduced and the adsorption test was repeated. This cycle was repeated four times.
[0055] The test results are as follows Figure 5 As shown in the figure, the isothermal cyclic adsorption curve of ethylene at 0℃, the adsorption-desorption cycle characteristics: the curve shows obvious periodic fluctuations, each rising segment represents the adsorption process of ethylene by the adsorbent, and the adsorption amount increases rapidly with time until it reaches a relatively stable peak value, indicating that the adsorbent can effectively adsorb ethylene within a certain period of time; each descending segment represents the desorption process, and the adsorption amount decreases rapidly, indicating that ethylene can be desorbed from the adsorbent surface under the corresponding conditions.
[0056] Cyclic Stability: As can be seen from the figure, although the peak adsorption amount and the residual adsorption amount after desorption vary slightly during each cycle, the overall fluctuation is not large. This indicates that the 2%Cu@TS-1 molecular sieve adsorbent has good cyclic adsorption stability at 0°C and can maintain relatively stable adsorption performance over multiple adsorption-desorption cycles.
[0057] Adsorption Performance Evaluation: The maximum adsorption capacity of the adsorbent reached approximately 2.4 mmol / g during each cycle, demonstrating its robust ethylene adsorption capacity at 0°C. This adsorption capacity and cyclic stability are crucial for processes requiring repeated use of the adsorbent, such as ethylene adsorption separation.
[0058] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the various embodiments of the present invention.
Claims
1. A method for preparing a molecular sieve adsorbent for adsorbing ethylene, characterized in that: include: A gel-like substance containing a silicon source, a titanium source and a first template is mixed with a 2+ Mixing with a solution of a second template and performing a hydrothermal reaction to obtain a colloid; The colloid is pretreated and then calcined to obtain the molecular sieve adsorbent.
2. The method for preparing a molecular sieve adsorbent for adsorbing ethylene according to claim 1, characterized in that: The mass ratio of the titanium source to the silicon source is 0.5-1.5:15-25.
3. The method for preparing a molecular sieve adsorbent for adsorbing ethylene according to claim 1 or 2, characterized in that: The silicon source is selected from one or a combination of two or more of tetraethyl orthosilicate, tetramethyl orthosilicate, tetrapropyl orthosilicate, tetraisopropoxysilane and trifluoropropyltriethoxysilane; preferably tetraethyl orthosilicate; And / or, the titanium source is selected from one or a combination of two or more of tetrabutyl titanate, tetraisopropyl titanate, tetraethyl titanate, bis(acetylacetonato)diisopropoxy titanate, polybutyl titanate and diisopropyl acetylacetonate titanate; preferably tetrabutyl titanate.
4. The method for preparing a molecular sieve adsorbent for adsorbing ethylene according to any one of claims 1 to 3, characterized in that: The first template is tetrapropylammonium hydroxide; And / or, the second template is tetraethylenepentamine.
5. The method for preparing a molecular sieve adsorbent for adsorbing ethylene according to any one of claims 1 to 4, characterized in that: Mixing a silicon source, tetrapropylammonium hydroxide and water to obtain a first solution; mixing a titanium source with an alcohol to obtain a second solution; mixing the first solution and the second solution to obtain a third solution; heating the third solution to obtain a gel-like substance; Copper nitrate, tetraethylenepentamine and water are mixed to prepare a Cu-TEPA solution; mixing the gel-like substance and the Cu-TEPA solution to obtain a mixture; subjecting the mixture to a hydrothermal reaction to obtain a colloid; The colloid is centrifuged, washed, dried and calcined to obtain the molecular sieve adsorbent.
6. The method for preparing a molecular sieve adsorbent for adsorbing ethylene according to claim 5, characterized in that: The mass ratio of silicon source to tetrapropylammonium hydroxide is 15-25:5-10; and / or, the mass concentration of the silicon source in the first solution is 25-35%; and / or, the mass concentration of the titanium source in the second solution is 5-10%; and / or, the mass ratio of copper nitrate to tetraethylenepentamine is 3-5:3-4; and / or, the mass concentration of copper nitrate trihydrate in the Cu-TEPA solution is 2-6%; And / or, the mass ratio of copper nitrate trihydrate added to the mixture to tetraethyl orthosilicate used to form the gel-like substance is 0.3-0.5:15-25.
7. The method for preparing a molecular sieve adsorbent for adsorbing ethylene according to any one of claims 1 to 6, characterized in that: include: Mixing tetraethyl orthosilicate and tetrapropylammonium hydroxide aqueous solution, then adding deionized water and stirring until a first solution is formed; dissolving tetrabutyl titanate in isopropyl alcohol to obtain a second solution; mixing the second solution and the first solution to obtain a third solution; Heating the third solution to 50-70° C. and stirring at a stirring speed of 300-400 rpm for 2-4 hours to form a gel-like substance; Dissolve copper nitrate trihydrate in water and mix with tetraethylenepentamine to obtain Cu-TEPA solution; The Cu-TEPA solution was added to the gel-like substance and stirred at a stirring speed of 300-400 rpm for 2-4 hours to obtain a mixture; The mixture is reacted under hydrothermal conditions at a reaction temperature of 150-180°C for more than 36 hours to obtain a colloid; The colloidal mixture is centrifuged to collect solid powder, which is then washed with water, dried, and finally calcined in air at a calcination temperature of 500-600° C. for 5-8 hours, followed by cooling to obtain the molecular sieve adsorbent.
8. A molecular sieve adsorbent for adsorbing ethylene, characterized in that: Prepared by the preparation method according to any one of claims 1 to 7.
9. The molecular sieve adsorbent for adsorbing ethylene according to claim 8, characterized in that: The specific surface area of the molecular sieve adsorbent is greater than 400.
10. Use of the molecular sieve adsorbent prepared by the preparation method according to any one of claims 1 to 7, or the molecular sieve adsorbent according to claims 8 to 9, in ethylene adsorption in the food field.