Preparation method of cellulose material for delaying CO2 release from water

Abstract

This invention provides a method for preparing cellulose materials that delay CO2 release from water, belonging to the field of carbon emission reduction applications. It involves modifying cellulose materials with amine groups to form biodegradable cellulose materials loaded with tertiary or secondary amine groups. The epoxidation grafting method in this invention achieves cellulose modification through alkali treatment, epoxidation, and amination grafting; the glutaraldehyde crosslinking method uses glutaraldehyde as a crosslinking agent to connect the cellulose material and organic amines to achieve cellulose modification. This method further increases the residence time of CO2 in water by adsorbing and converting CO2. Compared with unmodified cellulose materials, the modified material can reduce the amount of CO2 released from water by more than 60%, which helps to construct a CO2 slow-release system in water and can assist in improving the actual utilization efficiency of CO2 gas by microorganisms.

Description

Technical Field

[0001] This invention belongs to the field of carbon emission reduction applications and relates to a method for preparing cellulose materials that delay the release of CO2 from water. Background Technology

[0002] The increase in global CO2 emissions has posed a huge threat to the human living environment. With the continuous development of carbon capture, utilization and storage technologies, the use of microorganisms to convert CO2 into chemicals or biomass can turn waste into resources and significantly improve the benefits of carbon reduction and carbon neutrality.

[0003] CO2 in water mainly exists as free gas and HCO3-. - and CO3 2- Both can exist in various forms and enter cells to participate in synthesis through different transport methods. However, under normal pressure, CO2 gas has extremely low solubility in water, causing most of the CO2 gas introduced into the water to overflow instantly and not be directly utilized by microorganisms. Studies have shown that only 2.08% of the CO2 gas introduced into the liquid culture medium is captured by microorganisms and converted into products (Chemical Engineering, 2009, 37(1):49-52). Micro- and nano-bubbles have the advantages of small size, large specific surface area, and slow rising speed. They can stay in water for a long time and have natural slow-release properties. However, microbial culture systems are generally maintained at normal pressure or low pressure, and micro- and nano-bubbles will still overflow in large quantities.

[0004] Recent studies have shown that organic amine modification can enhance the adsorption efficiency of materials for CO2 gas. Some researchers have used highly toxic aziridine grafted onto porous polymer materials to absorb CO2 from gases; these materials exhibit even stronger CO2 adsorption capacity when the air contains moisture (Microporous and Mesoporous Materials, 2022, 330:111585). Amines, with the participation of water, can convert CO2 gas into HCO3, which is more soluble in water. - (See reaction mechanism) Figure 1 This helps to further reduce the leakage of CO2 gas, while the generated HCO3 - It is also easily utilized by microorganisms.

[0005] Cellulose materials, derived from renewable biological resources, are rich in hydroxyl groups. These hydroxyl groups can form hydrogen bonds and even electrostatic attraction with CO2, promoting its adsorption. The presence of hydroxyl groups also facilitates amine modification. Researchers have used impregnation methods to immobilize organic amines or piperazines onto sugarcane bagasse, which can improve the material's CO2 adsorption capacity (Environmental Technology, 2012, 33:2645-2651). However, the organic amines in impregnated cellulose materials tend to volatilize or dissipate significantly under high-temperature treatment, limiting their application. Currently, there are no publicly reported methods for preparing cellulose materials for absorbing CO2 in water. Therefore, developing corresponding methods for preparing modified cellulose materials is of positive significance for constructing CO2 slow-release systems in water and thereby promoting the actual utilization efficiency of CO2 gas by microorganisms. Summary of the Invention

[0006] The technical problem to be solved by the present invention is to address the shortcomings of the prior art by providing a method for preparing cellulose materials that delay the release of CO2 from water.

[0007] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0008] A method for preparing cellulose materials that delay CO2 release from water includes the following steps:

[0009] (1) Cellulose materials are pretreated by one of the following two methods:

[0010] Cellulose materials are pretreated using a hydrothermal method: the cellulose material is mixed with water and subjected to a first heating reaction. After the reaction is complete, the system is washed until neutral and dried to obtain the pretreated cellulose material; or

[0011] Cellulose materials are pretreated by an alkaline treatment method: the cellulose materials are added to a first sodium hydroxide aqueous solution for a second heating reaction. After the reaction is completed, the system is washed until neutral and dried to obtain the pretreated cellulose materials.

[0012] (2) The pretreated cellulose material is modified with amine groups using one of the following two methods:

[0013] The pretreated cellulose material was modified with amine groups by epoxidative grafting: the pretreated cellulose material obtained in step (1) was soaked in a second sodium hydroxide aqueous solution, then washed until neutral, and dried to obtain dried cellulose material; the dried cellulose material and epichlorohydrin were added to a third sodium hydroxide aqueous solution for epoxidative grafting reaction, and after the reaction, the solid and liquid were separated, the solid part was washed with water until neutral, and dried to obtain epoxidized cellulose material; the epoxidized cellulose material was added to an organic amine solution for amine grafting reaction, and after the reaction, the solid part was washed with water until neutral, and dried to obtain the final product; or

[0014] The pretreated cellulose material was modified with amines by glutaraldehyde crosslinking: organic amines were directly added to the potassium phosphate buffer solution of glutaraldehyde to carry out the amine crosslinking reaction. Then, the pretreated cellulose material obtained in step (1) was added to the system to continue the hydroxyl crosslinking reaction. After the reaction was completed, the solid and liquid were separated. The solid part was washed with water until neutral and dried to obtain the final product.

[0015] Specifically, in step (1), the cellulose material is a natural loofah sponge or an artificially prepared cellulose sponge.

[0016] Specifically, in step (1), in the hydrothermal method, the mass-to-volume ratio of the cellulose material to water is 1g:30mL~60mL; the first heating reaction is carried out at a temperature of 150~170℃, preferably 160℃, and for a reaction time of 20~40min, preferably 20min.

[0017] Specifically, in step (1), in the alkali treatment method, the mass-to-volume ratio of the cellulose material to the first sodium hydroxide aqueous solution is 1g:90mL-110mL, preferably 1g:100mL; the concentration of sodium hydroxide in the first sodium hydroxide aqueous solution is 4-10wt%; the second heating reaction is carried out at a temperature of 80-90℃, preferably 85℃, and for a reaction time of 1.5-2.5h.

[0018] Specifically, in step (2), in the epoxidation grafting method, the mass-to-volume ratio of the pretreated cellulose material to the second sodium hydroxide aqueous solution is 1g:20mL to 60mL, preferably 1g:30mL; the concentration of sodium hydroxide in the second sodium hydroxide aqueous solution is 20 to 40wt%, preferably 30wt%; the soaking time is 2 to 4h, preferably 2h.

[0019] Specifically, in step (2), in the epoxidation grafting method, the mass-to-volume ratio of the dried cellulose material to epichlorohydrin is 1g:6mL-10mL, preferably 1g:7mL; the mass-to-volume ratio of the dried cellulose material to the third sodium hydroxide aqueous solution is 1g:30mL-90mL, preferably 1g:60mL; the concentration of sodium hydroxide in the third sodium hydroxide aqueous solution is 1-10wt%; the epoxidation grafting reaction is carried out at a temperature of 30-50℃ for 2-4h, preferably 2h.

[0020] Specifically, in step (2), the organic amine is a primary amine or a secondary amine; the primary amine is any one or a combination of several of ethanolamine, diethylenetriamine, isobutanolamine, n-butylamine, 2-aminobutanol, and ethylenediamine; the secondary amine is any one or a combination of several of diethanolamine, diethylamine, and N-ethylethanolamine.

[0021] Specifically, in step (2), in the epoxidation grafting method, the organic amine solution is a 50 v / v% ethanol aqueous solution, and the molar ratio of the organic amine to epichlorohydrin in the organic amine solution is 1:1; the amine grafting reaction is carried out at a temperature of 40-60°C, preferably 50°C, and for a reaction time of 1.5-4 h, preferably 2 h.

[0022] Specifically, in step (2), when the organic amine in the organic amine solution is a primary amine, the molar concentration of the primary amine is 0.6 mol / L; when the organic amine in the organic amine solution is a secondary amine, the molar concentration of the secondary amine is 1.2 mol / L.

[0023] Specifically, in step (2), in the glutaraldehyde crosslinking method, the molar ratio of the organic amine to glutaraldehyde is 1:1; the concentration of glutaraldehyde in the potassium phosphate buffer solution is 2-4 g / L, preferably 2 g / L; the potassium phosphate buffer solution is composed of equal volumes of 0.05 mol / L potassium dihydrogen phosphate and 0.05 mol / L dipotassium hydrogen phosphate, with a pH of 6.8-7; the amine crosslinking reaction is carried out at a temperature of 30-40°C, preferably 35°C, for a reaction time of 2-4 h, preferably 2 h.

[0024] Specifically, in step (2), in the glutaraldehyde crosslinking method, the mass-to-volume ratio of the pretreated cellulose material to the potassium phosphate buffer solution of glutaraldehyde is 1g:30mL~90mL; the hydroxyl crosslinking reaction is carried out at a temperature of 30~40℃, preferably 35℃, and for a reaction time of 3~6h, preferably 4h.

[0025] The cellulose material that delays the release of CO2 from water prepared by the above preparation method is also within the scope of protection of this invention.

[0026] The application of the aforementioned cellulose materials in delaying the release of CO2 from water is also within the scope of protection of this invention.

[0027] Beneficial effects:

[0028] (1) This invention provides two methods for preparing cellulose materials that delay the release of CO2 from water. The raw materials of the cellulose materials are all derived from renewable biomass resources and contain abundant hydroxyl groups. By modifying and loading organic amines, the adsorption and decomposition of CO2 are further promoted, which is beneficial to further enhance the slow release effect of CO2 in water.

[0029] (2) The loofah sponge and cellulose sponge used in this invention have more pores, which can release CO2 slowly and also reduce the mass transfer resistance between microbial cells and CO2.

[0030] (3) The amine-modified cellulose material provided by the present invention has no inhibitory effect on microbial growth. Attached Figure Description

[0031] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments, and the advantages of the present invention in the above and / or other aspects will become clearer.

[0032] Figure 1 This is a diagram illustrating the adsorption reaction mechanism of amines with CO2.

[0033] Figure 2 A diagram illustrating the method for preparing cellulose materials that delay CO2 release from water according to the present invention; Figure 2 a) describes the preparation of cellulose materials through epoxidation grafting with amine groups. Figure 2 b represents the preparation of cellulose materials by glutaraldehyde crosslinking with amine modification; where R1 and R2 groups refer to carbon chains, which may be linked with hydroxyl or amine groups.

[0034] Figure 3 A comparative graph showing the CO2 sustained-release effect of modified loofah sponges prepared by amine modification with different modifiers via epoxidation grafting.

[0035] Figure 4 A comparative graph showing the CO2 sustained-release effect of different modifiers on amine-modified loofah sponge via glutaraldehyde crosslinking.

[0036] Figure 5 A comparative graph showing the CO2 sustained-release effect of modified cellulose sponges prepared with different modifiers.

[0037] Figure 6The images show the infrared spectra of loofah sponges before and after modification; where C: untreated loofah sponge; C-EPI: epoxidized loofah sponge; [C-EPI]-DEA: modified loofah sponge material obtained by epoxidation grafting with diethanolamine; [C-EPI]-EA: modified loofah sponge material obtained by epoxidation grafting with ethanolamine; [C-EPI]-DETA: modified loofah sponge material obtained by epoxidation grafting with diethylenetriamine.

[0038] Figure 7 The images show the infrared spectra of cellulose sponges before and after modification; where S: untreated cellulose sponge; [S-EPI]-DETA: modified cellulose sponge obtained by epoxidative grafting with diethylenetriamine; [S-EPI]-EA: modified cellulose sponge obtained by epoxidative grafting with ethanolamine; [S-EPI]-DEA: modified cellulose sponge obtained by epoxidative grafting with diethanolamine; and S-GA-DEtA: modified cellulose sponge obtained by glutaraldehyde crosslinking with diethylamine. Detailed Implementation

[0039] The present invention will be further described in detail below with reference to specific embodiments. These descriptions are for explanation purposes only and are not intended to limit the scope of the invention.

[0040] The following examples illustrate the method for determining the sustained CO2 release:

[0041] 0.08 g of the material was added to 20 mL of CO2-absorbing water containing micro-nano bubbles. The change in sample mass before and after 2 hours was measured using a high-precision balance. Combined with the change in evaporation of an equal volume of pure water under the same environmental conditions (blank control and standard control), the amount of CO2 released from the water was calculated. Simultaneously, the CO32 content in the CO2-absorbing water before and after 2 hours was measured using acid-base titration. 2- and HCO3 - The concentration change.

[0042] For details on the specific preparation and synthesis route of the cellulose material for delaying CO2 release from water in the embodiments of this invention, please refer to [link / reference needed]. Figure 2 ,in, Figure 2 a) describes the preparation of cellulose materials through epoxidation grafting with amine groups. Figure 2 b represents the preparation of cellulose materials by glutaraldehyde crosslinking with amine modification; where R1 and R2 groups refer to carbon chains, which may be linked with hydroxyl or amine groups.

[0043] Example 1

[0044] Cellulose materials that delay CO2 release from water were prepared by amine modification using the epoxidation grafting method.

[0045] Cut the loofah sponge into small pieces of 1cm×1cm×0.5cm. Add the loofah sponge material to a 10% sodium hydroxide aqueous solution at a mass-volume ratio of 1g:100mL. React at 85℃ for 2.5 hours. After the reaction is complete, wash until neutral and dry at 60℃ to obtain the pretreated loofah sponge material.

[0046] Pretreated loofah sponge material was added to a 30% sodium hydroxide aqueous solution at a mass-to-volume ratio of 1 g:30 mL. After soaking at room temperature for 2 hours, the material was removed, washed with water until neutral, and dried at 60°C to obtain dried cellulose material. The dried cellulose material was then added to a 4% sodium hydroxide aqueous solution at a mass-to-volume ratio of 1 g:60 mL. Epichlorohydrin was slowly added dropwise at a mass-to-volume ratio of 1 g:7 mL while the temperature was raised to 40°C, and the reaction was allowed to proceed for 2 hours. After the reaction was complete, the material was removed, washed with water until neutral, and dried at 60°C to obtain epoxidized cellulose material. A diethanolamine solution was prepared by mixing a 50 v / v ethanol aqueous solution with diethanolamine (the molar concentration of diethanolamine in the diethanolamine solution was 1.2 mol / L, and the molar ratio of diethanolamine to epichlorohydrin was 1:1). The above-mentioned epoxidized cellulose material was added to the diethanolamine solution, reacted at 50°C for 2 hours, removed, washed with water until neutral, and dried at 60°C to obtain the amine-modified cellulose material.

[0047] Example 2

[0048] Cellulose materials that delay CO2 release from water were prepared by amine modification using the epoxidation grafting method.

[0049] Cut the loofah sponge into small pieces of 1cm×1cm×0.5cm. Mix the loofah sponge material and water at a mass-volume ratio of 1g:50mL and place them in a homogeneous reactor. React at 160℃ for 20 minutes, wash until neutral, and dry at 60℃ to obtain the pretreated loofah sponge material.

[0050] Pretreated loofah sponge material was added to a 30% sodium hydroxide solution at a mass-to-volume ratio of 1 g:30 mL. After soaking at room temperature for 2 hours, the material was removed, washed with water until neutral, and dried at 60°C to obtain dried cellulose material. The dried cellulose material was then added to a 2% sodium hydroxide aqueous solution at a mass-to-volume ratio of 1 g:50 mL. Epichlorohydrin was slowly added dropwise at a mass-to-volume ratio of 1 g:7 mL while the temperature was raised to 30°C, and the reaction was allowed to proceed for 2 hours. After the reaction was complete, the material was removed, washed with water until neutral, and dried at 60°C to obtain epoxidized cellulose material. A diethylamine solution was prepared by mixing a 50 v / v ethanol aqueous solution with diethylamine (the molar concentration of diethylamine in the diethylamine solution was 1.2 mol / L, and the molar ratio of diethylamine to epichlorohydrin was 1:1). The above-mentioned epoxidized cellulose material was added to the diethylamine solution, reacted at 40°C for 2 hours, removed, washed with water until neutral, and dried at 60°C to obtain the amino-modified cellulose material.

[0051] Example 3

[0052] Cellulose materials that delay CO2 release from water were prepared by amine modification using the epoxidation grafting method.

[0053] Cut the loofah sponge into small pieces of 1cm×1cm×0.5cm. Add the material to a 4% sodium hydroxide aqueous solution at a mass-volume ratio of 1g:100mL. React at 85℃ for 2 hours. After the reaction is complete, wash until neutral and dry at 60℃ to obtain the pretreated loofah sponge material.

[0054] Pretreated material was added to a 30% sodium hydroxide aqueous solution at a mass-to-volume ratio of 1 g:30 mL. After soaking at room temperature for 2 hours, the material was removed, washed with water until neutral, and dried at 60°C to obtain dried cellulose material. The dried cellulose material was then added to a 6% sodium hydroxide aqueous solution at a mass-to-volume ratio of 1 g:70 mL. Epichlorohydrin was slowly added dropwise at a mass-to-volume ratio of 1 g:7 mL while the temperature was raised to 50°C, and the reaction was allowed to proceed for 2 hours. After the reaction, the material was removed, washed with water until neutral, and dried at 60°C to obtain epoxidized cellulose material. An ethanolamine solution was prepared using a 50 v / v% ethanol aqueous solution and ethanolamine (the molar concentration of ethanolamine in the ethanolamine solution was 0.6 mol / L, and the molar ratio of ethanolamine to epichlorohydrin was 1:1). The above epoxidized cellulose material was added to the ethanolamine solution, reacted at 60°C for 2 hours, removed, washed with water until neutral, and dried at 60°C to obtain amino-modified cellulose material.

[0055] Example 4

[0056] Cellulose materials that delay CO2 release from water were prepared by glutaraldehyde crosslinking with amine modification.

[0057] Cut the loofah sponge into small pieces of 1cm×1cm×0.5cm. Add the material to a 4% sodium hydroxide aqueous solution at a mass-volume ratio of 1g:100mL. React at 85℃ for 2 hours. After the reaction is complete, wash until neutral and dry at 60℃ to obtain the pretreated loofah sponge material.

[0058] A potassium phosphate buffer solution containing 2 g / L glutaraldehyde (the potassium phosphate buffer solution was prepared by mixing equal volumes of 0.05 mol / L potassium dihydrogen phosphate and 0.05 mol / L dipotassium hydrogen phosphate, pH = 6.8–7) was added. N-ethylethanolamine was added at a molar ratio of 1:1 to glutaraldehyde, and the mixture was stirred at 35°C for 2 hours. Subsequently, the pretreated loofah sponge material was added to the potassium phosphate buffer solution at a mass-to-volume ratio of 1 g: 60 mL, and the mixture was stirred for another 4 hours. After washing with water until neutral, the mixture was dried at 60°C to obtain the amino-modified cellulose material.

[0059] Example 5

[0060] Cellulose materials that delay CO2 release from water were prepared by glutaraldehyde crosslinking with amine modification.

[0061] Cut the loofah sponge into small pieces of 1cm×1cm×0.5cm. Mix the material and water at a mass-volume ratio of 1g:60mL and place them in a homogeneous reactor. React at 160℃ for 20 minutes, wash until neutral, and dry at 60℃ to obtain the pretreated loofah sponge material.

[0062] A potassium phosphate buffer solution containing 2 g / L glutaraldehyde (the potassium phosphate buffer solution was prepared by mixing equal volumes of 0.05 mol / L potassium dihydrogen phosphate and 0.05 mol / L dipotassium hydrogen phosphate, pH = 6.8–7) was added. Diethylenetriamine was added at a molar ratio of 1:1 to glutaraldehyde, and the mixture was stirred at 35°C for 2 hours. Subsequently, the pretreated loofah sponge material was added to the potassium phosphate buffer solution at a mass-to-volume ratio of 1 g:50 mL, and the mixture was stirred for another 4 hours. After washing with water until neutral, the mixture was dried at 60°C to obtain the amino-modified cellulose material.

[0063] Example 6

[0064] Comparison of the sustained-release performance of organic amine-modified loofah sponge on CO2 in water: In this example, cellulose material was prepared by the same method as in Example 1. The cellulose material used was loofah sponge. The organic amine modifiers used were diethylamine, N-ethylethanolamine, ethanolamine, diethylenetriamine, isobutanolamine, ethylenediamine, n-butylamine, and 2-aminobutanol, respectively, resulting in different modified materials.

[0065] The modified materials obtained in Example 1 and Example 6 were tested for their CO2 sustained-release effect. The results are as follows: Figure 3 As shown, by Figure 3 a and Figure 3 b. As far as we know: the effect of unmodified loofah sponge on CO2 release was not significantly different from that of the blank control without added materials. Figure 3 According to known information: Compared with the blank control without added materials, the CO2 emission of the materials prepared by amine modification via epoxidation grafting was reduced by 82.5%, 29.55%, 45.89%, 75.91%, 60.91%, 40.53%, 27.37%, 3.16%, and 1.05% respectively after being added to water. Figure 3 b. As known to us: Among them, the modified loofah material obtained by epoxidation grafting for amine modification, and by using ethanolamine modification, not only reduced CO2 emissions by 75.91%, but also reduced CO3 in the water. 2- and HCO3 - The total amount was also 41.18% higher than the blank control, indicating that the modified material has a significant effect on CO2 slow release.

[0066] Example 7

[0067] Comparison of the sustained-release performance of organic amine-modified loofah sponge on CO2 in water: In this example, the cellulose material was prepared by the same method as in Example 4. The cellulose material used was loofah sponge, and the organic amine modifiers used were diethanolamine, diethylamine, ethanolamine, diethylenetriamine, isobutanolamine, ethylenediamine, n-butylamine, and 2-aminobutanol, respectively, resulting in different modified materials.

[0068] The modified materials obtained in Example 4 and Example 7 were tested for their CO2 sustained-release effect. The results are as follows: Figure 4 As shown, by Figure 4 a and Figure 4 b. As far as we know: the effect of unmodified loofah sponge on CO2 release was not significantly different from that of the blank control without added materials. Figure 4 a. To the knowledge of the matter: Compared with the blank control without any added materials, the CO2 emission of the materials prepared by glutaraldehyde crosslinking and amine modification was reduced by 50.8%, 51.37%, 3%, 14.93%, 22.06%, 26.47%, 38.24%, 33.64%, and 8.82% respectively after being added to water.

[0069] Example 8

[0070] In this embodiment, the cellulose material was prepared by the same method as in Example 4. The cellulose material used was cellulose sponge, and the organic amine modifier used was diethylamine. The modified material was prepared by glutaraldehyde crosslinking.

[0071] Example 9

[0072] In this embodiment, cellulose materials were prepared using the same method as in Example 1. The cellulose material used was cellulose sponge, and the organic amine modifiers used were diethanolamine, ethanolamine, and diethylenetriamine. Different modified materials were obtained by epoxidation grafting to modify the amine groups.

[0073] The performance of cellulose sponges in releasing CO2 from water was investigated: the CO2 release effect of the modified materials prepared in Examples 8 and 9 was tested, and the results are as follows. Figure 5 As shown, by Figure 5 It can be seen that all the prepared modified sponges have a certain slow-release effect on CO2 in water. Compared with the blank control without added materials, CO2 leakage was reduced by 84.95%, 82.09%, 72.27%, and 90%, respectively. Among them, the modified sponge material obtained by glutaraldehyde crosslinking and then by diethylamine modification not only reduced CO2 leakage by 84.95%, but also reduced CO3 in water. 2- and HCO3 - The total amount was also 12.3% higher than the blank control (see data). Figure 5 b) indicates that the modified material has a significant effect on CO2 slow release.

[0074] Example 10

[0075] This embodiment uses the potassium bromide pellet method and Fourier transform infrared spectroscopy (FTIR) to detect changes in functional groups in cellulose materials to infer whether the grafting of the modifier was successful. The scanning range is 500–4000 cm⁻¹. -1 .

[0076] The infrared spectrum of the loofah sponge material modified by diethanolamine (Example 1), ethanolamine (Example 6), and diethylenetriamine (Example 6) is shown below. Figure 6 As shown, from Figure 6 From this, we can see that in the C-EPI curve, 705cm -1 The absorption peak at 3433-3427 cm⁻¹ represents the vibrational absorption of the epoxy group, indicating that the loofah sponge has successfully undergone epoxidation. -1 The nearby absorption peaks are attributed to the stretching vibration of OH groups. The most significant change in the [C-EPI]-EA absorption peak can be observed at 1451 cm⁻¹. -1 The weak absorption peak of CN indicates that [C-EPI]-DEA, [C-EPI]-EA, and [C-EPI]-DETA have been successfully loaded with amine groups. However, [C-EPI]-DETA still has an absorption peak of epoxy groups, indicating that the amine loading is relatively low.

[0077] The infrared spectrum of the cellulose sponge material modified by diethylamine (Example 8), diethanolamine (Example 9), ethanolamine (Example 9), and diethylenetriamine (Example 9) is shown below. Figure 7 As shown, from Figure 7 From this, we can see that in the S-curve, 3439cm -1 The peak at this point corresponds to the stretching vibration of the hydroxyl group (-OH). The other four curves show varying degrees of shift in their peak values ​​at this point due to the presence of primary amines (-NH₂) or secondary amines (-NH₃). The most significant change is observed in the OH absorption peak of S-GA-DEtA, particularly at 1234 cm⁻¹. -1 The newly appearing absorption peak belongs to the CN absorption peak. In the three curves [S-EPI]-DETA, [S-EPI]-EA, and [S-EPI]-DEA, the peak at 1725 cm⁻¹ is... -1 The peak at this location belongs to the deformation vibration of CN, which indicates that the modified cellulose sponge has been successfully grafted with amination.

[0078] As can be seen from the above examples, the amine-modified cellulose material preparation method provided by this invention can significantly slow down the release of CO2 from water compared to unmodified cellulose materials, which is beneficial for further increasing the residence time of CO2 in water. Seven of the modified cellulose materials can reduce the amount of CO2 released from water by more than 60%. This invention helps to construct a slow-release system for CO2 in water and can assist in improving the actual utilization efficiency of CO2 gas by microorganisms.

[0079] This invention provides a method for preparing cellulose materials that delay CO2 release from water. Many methods and approaches exist for implementing this technical solution; the above description is merely a preferred embodiment of the invention. It should be noted that those skilled in the art can make various improvements and modifications without departing from the principles of this invention, and these improvements and modifications should also be considered within the scope of protection of this invention. All components not explicitly stated in this embodiment can be implemented using existing technologies.

Claims

1. A method for preparing a cellulose material that delays the release of CO2 from water, characterized in that, Includes the following steps: (1) Cellulose materials are pretreated by one of the following two methods: Cellulose materials are pretreated by a hydrothermal method: the cellulose material is mixed with water and subjected to a first heating reaction. After the reaction is completed, the system is washed until neutral and dried to obtain the pretreated cellulose material. or Cellulose materials are pretreated by an alkaline treatment method: the cellulose materials are added to a first sodium hydroxide aqueous solution for a second heating reaction. After the reaction is completed, the system is washed until neutral and dried to obtain the pretreated cellulose materials. (2) The pretreated cellulose material is modified with amine groups by one of the following two methods: The pretreated cellulose material was modified with amine by epoxidation grafting: the pretreated cellulose material obtained in step (1) was soaked in the second sodium hydroxide aqueous solution, then washed until neutral, and dried to obtain the dried cellulose material; the dried cellulose material and epichlorohydrin were added to the third sodium hydroxide aqueous solution to carry out the epoxidation grafting reaction. After the reaction was completed, the solid and liquid were separated, the solid part was washed with water until neutral, and dried to obtain the epoxidized cellulose material; Epoxidized cellulose material was added to an organic amine solution to carry out an amine grafting reaction. After the reaction was completed, the solid and liquid were separated. The solid part was washed with water until neutral and then dried to obtain the final product. or The pretreated cellulose material was modified with amine by glutaraldehyde crosslinking: organic amine was directly added to the potassium phosphate buffer solution of glutaraldehyde to carry out the amine crosslinking reaction, and then the pretreated cellulose material obtained in step (1) was added to the system to continue the hydroxyl crosslinking reaction. After the reaction was completed, the solid and liquid were separated, the solid part was washed with water until neutral, and dried to obtain the final product. In step (1), when the pretreated cellulose material is modified with amine groups by epoxidation grafting, the cellulose material is a natural loofah or an artificially prepared cellulose sponge. In step (1), when the pretreated cellulose material is modified with amines by glutaraldehyde crosslinking, the cellulose material is an artificially prepared cellulose sponge. In step (2), when the pretreated cellulose material is modified with amines by epoxidation grafting, the organic amine is ethanolamine or diethanolamine. In step (2), when the pretreated cellulose material is modified with amines by glutaraldehyde crosslinking, the organic amine is diethanolamine or diethylamine.

2. The preparation method according to claim 1, characterized in that, In step (1), in the hydrothermal method, the mass-to-volume ratio of the cellulose material to water is 1 g: 30 mL~60 mL; the first heating reaction is carried out at a temperature of 150~170℃ and for a time of 20~40 min.

3. The preparation method according to claim 1, characterized in that, In step (1), in the alkali treatment method, the mass-to-volume ratio of the cellulose material to the first sodium hydroxide aqueous solution is 1 g: 90 mL~110 mL; the concentration of sodium hydroxide in the first sodium hydroxide aqueous solution is 4~10 wt%; the second heating reaction is carried out at a temperature of 80~90℃ for 1.5~2.5 h.

4. The preparation method according to claim 1, characterized in that, In step (2), in the epoxidation grafting method, the mass-to-volume ratio of the pretreated cellulose material to the second sodium hydroxide aqueous solution is 1 g: 20 mL~60 mL; the concentration of sodium hydroxide in the second sodium hydroxide aqueous solution is 20~40 wt%; and the soaking time is 2~4 h.

5. The preparation method according to claim 1, characterized in that, In step (2), in the epoxidation grafting method, the mass-to-volume ratio of the dried cellulose material to epichlorohydrin is 1 g: 6 mL~10 mL; the mass-to-volume ratio of the dried cellulose material to the third sodium hydroxide aqueous solution is 1 g: 30 mL~90 mL; the concentration of sodium hydroxide in the third sodium hydroxide aqueous solution is 1~10 wt%; the epoxidation grafting reaction is carried out at a reaction temperature of 30~50℃ and a reaction time of 2~4 h.

6. The preparation method according to claim 1, characterized in that, In step (2), in the epoxidation grafting method, the organic amine solution is a 50 v / v% ethanol aqueous solution, and the molar ratio of organic amine to epichlorohydrin in the organic amine solution is 1:1; the amine grafting reaction is carried out at a temperature of 40~60℃ and a reaction time of 1.5~4 h.

7. The preparation method according to claim 1, characterized in that, In step (2), when the organic amine in the organic amine solution is a primary amine, the molar concentration of the primary amine is 0.6 mol / L; when the organic amine in the organic amine solution is a secondary amine, the molar concentration of the secondary amine is 1.2 mol / L.

8. The preparation method according to claim 1, characterized in that, In step (2), in the glutaraldehyde crosslinking method, the molar ratio of the organic amine to glutaraldehyde is 1:1; the concentration of glutaraldehyde in the potassium phosphate buffer solution is 2~4 g / L; the potassium phosphate buffer solution is prepared by mixing equal volumes of 0.05 mol / L potassium dihydrogen phosphate and 0.05 mol / L dipotassium hydrogen phosphate, with a pH of 6.8~7; the amine crosslinking reaction is carried out at a reaction temperature of 30~40℃ for 2~4 h.

9. The preparation method according to claim 1, characterized in that, In step (2), in the glutaraldehyde crosslinking method, the mass-volume ratio of the pretreated cellulose material to the potassium phosphate buffer solution of glutaraldehyde is 1 g: 30 mL~90 mL; the hydroxyl crosslinking reaction is carried out at a temperature of 30~40℃ and a reaction time of 3~6 h.

10. The cellulose material for delaying the release of CO2 from water prepared by the preparation method according to any one of claims 1 to 9.

11. The use of the cellulose material of claim 10 in delaying the release of CO2 from water.

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