Carbon dioxide solid adsorption gel and preparation method and application thereof

Abstract

The application provides a carbon dioxide solid adsorption gel and a preparation method and application thereof. The preparation method of the carbon dioxide solid adsorption gel comprises the following steps: S1, mixing acid-soluble chitosan and desulfurization wastewater to prepare a chitosan solution; S2, mixing the chitosan solution and a sodium alginate solution, and then heating to prepare a viscous liquid; S3, adding lime milk into the desulfurization wastewater to neutralize to neutral, and then adding TRIS, and fully stirring and dissolving to prepare a mixed solution; and S4, dropping the viscous liquid into the mixed solution to form a hydrogel, and then taking out the hydrogel, freezing and drying to prepare the carbon dioxide solid adsorption gel. The carbon dioxide solid adsorption gel with excellent carbon dioxide capture effect is prepared by combining natural products and desulfurization wastewater treatment.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of carbon dioxide capture, in particular to a carbon dioxide solid adsorption gel and a preparation method and application thereof. BACKGROUND

[0002] Carbon capture aims to collect and purify carbon dioxide in industrial production, energy activities or atmosphere, and then directly utilize or store it to achieve the purpose of reducing carbon emissions. Carbon capture technologies include chemical absorption, physical absorption, adsorption separation and the like. Chemical absorption mainly captures carbon dioxide by chemical reaction between chemical reagents and carbon dioxide. Physical absorption mainly separates carbon dioxide by using the characteristics that the solubility of certain physical solvents to carbon dioxide is much greater than that to other components.

[0003] Adsorption separation mainly separates different gas components by using the difference in attraction between active points on the surface of adsorbents and different gas molecules. At present, the adsorbents used for carbon dioxide adsorption separation are generally porous materials, and common adsorbents include molecular sieves, activated carbon, silica gel, activated alumina and the like. However, most of the adsorbents have relatively high prices, and have limited adsorption capacity to carbon dioxide. In addition, it is difficult to desorb carbon dioxide, which is not conducive to the recycling of carbon dioxide.

[0004] In view of this, the present application is proposed. SUMMARY

[0005] The present application aims to provide a carbon dioxide solid adsorption gel and a preparation method and application thereof. The carbon dioxide solid adsorption gel has high strength and excellent carbon dioxide capture effect.

[0006] The present application provides a preparation method of a carbon dioxide solid adsorption gel, comprising the following steps:

[0007] S1: fully stirring and mixing acid-soluble chitosan and desulfurization wastewater to prepare a chitosan solution;

[0008] S2: fully stirring and mixing the chitosan solution and a sodium alginate solution, and then heating to prepare a viscous liquid;

[0009] S3: adding lime milk to the desulfurization wastewater to neutralize it, and then adding TRIS and fully stirring and dissolving to prepare a mixed solution;

[0010] S4: dropping the viscous liquid into the mixed solution to form a hydrogel, and then taking out the hydrogel, freezing and drying to prepare a carbon dioxide solid adsorption gel.

[0011] In the present application, the pH value of the desulfurization wastewater is 5-6; the mass content of calcium chloride in the desulfurization wastewater is 12-15 mg / L, and the mass content of magnesium chloride is 10-12 mg / L.

[0012] In step S1, the mass ratio of the acid-dissolved chitosan to the desulfurization wastewater is 1:(5-8). The desulfurization wastewater is used to dissolve the acid-dissolved chitosan, which can not only utilize the acidity of the desulfurization wastewater to dissolve the acid-dissolved chitosan and protonate the amino groups of the acid-dissolved chitosan, but also does not affect the function of the acid-dissolved chitosan to absorb carbon dioxide, and especially can realize the resource utilization of the desulfurization wastewater.

[0013] In step S2, the mass content of the sodium alginate solution is 2-4%; the mass ratio of the viscous substance to the sodium alginate solution is 1:(1-2); the heating temperature is 50-70 DEG C, and the heating time is 2-4h. The chitosan solution and the sodium alginate solution are fully stirred and mixed, and the hydrogen ions in the desulfurization wastewater are used to promote the formation of ester groups between the carboxyl groups of the alginate and the amino groups of the chitosan, so that the cross-linking is more firm.

[0014] In step S3, the mass content of TRIS in the mixed solution is controlled to be 10-15%. The chloride component in the desulfurization wastewater can make TRIS present in a liquid-solid intermediate state, and the precipitation is not precipitated, so that the hydroxyl ions can be fully played; the lime milk (i.e. calcium hydroxide) enhances the strength of the sodium alginate-chitosan cross-linked material, and after the calcium ions are captured, more hydroxyl ions and TIRS are covered by the gel, and after the metal ions are captured, the gel resolution temperature is greatly degraded, and the gel resolution temperature after capture is 60-80 DEG C.

[0015] In step S4, the freezing temperature is-18 DEG C to-22 DEG C, and the freezing time is 6-10h; the drying is vacuum drying, and the drying time is 20-30h. Through freezing and drying, a gel with sufficient strength can be obtained, which contains chitosan amino, molten TRIS, and a large amount of hydroxyl groups, and the effect of directly capturing carbon dioxide in the air is excellent.

[0016] The application also provides a carbon dioxide solid adsorption gel prepared according to the above preparation method.

[0017] The application also provides the application of the above carbon dioxide solid adsorption gel in carbon dioxide adsorption.

[0018] The application relies on chitosan and other natural products to prepare a carbon dioxide solid adsorption gel by combining desulfurization wastewater treatment, which not only greatly reduces the manufacturing cost of the adsorbent, but also effectively treats the desulfurization wastewater, and the prepared carbon dioxide solid adsorption gel has excellent carbon dioxide capture effect and low capture resolution temperature, which is particularly advantageous for carbon dioxide capture and utilization. DETAILED DESCRIPTION

[0019] It should be noted that the following detailed description is illustrative only, and is intended to provide further description in order to provide a thorough understanding of the present application. Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which the application pertains.

[0020] It is to be understood that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of example embodiments in accordance with the present application. As used herein, the singular forms "a", "an" and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms "comprises" and / or "comprising," when used in this specification, specify the presence of stated features, steps, operations, elements, components, and / or groups thereof, but do not preclude the presence or addition of one or more other features, steps, operations, elements, components, and / or groups thereof.

[0021] The technical solutions of the present application will be described clearly and completely below in conjunction with the embodiments. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative work fall within the scope of protection of the present application.

[0022] Embodiment 1

[0023] In this embodiment, the desulfurization wastewater is used to prepare the carbon dioxide solid adsorption gel. The pH value of the desulfurization wastewater is 5.5, the mass content of calcium chloride is 12 mg / L, and the mass content of magnesium chloride is 10 mg / L. The preparation method comprises the following steps:

[0024] 1) Preparation of chitosan solution

[0025] The acid-soluble chitosan and the supernatant of the desulfurization wastewater are fully stirred and mixed at a mass ratio of 4:25 to prepare the chitosan solution.

[0026] 2) Preparation of viscous liquid

[0027] The chitosan solution and the sodium alginate solution with a mass content of 3% are fully stirred and mixed at a mass ratio of 1:1, and then heated at 60°C for 3h to prepare the viscous liquid.

[0028] 3) Preparation of mixed solution

[0029] The desulfurization wastewater is neutralized to neutral by adding lime milk, and then TRIS is added and fully stirred and dissolved to prepare the mixed solution. The mass content of TRIS in the mixed solution is 12%.

[0030] 4) Freezing and drying

[0031] The viscous liquid of step 2) is added dropwise into the mixed solution of step 3) by a syringe by gravity to form a hydrogel. The hydrogel is taken out, frozen at -18°C for 8h, and then vacuum dried for 24h to prepare the carbon dioxide solid adsorption gel.

[0032] Example 2

[0033] In this example, the desulfurization wastewater is used to prepare the carbon dioxide solid adsorption gel. The pH value of the desulfurization wastewater is 5.5, the mass content of calcium chloride is 13 mg / L, and the mass content of magnesium chloride is 11 mg / L. The preparation method comprises the following steps:

[0034] 1) Preparation of chitosan solution

[0035] The acid-soluble chitosan and the supernatant of the desulfurization wastewater are fully stirred and mixed at a mass ratio of 1:5 to prepare the chitosan solution.

[0036] 2) Preparation of viscous liquid

[0037] The chitosan solution and the sodium alginate solution with a mass content of 2% are fully stirred and mixed at a mass ratio of 1:1, and then heated at 50°C for 4 h to prepare the viscous liquid.

[0038] 3) Preparation of mixed solution

[0039] The desulfurization wastewater is neutralized to neutral by adding lime milk, and then TRIS is added and fully stirred and dissolved to prepare the mixed solution. The mass content of TRIS in the mixed solution is 10%.

[0040] 4) Freezing and drying

[0041] The viscous liquid of step 2) is added dropwise into the mixed solution of step 3) by a syringe by gravity to form a hydrogel. The hydrogel is removed, first frozen at -20°C for 10 h, and then vacuum dried for 20 h to prepare the carbon dioxide solid adsorption gel.

[0042] Example 3

[0043] In this example, the desulfurization wastewater is used to prepare the carbon dioxide solid adsorption gel. The pH value of the desulfurization wastewater is 6, the mass content of calcium chloride is 13 mg / L, and the mass content of magnesium chloride is 11 mg / L. The preparation method comprises the following steps:

[0044] 1) Preparation of chitosan solution

[0045] The acid-soluble chitosan and the supernatant of the desulfurization wastewater are fully stirred and mixed at a mass ratio of 1:8 to prepare the chitosan solution.

[0046] 2) Preparation of viscous liquid

[0047] The chitosan solution and the sodium alginate solution with a mass content of 2% are fully stirred and mixed at a mass ratio of 1:2, and then heated at 70°C for 2 h to prepare the viscous liquid.

[0048] 3) Preparation of mixed solution

[0049] The desulfurization wastewater is neutralized to neutral by adding lime milk, and then TRIS is added and dissolved by stirring to prepare a mixed solution; wherein the mass content of TRIS in the mixed solution is 15%.

[0050] 4) freezing, drying

[0051] The viscous liquid of step 2) is added dropwise by gravity through a syringe into the mixed solution of step 3) to form a hydrogel; the hydrogel is removed, frozen at -22°C for 6h, and then vacuum dried for 30h to prepare a carbon dioxide solid adsorption gel.

[0052] Comparative Example 1

[0053] The carbon dioxide solid adsorption gel of the present comparative example is prepared by the following steps:

[0054] 1) preparation of a chitosan solution

[0055] The acid-soluble chitosan is mixed with an ester acid solution with a pH of 5.5 at a mass ratio of 4:25 by stirring to prepare a chitosan solution.

[0056] 2) preparation of a viscous liquid

[0057] The chitosan solution is mixed with a 3% mass content sodium alginate solution at a mass ratio of 1:1 by stirring, and then heated at 60°C for 3h to prepare a viscous liquid.

[0058] 3) preparation of a mixed solution

[0059] The same amount of lime milk as in Example 1 is added to water, and then TRIS is added and dissolved by stirring to prepare a mixed solution; wherein the mass content of TRIS in the mixed solution is 12%.

[0060] 4) freezing, drying

[0061] The viscous liquid of step 2) is added dropwise by gravity through a syringe into the mixed solution of step 3) to form a hydrogel; the hydrogel is removed, frozen at -18°C for 8h, and then vacuum dried for 24h to prepare a carbon dioxide solid adsorption gel.

[0062] Comparative Example 2

[0063] Except that 0.01 mol / L sodium hydroxide solution is used instead of lime milk in step 3) of Example 1, the rest is the same as Example 1.

[0064] Comparative Example 3

[0065] Except that no TRIS is added when preparing the mixed solution in step 3), the rest is the same as Example 1.

[0066] Comparative Example 4

[0067] The rest is the same as Example 1 except that pure water is used instead of desulfurization wastewater.

[0068] Test Example 1

[0069] A gas adsorption test was performed using the carbon dioxide solid adsorption gel prepared in Example 1; the gas adsorption test method was as follows:

[0070] A 30 cubic meter sealed laboratory was used for the test, and the laboratory was equipped with a carbon dioxide sensor and a fan. The carbon dioxide solid adsorption gel was filled into the fan inlet, and a non-woven fabric was used to fix the adsorption layer to a thickness of 2 cm. The initial concentration of carbon dioxide in the laboratory before the adsorption test was 500 ppm, and the carbon dioxide concentration after adsorption for different times under a 300 m 3 / h air volume is shown in Table 1.

[0071] Table 1 Carbon dioxide concentration after adsorption for different times

[0072] Adsorption time (min) Carbon dioxide concentration (ppm) 0 500 1 462 2 418 3 378 4 346 5 319 6 287 7 253 8 215 9 181 10 144

[0073] Test Example 2

[0074] A gas adsorption test was performed using the carbon dioxide solid adsorption gel prepared in each of the examples and the comparative example, and the test method was the same as that of Test Example 1; the carbon dioxide concentration after adsorption for 10 min under a 300 m 3 / h air volume is shown in Table 2.

[0075] Table 2 Adsorption results of different carbon dioxide solid adsorption gels

[0076]

[0077]

[0078] Test Example 3

[0079] The carbon dioxide solid adsorption gel after adsorption for 10 min in Test Example 2 was desorbed at a desorption temperature of 60°C for 12 h, and a gas adsorption test was performed using the carbon dioxide solid adsorption gel prepared in each of the examples and the comparative example. The test method was the same as that of Test Example 1; the carbon dioxide concentration after adsorption for 10 min under a 300 m 3 / h air volume is shown in Table 3.

[0080] Table 3 Adsorption results of different carbon dioxide solid adsorption gels

[0081] Carbon dioxide solid adsorption gel Carbon dioxide concentration (ppm) Example 1 145 Example 2 158 Example 3 123 Comparative Example 1 257 Comparative Example 2 333 Comparative Example 3 292 Comparative Example 4 256

[0082] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present application, and are not intended to limit the present application; although the present application has been described in detail with reference to the above embodiments, those skilled in the art should understand that the technical solutions recorded in the above embodiments can be modified, or some or all of the technical features can be replaced by equivalents; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present application.

Claims

1. A method for preparing a carbon dioxide solid adsorption gel, characterized by, It comprises the following steps: S1: mixing acid-dissolved chitosan and desulfurization wastewater to prepare a chitosan solution; S2: mixing the chitosan solution and a sodium alginate solution, and then heating to prepare a viscous liquid; S3: adding lime milk to the desulfurization wastewater to neutralize it, and then adding TRIS and stirring to dissolve, to prepare a mixed solution; S4: adding the viscous liquid to the mixed solution to form a hydrogel, and then freezing and drying the hydrogel to prepare a carbon dioxide solid adsorption gel; The pH value of the desulfurization wastewater is 5-6; the mass content of calcium chloride in the desulfurization wastewater is 12-15 mg / L, and the mass content of magnesium chloride is 10-12 mg / L.

2. The production method according to claim 1, characterized by, In step S1, the mass ratio of acid-dissolved chitosan to desulfurization wastewater is 1: (5-8).

3. The production method according to claim 1, characterized by, In step S2, the mass content of the sodium alginate solution is 2-4 %.

4. The production method according to claim 1, characterized by, In step S2, the heating temperature is 50-70 ℃, and the heating time is 2-4 h.

5. The production method according to claim 1, characterized by, In step S3, the mass content of TRIS in the mixed solution is controlled to be 10-15 %.

6. The production method according to claim 1, characterized by, In step S4, the freezing temperature is-18 ℃ to-22 ℃, and the freezing time is 6-10 h.

7. The production method according to claim 1, characterized by, In step S4, vacuum drying is used for drying, and the drying time is 20-30 h.

8. A carbon dioxide solid adsorption gel, characterized by, The preparation method according to any one of claims 1-7.

9. The carbon dioxide solid adsorption gel according to claim 8 is used for carbon dioxide adsorption.

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