Adsorbent for adsorbing sulfur dioxide and nitrogen oxide in coke oven flue gas and preparation method thereof

Abstract

The invention provides an adsorbent for adsorbing sulfur dioxide and nitrogen oxides in coke oven flue gas and a preparation method thereof.The preparation method comprises the following steps that S1, magnesium acetate and 2, 5-dihydroxyterephthalic acid are dissolved in a solvent, a solvothermal reaction is conducted, and after the reaction is finished, filtering is conducted to obtain yellow crystals; s2, washing the yellow crystal with N, N-dimethylformamide, filtering the yellow crystal, soaking the yellow crystal in methanol, filtering the yellow crystal, and carrying out vacuum drying to obtain Mg-MOF-74; and S3, coating the Mg-MOF-74 with a methyl red dye, and then sequentially and respectively irradiating the Mg-MOF-74 with ultraviolet light and visible light, so as to obtain the Mg-MOF-74 adsorbent with the pore size of 0.3-0.5 nm. The adsorbent can effectively adsorb sulfur dioxide and nitrogen oxide in coke oven flue gas, the adsorption effect is good, and near-zero emission can be achieved.

Description

Technical Field

[0001] The present invention belongs to the technical field of flue gas purification, and in particular, relates to an adsorbent for adsorbing sulfur dioxide and nitrogen oxides in coke oven flue gas and a preparation method thereof. Background Art

[0002] With the rapid development of the domestic and global steel industry, the demand for coking products has increased dramatically, investment has increased, and the industry's capacity has expanded rapidly. However, the coking industry has high resource consumption and large production emissions, especially the high content of harmful substances in the emissions, which has caused serious waste of resources and environmental pollution, brought huge pressure on the healthy and sustainable development of the national economy, and thus hindered the rapid development of the coking industry.

[0003] The coke oven flue gas produced by coking is a kind of gas containing a large amount of sulfur dioxide (SO2) and nitrogen oxides (NO X ) of exhaust gas, SO2 and NO X It is the main cause of air pollution and acid rain, and it also directly harms human health. As a major coke producer, my country emits SO2 and NO from coke oven flues during coking. X The total amount should not be underestimated. Therefore, SO2 and NO in coke oven flue gas X The removal technology is crucial.

[0004] Activated carbon has a high specific surface area and pore volume, and thus has a strong adsorption capacity, and has been widely studied and applied in the field of flue gas purification. However, during the process of flue gas desulfurization and denitrification, the pore structure and surface characteristics of activated carbon determine the adsorption of SO2 and NO. X The adsorption capacity and catalytic capacity of activated carbon make it difficult to control the adsorption effect. X Achieve ultra-low emissions (SO2≤35mg / Nm 3 , NO X ≤50mg / Nm 3 ), but due to the huge total amount of industrial flue gas emissions, SO2 and NO X The absolute value of emissions is still not negligible. SO2 and NO X Near-zero emissions are imperative. Summary of the invention

[0005] In view of this, the present invention aims to solve one of the technical problems in the related art at least to a certain extent. To this end, an embodiment of the present invention provides an adsorbent for adsorbing sulfur dioxide and nitrogen oxides in coke oven flue gas and a preparation method thereof.

[0006] In a first aspect, an embodiment of the present invention provides a method for preparing an adsorbent for adsorbing sulfur dioxide and nitrogen oxides in coke oven flue gas, comprising the following steps:

[0007] S1: dissolving magnesium acetate and 2,5-dihydroxyterephthalic acid in a solvent, performing a solvothermal reaction, and filtering to obtain yellow crystals after the reaction is completed;

[0008] S2: washing the yellow crystals with N,N-dimethylformamide, filtering and soaking them in methanol, filtering and vacuum drying them to obtain Mg-MOF-74;

[0009] S3: coating the Mg-MOF-74 with methyl red dye, and then irradiating it with ultraviolet light and visible light in sequence to obtain a Mg-MOF-74 adsorbent with a pore size of 0.3 nm to 0.5 nm.

[0010] The embodiment of the present invention firstly obtains the Mg-MOF-74 material with good adsorption effect through solvothermal reaction, and then uses light-induced structural changes of methyl red dye to open the entrance of the internal pores of Mg-MOF-74 and adjust its pore size to make it more suitable for absorbing sulfur dioxide and nitrogen oxides in coke oven flue gas, thereby significantly improving the adsorption capacity.

[0011] In some embodiments, in step S1, the molar ratio of the magnesium acetate to the 2,5-dihydroxyterephthalic acid is (2.5-3.5):1;

[0012] And / or, the solvent comprises a mixture of N,N-dimethylformamide, ethanol and water, preferably, the volume ratio of N,N-dimethylformamide, ethanol and water is (12-18):1:1.

[0013] In some embodiments, in step S1, the temperature of the solvent thermal reaction is 110°C to 130°C, and the reaction time is 15h to 25h.

[0014] In some embodiments, in step S2, the soaking time is 40h to 60h;

[0015] And / or, the vacuum drying temperature is 150° C. to 200° C., and the drying time is 8 h to 15 h.

[0016] In some embodiments, in step S3, the wavelength of the ultraviolet light is 280nm to 350nm, and the irradiation time using the ultraviolet light is 0.5h to 1h;

[0017] And / or, the wavelength of the visible light is 500nm to 700nm, and the irradiation time with the visible light is 1h to 3h.

[0018] In the second aspect, the embodiment of the present invention further provides an adsorbent for adsorbing sulfur dioxide and nitrogen oxides in coke oven flue gas, wherein the adsorbent is prepared by the method described in the first aspect. The adsorbent exhibits a good adsorption effect on sulfur dioxide and nitrogen oxides in coke oven flue gas.

[0019] In a third aspect, an embodiment of the present invention further proposes a method for adsorbing sulfur dioxide and nitrogen oxides in coke oven flue gas, wherein the method uses the adsorbent described in the second aspect to physically adsorb sulfur dioxide and nitrogen oxides in coke oven flue gas.

[0020] In some embodiments, the physical adsorption temperature is -80°C to -5°C, preferably -20°C to -5°C.

[0021] In some embodiments, the concentration of sulfur dioxide in the coke oven flue gas is 100 mg / Nm 3 ~800mg / Nm 3 ; The concentration of nitrogen oxides is 500mg / Nm 3 ~1000mg / Nm 3 .

[0022] The advantages and beneficial effects of the embodiments of the present invention are as follows:

[0023] (1) In the embodiment of the present invention, a Mg-MOF-74 material with good adsorption effect is firstly prepared by a solvothermal reaction, and then the pore size of Mg-MOF-74 is adjusted by utilizing the light-induced structural change of methyl red dye, thereby improving its adsorption capacity for sulfur dioxide and nitrogen oxides in coke oven flue gas. The preparation process of the catalyst is simple, easy to operate, and suitable for industrial application.

[0024] (2) The embodiment of the present invention can significantly improve the adsorption effect of the adsorbent by physically adsorbing sulfur dioxide and nitrogen oxides in the coke oven flue gas using an adsorbent under a low temperature environment, thereby achieving near-zero emissions of sulfur dioxide and nitrogen oxides in the coke oven flue gas; and the physical adsorption method is safer and more environmentally friendly than the chemical adsorption method. DETAILED DESCRIPTION

[0025] In order to make the purpose, technical solution and advantages of the embodiment of the present invention clearer, the technical solution of the embodiment of the present invention will be clearly and completely described below. Obviously, the described embodiment is a part of the embodiment of the present invention, not all the embodiments. Based on the described embodiment of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work belong to the protection scope of the present invention.

[0026] Unless otherwise defined, technical or scientific terms used in the present invention shall have the common meanings understood by those having ordinary skills in the field to which the present invention belongs.

[0027] Where values ​​are described herein as a range, it should be understood that such disclosure includes disclosure of all possible sub-ranges within that range, as well as specific values ​​falling within that range, regardless of whether a specific value or a specific sub-range is explicitly stated.

[0028] Herein, the words "comprises" and "includes" and variations thereof mean that other elements or integers which are permitted but not specifically described may be included.

[0029] In this article, the term "and / or" is merely a term used to describe the association relationship of associated objects, indicating that three relationships may exist. For example, A and / or B may represent three situations: A exists alone, A and B exist at the same time, and B exists alone.

[0030] In a first aspect, an embodiment of the present invention provides a method for preparing an adsorbent for adsorbing sulfur dioxide and nitrogen oxides in coke oven flue gas, comprising the following steps:

[0031] S1: dissolving magnesium acetate and 2,5-dihydroxyterephthalic acid in a solvent, performing a solvothermal reaction, and filtering to obtain yellow crystals after the reaction is completed;

[0032] S2: Wash the yellow crystals with N,N-dimethylformamide, filter and soak them in methanol solvent, then filter and vacuum dry to obtain Mg-MOF-74;

[0033] S3: Mg-MOF-74 is coated with methyl red dye, and then irradiated with ultraviolet light and visible light respectively to obtain a Mg-MOF-74 adsorbent with a pore size of 0.3nm to 0.5nm.

[0034] In the preparation method of the adsorbent of the embodiment of the present invention, the Mg-MOF-74 material with good adsorption effect is first obtained by solvent thermal reaction, and then the entrance of the internal pores of Mg-MOF-74 is opened by utilizing the structural change of light-induced methyl red dye, and its pore size is adjusted to make it more suitable for absorbing sulfur dioxide and nitrogen oxides in coke oven flue gas, thereby significantly improving the adsorption capacity, thereby effectively reducing the emission of harmful substances in coke oven flue gas and protecting the environment and human health.

[0035] Since the Mg-MOF-74 structure contains many micron-level channels and micropores, it exhibits extremely high selectivity and efficiency in the adsorption of sulfur dioxide and nitrogen oxide gases; and the present application also uses raw materials that induce structural changes in methyl red dye to adjust the pore size of Mg-MOF-74 to further improve its adsorption capacity for sulfur dioxide and nitrogen oxides. Specifically: due to the rigid structure of Mg-MOF-74, after the Mg-MOF-74 coated with methyl red is irradiated with ultraviolet light and visible light, methyl red can more easily enter the channels, thereby achieving the adjustment of the pore size.

[0036] In some specific embodiments, in step S1, the molar ratio of magnesium acetate to 2,5-dihydroxyterephthalic acid is (2.5-3.5):1, for example, it can be 2.5:1, 2.8:1, 3:1, 3.2:1 or 3.5:1, but it is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable;

[0037] and / or, the solvent comprises a mixture of N,N-dimethylformamide, ethanol and water, wherein N,N-dimethylformamide is used as an organic solvent mainly to dissolve the organic ligand;

[0038] Preferably, the volume ratio of N,N-dimethylformamide, ethanol and water is (12-18):1:1, for example, it can be 12:1:1, 15:1:1, 16:1:1 or 18:1:1, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0039] In some specific embodiments, in step S1, the temperature of the solvent thermal reaction is 110°C to 130°C, for example, it can be 110°C, 120°C, 125°C or 130°C, but is not limited to the listed values, and other unlisted values ​​within the numerical range are equally applicable; the reaction time is 15h to 25h, for example, it can be 15h, 18h, 20h, 24h or 25h, but is not limited to the listed values, and other unlisted values ​​within the numerical range are equally applicable.

[0040] In some specific embodiments, in step S2, the soaking time is 40h to 60h, for example, 40h, 48h, 50h, 55h or 60h, etc., but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable;

[0041] And / or, the vacuum drying temperature is 150°C to 200°C, for example, it can be 150°C, 160°C, 180°C or 200°C, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable; the drying time is 8h to 15h, for example, it can be 8h, 10h, 12h or 15h, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0042] In step S2 of the preparation method of the embodiment of the present invention, the yellow crystals obtained in step S1 are first washed with N,N-dimethylformamide to wash away excess metal ions or organic ligands; the washed material is then soaked in methanol to wash away excess N,N-dimethylformamide, thereby ensuring that the product has a high purity; and then vacuum drying is performed to activate the Mg-MOF-74 material and volatilize the methanol.

[0043] In some specific embodiments, in step S3, the wavelength of the ultraviolet light is 280nm to 350nm, for example, it can be 280nm, 300nm, 315nm, 320nm or 350nm, but it is not limited to the listed values, and other values ​​not listed in the numerical range are also applicable; the time for irradiation with ultraviolet light is 0.5h to 1h, for example, it can be 0.5h, 0.8h or 1h, but it is not limited to the listed values, and other values ​​not listed in the numerical range are also applicable;

[0044] And / or, the wavelength of visible light is 500nm to 700nm, for example, it can be 500nm, 550nm, 600nm, 680nm or 700nm, but it is not limited to the listed values, and other values ​​not listed within the numerical range are equally applicable; the time for irradiation with visible light is 1h to 3h, for example, it can be 1h, 1.5h, 2h or 3h, but it is not limited to the listed values, and other values ​​not listed within the numerical range are equally applicable.

[0045] In a second aspect, an embodiment of the present invention further provides an adsorbent for adsorbing sulfur dioxide and nitrogen oxides in coke oven flue gas, wherein the adsorbent is prepared by the method described in the first aspect.

[0046] In a third aspect, an embodiment of the present invention further proposes a method for adsorbing sulfur dioxide and nitrogen oxides in coke oven flue gas, wherein the method uses the adsorbent described in the second aspect to physically adsorb sulfur dioxide and nitrogen oxides in coke oven flue gas.

[0047] In some specific embodiments, the temperature of physical adsorption is -80℃~-5℃, for example, it can be -80℃, -65℃, -50℃, -45℃, -20℃, -10℃ or -5℃, etc., but it is not limited to the listed values, and other values ​​not listed in the numerical range are also applicable; further, the temperature of physical adsorption is preferably -20℃~-5℃, for example, it can be -20℃, -15℃, -10℃ or -5℃, etc., but it is not limited to the listed values, and other values ​​not listed in the numerical range are also applicable. The inventor found through research that the lower the temperature during physical adsorption, the more beneficial it is for adsorption purification. However, if the temperature is too low, the cooling equipment structure will be complicated and the energy consumption will increase. For example, it is required to set an insulation layer for the cooling equipment, the adsorption tower and the pipeline, and the sealing requirements are high, which will increase the cost. In addition, too low temperature conditions will easily cause condensation water to appear in the adsorption tower, causing the adsorbent to stick and clog, affecting the adsorption. Therefore, it is beneficial to cool the flue gas temperature to -20℃~-5℃. In addition, the embodiment of the present invention achieves near-zero emissions of sulfur dioxide and nitrogen oxides in coke oven flue gas through a physical adsorption method, which is safer, green and pollution-free than a chemical adsorption method.

[0048] In some specific embodiments, the concentration of sulfur dioxide in the coke oven flue gas is 100 mg / Nm 3 ~800mg / Nm 3 , for example, it can be 100 mg / Nm 3 、450mg / Nm 3 、500mg / Nm 3 、600mg / Nm 3 or 800mg / Nm 3 etc., but are not limited to the listed values. Other values ​​not listed in this value range are also applicable; the concentration of nitrogen oxides is 500mg / Nm 3 ~1000mg / Nm 3 , for example, it can be 500mg / Nm 3 、600mg / Nm 3 、750mg / Nm 3 、800mg / Nm 3 or 1000mg / Nm 3 The above range is not limited to the listed values, and other values ​​not listed within the above range are also applicable.

[0049] The following are non-limiting examples and comparative examples of the present invention. It should be noted that the schemes of the comparative examples are not prior art and are only provided for comparison with the schemes of the embodiments and are not intended to limit the present invention. Unless otherwise specified, the various raw materials used in the embodiments and comparative examples are conventional commercial products or can be prepared by known methods, and their specifications are conventional specifications in the art.

[0050] Example 1

[0051] This embodiment proposes a method for preparing an adsorbent for adsorbing sulfur dioxide and nitrogen oxides in coke oven flue gas, comprising the following steps:

[0052] S1: 1.758 g of magnesium acetate (Mg(OAc)2·4H2O) and 0.478 g of 2,5-dihydroxyterephthalic acid (H4DOBDC) were dissolved in a mixed solvent containing 176.5 mL of N,N-dimethylformamide (DMF), 11.8 mL of anhydrous ethanol and 11.8 mL of deionized water, and a solvothermal reaction was carried out at 125°C. After the reaction for 20 h, the reaction product was cooled to room temperature and filtered to obtain yellow crystals;

[0053] S2: Wash the yellow crystals with N,N-dimethylformamide, filter and soak them in methanol solvent, change the methanol solvent twice a day for 2 consecutive days, filter the product and dry it in vacuum at 180°C for 12 hours to obtain Mg-MOF-74;

[0054] S3: The above-mentioned Mg-MOF-74 is coated with methyl red dye, and then the mixture is irradiated with ultraviolet light (wavelength of 300nm) for 0.5h and then with visible light (wavelength of 500nm) for 1h to obtain a Mg-MOF-74 adsorbent with a pore size of about 0.3nm.

[0055] The Mg-MOF-74 adsorbent prepared in this example is used to adsorb sulfur dioxide (SO2) and nitrogen oxides (NO X ), the SO2 content in the flue gas is 600mg / Nm 3 , NO X The content is 700mg / Nm 3 , the adsorption temperature is -20℃.

[0056] After the adsorption is completed, the SO2 content in the obtained flue gas is ≤1mg / Nm 3 , NO X Content ≤1mg / Nm 3 .

[0057] Example 2

[0058] This embodiment proposes a method for preparing an adsorbent for adsorbing sulfur dioxide and nitrogen oxides in coke oven flue gas, comprising the following steps:

[0059] S1: 1.758 g of magnesium acetate (Mg(OAc)2·4H2O) and 0.478 g of 2,5-dihydroxyterephthalic acid (H4DOBDC) were dissolved in a mixed solvent containing 176.5 mL of N,N-dimethylformamide (DMF), 11.8 mL of anhydrous ethanol and 11.8 mL of deionized water, and a solvothermal reaction was carried out at 125°C. After the reaction for 20 h, the reaction product was cooled to room temperature and filtered to obtain yellow crystals;

[0060] S2: Wash the yellow crystals with N,N-dimethylformamide, filter and soak them in methanol solvent, change the methanol solvent twice a day for 2 consecutive days, filter the product and dry it in vacuum at 180°C for 12 hours to obtain Mg-MOF-74;

[0061] S3: The above-mentioned Mg-MOF-74 is coated with methyl red dye, and then the mixture is irradiated with ultraviolet light (wavelength of 320nm) for 1h and then with visible light (wavelength of 600nm) for 2h to obtain a Mg-MOF-74 adsorbent with a pore size of about 0.4nm.

[0062] The Mg-MOF-74 adsorbent prepared in this example is used to adsorb SO2 and NO in coke oven flue gas. X , the SO2 content in the flue gas is 600mg / Nm 3 , NO X The content is 700mg / Nm 3 , the adsorption temperature is -20℃.

[0063] After the adsorption is completed, the SO2 content in the obtained flue gas is ≤1mg / Nm 3 , NO X Content ≤1mg / Nm 3 .

[0064] Example 3

[0065] This embodiment proposes a method for preparing an adsorbent for adsorbing sulfur dioxide and nitrogen oxides in coke oven flue gas, comprising the following steps:

[0066] S1: 1.552 g of magnesium acetate (Mg(OAc)2·4H2O) and 0.478 g of 2,5-dihydroxyterephthalic acid (H4DOBDC) were dissolved in a mixed solvent containing 176.5 mL of N,N-dimethylformamide (DMF), 11.8 mL of anhydrous ethanol and 11.8 mL of deionized water, and a solvothermal reaction was carried out at 120°C. After the reaction for 15 h, the reaction product was cooled to room temperature and filtered to obtain yellow crystals;

[0067] S2: Wash the yellow crystals with N,N-dimethylformamide, filter and soak them in methanol solvent, change the methanol solvent twice a day for 2 consecutive days, filter the product and dry it in vacuum at 180°C for 12 hours to obtain Mg-MOF-74;

[0068] S3: The above-mentioned Mg-MOF-74 is coated with methyl red dye, and then the mixture is irradiated with ultraviolet light (wavelength of 300 nm) for 1 hour and then with visible light (wavelength of 500 nm) for 1 hour to obtain a Mg-MOF-74 adsorbent with a pore size of about 0.38 nm.

[0069] The Mg-MOF-74 adsorbent prepared in this example is used to adsorb SO2 and NO in coke oven flue gas. X , the SO2 content in the flue gas is 500mg / Nm 3 , NO X The content is 800mg / Nm 3 , the adsorption temperature is -15℃.

[0070] After the adsorption is completed, the SO2 content in the obtained flue gas is ≤1mg / Nm 3 , NO X Content ≤1mg / Nm 3 .

[0071] Example 4

[0072] This embodiment proposes a method for preparing an adsorbent for adsorbing sulfur dioxide and nitrogen oxides in coke oven flue gas, comprising the following steps:

[0073] S1: 1.758 g of magnesium acetate (Mg(OAc)2·4H2O) and 0.478 g of 2,5-dihydroxyterephthalic acid (H4DOBDC) were dissolved in a mixed solvent containing 176.5 mL of N,N-dimethylformamide (DMF), 11.8 mL of anhydrous ethanol and 11.8 mL of deionized water, and a solvothermal reaction was carried out at 110°C. After the reaction for 24 h, the reaction product was cooled to room temperature and filtered to obtain yellow crystals;

[0074] S2: Wash the yellow crystals with N,N-dimethylformamide, filter and soak them in methanol solvent, change the methanol solvent twice a day for 2 consecutive days, filter the product and dry it in vacuum at 180°C for 12 hours to obtain Mg-MOF-74;

[0075] S3: The above-mentioned Mg-MOF-74 is coated with methyl red dye, and then the mixture is irradiated with ultraviolet light (wavelength of 350 nm) for 1 hour and then with visible light (wavelength of 500 nm) for 1.5 hours to obtain a Mg-MOF-74 adsorbent with a pore size of about 0.45 nm.

[0076] The Mg-MOF-74 adsorbent prepared in this example is used to adsorb SO2 and NO in coke oven flue gas. X , the SO2 content in the flue gas is 700mg / Nm 3 , NO X The content is 850mg / Nm 3 , the adsorption temperature is -10℃.

[0077] After the adsorption is completed, the SO2 content in the obtained flue gas is ≤1mg / Nm 3 , NO X Content ≤1mg / Nm 3 .

[0078] Example 5

[0079] This embodiment proposes a method for preparing an adsorbent for adsorbing sulfur dioxide and nitrogen oxides in coke oven flue gas, comprising the following steps:

[0080] S1: 1.552 g of magnesium acetate (Mg(OAc)2·4H2O) and 0.478 g of 2,5-dihydroxyterephthalic acid (H4DOBDC) were dissolved in a mixed solvent containing 176.5 mL of N,N-dimethylformamide (DMF), 11.8 mL of anhydrous ethanol and 11.8 mL of deionized water, and a solvothermal reaction was carried out at 125°C. After the reaction for 20 h, the reaction product was cooled to room temperature and filtered to obtain yellow crystals;

[0081] S2: Wash the yellow crystals with N,N-dimethylformamide, filter and soak them in methanol solvent, change the methanol solvent twice a day for 2 consecutive days, filter the product and dry it in vacuum at 180°C for 12 hours to obtain Mg-MOF-74;

[0082] S3: The above-mentioned Mg-MOF-74 is coated with methyl red dye, and then the mixture is irradiated with ultraviolet light (wavelength of 350nm) for 1h and then with visible light (wavelength of 700nm) for 3h to obtain a Mg-MOF-74 adsorbent with a pore size of about 0.5nm.

[0083] The Mg-MOF-74 adsorbent prepared in this example is used to adsorb SO2 and NO in coke oven flue gas. X , the SO2 content in the flue gas is 600mg / Nm 3 , NO X The content is 700mg / Nm 3 , the adsorption temperature is -5℃.

[0084] After the adsorption is completed, the SO2 content in the obtained flue gas is ≤1mg / Nm 3, NO X Content ≤1mg / Nm 3 .

[0085] Comparative Example 1

[0086] This comparative example proposes a method for preparing an adsorbent for adsorbing sulfur dioxide and nitrogen oxides in coke oven flue gas, comprising the following steps:

[0087] S1: 0.862 g of magnesium acetate (Mg(OAc)2·4H2O) and 0.65 g of 2,5-dihydroxyterephthalic acid (H4DOBDC) were dissolved in a mixed solvent containing 176.5 mL of N,N-dimethylformamide (DMF), 11.8 mL of anhydrous ethanol and 11.8 mL of deionized water, and a solvothermal reaction was carried out at 80°C. After the reaction for 10 h, the reaction product was cooled to room temperature and filtered to obtain yellow crystals;

[0088] S2: Wash the yellow crystals with N,N-dimethylformamide, filter and soak them in methanol solvent, change the methanol solvent twice a day for 2 consecutive days, filter the product and dry it in vacuum at 180°C for 12 hours to obtain Mg-MOF-74;

[0089] S3: The above Mg-MOF-74 was coated with methyl red dye, and then the mixture was irradiated with ultraviolet light (wavelength of 300 nm) for 0.5 h and then with visible light (wavelength of 500 nm) for 0.5 h to obtain a Mg-MOF-74 adsorbent with a pore size of about 0.1 nm.

[0090] The Mg-MOF-74 adsorbent prepared in this example is used to adsorb SO2 and NO in coke oven flue gas. X , the SO2 content in the flue gas is 600mg / Nm 3 , NO X The content is 700mg / Nm 3 , the adsorption temperature is -20℃.

[0091] After the adsorption is completed, the SO2 content in the obtained flue gas is about 10mg / Nm 3 , NO X The content is about 20mg / Nm 3 , but did not reach the SO2 and NO X Nearly zero emissions.

[0092] Comparative Example 2

[0093] This comparative example proposes a method for preparing an adsorbent for adsorbing sulfur dioxide and nitrogen oxides in coke oven flue gas, comprising the following steps:

[0094] S1: 1.552 g of magnesium acetate (Mg(OAc)2·4H2O) and 0.478 g of 2,5-dihydroxyterephthalic acid (H4DOBDC) were dissolved in a mixed solvent containing 176.5 mL of N,N-dimethylformamide (DMF), 11.8 mL of anhydrous ethanol and 11.8 mL of deionized water, and a solvothermal reaction was carried out at 125°C. After the reaction for 20 h, the reaction product was cooled to room temperature and filtered to obtain yellow crystals;

[0095] S2: Wash the yellow crystals with N,N-dimethylformamide, filter and soak them in methanol solvent, change the methanol solvent twice a day for 2 consecutive days, filter the product and dry it in vacuum at 180°C for 12 hours to obtain Mg-MOF-74;

[0096] S3: The Mg-MOF-74 was coated with methyl red dye, and then irradiated with visible light (wavelength of 500 nm) for 0.5 h to obtain a Mg-MOF-74 adsorbent with a pore size of about 0.1 nm.

[0097] The Mg-MOF-74 adsorbent prepared in this example is used to adsorb SO2 and NO in coke oven flue gas. X , the SO2 content in the flue gas is 800mg / Nm 3 , NO X The content is 700mg / Nm 3 , the adsorption temperature is 25℃.

[0098] After the adsorption, the SO2 content in the flue gas is about 25mg / Nm 3 , NO X The content is about 40mg / Nm 3 , but did not reach the SO2 and NO X Nearly zero emissions.

[0099] In the present invention, the terms "one embodiment", "some embodiments", "examples", "specific examples", or "some examples" etc. mean that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the described specific features, structures, materials or characteristics may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine the different embodiments or examples described in this specification and the features of the different embodiments or examples, without contradiction.

[0100] Although the embodiments of the present invention have been shown and described above, it is to be understood that the above embodiments are exemplary and are not to be construed as limitations of the present invention. A person skilled in the art may change, modify, replace and vary the above embodiments within the scope of the present invention.

Claims

1. A method for preparing an adsorbent for adsorbing sulfur dioxide and nitrogen oxides in coke oven flue gas, characterized in that: The steps include: S1: dissolving magnesium acetate and 2,5-dihydroxyterephthalic acid in a solvent, performing a solvothermal reaction, and filtering to obtain yellow crystals after the reaction is completed; S2: washing the yellow crystals with N,N-dimethylformamide, filtering and soaking them in methanol, filtering and vacuum drying them to obtain Mg-MOF-74; S3: coating the Mg-MOF-74 with methyl red dye, and then irradiating it with ultraviolet light and visible light in sequence to obtain a Mg-MOF-74 adsorbent with a pore size of 0.3 nm to 0.5 nm.

2. The method for preparing an adsorbent for adsorbing sulfur dioxide and nitrogen oxides in coke oven flue gas according to claim 1, characterized in that: In step S1, the molar ratio of the magnesium acetate to the 2,5-dihydroxyterephthalic acid is (2.5-3.5):1; And / or, the solvent comprises a mixture of N,N-dimethylformamide, ethanol and water, preferably, the volume ratio of N,N-dimethylformamide, ethanol and water is (12-18):1:

1.

3. The method for preparing an adsorbent for adsorbing sulfur dioxide and nitrogen oxides in coke oven flue gas according to claim 1, characterized in that: In step S1, the temperature of the solvent thermal reaction is 110° C. to 130° C., and the reaction time is 15 h to 25 h.

4. The method for preparing an adsorbent for adsorbing sulfur dioxide and nitrogen oxides in coke oven flue gas according to claim 1, characterized in that: In step S2, the soaking time is 40h to 60h; And / or, the vacuum drying temperature is 150° C. to 200° C., and the drying time is 8 h to 15 h.

5. The method for preparing an adsorbent for adsorbing sulfur dioxide and nitrogen oxides in coke oven flue gas according to claim 1, characterized in that: In step S3, the wavelength of the ultraviolet light is 280nm to 350nm, and the irradiation time using the ultraviolet light is 0.5h to 1h; And / or, the wavelength of the visible light is 500nm to 700nm, and the irradiation time with the visible light is 1h to 3h.

6. An adsorbent for adsorbing sulfur dioxide and nitrogen oxides in coke oven flue gas, characterized in that: The adsorbent is prepared by the method according to any one of claims 1 to 5.

7. A method for adsorbing sulfur dioxide and nitrogen oxides in coke oven flue gas, characterized in that: The adsorbent according to claim 6 is used to physically adsorb sulfur dioxide and nitrogen oxides in coke oven flue gas.

8. The method for adsorbing sulfur dioxide and nitrogen oxides in coke oven flue gas according to claim 7, characterized in that: The temperature of the physical adsorption is -80°C to -5°C.

9. The method for adsorbing sulfur dioxide and nitrogen oxides in coke oven flue gas according to claim 8, characterized in that: The temperature of the physical adsorption is -20°C to -5°C.

10. The method for adsorbing sulfur dioxide and nitrogen oxides in coke oven flue gas according to claim 7, characterized in that: The concentration of sulfur dioxide in the coke oven flue gas is 100 mg / Nm 3 ~800mg / Nm 3 ; The concentration of nitrogen oxides is 500mg / Nm 3 ~1000mg / Nm 3 .