Accelerating agent for rapid sedimentation of biochemical sludge as well as preparation method and application of accelerating agent

Abstract

The invention relates to an accelerator for rapid sedimentation of biochemical sludge as well as a preparation method and application of the accelerator. The preparation method comprises the following steps: extracting a polysaccharide substance MI from biochemical activated sludge as an imprinting template molecule; the preparation method comprises the following steps: dissolving ferrite, cobalt nitrate and sodium fluoride in water, and stirring to form a solution A; selecting imidazole-dicarboxylic acid, dissolving in a sodium hydroxide solution, and stirring to form a solution B; adding the solution B into the solution A for reaction to obtain MOF turbid liquid; transferring the MOF suspension into a reaction kettle under the protection of nitrogen, adding imprinting template molecules, a cross-linking agent and an initiator for reaction, freeze-drying a reaction mixture, and washing to remove the imprinting template molecules, so as to obtain an MI-MOF compound with an MI vacancy; and mixing the MI-MOF compound with the MI vacancy with a high-molecular polymer to obtain the MI-MOF accelerator. According to the accelerator, through the synergistic effect of the MI-MOF compound with the MI vacancy and the high-molecular polymer, the flocculation effect of the flocculant is greatly improved.

Description

Technical Field

[0001] The invention belongs to the technical field of sewage treatment, and in particular relates to an accelerating coagulant for rapid sedimentation of biochemical sludge and a preparation method and application thereof. Background Art

[0002] At present, with the rapid development of society and economy, the treatment capacity of traditional municipal engineering - sewage treatment plants and municipal pipe networks is relatively lagging behind, resulting in a large amount of untreated sewage being directly or indirectly discharged into the ecological environment. Therefore, improving the treatment capacity and effluent quality of existing sewage treatment facilities has become the focus of public attention.

[0003] Sludge bulking and poor settling performance are common problems in sewage treatment plants. It usually takes a long time to restore the good settling performance of bulking sludge. During this period, the effluent quality of the water plant is difficult to meet the discharge standards and there is a risk of sludge loss. Therefore, in this process, choosing the right flocculant is a key factor affecting the treatment effect and operating costs.

[0004] In practical applications, the macromolecules of polymer flocculants are easily affected by external factors and destroyed, resulting in performance degradation. Traditional inorganic flocculants, such as aluminates and ferrites, often have the problem of excessive flocculant dosage, easy precipitation and excessive residues in the water during operation. Therefore, both polymer flocculants and inorganic flocculants have poor flocculation and sedimentation effects on high-concentration expanded sludge, and cannot improve the biochemical treatment capacity of high-concentration expanded sludge. Summary of the invention

[0005] In order to solve the above problems existing in the prior art, the present invention provides an accelerating coagulant for rapid sedimentation of biochemical sludge and its preparation method and application. The technical problem to be solved by the present invention is achieved by the following technical solutions:

[0006] The embodiment of the present invention provides a method for preparing an accelerating setting agent for rapid sedimentation of biochemical sludge, comprising the steps of:

[0007] Extracting polysaccharide MI from biochemical activated sludge as imprinting template molecules;

[0008] Select ferrous salt, cobalt nitrate and sodium fluoride, dissolve them in water, and stir to form solution A;

[0009] Select imidazole-dicarboxylic acid and dissolve it in sodium hydroxide solution, and stir to form solution B;

[0010] Adding the solution B to the solution A for reaction to obtain a MOF suspension;

[0011] The MOF suspension is transferred to a nitrogen-protected reactor, the imprinted template molecule, the cross-linking agent and the initiator are added to react, and the reaction mixture is freeze-dried and then washed to remove the imprinted template molecule to obtain a MI-MOF compound with MI vacancies;

[0012] The MI-MOF compound having MI vacancies is mixed with a high molecular polymer to obtain a MI-MOF accelerating setting agent.

[0013] In one embodiment of the present invention, extracting polysaccharide MI from biochemical activated sludge as imprint template molecules comprises:

[0014] The activated sludge in the biochemical pool is washed with water for several times, and the polysaccharide substance MI is extracted from the washed activated sludge by column chromatography to obtain the imprint template molecule.

[0015] In one embodiment of the present invention, the polysaccharide material MI includes one or more of cellulose and hemicellulose.

[0016] In one embodiment of the present invention, the ferrous salt includes one or more of ferrous sulfate and ferrous chloride;

[0017] The molar ratio of the ferrous salt, the cobalt nitrate and the sodium fluoride is 2-8:1:1-3.

[0018] In one embodiment of the present invention, the volume ratio of the imidazole-dicarboxylic acid to the sodium hydroxide solution is 2 to 3:1;

[0019] The pH value of the sodium hydroxide solution is 11-13.

[0020] In one embodiment of the present invention, the solution B is added to the solution A for reaction to obtain a MOF suspension, comprising:

[0021] The solution B is injected into the reactor containing the solution A, and stirred at a speed of 500 to 1000 r / min for 5 to 20 min to react to obtain a MOF suspension;

[0022] Wherein, the volume ratio of the solution B to the solution A is 1 to 2:1.

[0023] In one embodiment of the present invention, the MOF suspension is transferred to a nitrogen-protected reactor, the imprinted template molecule, the crosslinking agent and the initiator are added to react, and the reaction mixture is freeze-dried and washed to remove the imprinted template molecule to obtain a MI-MOF compound with MI vacancies, comprising:

[0024] The MOF suspension is transferred to a nitrogen-protected reactor, and the imprinted template molecule, the crosslinking agent and the initiator are added, and stirred at 35-45° C. for 12-24 hours to react to obtain a reaction mixture containing a MI-MOF compound; wherein the mass ratio of the imprinted template molecule to the MOF suspension is 1:1, the mass ratio of the crosslinking agent to the MOF suspension is 1:100, and the mass ratio of the initiator to the MOF suspension is 1:100;

[0025] The reaction mixture is placed in a vacuum freeze dryer, the temperature is controlled at -20 to -40°C, and freeze-dried for 12 to 24 hours under vacuum to obtain a freeze-dried material;

[0026] The freeze-dried material is washed with a mixture of methanol and sodium hydroxide to remove the imprint template molecules, thereby obtaining the MI-MOF compound with MI vacancies, wherein the volume ratio of methanol to sodium hydroxide solution in the mixture of methanol and sodium hydroxide is 9-8:1-2.

[0027] In one embodiment of the present invention, the high molecular polymer includes polyacrylamide.

[0028] Another embodiment of the present invention provides an accelerator for rapid sedimentation of biochemical sludge, which is prepared by the preparation method described in the above embodiment. The accelerator is a mixture of an MI-MOF compound and a high molecular polymer, wherein the MI-MOF compound has MI vacancies, and the MOF structure uses iron ions and cobalt ions as the metal ion core of the MOF material.

[0029] Another embodiment of the present invention provides an application of a MI-MOF accelerating coagulant to flocculate and settle biochemical activated sludge in sewage treatment.

[0030] Compared with the prior art, the present invention has the following beneficial effects:

[0031] 1. The present invention uses polysaccharide MI that affects the biochemical sludge settling performance as an imprint template molecule, and after MI is compounded with a metal organic framework MOF structure, MI is washed and removed, so that MI vacancies are formed in the MI-MOF compound. The MI-MOF compound with MI vacancies is compounded with a polymer through a connecting bridge to form an accelerating agent; in the accelerating agent, on the one hand, the polymer acts as a flocculant and has a sludge flocculation and sedimentation effect; on the other hand, the MI vacancies in the MI-MOF compound have a strong correlation, and can be combined with the polysaccharide of the activated sludge during the sludge flocculation and sedimentation process, which has a strong targeted effect and helps The activated sludge forms large-size flocs, thereby improving the sedimentation and adsorption performance of the sludge; at the same time, the metal organic framework MOF structure in the MI-MOF compound uses iron and cobalt ions as the metal ion core of the MOF material, which has stronger adsorption and surface nuclear power capabilities, can effectively prevent the reverse dissolution of metal ions, and ensure the flocculation effect. The space structure of iron and cobalt ions is also easier to combine with conventional high molecular polymers to form a higher performance flocculant; therefore, the quick-setting agent of the present invention greatly improves the flocculation effect of the flocculant through the synergistic effect of the MI-MOF compound with MI vacancies and the high molecular polymer;

[0032] 2. The preparation process of the quick-setting agent for rapid sedimentation of biochemical sludge of the present invention is simple, green and harmless. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 A schematic flow chart of a method for preparing an accelerating setting agent for rapid sedimentation of biochemical sludge provided in an embodiment of the present invention. DETAILED DESCRIPTION

[0034] The present invention is further described in detail below with reference to specific embodiments, but the embodiments of the present invention are not limited thereto.

[0035] See also Figure 1 , Figure 1 A schematic flow chart of a method for preparing an accelerating setting agent for rapid sedimentation of biochemical sludge provided in an embodiment of the present invention.

[0036] The preparation method of the quick-setting agent for rapid sedimentation of biochemical sludge in this embodiment comprises the following steps:

[0037] S1. Extract polysaccharide MI from biochemical activated sludge as imprinting template molecules.

[0038] Specifically, the activated sludge in the biochemical pool is washed with water for 2 to 5 times, and the polysaccharide substance MI is extracted from the washed activated sludge by column chromatography to obtain the imprint template molecule, wherein the polysaccharide substance includes one or more of cellulose and hemicellulose.

[0039] S2. Select ferrous salt, cobalt nitrate and sodium fluoride, dissolve them in water, and stir to form solution A.

[0040] Specifically, the molar ratio of ferrous salt, cobalt nitrate and sodium fluoride is 2-8:1:1-3; the ferrous salt includes one or more of ferrous sulfate and ferrous chloride; and the water can be pure water.

[0041] S3. Select imidazole-dicarboxylic acid and dissolve it in sodium hydroxide solution, and stir to form solution B.

[0042] Specifically, the volume ratio of imidazole-dicarboxylic acid to sodium hydroxide solution is 2-3:1, and the pH value of the sodium hydroxide solution is 11-13.

[0043] S4. Add solution B into solution A to react and obtain a MOF suspension.

[0044] Specifically, solution B is rapidly injected into the reactor of solution A through a syringe in a certain proportion, and vigorously stirred at a speed of 500 to 1000 r / min for 5 to 20 minutes to react to obtain a MOF suspension, wherein the volume ratio of solution B to solution A is 1 to 2:1.

[0045] In this embodiment, solution B and solution A are quickly injected and stirred vigorously, so that the substances in solution B and solution A are quickly and fully mixed and contacted to ensure the reaction between the two.

[0046] S5. The MOF suspension is transferred to a nitrogen-protected reactor, and the imprinted template molecules, cross-linking agent and initiator are added to react. The reaction mixture is freeze-dried and then washed to remove the imprinted template molecules to obtain a MI-MOF compound with MI vacancies.

[0047] Specifically, first, the MOF suspension is transferred to a nitrogen-protected reactor, and the imprinted template molecules, crosslinkers and initiators are added, and stirred at 35-45°C for 12-24 hours to react. The reaction introduces polysaccharides on the surface of the sludge during the molecular self-assembly process to obtain a reaction mixture, which contains MI-MOF compounds. Among them, the mass ratio of the imprinted template molecules to the MOF suspension is 1:1, the mass ratio of the crosslinker to the MOF suspension is 1:100, and the mass ratio of the initiator to the MOF suspension is 1:100. The crosslinker includes a polyamine crosslinker, such as propylenediamine; the initiator includes one or more of ammonium persulfate and potassium persulfate.

[0048] In this embodiment, the imprint template molecule contains hydroxyl groups. Under the action of the cross-linking agent and the initiator, the hydroxyl groups react with the carboxylic acid groups in the MOF material through polymerization to form MI-MOF.

[0049] Then, the reaction mixture is placed in a vacuum freeze dryer, the temperature is controlled at -20 to -40°C, and freeze-dried for 12 to 24 hours under vacuum to obtain a freeze-dried material.

[0050] Finally, the freeze-dried material is washed with a mixture of methanol and sodium hydroxide to remove the imprinted template molecules and obtain a MI-MOF compound with MI vacancies, wherein the volume ratio of methanol to sodium hydroxide solution (pH 12) in the mixture of methanol and sodium hydroxide is 9-8:1-2.

[0051] In this embodiment, the methanol and sodium hydroxide mixture is an effective solution for cleaning polysaccharides, wherein methanol removes soluble organic matter under the action of sodium hydroxide alkaline washing based on the principle of like dissolves like.

[0052] S6. Mixing the MI-MOF compound with MI vacancies with a polymer to obtain an accelerating setting agent. Specifically, physically mixing the MI-MOF compound with MI vacancies with the polymer, the carboxylic acid group in the MOF material and the amino group in the polymer form a covalent bond bridge, and the covalent bond bridge serves as a connecting bridge to allow the MI-MOF compound to be compounded with the polymer to obtain an accelerating setting agent. The polymer includes but is not limited to polyacrylamide.

[0053] This embodiment also provides an accelerator for rapid sedimentation of biochemical sludge. The accelerator is prepared by the above-mentioned preparation method and is a mixture of MI-MOF compound and high molecular polymer, wherein the MI-MOF compound has MI vacancies, and the MOF structure uses iron ions and cobalt ions as the metal ion core of the MOF material.

[0054] This embodiment also provides an application of the above MI-MOF rapid coagulant to flocculate and settle biochemical activated sludge in sewage treatment. The MI-MOF rapid coagulant is applied in sewage treatment to improve the settling performance of biochemical activated sludge and significantly increase the surface flow velocity of the secondary sedimentation tank.

[0055] This embodiment further illustrates the quick-setting agent for rapid sedimentation of biochemical sludge and its preparation method and application through the following examples.

[0056] Embodiment 1

[0057] A method for preparing an accelerating coagulant for rapid sedimentation of biochemical sludge comprises the following steps:

[0058] S1. Select the activated sludge at the end of the aerobic zone of the problem water plant, rinse it with clean water for 3 times, and use column chromatography to extract the polysaccharide MI as the imprint template molecule.

[0059] S2. Weigh ferrous sulfate, cobalt nitrate and sodium fluoride in a molar ratio of 2:1:2 and dissolve them in pure water, stirring to form solution A.

[0060] S3. Take imidazole-dicarboxylic acid and sodium hydroxide solution with a pH value of 12 in a volume ratio of 2:1, dissolve the imidazole-dicarboxylic acid in the sodium hydroxide solution, and stir to form solution B.

[0061] S4. Take solution A and solution B in a volume ratio of 2:3, and quickly inject solution B into the reactor containing solution A through a syringe. After vigorous stirring for 10 minutes, a MOF suspension is obtained.

[0062] S5. Transfer the MOF suspension to a nitrogen-protected reactor, add the polysaccharide MI into the reactor, and add the cross-linking agent propylene diamine and the initiator ammonium persulfate. The mass ratio of the MOF suspension, the polysaccharide MI, the cross-linking agent propylene diamine and the initiator ammonium persulfate is 100:100:1:1. Stir at 35°C for 12 hours to obtain a reaction mixture containing the MI-MOF compound.

[0063] Then, the reaction mixture was placed in a vacuum freeze dryer, the temperature was controlled at -20°C, and freeze-dried for 24 hours under vacuum to obtain a freeze-dried material.

[0064] Finally, the freeze-dried material was washed with a mixture of methanol and sodium hydroxide to remove the imprinted template molecules and obtain a MI-MOF compound with MI vacancies, wherein the volume ratio of methanol to sodium hydroxide solution in the mixture of methanol and sodium hydroxide was 9:1.

[0065] S6. Mixing the MI-MOF compound having MI vacancies with polyacrylamide to obtain a quick-setting agent for biochemical sludge.

[0066] In the biochemical sludge mixture of a sewage treatment plant, the sludge concentration is 5100 mg / L, and the sludge settling ratio SV30 is 950. When the above-mentioned targeted accelerating coagulant is added to the system at a dosage of 10 ppm, the sludge settling ratio SV30 drops to 450 when other conditions remain unchanged, and the sludge settling performance is improved by 52.6%.

[0067] Embodiment 2

[0068] A method for preparing an accelerating coagulant for rapid sedimentation of biochemical sludge comprises the following steps:

[0069] S1. Select the activated sludge at the end of the aerobic zone of the problem water plant, rinse it with clean water for 3 times, and use column chromatography to extract the polysaccharide MI as the imprint template molecule.

[0070] S2. Weigh ferrous sulfate, cobalt nitrate and sodium fluoride in a molar ratio of 4:1:2 and dissolve them in pure water, stirring to form solution A.

[0071] S3. Take imidazole-dicarboxylic acid and sodium hydroxide solution with a pH value of 12 in a volume ratio of 2:1, dissolve the imidazole-dicarboxylic acid in the sodium hydroxide solution, and stir to form solution B.

[0072] S4. Solution A and solution B were measured in a volume ratio of 1:1, and solution B was quickly injected into the reactor containing solution A through a syringe. After vigorous stirring for 10 minutes, a MOF suspension was obtained.

[0073] S5. Transfer the MOF suspension to a nitrogen-protected reactor, add the polysaccharide MI into the reactor, and add the cross-linking agent propylene diamine and the initiator ammonium persulfate. The mass ratio of the MOF suspension, the polysaccharide MI, the cross-linking agent propylene diamine and the initiator ammonium persulfate is 100:100:1:1. Stir at 40°C for 18 hours to obtain a reaction mixture containing the MI-MOF compound.

[0074] Then, the reaction mixture was placed in a vacuum freeze dryer, the temperature was controlled at -25°C, and freeze-dried for 20 hours under vacuum to obtain a freeze-dried material.

[0075] Finally, the freeze-dried material was washed with a mixture of methanol and sodium hydroxide to remove the imprinted template molecules and obtain a MI-MOF compound with MI vacancies, wherein the volume ratio of methanol to sodium hydroxide solution in the mixture of methanol and sodium hydroxide was 9:1.

[0076] S6. Mixing the MI-MOF compound having MI vacancies with polyacrylamide to obtain a quick-setting agent for biochemical sludge.

[0077] In the biochemical sludge mixture of a sewage treatment plant, the sludge concentration is 7300 mg / L, and the sludge settling ratio SV30 is 960. When the above-mentioned targeted accelerating coagulant is added to the system at a dosage of 20 ppm, the sludge settling ratio SV30 drops to 570 when other conditions remain unchanged, and the sludge settling performance is improved by 40.6%.

[0078] Embodiment 3

[0079] A method for preparing an accelerating coagulant for rapid sedimentation of biochemical sludge comprises the following steps:

[0080] S1. Select the activated sludge at the end of the aerobic zone of the problem water plant, rinse it with clean water for 3 times, and use column chromatography to extract the polysaccharide MI as the imprint template molecule.

[0081] S2. Weigh ferrous sulfate, cobalt nitrate and sodium fluoride in a molar ratio of 6:1:3 and dissolve them in pure water. Stir to form solution A.

[0082] S3. Take imidazole-dicarboxylic acid and sodium hydroxide solution with a pH value of 13 in a volume ratio of 3:1, dissolve the imidazole-dicarboxylic acid in the sodium hydroxide solution, and stir to form solution B.

[0083] S4. Solution A and solution B were measured in a volume ratio of 1:1, and solution B was quickly injected into the reactor containing solution A through a syringe. After vigorous stirring for 10 minutes, a MOF suspension was obtained.

[0084] S5. Transfer the MOF suspension to a nitrogen-protected reactor, add the polysaccharide MI into the reactor, and add the cross-linking agent propylene diamine and the initiator ammonium persulfate. The mass ratio of the MOF suspension, the polysaccharide MI, the cross-linking agent propylene diamine and the initiator ammonium persulfate is 100:100:1:1. Stir at 45°C for 24 hours to obtain a reaction mixture containing the MI-MOF compound.

[0085] Then, the reaction mixture was placed in a vacuum freeze dryer, the temperature was controlled at -30°C, and freeze-dried for 16 hours under vacuum to obtain a freeze-dried material.

[0086] Finally, the freeze-dried material was washed with a mixture of methanol and sodium hydroxide to remove the imprinted template molecules and obtain a MI-MOF compound with MI vacancies, wherein the volume ratio of methanol to sodium hydroxide solution in the mixture of methanol and sodium hydroxide was 8:2.

[0087] S6. Mixing the MI-MOF compound having MI vacancies with polyacrylamide to obtain a quick-setting agent for biochemical sludge.

[0088] In the biochemical sludge mixture of a sewage treatment plant, the sludge concentration is 5500 mg / L, the sludge settling ratio SV30 is 720, and the water volume treated in the secondary sedimentation tank is 3900 m 3 / h, the above targeted accelerating coagulant was added into the system at a dosage of 15ppm. When other conditions remained unchanged, the sludge settling ratio SV30 dropped to 570, and the water treatment volume of the secondary sedimentation tank was 6200m 3 / h, the amount of water treated increased by 53.8%.

[0089] Embodiment 4

[0090] A method for preparing an accelerating coagulant for rapid sedimentation of biochemical sludge comprises the following steps:

[0091] S1. Select the activated sludge at the end of the aerobic zone of the problem water plant, rinse it with clean water for 3 times, and use column chromatography to extract the polysaccharide MI as the imprint template molecule.

[0092] S2. Weigh ferrous sulfate, cobalt nitrate and sodium fluoride in a molar ratio of 8:1:1 and dissolve them in pure water. Stir to form solution A.

[0093] S3. Take imidazole-dicarboxylic acid and sodium hydroxide solution with a pH value of 13 in a volume ratio of 3:1, dissolve the imidazole-dicarboxylic acid in the sodium hydroxide solution, and stir to form solution B.

[0094] S4. Solution A and solution B were measured at a volume ratio of 2:1, and solution B was quickly injected into the reactor containing solution A through a syringe. After vigorous stirring for 10 minutes, a MOF suspension was obtained.

[0095] S5. Transfer the MOF suspension to a nitrogen-protected reactor, add the polysaccharide MI into the reactor, and add the cross-linking agent propylene diamine and the initiator ammonium persulfate. The mass ratio of the MOF suspension, the polysaccharide MI, the cross-linking agent propylene diamine and the potassium persulfate is 100:100:1:1. Stir at 45°C for 24 hours to obtain a reaction mixture containing the MI-MOF compound.

[0096] Then, the reaction mixture was placed in a vacuum freeze dryer, the temperature was controlled at -40°C, and freeze-dried for 12 hours under vacuum to obtain a freeze-dried material.

[0097] Finally, the freeze-dried material was washed with a mixture of methanol and sodium hydroxide to remove the imprinted template molecules and obtain a MI-MOF compound with MI vacancies, wherein the volume ratio of methanol to sodium hydroxide solution in the mixture of methanol and sodium hydroxide was 8:2.

[0098] S6. Mixing the MI-MOF compound having MI vacancies with polyacrylamide to obtain a quick-setting agent for biochemical sludge.

[0099] In a sewage treatment plant, the sludge concentration in the biochemical sludge mixture is 4600 mg / L, the sludge settling ratio SV30 is 690, and the water volume treated in the secondary sedimentation tank is 2083 m 3 / h, the above targeted accelerating coagulant was added into the system at a dosage of 10ppm. When other conditions remained unchanged, the sludge settling ratio SV30 dropped to 450, and the water volume treated in the secondary sedimentation tank was 3230m 3 / h, the amount of water treated increased by 55.1%.

[0100] In this embodiment, polysaccharide MI, which affects the settling performance of biochemical sludge, is used as an imprint template molecule. MI is compounded with a metal organic framework MOF structure and then washed to remove MI, so that MI vacancies are formed in the MI-MOF compound. The MI-MOF compound with MI vacancies is compounded with a polymer via a connecting bridge to form an accelerating coagulant. In the accelerating coagulant, on the one hand, the polymer acts as a flocculant and has a sludge flocculation and sedimentation effect; on the other hand, the MI vacancies in the MI-MOF compound have a strong correlation and can be combined with the polysaccharide of the activated sludge during the sludge flocculation and sedimentation process, so the targeted effect is strong and helpful. The activated sludge forms large-size flocs, thereby improving the sedimentation and adsorption performance of the sludge; at the same time, the metal organic framework MOF structure in the MI-MOF compound uses iron and cobalt ions as the metal ion core of the MOF material, has stronger adsorption and surface nuclear power capabilities, can effectively prevent the reverse dissolution of metal ions, and ensure the flocculation effect. The spatial structure of iron and cobalt ions is also easier to combine with conventional high-molecular polymers to form a higher-performance flocculant; therefore, the rapid coagulant of the present invention greatly improves the flocculation effect of the flocculant through the synergistic effect of the MI-MOF compound with MI vacancies and the high-molecular polymer;

[0101] The preparation process of the quick-setting agent for rapid sedimentation of biochemical sludge in this embodiment is simple, green and harmless.

[0102] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" etc. means 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 specific features, structures, materials or characteristics described 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.

[0103] Although the present application is described herein in conjunction with various embodiments, in the process of implementing the claimed application, those skilled in the art may understand and implement other variations of the disclosed embodiments by viewing the drawings, the disclosure, and the appended claims. In the claims, the word "comprising" does not exclude other components or steps, and "one" or "an" does not exclude multiple situations. A single processor or other unit may implement several functions listed in a claim. Certain measures are recorded in different dependent claims, but this does not mean that these measures cannot be combined to produce good results.

[0104] The above contents are further detailed descriptions of the present invention in combination with specific preferred embodiments, and it cannot be determined that the specific implementation of the present invention is limited to these descriptions. For ordinary technicians in the technical field to which the present invention belongs, several simple deductions or substitutions can be made without departing from the concept of the present invention, which should be regarded as falling within the protection scope of the present invention.

Claims

1. A method for preparing an accelerating setting agent for rapid sedimentation of biochemical sludge, characterized in that: Includes steps: Extracting polysaccharide MI from biochemical activated sludge as imprinting template molecules; Select ferrous salt, cobalt nitrate and sodium fluoride, dissolve them in water, and stir to form solution A; Select imidazole-dicarboxylic acid and dissolve it in sodium hydroxide solution, and stir to form solution B; Adding the solution B to the solution A for reaction to obtain a MOF suspension; The MOF suspension is transferred to a nitrogen-protected reactor, the imprinted template molecule, the cross-linking agent and the initiator are added to react, and the reaction mixture is freeze-dried and then washed to remove the imprinted template molecule to obtain a MI-MOF compound with MI vacancies; The MI-MOF compound having MI vacancies is mixed with a high molecular polymer to obtain a MI-MOF accelerating setting agent.

2. The method for preparing an accelerating setting agent for rapid sedimentation of biochemical sludge according to claim 1, characterized in that: Extraction of polysaccharide MI from biochemical activated sludge as imprint template molecules, including: The activated sludge in the biochemical pool is washed with water for several times, and the polysaccharide substance MI is extracted from the washed activated sludge by column chromatography to obtain the imprint template molecule.

3. The method for preparing an accelerating setting agent for rapid sedimentation of biochemical sludge according to claim 1, characterized in that: The polysaccharide material MI includes one or more of cellulose and hemicellulose.

4. The method for preparing an accelerating setting agent for rapid sedimentation of biochemical sludge according to claim 1, characterized in that: The ferrous salt includes one or more of ferrous sulfate and ferrous chloride; The molar ratio of the ferrous salt, the cobalt nitrate and the sodium fluoride is 2-8:1:1-3.

5. The method for preparing an accelerating setting agent for rapid sedimentation of biochemical sludge according to claim 1, characterized in that: The volume ratio of the imidazole-dicarboxylic acid to the sodium hydroxide solution is 2 to 3:1; The pH value of the sodium hydroxide solution is 11-13.

6. The method for preparing an accelerating setting agent for rapid sedimentation of biochemical sludge according to claim 1, characterized in that: The solution B is added to the solution A to react to obtain a MOF suspension, comprising: The solution B is injected into the reactor containing the solution A, and stirred at a speed of 500 to 1000 r / min for 5 to 20 min to react to obtain a MOF suspension; Wherein, the volume ratio of the solution B to the solution A is 1-2:

1.

7. The method for preparing an accelerating setting agent for rapid sedimentation of biochemical sludge according to claim 1, characterized in that: The MOF suspension is transferred to a nitrogen-protected reactor, the imprinted template molecule, the cross-linking agent and the initiator are added to react, and the reaction mixture is freeze-dried and then washed to remove the imprinted template molecule to obtain a MI-MOF compound with MI vacancies, including: The MOF suspension is transferred to a nitrogen-protected reactor, and the imprinted template molecule, the crosslinking agent and the initiator are added, and stirred at 35-45° C. for 12-24 hours to react to obtain a reaction mixture containing a MI-MOF compound; wherein the mass ratio of the imprinted template molecule to the MOF suspension is 1:1, the mass ratio of the crosslinking agent to the MOF suspension is 1:100, and the mass ratio of the initiator to the MOF suspension is 1:100; The reaction mixture is placed in a vacuum freeze dryer, the temperature is controlled at -20 to -40°C, and freeze-dried for 12 to 24 hours under vacuum to obtain a freeze-dried material; The freeze-dried material is washed with a mixture of methanol and sodium hydroxide to remove the imprint template molecules, thereby obtaining the MI-MOF compound with MI vacancies, wherein the volume ratio of methanol to sodium hydroxide solution in the mixture of methanol and sodium hydroxide is 9-8:1-2.

8. The method for preparing an accelerating setting agent for rapid sedimentation of biochemical sludge according to claim 1, characterized in that: The high molecular polymer includes polyacrylamide.

9. A quick-setting agent for rapid sedimentation of biochemical sludge, characterized in that: The accelerator is prepared by the preparation method according to any one of claims 1 to 8, wherein the accelerator is a mixture of an MI-MOF compound and a high molecular polymer, wherein the MI-MOF compound has MI vacancies, and the MOF structure uses iron ions and cobalt ions as the metal ion core of the MOF material.

10. Use of the quick-setting agent as claimed in claim 9 for flocculation and sedimentation of biochemical activated sludge in sewage treatment.

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