Large-aperture biocompatible polyurethane sponge as well as preparation method and application thereof

Abstract

The invention belongs to the technical field of polyurethane, and particularly relates to large-aperture biocompatible polyurethane sponge as well as a preparation method and application thereof. The large-aperture biocompatible polyurethane sponge is prepared by soaking a component A and a component B, wherein the component A comprises polyether polyol X, polyether polyol Y, a chain extender, a catalyst, a pore opening agent and a foaming agent; wherein the component B is prepared from modified MDI and liquefied MDI; the polyether polyol X is prepared by taking hydroxy anthraquinone and low-molecular-weight polyether polyol as a composite initiator and epoxypropane as a polymerization monomer; the average functionality of the polyether polyol Y is 3 to 4, and the number-average molecular weight of the polyether polyol Y is 4000 to 7000 g / mol. The large-aperture biocompatibility polyurethane sponge provided by the invention is large in aperture and strong in biocompatibility. The preparation method is simple in process and safe to operate. The prepared polyurethane sponge is used for sewage treatment, and the degradation rate of microorganisms is increased.

Description

Technical Field

[0001] This invention belongs to the field of polyurethane technology, specifically relating to large-pore biocompatible polyurethane sponges, their preparation methods, and applications. Background Technology

[0002] Polyurethane foam (PUF) has been widely used as a carrier for microbial attachment in biofilm wastewater treatment processes due to its large specific surface area, high porosity, excellent mechanical strength, good chemical stability, and strong plasticity. In processes such as moving bed biofilm reactors (MBBR), the performance of the carrier material directly affects the attachment rate of functional microorganisms (such as nitrifying bacteria and denitrifying bacteria), the formation rate and stability of the biofilm, and thus the removal efficiency of pollutants such as ammonia nitrogen and total nitrogen.

[0003] However, conventional polyurethane foams are mostly hydrophobic materials with insufficient surface hydrophilicity, resulting in limited biocompatibility with microbial cells and extracellular polymeric substances (EPS). This leads to difficulties in effective microbial attachment during the biofilm formation and slow biofilm formation, thus prolonging the system's start-up time and limiting further improvements in the treatment efficiency of the biological treatment tank. For example, Chinese patent CN109607761 discloses a tourmaline / polyurethane composite filler and its preparation method, which improves the efficiency of the wastewater treatment biofilm system through the synergistic effect of tourmaline and polyurethane. However, tourmaline has a highly polar and hydrophobic surface, poor compatibility with polyurethane, and is prone to forming agglomerates during blending, reducing the mechanical strength of the filler. Uneven dispersion causes local failure of the tourmaline's negative ion release and pH adjustment functions, resulting in fluctuations in the biofilm formation effect. Chinese patent CN117586474A discloses a hydrophilic polyurethane filler and its preparation method. The hydrophilicity is improved by adding a hydrophilic agent (ZL-480) and konjac glucomannan-acrylic acid graft copolymer (KSAP) instead of chemically bonding it to the polyurethane molecular chain. However, KSAP is a natural high-molecular-weight graft product with a large molecular weight and strong polarity, which makes it difficult to disperse evenly in the polyurethane matrix. It is easy to form local agglomerates, resulting in uneven cell wall structure and reduced mechanical strength.

[0004] Existing technologies mainly modify PUFs through two approaches: one is post-modification, such as surface amylation or grafting of bioactive molecules onto the finished sponge to introduce hydrophilic or functional groups; the other is adding inorganic powders (such as diatomaceous earth, activated carbon, etc.) during the preparation process to improve surface properties. However, these methods have significant drawbacks: post-modification is cumbersome and costly, and the functional groups introduced through physical adsorption or weak chemical bonding are easily detached under long-term hydraulic erosion and biological action, making the modification effect difficult to sustain; while the addition of inorganic powders can improve hydrophilicity to some extent, it can easily clog the inherent open-pore structure of the sponge, leading to reduced pore size or even closed pores, which seriously affects the mass transfer efficiency of reactants, products, and nutrients inside the biofilm, and may ultimately limit the activity and metabolism of microorganisms.

[0005] To improve the biocompatibility of carriers, various existing technologies exist for hydrophilic polyurethane foams. For example, Chinese patent CN115197386A discloses a method for preparing a prepolymer using a specific hydrophilic polymer polyol and modified MDI, followed by reaction with water to foam and obtain a hydrophilic foam. Another patent, CN106832214A, discloses a method for preparing polyurethane foam by adding humic substances as a hydrophilic component. However, these existing technologies mainly focus on improving the conventional hydrophilicity or water absorption and retention capacity of the sponge, without designing for the specific biocompatibility required for microbial attachment. They also fail to address the crucial contradiction of maintaining or even expanding the material pore size to ensure excellent mass transfer performance while maintaining high hydrophilicity and biocompatibility. Summary of the Invention

[0006] The technical problem this invention aims to solve is to overcome the aforementioned deficiencies in existing technologies and provide a large-pore, biocompatible polyurethane sponge with large pore size and strong biocompatibility. The preparation method of this invention is simple, safe, and highly efficient. Using the polyurethane sponge prepared by this invention in wastewater treatment improves the degradation rate of microorganisms.

[0007] The large-pore biocompatible polyurethane foam of this invention is prepared by foaming component A and component B in a mass ratio of 100:50~80. Component A, by weight, includes: polyether polyol X: 50-80 parts; polyether polyol Y: 20-50 parts; chain extender: 5-10 parts; catalyst: 1-1.3 parts; cell opener: 1-3 parts; foaming agent: 2-4 parts. Component B, by weight, includes: modified MDI: 70-95 parts; liquefied MDI: 5-30 parts; The polyether polyol X is prepared by using hydroxyanthraquinone and low molecular weight polyether polyol as composite initiators and propylene oxide as a polymerization monomer. The polyether polyol Y has an average functionality of 3-4 and a number average molecular weight of 4000-7000 g / mol.

[0008] The hydroxyanthraquinone is one or both of 1,4-dihydroxyanthraquinone and 1,5-dihydroxyanthraquinone.

[0009] The low molecular weight polyether polyol has an average functionality of 3 and a number-average molecular weight of 300-700 g / mol. Preferably, it is one of INOVOL C303, INOVOL C305, or INOVOL C307 from Shandong Yinuowei New Materials Co., Ltd.

[0010] The specific preparation process of the polyether polyol X is as follows: Hydroxyanthraquinone, low molecular weight polyether polyol, and bimetallic catalyst are added to a pressure-resistant reactor and mixed. Nitrogen is used to purge the reactor to reduce the oxygen content to below 50 ppm. After dehydration, propylene oxide is added for initiation. Once initiation is successful, propylene oxide is slowly added. After the reaction is complete, unreacted monomers and small molecule products are removed under vacuum to obtain polyether polyol X. The amount of hydroxyanthraquinone added is 10-15% of the total mass of the polyether polyol X reaction system. The polyether polyol X has an average functionality of 2.5, a hydroxyl value of 60-90, and a number-average molecular weight of 1600-2200 g / mol.

[0011] The specific preparation process of the polyether polyol Y is as follows: using glycerol and sorbitol as a mixed initiator, under the catalysis of KOH, propylene oxide and ethylene oxide are copolymerized, or copolymerized and then capped with ethylene oxide. The polyether polyol Y has an average functionality of 3-4, a hydroxyl value of 34, a number average molecular weight of 4000-7000 g / mol, and an ethylene oxide content of 70-80%.

[0012] The chain extender is one or a mixture of 1,4-butanediol, ethylene glycol, diethylene glycol, and 1,6-hexanediol.

[0013] The catalyst is a mixture of bis(dimethylaminoethyl) ether, triethylenediamine and dimethylcyclohexylamine.

[0014] The cell opener is INOVOL S1900, and the foaming agent is water.

[0015] The preparation method of the large-pore biocompatible polyurethane sponge includes the following steps: (1) Preparation of component A: At 30~40℃, polyether polyol X and polyether polyol Y are added to the reactor and stirred. Then chain extender, catalyst, pore opener and foaming agent are added and stirred for 1-3 min at 500-1000 rpm. The mixture is then sealed and stored. (2) Preparation of component B: Modified MDI and liquefied MDI are added to the reaction vessel at 30~40℃ and stirred evenly, then sealed and stored. (3) Mix components A and B evenly, foam, open mold, and cure at room temperature to obtain a large-pore biocompatible polyurethane sponge.

[0016] Application of the large-pore biocompatible polyurethane sponge: The prepared polyurethane sponge is used in wastewater treatment.

[0017] Compared with the prior art, the beneficial effects of the present invention are: (1) The polyether polyol X used in this invention directly introduces redox (RMs) anthraquinone groups into the polyether molecule. These groups have both conjugated aromatic rings and active carbonyl C=O structures, which can increase biocompatibility, accelerate the extracellular electron transfer of microorganisms, improve the degradation rate of pollutants by microorganisms, and reduce compatibility problems and precipitation risks that may be caused by additives.

[0018] (2) In component A of this invention, by optimizing the copolymerization composition of ethylene oxide and propylene oxide in the main polyether, not only can the pore size of the polyurethane foam be increased and the specific surface area of ​​the PUF be increased, but the hydrophilicity of the PUF can also be adjusted to prevent insufficient hydrophilicity, resulting in low microbial adhesion, or excessive hydrophilicity leading to cell collapse. The addition of small molecule alcohols and the adjustment of the type and ratio of isocyanates enhance mechanical strength and impact resistance, enabling the structure to maintain its integrity in a continuously disturbed aquatic environment. The large-pore PUF and anthraquinone groups form a dual mechanism of physical anchoring and chemical adsorption, which helps microorganisms to quickly form a dense and stable biofilm on the surface. Detailed Implementation

[0019] The present invention will be further described below with reference to specific embodiments.

[0020] Unless otherwise specified, all raw materials used in the examples were commercially available. The proportions of each component are adjustable and can be measured in parts by weight.

[0021] The following is a description of some of the raw materials used in the examples and comparative examples: INOVOL C303 (glyceryl polyether, functionality 3, number-average molecular weight 350 g / mol), Shandong Yinuowei New Materials Co., Ltd. INOVOL C305 (glyceryl polyether, functionality 3, number average molecular weight 500 g / mol), Shandong Yinuowei New Material Co., Ltd. INOVOL C307 (glyceryl polyether, functionality 3, number average molecular weight 700 g / mol), Shandong Yinuowei New Materials Co., Ltd. Modified MDI: DG5412 (NCO content 28%), Shandong Yinuowei Polyurethane Co., Ltd. INOVOL S1900 pore opener: Shandong Yinuowei New Material Co., Ltd.; Bimetallic catalyst: DMC catalyst, Jiangsu Baer Polyurethane Co., Ltd.; Liquefied MDI: MDI-50, Yantai Wanhua Chemical Co., Ltd.

[0022] Example 1 The aforementioned large-pore biocompatible polyurethane sponge is prepared by reacting component A and component B. Component A comprises the following raw materials in parts by weight: Polyether polyol X1: 80 parts; Polyether polyol Y1: 20 parts; 1,4-Butanediol: 5 parts; Bis(dimethylaminoethyl) ether: 0.16 parts; Terryethylenediamine: 0.64 parts; Dimethylcyclohexylamine: 0.48 parts; INOVOL S1900: 3 copies; H2O: 2.5 parts; Component B comprises the following raw materials in parts by weight: DG5412: 80 copies; MDI-50: 20 servings; The mass ratio of component A to component B is 100:53.06; Preparation of polyether polyol X1: 240g of 1,4-dihydroxyanthraquinone, 350g of INOVOLC303 and 0.24g of bimetallic catalyst were added to a pressure-resistant reactor and mixed. Nitrogen was used to purge the oxygen content in the reactor to below 50ppm. After dehydration at 110℃ for 2h, the temperature was raised to 140℃ under negative pressure. 60g of propylene oxide was added for initiation. After successful initiation, 950g of propylene oxide was slowly added. After the reaction was completed, the internal pressure was maintained for 2h. Unreacted monomers and small molecule products were removed under vacuum to obtain polyether polyol X1 with an average functionality of 2.5, a hydroxyl value of 87.7mgKOH / g, and a number average molecular weight of 1600g / mol. Preparation of polyether polyol Y1: 92g of glycerol and 15g of KOH solid were added to a pressure-resistant reactor and mixed. Nitrogen was used to purge the oxygen content in the reactor to below 50ppm. The temperature was raised to 110℃ for 2h to remove water. A mixture of 1408g of propylene oxide and 3500g of ethylene oxide was continuously added to the reactor. The reaction temperature was controlled at 110℃ and the pressure inside the reactor was ≤0.3MPa. After the reaction was completed, the internal pressure was reduced for 2h and the monomer was removed for 0.5h. After acid purification, polyether polyol Y1 was obtained with an average functionality of 3, a hydroxyl value of 34mgKOH / g, and a number average molecular weight of 4950g / mol. The method for preparing the large-pore biocompatible polyurethane sponge includes the following steps: (1) Preparation of component A: At 30°C, polyether polyol X1 and polyether polyol Y1 were added to the reactor and stirred. Then, 1,4-butanediol, bis(dimethylaminoethyl) ether, triethylenediamine, dimethylcyclohexylamine, INOVOL S1900 and H2O were added and stirred for 3 min at 500 rpm. The mixture was then sealed and stored. (2) Preparation of component B: DG5412 and MDI-50 were added to the reactor at 30°C and stirred evenly, then sealed and stored. (3) Place components A and B in a mechanically stirred container to mix them evenly, then quickly pour them into a foaming box for foaming. After 3 minutes, open the mold, remove the soft polyurethane foam, and cure it at room temperature for 24 hours to obtain a large-pore biocompatible polyurethane sponge.

[0023] Example 2 The aforementioned large-pore biocompatible polyurethane sponge is prepared by reacting component A and component B. Component A comprises the following raw materials in parts by weight: Polyether polyol X2: 60 parts; Polyether polyol Y2: 40 parts; 1,4-Butanediol: 5 parts; Ethylene glycol: 5 parts; Bis(dimethylaminoethyl) ether: 0.14 parts; Terryethylenediamine: 0.58 parts; Dimethylcyclohexylamine: 0.43 parts; INOVOL S1900: 2 copies; H2O: 3 parts; Component B comprises the following raw materials in parts by weight: DG5412: 70 copies; MDI-50: 30 servings; The mass ratio of component A to component B is 100:69.34; Preparation of polyether polyol X2: 240g of 1,5-dihydroxyanthraquinone, 500g of INOVOL C305 and 0.2g of bimetallic catalyst were added to a pressure-resistant reactor and mixed. Nitrogen was used to purge the oxygen content in the reactor to below 50ppm. After dehydration at 110℃ for 2h, the temperature was raised to 140℃ under negative pressure. 70g of propylene oxide was added for initiation. After successful initiation, 1190g of propylene oxide was slowly added. After the reaction was completed, the internal pressure was maintained for 2h. Unreacted monomers and small molecule products were removed under vacuum to obtain polyether polyol X2 with an average functionality of 2.5, a hydroxyl value of 70mgKOH / g, and a number average molecular weight of 2000g / mol. Preparation of polyether polyol Y2: 460g glycerol, 182g sorbitol and 17.4g KOH solid were added to a pressure-resistant reactor and mixed. Nitrogen was used to purge the oxygen content in the reactor to below 50ppm. The temperature was raised to 110℃ for 2h to dehydrate. A mixture of 1450g propylene oxide and 3418g ethylene oxide was continuously added to the reactor. The reaction temperature was controlled at 110℃ and the pressure inside the reactor was ≤0.3MPa. After the reaction was completed, the reactor was aged for 2h. Then, 290g ethylene oxide was continuously added to the reactor. The reaction temperature was controlled at 110℃ and the pressure inside the reactor was ≤0.3MPa. After the reaction was completed, the reactor was depressurized for 2h and the monomer was removed for 0.5h. After acid purification, polyether polyol Y2 was obtained with an average functionality of 3.5, a hydroxyl value of 34mgKOH / g, and a number average molecular weight of 5775g / mol. The method for preparing the large-pore biocompatible polyurethane sponge includes the following steps: (1) Preparation of component A: Polyether polyol X2 and polyether polyol Y2 were added to the reactor at 35°C and stirred. Then 1,4-butanediol, ethylene glycol, bis(dimethylaminoethyl) ether, triethylenediamine, dimethylcyclohexylamine, INOVOLS1900 and H2O were added and stirred for 2 min at 750 rpm. The mixture was then sealed and stored. (2) Preparation of component B: DG5412 and MDI-50 were added to the reactor at 35°C and stirred evenly, then sealed and stored. (3) Place components A and B in a polyurethane foaming machine and mechanically stir them to make them evenly mixed in proportion. Quickly pour them into a foaming box, foam, open the mold after 3 minutes, and cure at room temperature for 24 hours to obtain a large-pore biocompatible polyurethane sponge.

[0024] Example 3 The aforementioned large-pore biocompatible polyurethane sponge is prepared by reacting component A and component B. Component A comprises the following raw materials in parts by weight: Polyether polyol X3: 50 parts; Polyether polyol Y3: 50 parts; 1,4-Butanediol: 5 parts; Diethylene glycol monohydrate: 5 parts; Bis(dimethylaminoethyl) ether: 0.13 parts; Thyethylenediamine: 0.5 parts; Dimethylcyclohexylamine: 0.38 parts; INOVOL S1900: 1 copy; H2O: 3.6 parts; Component B comprises the following raw materials in parts by weight: DG5412: 95 copies; MDI-50: 5 servings; The mass ratio of component A to component B is 100:74.08; Preparation of polyether polyol X3: 240g of 1,5-dihydroxyanthraquinone, 700g of INOVOL C307 and 0.22g of bimetallic catalyst were added to a pressure-resistant reactor and mixed. Nitrogen was used to purge the oxygen content in the reactor to below 50ppm. After dehydration at 110℃ for 2h, the temperature was raised to 140℃ under negative pressure. 90g of propylene oxide was added for initiation. After successful initiation, 1170g of propylene oxide was slowly added. After the reaction was completed, the internal pressure was maintained for 2h. Unreacted monomers and small molecule products were removed under vacuum to obtain polyether polyol X3 with an average functionality of 2.5, a hydroxyl value of 63.8mgKOH / g, and a number average molecular weight of 2200g / mol. Preparation of polyether polyol Y3: 184g glycerol, 182g sorbitol and 19.8g KOH solid were added to a pressure-resistant reactor and mixed. Nitrogen was used to purge the oxygen content in the reactor to below 50ppm. The temperature was raised to 110℃ for 2h to dehydrate. A mixture of 1320g propylene oxide and 4254g ethylene oxide was continuously added to the reactor. The reaction temperature was controlled at 110℃ and the pressure inside the reactor was ≤0.3MPa. After the reaction was completed, the reactor was aged for 2h. Then, 660g ethylene oxide was continuously added to the reactor. The reaction temperature was controlled at 110℃ and the pressure inside the reactor was ≤0.3MPa. After the reaction was completed, the reactor was depressurized for 2h and the monomer was removed for 0.5h. After acid purification, polyether polyol Y3 was obtained with an average functionality of 4, a hydroxyl value of 34mgKOH / g, and a number average molecular weight of 6600g / mol. The method for preparing the large-pore biocompatible polyurethane sponge includes the following steps: (1) Preparation of component A: Polyether polyol X3 and polyether polyol Y3 were added to the reactor and stirred at 40°C. Then 1,4-butanediol, diethylene glycol, bis(dimethylaminoethyl) ether, triethylenediamine, dimethylcyclohexylamine, INOVOL S1900 and H2O were added and stirred for 1 min at 1000 rpm. The mixture was then sealed and stored. (2) Preparation of component B: DG5412 and MDI-50 were added to the reactor at 40℃ and stirred evenly, then sealed and stored. (3) Place components A and B in a polyurethane foaming machine and mechanically stir them to make them evenly mixed in proportion. Quickly pour them into a foaming box, foam, open the mold after 3 minutes, and cure at room temperature for 24 hours to obtain a large-pore biocompatible polyurethane sponge.

[0025] Comparative Example 1 Synthesize polyether polyol X1-1 to replace polyether polyol X1.

[0026] Preparation of polyether polyol X1-1: Without adding 1,4-dihydroxyanthraquinone, only 350g of INOVOL C303 and 0.048g of bimetallic catalyst were added to a pressure-resistant reactor and mixed. Nitrogen was used to purge the oxygen content in the reactor to below 50ppm. After dehydration at 110℃ for 2h, the temperature was raised to 140℃ under negative pressure. 60g of propylene oxide was added for initiation. After successful initiation, 1190g of propylene oxide was slowly added. After the reaction was completed, the internal pressure was maintained for 2h. Unreacted monomers and small molecule products were removed under vacuum to obtain polyether polyol X1-1 with an average functionality of 3, a hydroxyl value of 105.2mgKOH / g, and a number average molecular weight of 1600g / mol. Other raw materials and preparation methods are the same as in Example 1.

[0027] Comparative Example 2 Polyether polyol Y1-1 was synthesized to replace polyether polyol Y1.

[0028] Preparation of polyether polyol Y1-1: 92g of glycerol and 15g of KOH solid were added to a pressure-resistant reactor and mixed. Nitrogen was used to purge the oxygen content in the reactor to below 50ppm. The temperature was raised to 110℃ for 2h to remove water. 4908g of propylene oxide was continuously added to the reactor. The reaction temperature was controlled at 110℃ and the pressure inside the reactor was ≤0.3MPa. After the reaction was completed, the internal pressure was reduced for 2h, and the monomer was removed for 0.5h. After acid purification, polyether polyol Y1-1 was obtained with an average functionality of 3, a hydroxyl value of 34mgKOH / g, and a number average molecular weight of 4950g / mol. Other raw materials and preparation methods are the same as in Example 1.

[0029] The performance of the large-pore biocompatible polyurethane sponges prepared in Examples 1-3 and Comparative Examples 1-2 was tested using the following methods: The water contact angle was tested in accordance with GB / T 30693-2014.

[0030] Application Testing: Anaerobic effluent from the AO biological treatment tank of a polyether plant was placed in a pilot-scale apparatus. The COD was measured to be 1000 mg / L and ammonia nitrogen to be 11 mg / L. Polyurethane sponges prepared in Examples 1-3 and Comparative Examples 1-2 were added to fill the bottom of the pilot-scale apparatus to a height of one-tenth of the liquid level. The temperature was controlled at 30℃, and the DO was controlled at 2-4 mg / L. NH3 levels were recorded. 4+ The hydraulic retention time (HRT) required for -N < 5 mg / L and COD < 100 mg / L. PPI refers to the number of bubbles per inch. The test results are shown in Table 1.

[0031] Table 1 Test Results

[0032] As can be seen from the data in Table 1, adding polyether polyol X to the main polyether of polyurethane foam and adjusting the copolymerization composition of ethylene oxide and propylene oxide in the main polyether can significantly improve the biocompatibility, hydrophilicity and open porosity of polyurethane foam, thereby improving the treatment efficiency of the aerobic stage (Comparative Examples 1 and 2).

Claims

1. A large-pore biocompatible polyurethane sponge, characterized in that: It is prepared by foaming component A and component B in a mass ratio of 100:50~80. Component A, by weight, includes: polyether polyol X: 50-80 parts; polyether polyol Y: 20-50 parts; chain extender: 5-10 parts; catalyst: 1-1.3 parts; cell opener: 1-3 parts; foaming agent: 2-4 parts. Component B, by weight, includes: modified MDI: 70-95 parts; liquefied MDI: 5-30 parts; The polyether polyol X is prepared by using hydroxyanthraquinone and low molecular weight polyether polyol as composite initiators and propylene oxide as a polymerization monomer. The polyether polyol Y is prepared by polymerizing propylene oxide and ethylene oxide using glycerol and sorbitol as composite initiators.

2. The large-pore biocompatible polyurethane sponge according to claim 1, characterized in that: The hydroxyanthraquinone is one or both of 1,4-dihydroxyanthraquinone and 1,5-dihydroxyanthraquinone.

3. The large-pore biocompatible polyurethane sponge according to claim 2, characterized in that: The low molecular weight polyether polyol has an average functionality of 3 and a number average molecular weight of 300-700 g / mol.

4. The large-pore biocompatible polyurethane sponge according to claim 3, characterized in that: The specific preparation process of the polyether polyol X is as follows: using hydroxyanthraquinone and low molecular weight polyether polyol as mixed initiators, and catalyzing the ring-opening polymerization reaction of propylene oxide under the catalysis of a bimetallic catalyst, the amount of hydroxyanthraquinone added is 10-15% of the total mass of the polyether polyol X reaction system.

5. The large-pore biocompatible polyurethane sponge according to claim 4, characterized in that: The polyether polyol X has an average functionality of 2.5, a hydroxyl value of 60-90, and a number-average molecular weight of 1600-2200 g / mol; the polyether polyol Y has an average functionality of 3-4, a hydroxyl value of 34, a number-average molecular weight of 4000-7000 g / mol, and an ethylene oxide content of 70-80%.

6. The large-pore biocompatible polyurethane sponge according to claim 1, characterized in that: The chain extender is one or a mixture of 1,4-butanediol, ethylene glycol, diethylene glycol, and 1,6-hexanediol.

7. The large-pore biocompatible polyurethane sponge according to claim 1, characterized in that: The catalyst is a mixture of bis(dimethylaminoethyl) ether, triethylenediamine and dimethylcyclohexylamine.

8. The large-pore biocompatible polyurethane sponge according to claim 1, characterized in that: The cell opener is INOVOL S1900, and the foaming agent is water.

9. A method for preparing the large-pore biocompatible polyurethane sponge according to any one of claims 1-8, characterized in that, Includes the following steps: (1) Preparation of component A: At 30~40℃, polyether polyol X and polyether polyol Y are added to the reactor and stirred. Then chain extender, catalyst, pore opener and foaming agent are added and stirred for 1-3 min at 500-1000 rpm. The mixture is then sealed and stored. (2) Preparation of component B: Modified MDI and liquefied MDI are added to the reaction vessel at 30~40℃ and stirred evenly, then sealed and stored. (3) Mix components A and B evenly, foam, open mold, and cure at room temperature to obtain a large-pore biocompatible polyurethane sponge.

10. The application of the large-pore biocompatible polyurethane sponge according to any one of claims 1-8, characterized in that: The prepared polyurethane foam was used in wastewater treatment.

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