Hydrophilic modified HDPE composition and application thereof

Abstract

The invention provides a hydrophilic modified HDPE composition and application thereof, and relates to the technical field of composite materials. The hydrophilic modified HDPE composition is prepared from the following raw material components in parts by weight: 100 parts of HDPE and 1 to 10 parts of a hydrophilic anthraquinone compound. Preferably, the raw material component also can comprise 0.1-2 parts of a carbon-based material. The hydrophilic anthraquinone compound is obtained by reacting an anthraquinone compound with a diisocyanate compound and then reacting with a hydrophilic compound. According to the hydrophilic modified HDPE composition disclosed by the invention, the hydrophilicity of HDPE is improved, and an anthraquinone structure is introduced, so that the denitrification effect on nitrogen-containing sewage can be improved.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of composite materials, and relates to a hydrophilic modified HDPE composition and application thereof. BACKGROUND

[0002] Nitrogen-containing sewage not only has important harm to water bodies, but also has adverse effects on ecosystems and humans. Promoting microbial degradation of nitrogen-containing compounds under anthraquinone compounds as redox mediators is an effective method for treating nitrogen-containing sewage. In order to improve the utilization rate of anthraquinone compounds and avoid the loss of water-soluble anthraquinone compounds and the "secondary pollution" to water bodies, loading anthraquinone compounds on carriers is an effective method. Among them, the polymer carrier (such as high-density polyethylene HDPE) has the advantages of good corrosion resistance, good chemical stability, high mechanical strength, low density, easy processing and the like, but has the disadvantages of poor compatibility with anthraquinone compounds and hydrophobicity, which will affect the effect of anthraquinone compounds as redox mediators.

[0003] Therefore, the technology of loading anthraquinone compounds on HDPE needs to be further improved and optimized to better play the role of anthraquinone compounds as redox mediators and improve the denitrification effect on nitrogen-containing sewage. SUMMARY

[0004] In order to solve the above technical problems, the present application provides a hydrophilic modified HDPE composition and application thereof.

[0005] The technical scheme of the present application is as follows: A hydrophilic modified HDPE composition, the raw material components comprise, by weight fraction: 100 parts of HDPE and 1-10 parts of hydrophilic anthraquinone compound; The preparation method of the hydrophilic anthraquinone compound is: The anthraquinone compound and the diisocyanate compound are reacted to obtain an anthraquinone prepolymer; The anthraquinone prepolymer and the hydrophilic compound are reacted to obtain the hydrophilic anthraquinone compound; The hydrophilic compound contains active hydrogen that can react with NCO groups at 100°C.

[0006] Preferably, the anthraquinone compound contains one or a combination of two or more of primary amino groups, secondary amine groups and hydroxyl groups; Preferably, the sum of the number of primary amino groups, secondary amine groups and hydroxyl groups on the structure of the anthraquinone compound is 1-2.

[0007] Preferably, the molar ratio of the anthraquinone compound to the diisocyanate compound is 1:1-2.

[0008] Preferably, the diisocyanate compound is selected from diisocyanate monomers and combinations thereof; The combination is obtained by reacting the diisocyanate monomer with polyethylene glycol, polysiloxane diol or hydroxyl-terminated polyethylene glycol / polysiloxane block copolymer; The NCO group content in the combination is not less than 5wt%.

[0009] Preferably, the active hydrogen in the hydrophilic compound is selected from one or a combination of two or more of hydroxyl, primary amino and secondary amino groups; The hydrophilic compound further contains one or a combination of two or more of polyethylene glycol segment, sulfonic acid and its salt structure, carboxylic acid and its salt structure, sulfuric acid and its salt structure, phenol and its salt structure and phosphoric acid and its salt structure.

[0010] Preferably, the molar ratio of the NCO group in the anthraquinone prepolymer to the active hydrogen in the hydrophilic compound is 1:0.6-2.

[0011] More preferably, the hydrophilic compound is selected from a hydrophilic aspartate resin; The structure of the hydrophilic aspartate resin is shown in the following formula (1), (1) Wherein, X is C8-C24 alkylene, or a first polyethylene glycol divalent segment or a first polysiloxane divalent segment; The structure of the first polyethylene glycol divalent segment is shown in the following formula (2), -O(CH2CH2O) m (2) Wherein, m=4-50; The structure of the first polysiloxane divalent segment is shown in the following formula (3), -Me2SiO(SiOMe2) p (SiOMeR3) q SiMe2- (3) Wherein, Me represents methyl, R3 is selected from substituted C3-C20 hydrocarbon group, p=10-200, q=0-100; R1 and R2 are both selected from a second polyethylene glycol monovalent segment; The structure of the second polyethylene glycol monovalent segment is shown in the following formula (4), -O(CH2CH2O) n CH3 (4) Wherein, n=4-50; The average polymerization degree of the first polyethylene glycol divalent segment and the second polyethylene glycol monovalent segment is the same or different.

[0013] Preferably, the raw material component further comprises 0.1-2 parts of carbon-based material; The carbon-based material is selected from carbon nanotubes, graphene or graphene oxide.

[0014] More preferably, the surface of the carbon-based material is treated with epoxy, primary amino, secondary amine or NCO groups.

[0015] Use of the hydrophilically modified HDPE composition described in any of the above embodiments for the treatment of nitrogen-containing wastewater.

[0016] The beneficial effects of the present application are: (1) The present application obtains a hydrophilic anthraquinone compound by the reaction of an anthraquinone prepolymer and a hydrophilic compound, which improves the hydrophilicity of HDPE, is conducive to the wetting of nitrogen-containing wastewater on HDPE, and improves the promoting effect of anthraquinone as a redox mediator on denitrification, so that the hydrophilic anthraquinone compound can further exert the denitrification effect of anthraquinone.

[0017] (2) When the hydrophilic anthraquinone compound further contains active hydrogen such as secondary amine group and hydroxyl group, it can further react with carbon-based material to combine anthraquinone, carbon-based material and hydrophilic structure together, and better exert the denitrification effect. DETAILED DESCRIPTION

[0018] The technical solutions of the present application are further described and explained below through specific embodiments.

[0019] In one aspect, the present application provides a hydrophilically modified HDPE composition, the raw material components comprise, by weight fraction: 100 parts of HDPE and 1-10 parts of a hydrophilic anthraquinone compound. The preparation method of the hydrophilic anthraquinone compound is: The anthraquinone compound and the diisocyanate compound are reacted to obtain an anthraquinone prepolymer; The anthraquinone prepolymer and the hydrophilic compound are reacted to obtain a hydrophilic anthraquinone compound; The hydrophilic compound contains active hydrogen that can react with NCO groups at 100°C.

[0020] The present application adds a hydrophilic anthraquinone compound to HDPE, which improves the hydrophilicity of HDPE, is more conducive to the wettability of nitrogen-containing wastewater on the hydrophilically modified HDPE composition (or the treatment filler made therefrom), and anthraquinone can more fully contact nitrogen-containing wastewater and better exert the effect of redox mediator.

[0021] For the preparation of hydrophilic anthraquinone compounds, this invention involves reacting anthraquinone compounds with diisocyanate compounds to obtain anthraquinone prepolymers containing NCO groups, which are then further reacted with hydrophilic compounds to obtain the final product. Different properties can be introduced into the hydrophilic anthraquinone compounds based on their properties, thus imparting different properties to the hydrophilically modified HDPE compositions.

[0022] In this invention, the melt flow index (2.16 kg, 190°C) of HDPE is not particularly limited and can be 0.5-20 g / min. There are no particular limitations on the processing method of the hydrophilic modified HDPE composition; for example, twin-screw extrusion molding can be used to prepare fillers for wastewater treatment. The fillers can refer to CJ / T 461-2014 "High-density polyethylene suspended carrier fillers for water treatment" and be used in moving bed biofilm reactor (MBBR) systems to construct electron transport-enhanced biofilm reactor systems. Other raw materials can be added to the above components according to performance requirements, such as antioxidants, UV stabilizers, and inorganic fillers (e.g., talc, kaolin, glass microspheres, zeolite), etc.

[0023] In some embodiments, the anthraquinone compound contains one or more of a primary amino group, a secondary amino group, and a hydroxyl group; the primary amino group, the secondary amino group, and the hydroxyl group contain active hydrogen; the anthraquinone compound and the NCO group in the diisocyanate compound react to obtain anthraquinone prepolymer.

[0024] Furthermore, the anthraquinone compound has 1-2 primary amino groups, secondary amino groups, and hydroxyl groups in its structure. By employing the above technical solution, the formation of cross-linked products between the anthraquinone compound and the diisocyanate compound can be avoided, preventing the acquisition of usable anthraquinone prepolymers. For example, the anthraquinone compound can be 1-aminoanthraquinone, 2-aminoanthraquinone, 1,5-diaminoanthraquinone, 2,5-diaminoanthraquinone, 2,6-diaminoanthraquinone, 2-hydroxyanthraquinone, 1,8-dihydroxyanthraquinone, N-hydroxypropyl-2-aminoanthraquinone, N-hydroxypropyl-5-aminoanthraquinone, etc.

[0025] In some embodiments, the molar ratio of the anthraquinone compound to the diisocyanate compound is 1:1-2. For example, the molar ratio of the anthraquinone compound to the diisocyanate compound can be any value or any value between 1:1, 1:1.1, 1:1.2, 1:1.3, 1:1.4, 1:1.5, 1:1.6, 1:1.7, 1:1.8, 1:1.9, 1:2, etc. For instance, when the anthraquinone compound contains only one of the hydroxyl, secondary amine, and primary amino groups, the molar ratio of the anthraquinone compound to the diisocyanate compound can be 1:1; when the sum of the primary amino, secondary amine, and hydroxyl groups in the anthraquinone compound is 2, the molar ratio of the anthraquinone compound to the diisocyanate compound can be 1:1.2, 1:1.5, 1:1.8, 1:2, etc.

[0026] In some embodiments, the diisocyanate compound is selected from diisocyanate monomers and their conjugates; The conjugate is obtained by reacting diisocyanate monomers with polyethylene glycol, polysiloxane glycol or hydroxyl-terminated polyethylene glycol / polysiloxane block copolymers; The NCO group content in the complex is not less than 5 wt%.

[0027] For example, diisocyanate monomers can be dodecylbenzene-2,4-diisocyanate, 2-heptyl-3,4-bis(9-nonyl isocyanate)-1-pentyl-cyclohexane (diisocyanate), hexamethylene diisocyanate (HDI), isophorone diisocyanate (IPDI), etc. The reaction of diisocyanate monomers with polyethylene glycol introduces hydrophilic polyethylene glycol segments into the conjugate, further enhancing the hydrophilicity of the anthraquinone compound. The reaction of diisocyanate monomers with hydroxyl-terminated polyethylene glycol / polysiloxane block copolymers introduces hydrophilic polyethylene glycol segments and highly hydrophobic polysiloxane segments into the conjugate. The low surface energy of the polysiloxane segments allows for phase separation and migration of the hydrophilic anthraquinone compound from HDPE, leading to surface enrichment. This is beneficial for the enrichment of polyethylene glycol segments on the HDPE surface and enhances hydrophilicity. When the diisocyanate monomer contains long-chain alkyl groups (such as alkyl or alkylene groups with 8-18 carbon atoms), the compatibility between hydrophilic anthraquinone compounds and HDPE is improved, changing from strong incompatibility to a certain degree of incompatibility. This is more conducive to the migration and enrichment of hydrophilic anthraquinone compounds on the surface, avoiding the adverse effects of low surface energy polysiloxane segments on the surface, such as the shielding and hindrance of hydrophilic segments. For example, when the diisocyanate monomers are dodecylbenzene-2,4-diisocyanate, dimer diisocyanate, etc., which contain long-chain alkyl groups, the reaction of the diisocyanate monomers with hydroxyl-terminated polyethylene glycol / polysiloxane block copolymers to obtain anthraquinone prepolymers further makes the hydrophilic anthraquinone compounds incompatible with HDPE to a certain extent, causing them to migrate to the surface. Polyethylene glycol segments will also be enriched on the surface simultaneously, which is more conducive to the effect of anthraquinone as a redox mediator.

[0028] For hydroxyl-terminated polyethylene glycol / polysiloxane block copolymers, for example, the structure can be shown in formula (5) or (6) below. HO-EO-PDMS-EO-OH (5) HO-PDMS-EO-PDMS-OH (6) Where EO represents polyethylene glycol segment and PDMS represents second polysiloxane divalent segment, the average degree of polymerization (DP) of EO can be 4-50 and the DP of PDMS can be 10-200.

[0029] There are no particular limitations on the preparation method of the above-mentioned hydroxyl-terminated polyethylene glycol / polysiloxane block copolymer, such as using a hydrosilylation reaction. Taking the hydroxyl-terminated polyethylene glycol / polysiloxane block copolymer shown in formula (5) as an example, one preparation method can be: terminal allyl polyethylene glycol HO(CH2CH2O) a CH2CH=CH2 and the double-terminated silane HMe2Si(OSiMe2) b OSiMe2H undergoes a hydrosilylation reaction at a molar ratio of 2:1. Here, a and b represent the DP of EO and DP of PDMS, respectively.

[0030] The content of NCO groups in the complex can be any value or any value between 5wt%, 5.5wt%, 6wt%, 6.5wt%, 7wt%, 7.5wt%, 8wt%, 8.5wt%, 9wt%, 9.5wt%, 10wt%, 10.5wt%, 11wt%, 11.5wt%, 12wt%, 12.5wt%, 13wt%, 13.5wt%, 14wt%, 14.5wt%, and 15wt%.

[0031] In some embodiments, the active hydrogen in the hydrophilic compound is selected from one or a combination of two or more of hydroxyl, primary amino, and secondary amino groups; the hydrophilic compound contains active hydrogen such as hydroxyl, primary amino, and secondary amino groups, which can react with the NCO group of the anthraquinone prepolymer to obtain a hydrophilic anthraquinone compound.

[0032] Hydrophilic compounds also contain one or more of the following: polyethylene glycol segments, sulfonic acid and its salt structures, carboxylic acid and its salt structures, sulfuric acid and its salt structures, phenol and its salt structures, and phosphoric acid and its salt structures. These segments and / or structures have good hydrophilicity, thus yielding hydrophilic anthraquinone compounds. Examples of hydrophilic compounds include polyethylene glycol, polyethylene glycol / polypropylene glycol copolymers, p-aminobenzenesulfonic acid, sodium p-aminobenzenesulfonate, 2-aminoacetic acid, sodium 2-aminoacetate, alanine, sodium alanine, 6-aminohexanoic acid, and sodium 6-aminohexanoate.

[0033] In some embodiments, the hydrophilic compound is selected from hydrophilic aspartic ester resins; The structure of the hydrophilic aspartic acid ester resin is shown in formula (1) below. (1) Wherein, X is a C8-C24 alkylene group, or a first polyethylene glycol divalent segment or a first polysiloxane divalent segment; The structure of the first polyethylene glycol divalent segment is shown in equation (2) below. -O(CH2CH2O) m -(2) Where m = 4 - 50; The structure of the first polysiloxane divalent segment is shown in equation (3) below. -Me2SiO(SiOMe2) p (SiOMeR3) q SiMe2-(3) Where Me represents methyl, R3 is selected from substituted C3-C20 hydrocarbon groups, p=10-200, q=0-100; R1 and R2 are both selected from the second polyethylene glycol monovalent segment; The structure of the second polyethylene glycol monovalent segment is shown in equation (4) below. -O(CH2CH2O) n CH3(4) Where n = 4 - 50; The average degree of polymerization (DP) of the first divalent polyethylene glycol segment and the second monovalent polyethylene glycol segment may be the same or different.

[0035] The hydrophilic compound is a hydrophilic aspartic acid ester resin. The side chain of the hydrophilic aspartic acid ester resin contains two second polyethylene glycol monovalent segments, which have a high degree of freedom and can better exert the effect of the hydrophilic anthraquinone compound, which helps to wet nitrogen-containing wastewater. When X in the above formula (1) is a C8-C24 alkylene group, the compatibility between the hydrophilic aspartic acid ester resin and HDPE can be improved, and the high incompatibility between the hydrophilic aspartic acid ester resin and HDPE can be changed to a certain incompatibility. When X in the above formula (1) is a first polyethylene glycol divalent segment, the hydrophilicity of the hydrophilic anthraquinone compound can be enhanced. When X in the above formula (1) is a first polysiloxane divalent segment, it is beneficial for the hydrophilic anthraquinone compound to migrate to the surface of the hydrophilic modified HDPE composition (or the treatment filler made therefrom) and be enriched.

[0036] Considering the convenience of raw material acquisition and performance, the first and second polysiloxane divalent segments can both be polydimethylsiloxane segments. For example, for the first polysiloxane divalent segment shown in formula (3) above, q=0. When the second polysiloxane divalent segment is a polydimethylsiloxane segment, the average degree of polymerization DP can be 10-200.

[0037] There are no particular limitations on the preparation method of the above-mentioned hydrophilic aspartic ester resin. For example, it can be obtained by reacting diamine X(NH2)2 with diethyl maleate to obtain aspartic ester resin, and then carrying out transesterification reaction with polyethylene glycol monomethyl ether. This is well known to those skilled in the art.

[0038] In some embodiments, the molar ratio of NCO groups in the anthraquinone prepolymer to active hydrogen in the hydrophilic compound is 1:0.6-2. For example, the molar ratio of NCO groups to active hydrogen can be any value or any value between 1:0.6, 1:0.7, 1:0.8, 1:0.9, 1:1, 1:1.1, 1:1.2, 1:1.3, 1:1.5, 1:1.6, 1:1.8, 1:2, etc. When the molar ratio of NCO groups to active hydrogen is higher than 1:1, such as 1:0.6, 1:0.8, etc., the NCO groups are in excess, and the resulting hydrophilic anthraquinone compound still contains NCO groups, which can continue to react with compounds containing active hydrogen, which can be derived from primary amines, secondary amines, hydroxyl groups, etc. When the molar ratio of NCO groups to active hydrogen is less than 1:1, such as 1:1.2 or 1:1.5, the NCO groups are insufficient, and the resulting hydrophilic anthraquinone compound still contains active hydrogen, which can continue to react with some compounds, such as compounds containing NCO groups, epoxy groups, etc.

[0039] In some embodiments, the raw material component further comprises 0.1-2 parts of carbon-based material. Carbon-based material has good electrical conductivity, which can improve the performance of anthraquinone as a redox mediator, further enhancing the denitrification performance of nitrogen-containing wastewater. For example, the carbon-based material can be any value or any value between 0.1 parts, 0.2 parts, 0.3 parts, 0.5 parts, 0.6 parts, 0.8 parts, 1 part, 1.2 parts, 1.4 parts, 1.5 parts, 1.6 parts, 1.8 parts, and 2 parts. The carbon-based material can be carbon nanotubes, graphene, or graphene oxide.

[0040] Furthermore, the surface of the carbon-based material is treated with epoxy, primary amino, secondary amino, or NCO groups. Using this technique, the carbon-based material can further react with hydrophilic anthraquinone compounds and bond together through chemical bonds, thus better utilizing the properties of both the hydrophilic anthraquinone compounds and the carbon-based material. For the surface treatment of the carbon-based material, organic treatment agents can be used. Conventional organic treatment agents can be silane coupling agents, such as KH-792, KH-560, and KH-550.

[0041] On the other hand, the present invention also proposes an application of the hydrophilic modified HDPE composition described in any of the above embodiments for the treatment of nitrogen-containing wastewater. The nitrogen-containing compounds in the wastewater can be nitrates, ammonia nitrogen, nitrites, etc.

[0042] The technical solution of the present invention will be further described and illustrated below with reference to various embodiments. Unless otherwise specified, the parts mentioned in the following preparation examples and embodiments are parts by weight.

[0043] Preparation Examples 1-3: Preparation of Hydrophilic Anthraquinone Compounds Preparation Example 1 Under nitrogen protection, 1,5-diaminoanthraquinone and dodecylbenzene-2,4-diisocyanate were added to a reaction vessel at a molar ratio of 1:1.5, stirred at room temperature for 2 hours, and then heated to 80°C to continue the reaction for 2 hours to obtain anthraquinone prepolymer; Under nitrogen protection, anthraquinone prepolymer and polyethylene glycol (DP 12.6) were added to a reaction vessel at a molar ratio of 1:1.2. The mixture was stirred at room temperature for 3 hours, and then heated to 100°C and reacted for another 2 hours to obtain a hydrophilic anthraquinone compound.

[0044] Preparation Example 2 Under nitrogen protection, 1,5-diaminoanthraquinone and dodecylbenzene-2,4-diisocyanate were added to a reaction vessel at a molar ratio of 1:1.8, stirred at room temperature for 2 hours, and then heated to 80°C to continue the reaction for 2 hours to obtain anthraquinone prepolymer; Under nitrogen protection, anthraquinone prepolymer and hydroxyl-terminated polyethylene glycol / polysiloxane block copolymer were added to a reaction vessel at a molar ratio of 1:1.3, stirred at room temperature for 3 hours, and then heated to 100°C for another 2 hours to obtain a hydrophilic anthraquinone compound.

[0045] Hydroxyl-terminated polyethylene glycol / polysiloxane block copolymer is composed of allyl-terminated polyethylene glycol HO(CH2CH2O). 10.7 CH2CH=CH2 and the double-terminated silane HMe2Si(OSiMe2) 30.5 OSiMe2H was obtained by hydrosilylation reaction at a molar ratio of 2:1.

[0046] Preparation Example 3 Under nitrogen protection, HDI and dihydroxypropyl polydimethylsiloxane (DP=45.2) were added to a reaction vessel at a molar ratio of 1.6:1. The mixture was stirred at room temperature for 2 hours, and then heated to 60°C and reacted for another 2 hours to obtain the HDI conjugate.

[0047] Under nitrogen protection, the 2,6-diaminoanthraquinone and HDI complex were added to the reaction vessel at a molar ratio of 1:1.4, stirred at room temperature for 2 h, and then heated to 80 °C to continue the reaction for 3 h to obtain the anthraquinone prepolymer. Under nitrogen protection, anthraquinone prepolymer and hydrophilic aspartic ester resin were added to a reaction vessel at a molar ratio of 1.3:1, stirred at room temperature for 3 hours, and then heated to 100°C for another 3 hours to obtain a hydrophilic anthraquinone compound.

[0048] The hydrophilic aspartic ester resin is shown in the above formula (1), wherein X is dodecylene, and R1 and R2 are both polyethylene glycol monomethyl ether segments (DP is 15.4).

[0049] Example 1 The raw material components of the HDPE composition in this embodiment include 100 parts HDPE (melt index 5 g / min) and 5 parts of the hydrophilic anthraquinone compound of Preparation Example 1.

[0050] HDPE and the hydrophilic anthraquinone compound were dried separately to remove water, then mixed evenly and transferred to a twin-screw extruder for melt extrusion molding into a filler. The melt extrusion temperature was 170-190℃, and the die temperature was 180℃.

[0051] Comparative Example 1 The difference between this comparative example and Example 1 is that in Example 1, 5 parts of the hydrophilic anthraquinone compound were replaced with 1.1 parts of 1,5-diaminoanthraquinone. The remaining steps remained unchanged.

[0052] Comparative Example 2 The difference between this comparative example and Example 1 is that in Example 1, 5 parts of the hydrophilic anthraquinone compound were replaced with a combination of 1.1 parts of 1,5-diaminoanthraquinone and 4 parts of polyethylene glycol (DP 12.6). The remaining steps remained unchanged.

[0053] Example 2 The difference between this embodiment and Example 1 is that in Example 1, the hydrophilic anthraquinone compound used in Preparation Example 1 was replaced with an equal weight of the hydrophilic anthraquinone compound used in Preparation Example 2. All other steps remained unchanged.

[0054] Example 3 The difference between this embodiment and Example 2 is that in Example 2, the amount of the hydrophilic anthraquinone compound used to prepare Example 2 was reduced from 5 parts to 1 part. All other steps remained unchanged.

[0055] Example 4 The difference between this embodiment and Example 2 is that in Example 2, the amount of the hydrophilic anthraquinone compound used to prepare Example 2 was increased from 5 parts to 10 parts. All other steps remained unchanged.

[0056] Example 5 The difference between this embodiment and Embodiment 2 is that in Embodiment 2, the raw material components also included 0.2 parts of untreated single-walled carbon nanotubes (SWMT). The remaining steps remain unchanged.

[0057] Example 6 The difference between this embodiment and Embodiment 5 is that in Embodiment 5, the SWMT is of equal weight and its surface is treated with silane coupling agent KH-560. The remaining steps remain unchanged.

[0058] Example 7 The raw material components of the HDPE composition in this embodiment include 100 parts HDPE (melt index 5 g / min) and 6 parts of the hydrophilic anthraquinone compound of Preparation Example 3.

[0059] HDPE and the hydrophilic anthraquinone compound were dried separately to remove water, then mixed evenly and transferred to a twin-screw extruder for melt extrusion molding into a filler. The melt extrusion temperature was 170-190℃, and the die temperature was 180℃.

[0060] Comparative Example 3 The difference between this comparative example and Example 7 is that in Example 7, 6 parts of the hydrophilic anthraquinone compound were replaced with a combination of 1 part of 2-aminoanthraquinone and 5 parts of the hydrophilic aspartic ester resin from Preparation Example 3. The remaining steps remained unchanged.

[0061] Example 8 The difference between this embodiment and Embodiment 7 is that in Embodiment 7, the raw material components also included 0.5 parts of amino-modified SWMT. The remaining steps remain unchanged.

[0062] The amino-modified SWMT was prepared by surface modification of SWMT using KH-550 silane coupling agent.

[0063] Performance testing 1. Hydrophilicity: The hydrophilicity was tested using a water contact angle tester. The olefin polymer compositions of Examples 1-8 and Comparative Examples 1-3 were prepared into thin plates with dimensions of 20cm×20cm×2mm. The water contact angle was measured at five locations on the same surface of each thin plate, including the four corners and the middle. The average value of the five results is shown in Table 1 below.

[0064] Table 1. Water contact angle test results

[0065] Therefore, based on the data in Table 1 above, adding hydrophilic anthraquinone compounds to HDPE can significantly reduce the hydrophobicity of HDPE, and the resulting HDPE composition has better hydrophilicity.

[0066] 2. Denitrification performance test: Prepare 500 ml of denitrification medium with an initial concentration of 50 mg / L (initial nitrate concentration of 50 mg / L). Inoculate with 3% microorganisms activated and cultured in LB medium. Place the inoculated denitrification medium in a constant temperature shaker set at 36℃ and 120 r / min to ensure that 10 g of the test packing material in the medium is in a good fluidized state. Sampling is performed every 5 h. After centrifuging at 3000 rpm for 10 min, the supernatant of the sample is quantitatively diluted. The absorbance is measured by UV spectrophotometer to calculate the corresponding concentration, and the denitrification rate is calculated. The denitrification rate at time t = (C0 - C t ) / C0×100%, where C0 is the initial concentration of nitrate, C t Let t be the concentration of nitrate at time t. Each sample was measured three times, and the average of the three results was taken.

[0067] The results are shown in Table 2 below, where the blank group uses HDPE as the filler alone.

[0068] Table 2 Denitrification rate / %

[0069] Compared with Example 1 and Comparative Example 1, Comparative Example 1 lacks hydrophilic components, resulting in slower denitrification efficiency. Comparing Examples 1 and 2, and Examples 1 and 7, the anthraquinone content in Examples 2 and 7 is significantly lower than that in Example 1, and the anthraquinone content is also lower. However, because the hydrophilic anthraquinone compounds can migrate and accumulate on the surface of the packing material, the packing materials in Examples 2 and 7 still exhibit good denitrification effects. Comparing Examples 1, 5, and 6, and Examples 7 and 8, the addition of carbon-based materials significantly improves the denitrification effect.

[0070] 3. Packing Material Stability: The packing material to be tested was soaked in water for 72 hours, then removed and air-dried at room temperature for 24 hours. The denitrification performance was then tested according to the above-mentioned test, measuring the denitrification rate retention rate after 15 hours. Denitrification rate retention rate = (Denitrification rate after soaking / Denitrification rate before soaking) × 100%. The higher the denitrification rate retention rate, the better the stability of the packing material's denitrification performance.

[0071] The results are shown in Table 3 below.

[0072] Table 3 Denitrification rate retention rate / %

[0073] The results in Tables 2 and 3 show that when polyethylene glycol or hydrophilic aspartic ester resin is added directly to HDPE, the molecular weight is not large enough and the compatibility with HDPE is very poor, so it cannot provide a more durable denitrification effect for the filler.

[0074] As described above, the basic principles, main features, and advantages of the present invention have been shown and described. Those skilled in the art should understand that the present invention is not limited to the above embodiments, which are merely preferred embodiments and should not be construed as limiting the scope of the invention. All equivalent changes and modifications made in accordance with the scope of the patent and the description should still fall within the scope of the present invention. The scope of protection of this invention is defined by the appended claims and their equivalents.

Claims

1. A hydrophilically modified HDPE composition, characterized in that, The raw material components include 100 parts of HDPE and 1-10 parts of the hydrophilic anthraquinone compound by weight fraction; The preparation method of the hydrophilic anthraquinone compound is as follows: The anthraquinone compound and the diisocyanate compound are reacted to obtain an anthraquinone prepolymer; The anthraquinone prepolymer and a hydrophilic compound are reacted to obtain the hydrophilic anthraquinone compound; The hydrophilic compound contains active hydrogen that can react with the NCO group at 100℃.

2. The hydrophilically modified HDPE composition according to claim 1, characterized in that, The anthraquinone compound contains one or a combination of two or more of primary amino group, secondary amine group and hydroxyl group; The sum of the number of primary amino group, secondary amine group and hydroxyl group on the structure of the anthraquinone compound is 1-2.

3. The hydrophilically modified HDPE composition according to claim 1, characterized in that, The molar ratio of the anthraquinone compound to the diisocyanate compound is 1:1-2.

4. The hydrophilically modified HDPE composition of claim 1, wherein, The diisocyanate compound is selected from diisocyanate monomer and a combination thereof; The combination is obtained by reacting the diisocyanate monomer with polyethylene glycol, polysiloxane diol or terminal hydroxyl polyethylene glycol / polysiloxane block copolymer; The NCO group content in the combination is not less than 5wt%.

5. The hydrophilically modified HDPE composition of claim 1, wherein The active hydrogen in the hydrophilic compound is selected from one or a combination of two or more of hydroxyl group, primary amino group and secondary amine group; The hydrophilic compound further contains one or a combination of two or more of polyethylene glycol segment, sulfonic acid and its salt structure, carboxylic acid and its salt structure, sulfuric acid and its salt structure, phenol and its salt structure and phosphoric acid and its salt structure.

6. The hydrophilically modified HDPE composition of claim 1, wherein, The molar ratio of the NCO group in the anthraquinone prepolymer to the active hydrogen in the hydrophilic compound is 1:0.6-2.

7. The hydrophilically modified HDPE composition according to claim 5, characterized in that The hydrophilic compound is selected from hydrophilic aspartic acid ester resin; The structure of the hydrophilic aspartic acid ester resin is shown in the following formula (1), （1） wherein X is C8-C24 alkylene, or a first polyethylene glycol divalent segment or a first polysiloxane divalent segment; The structure of the first polyethylene glycol divalent segment is shown in the following formula (2), -0(CH2CH2O) m - (2) wherein m=4-50; The structure of the first polysiloxane divalent segment is shown in the following formula (3), - Me2SiO(SiOMe2) p (SiOMeR3) q SiMe2- (3) wherein Me represents methyl, R3 is selected from substituted C3-C20 hydrocarbon group, p=10-200, q=0-100; R1 and R2 are both selected from a second polyethylene glycol monovalent segment; The structure of the second polyethylene glycol monovalent segment is shown in the following formula (4), -O(CH2CH2O) n CH3(4) wherein n=4-50; The average polymerization degree of the first polyethylene glycol divalent segment and the second polyethylene glycol monovalent segment is the same or different.

8. The hydrophilically modified HDPE composition of claim 1, wherein, The raw material components further include 0.1-2 parts of carbon-based material; The carbon-based material is selected from carbon nanotube, graphene or graphene oxide.

9. The hydrophilically modified HDPE composition according to claim 8, characterized in that, The surface of the carbon-based material is treated with epoxy group, primary amino group, secondary amine group or NCO group.

10. Use of a hydrophilically modified HDPE composition according to any one of claims 1 to 9, characterized in that It is used for the treatment of nitrogen-containing sewage.

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