Polyethylene biological composite membrane for treating phenolic wastewater and preparation method of polyethylene biological composite membrane

Abstract

The invention relates to the field of water treatment technologies and high polymer materials, in particular to a polyethylene biological composite membrane for treating phenolic wastewater and a preparation method of the polyethylene biological composite membrane. The composite membrane is prepared from the following raw materials: polyethylene 1, a solvent, polyethylene 2, a reinforcing agent, a bioactive component and glutaraldehyde, the addition amounts of the polyethylene 1, the solvent, the polyethylene 2, the enhancer, the bioactive component and the glutaraldehyde are 5-30 parts by mass, 50-90 parts by mass, 1-20 parts by mass, 0.5-5 parts by mass, 3-10 parts by mass and 0.5-5 parts by mass respectively; the molecular weight of the polyethylene 1 is 1000000, and the molecular weight of the polyethylene 2 is 200000. The finally prepared polyethylene biological composite membrane has the characteristics of excellent phenolic substance removal property, small chlorococcus activity loss, deep treatment property, low cost, relatively low energy consumption, environmental protection and the like, and can be widely applied to the field of industrial phenolic wastewater treatment.

Description

Technical Field

[0001] The invention belongs to the technical field of water treatment technology and polymer membrane materials, and specifically relates to a polyethylene biocomposite membrane for treating phenol-containing wastewater and a preparation method thereof. Background Art

[0002] Phenol-containing wastewater is one of the common toxic pollutants in industrial wastewater, mainly from petrochemical, pharmaceutical and coal chemical industries. Phenol compounds are highly toxic, difficult to degrade and bioaccumulate, posing a serious threat to the ecological environment and human health.

[0003] Current treatment methods include adsorption, oxidation, and biodegradation. Among them, the adsorption method uses adsorption materials such as activated carbon to remove phenolic substances, but it needs to be replaced or regenerated after adsorption saturation, the operating cost is high, and it is easy to cause secondary pollution. The neutralization precipitation method removes phenolic compounds through chemical precipitation, but the treatment effect on phenolic mixtures in complex wastewater is limited. The chemical oxidation method has high costs, complex operating expenses and maintenance, and poor economic efficiency. Faced with high-concentration phenolic wastewater, traditional biological treatment methods are prone to failure, and it is necessary to improve biological carriers and degradation mechanisms.

[0004] At present, membrane separation is widely used in the treatment of high-concentration phenolic wastewater, which separates phenolic pollutants through nanofiltration or reverse osmosis membranes. However, the filtration membrane is mainly made of polysulfone (PSU). The production of PSU involves complex chemical reactions, requires the use of specific raw materials and catalysts, and is relatively expensive, resulting in high treatment costs for membrane separation. Therefore, under fierce market competition, researching and developing a low-cost biocomposite membrane that can deeply remove phenolic substances in wastewater is a key measure for the development of membrane separation.

[0005] Therefore, under the fierce market competition, developing a low-cost biocomposite membrane that can deeply remove phenolic substances in wastewater and has high tensile strength is a key measure for the development of membrane separation. Summary of the invention

[0006] Based on the shortcomings of the above-mentioned prior art, the present invention provides a polyethylene biocomposite membrane for treating phenol-containing wastewater and a preparation method thereof. The method replaces the polysulfone material of the original ultrafiltration and nanofiltration reverse osmosis membranes with polyethylene, effectively reducing the material cost of the membrane separation method, and at the same time, the spiral algae are composited with the polyethylene membrane to further biodegrade the phenolic substances in the wastewater, thereby improving the removal effect of the phenolic substances. In addition, through the formulation research of various compositions, the polyethylene membrane has a higher phenol degradation rate, a lower loss of algae activity, a higher tensile strength, elongation at break and porosity, which can greatly reduce the subsequent maintenance cost.

[0007] To achieve the above object, the present invention provides the following technical solutions:

[0008] A polyethylene biocomposite membrane for treating phenol-containing wastewater,

[0009] The composite film is made of the following substances: polyethylene 1, solvent, polyethylene 2, reinforcing agent, bioactive component and glutaraldehyde;

[0010] The amounts of polyethylene 1, solvent, polyethylene 2, enhancer, bioactive component and glutaraldehyde added are 5-30 parts by mass, 50-90 parts by mass, 1-20 parts by mass, 0.5-5 parts by mass, 3-10 parts by mass and 0.5-5 parts by mass respectively;

[0011] The molecular weight of the polyethylene 1 is 1,000,000, and the molecular weight of the polyethylene 2 is 200,000.

[0012] As a further preferred polyethylene biocomposite membrane for treating phenol-containing wastewater,

[0013] Preferably, the preferred addition amounts of polyethylene 1, solvent, polyethylene 2, enhancer, bioactive component and glutaraldehyde are: 15-30 mass parts, 60-90 mass parts, 10-20 mass parts, 0.5-2 mass parts, 6-10 mass parts and 2-5 mass parts, respectively.

[0014] Preferably, the solvent is a mixture of paraffin oil and white oil; the weight ratio of the paraffin oil to the white oil is 1:1.

[0015] Preferably, the reinforcing agent is one or both of polyvinyl alcohol (PVA) and nano silicon dioxide (SiO2).

[0016] Preferably, the biologically active component is Spirulina, which is purchased from Shanghai Ditian Biotechnology Co., Ltd. in a specification of 500 ml suspension culture medium.

[0017] The present invention also provides a method for preparing a polyethylene biocomposite membrane for treating phenol-containing wastewater, characterized in that the method comprises:

[0018] S1. Preparation of polyethylene mixed system: polyethylene 1 and polyethylene 2 are mixed evenly, and then dried in a drying oven at 35-100° C. for 1-4 hours to form a polyethylene resin mixed system;

[0019] S2, reinforcing agent addition: adding solvent and reinforcing agent to the polyethylene resin mixed system described in step S1, and mixing in a stirrer;

[0020] S3. Preparation of biologically active components: Place Spirulina in a beaker at room temperature, add deionized water using a pipette until the concentration of Spirulina is 1-2 g / L, and obtain a Spirulina suspension;

[0021] S4, preparing a casting solution: mixing the polyethylene reinforcement system described in step S1 with the Spirulina suspension described in step S3, stirring evenly to form a casting solution;

[0022] S5, preparing a base film: pouring the casting solution in step S4 into the feed port of a tape casting machine, preparing a base film by tape casting, adjusting the tape casting speed to 1-3 cm / s, and slowly evaporating the solvent at 40-60° C. for 1-2 hours to form a base film;

[0023] S6. Cross-linking and curing: drying the prepared base film, and cross-linking treatment with glutaraldehyde cross-linking agent for 2 to 4 hours to improve the stability and anti-swelling performance of the film.

[0024] S7. Preparation of composite membrane: The cross-linked and cured membrane is soaked and cleaned with deionized water, and cultured in a nutrient solution for 24 to 48 hours to restore the activity of Spirulina, and finally a polyethylene biocomposite membrane is prepared.

[0025] It is further preferred as a method for preparing a polyethylene biocomposite membrane for treating phenol-containing wastewater.

[0026] Preferably, in step S2, the rotation speed of the stirrer is 60-150 rpm, the reaction temperature is 100-180° C., and the reaction time is 20-80 min.

[0027] Compared with the prior art, the present invention has the following beneficial effects:

[0028] (1) Compared with the traditional membrane separation method, the advantages of the present invention are that the prepared biocomposite membrane combines the mechanical properties of polyethylene and the biodegradation characteristics of Spirulina, which can more deeply adsorb and degrade phenolic pollutants in wastewater, and the phenol removal efficiency is higher.

[0029] (2) Compared with the polysulfone materials used in conventional nanofiltration reverse osmosis membranes and ultrafiltration membranes, the ultra-high molecular weight polyethylene of the membrane material of the present invention has excellent acid and alkali resistance and anti-pollution properties, low cost, is suitable for long-term operation, and has low maintenance costs.

[0030] (3) In addition, by optimizing the experimental formula, the obtained composite membrane has a higher phenol degradation rate, lower loss of sphaerocephala activity, higher tensile strength, elongation at break, and porosity, which can significantly reduce subsequent maintenance costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 is a scanning electron microscope photograph of the composite membrane in Example 1;

[0032] Figure 2 is the phenol degradation rate curve when the composite membrane in the comparative example and Example 1-6 treats phenol-containing wastewater for 7 days;

[0033] Figure 3The activity loss curve of the sphaerocephala when the composite membrane in the comparative example and Example 1-6 treated the phenol-containing wastewater for 7 days;

[0034] Table 1 shows the tensile strength, elongation at break, and porosity of the composite films in the comparative examples and embodiments 1-6 and the comparative examples. DETAILED DESCRIPTION

[0035] In order to make the above-mentioned purposes, features and advantages of the present invention more obvious and easy to understand, the specific implementation methods of the present invention are described in detail in combination with the embodiments below. The following content is only an example and explanation of the concept of the present invention. The technicians in the relevant technical field make various modifications or supplements to the specific implementation cases described or replace them with similar methods. As long as they do not deviate from the concept of the invention or exceed the scope defined by the claims, they should all belong to the protection scope of the present invention.

[0036] The above-mentioned preparation method of the present invention is described below through specific examples and comparative examples.

[0037] Example 1

[0038] This embodiment provides a polyethylene biocomposite membrane for treating phenol-containing wastewater and a preparation method thereof.

[0039] S1. Preparation of polyethylene mixed system: 5 parts by weight of polyethylene 1 with a molecular weight of 1,000,000 and 1 part by weight of polyethylene 2 with a molecular weight of 200,000 are mixed evenly, and then dried in a drying oven at 35° C. for 1 hour to form a polyethylene resin mixed system;

[0040] S2, reinforcing agent addition: add 50 parts by mass of solvent and 0.5 parts by mass of reinforcing agent to the polyethylene resin mixed system described in step S1, and mix them in a stirrer, wherein the solvent is a mixture of paraffin oil and white oil in a ratio of 1:1, and the reinforcing agent is polyvinyl alcohol, wherein the speed of the stirrer is 60 rpm, the reaction temperature is 100° C., and the reaction time is 20 min;

[0041] S3. Preparation of biologically active components: 3 parts by mass of Spirulina were placed in a beaker at room temperature, and deionized water was added using a pipette until the concentration of Spirulina was 1 to 2 g / L to obtain a Spirulina suspension;

[0042] S4, preparing a casting solution: mixing the polyethylene reinforcement system described in step S1 with the Spirulina suspension described in step S3, stirring evenly to form a casting solution;

[0043] S5, preparing a base film: pouring the casting solution in step S4 into the feed port of a tape casting machine, preparing a base film by tape casting, adjusting the tape casting speed to 1 cm / s, and slowly evaporating the solvent at 40° C. for 1 h to form a base film;

[0044] S6. Cross-linking and curing: drying the prepared base film, and cross-linking treatment with 0.5 parts by mass of glutaraldehyde cross-linking agent for 2 hours to improve the stability and anti-swelling performance of the film.

[0045] S7. Preparation of composite membrane: The cross-linked and cured membrane is soaked and cleaned with deionized water, and cultured in a nutrient solution for 24 hours to restore the activity of Spirulina, and finally a polyethylene biocomposite membrane is prepared.

[0046] A polyethylene biocomposite membrane for treating phenol-containing wastewater is obtained through the preparation method.

[0047] Example 2

[0048] This embodiment provides a polyethylene biocomposite membrane for treating phenol-containing wastewater and a preparation method thereof.

[0049] Preparation method:

[0050] S1, preparation of polyethylene mixed system: 12 parts by weight of polyethylene 1 with a molecular weight of 1,000,000 and 8 parts by weight of polyethylene 2 with a molecular weight of 200,000 are mixed evenly, and then dried in a drying oven at 450° C. for 2 hours to form a polyethylene resin mixed system;

[0051] S2, reinforcing agent addition: add 45 parts by mass of solvent and 1 part by mass of reinforcing agent to the polyethylene resin mixed system described in step S1, and mix them in a stirrer, wherein the solvent is a mixture of paraffin oil and white oil in a ratio of 1:1, and the reinforcing agent is polyvinyl alcohol, wherein the speed of the stirrer is 80 rpm, the reaction temperature is 120° C., and the reaction time is 30 min;

[0052] S3. Preparation of biologically active components: 6 parts by mass of Spirulina were placed in a beaker at room temperature, and deionized water was added using a pipette until the concentration of Spirulina was 1.2 g / L to obtain a suspension of Spirulina;

[0053] S4, preparing a casting solution: mixing the polyethylene reinforcement system described in step S1 with the Spirulina suspension described in step S3, stirring evenly to form a casting solution;

[0054] S5, preparing a base film: pouring the casting solution in step S4 into the feed port of a tape casting machine, preparing a base film by tape casting, adjusting the tape casting speed to 1.5 cm / s, and slowly evaporating the solvent at 45° C. for 1.2 h to form a base film;

[0055] S6. Cross-linking and curing: the prepared base film is dried and cross-linked with 1.5 parts by mass of a glutaraldehyde cross-linking agent for 1.2 hours to improve the stability and anti-swelling performance of the film.

[0056] S7. Preparation of composite membrane: The cross-linked and cured membrane is soaked and cleaned with deionized water, and cultured in a nutrient solution for 30 hours to restore the activity of Spirulina, and finally a polyethylene biocomposite membrane is prepared.

[0057] A polyethylene biocomposite membrane for treating phenol-containing wastewater is obtained through the preparation method.

[0058] Example 3

[0059] This embodiment provides a polyethylene biocomposite membrane for treating phenol-containing wastewater and a preparation method thereof.

[0060] Preparation method:

[0061] S1. Preparation of polyethylene mixed system: 15 parts by weight of polyethylene 1 with a molecular weight of 1,000,000 and 10 parts by weight of polyethylene 2 with a molecular weight of 200,000 are mixed evenly, and then dried in a drying oven at 60° C. for 3 hours to form a polyethylene resin mixed system;

[0062] S2, reinforcing agent addition: add 60 parts by mass of solvent and 2 parts by mass of reinforcing agent to the polyethylene resin mixed system described in step S1, and mix them in a stirrer, wherein the solvent is a mixture of paraffin oil and white oil in a ratio of 1:1, and the reinforcing agent is polyvinyl alcohol, wherein the speed of the stirrer is 100 rpm, the reaction temperature is 150° C., and the reaction time is 40 min;

[0063] S3. Preparation of biologically active components: 6 parts by mass of Spirulina were placed in a beaker at room temperature, and deionized water was added using a pipette until the concentration of Spirulina was 1.5 g / L to obtain a Spirulina suspension;

[0064] S4, preparing a casting solution: mixing the polyethylene reinforcement system described in step S1 with the Spirulina suspension described in step S3, stirring evenly to form a casting solution;

[0065] S5, preparing a base film: pouring the casting solution in step S4 into the feed port of a tape casting machine, preparing a base film by tape casting, adjusting the tape casting speed to 2 cm / s, and slowly evaporating the solvent at 50° C. for 1.5 h to form a base film;

[0066] S6. Cross-linking and curing: drying the prepared base film, and cross-linking treatment with 2 parts by mass of glutaraldehyde cross-linking agent for 3 hours to improve the stability and anti-swelling performance of the film.

[0067] S7. Preparation of composite membrane: The cross-linked and cured membrane is soaked and cleaned with deionized water, and cultured in a nutrient solution for 36 hours to restore the activity of Spirulina, and finally a polyethylene biocomposite membrane is prepared.

[0068] A polyethylene biocomposite membrane for treating phenol-containing wastewater is obtained through the preparation method.

[0069] Example 4

[0070] This embodiment provides a polyethylene biocomposite membrane for treating phenol-containing wastewater and a preparation method thereof.

[0071] Preparation method:

[0072] S1. Preparation of polyethylene mixed system: 30 parts by weight of polyethylene 1 with a molecular weight of 1,000,000 and 20 parts by weight of polyethylene 2 with a molecular weight of 200,000 are mixed evenly, and then dried in a drying oven at 100° C. for 4 hours to form a polyethylene resin mixed system;

[0073] S2, reinforcing agent addition: add 90 parts by mass of solvent and 5 parts by mass of reinforcing agent to the polyethylene resin mixed system described in step S1, and mix them in a stirrer, wherein the solvent is a mixture of paraffin oil and white oil in a ratio of 1:1, and the reinforcing agent is polyvinyl alcohol, wherein the speed of the stirrer is 150 rpm, the reaction temperature is 180° C., and the reaction time is 80 min;

[0074] S3. Preparation of biologically active components: 10 parts by weight of Spirulina were placed in a beaker at room temperature, and deionized water was added using a pipette until the concentration of Spirulina was 2 g / L to obtain a suspension of Spirulina.

[0075] S4, preparing a casting solution: mixing the polyethylene reinforcement system described in step S1 with the Spirulina suspension described in step S3, stirring evenly to form a casting solution;

[0076] S5, preparing a base film: pouring the casting solution in step S4 into the feed port of a tape casting machine, preparing a base film by tape casting, adjusting the tape casting speed to 3 cm / s, and slowly evaporating the solvent at 60° C. for 2 h to form a base film;

[0077] S6, cross-linking and curing: drying the prepared base film, and cross-linking treatment with 5 parts by mass of glutaraldehyde cross-linking agent for 4 hours to improve the stability and anti-swelling performance of the film;

[0078] S7. Preparation of composite membrane: The cross-linked and cured membrane is soaked and cleaned with deionized water, and cultured in a nutrient solution for 48 hours to restore the activity of Spirulina, and finally a polyethylene biocomposite membrane is prepared.

[0079] A polyethylene biocomposite membrane for treating phenol-containing wastewater is obtained through the preparation method.

[0080] Example 5

[0081] The difference between Example 5 and Example 1 is that the preferred addition amounts of polyethylene 1, solvent, polyethylene 2, enhancer, bioactive component and glutaraldehyde are 17 parts by mass, 70 parts by mass, 12 parts by mass, 0.9 parts by mass, 7 parts by mass and 3 parts by mass, respectively.

[0082] Example 6

[0083] The difference between Example 6 and Example 1 is that the preferred addition amounts of polyethylene 1, solvent, polyethylene 2, enhancer, bioactive component and glutaraldehyde are 22 parts by mass, 75 parts by mass, 16 parts by mass, 1.3 parts by mass, 7 parts by mass and 5 parts by mass, respectively.

[0084] Comparative Example

[0085] The comparative example differs from Example 1 in that no biologically active component is added.

[0086] Figure 1 This is a scanning electron microscope photograph of the ultra-high molecular weight polyethylene biocomposite membrane prepared in Example 1. It can be seen that there are dense sponge-like pores on the cross section of the composite membrane, which can filter out impurities, and there are elliptical macropores rich in Spirulina, which can biodegrade the phenolic substances passing through.

[0087] Figure 2 The phenol degradation rate curves of the composite membranes in the comparative example and examples 1-6 when treating phenol-containing wastewater for 7 days are shown. It can be seen that the decomposition rates of examples 1-6 are higher than those of the comparative example, and further, the decomposition rates of examples 3-6 are higher than those of examples 1-2.

[0088] Figure 3 The activity loss curve of the sphaerocephala when the composite membrane in the comparative example and Example 1-6 treated the phenol-containing wastewater for 7 days; Figure 3 The ultra-high molecular weight polyethylene biocomposite membrane prepared in Examples 1-6 is a curve showing the change of different membrane activity losses when the same amount of phenolic pollutants is added every day during the continuous treatment of phenolic wastewater for 7 days. As can be seen from the figure, on the 1st to 3rd day, the activity loss rate of the algae in Examples 3, 5 and 6 is the lowest. After the 3rd day, the activity loss rate of the algae in Examples 5 and 6 rises sharply. After the 5th day, the activity loss rate of the algae in Examples 1 and 3 is the lowest, and the increase in the loss rate in Example 1 is the smallest. Therefore, it is compared that the formula of Example 1 is the formula with the lowest algae loss rate, and the algae loss rates of all examples are less than 10%, which meets the requirements.

[0089] Table 1 shows the tensile strength, elongation at break, and porosity of the composite films in the comparative examples and embodiments 1-6 and the comparative examples.

[0090]

[0091] The results in Table 1 show that the tensile strength, elongation at break and porosity of Examples 1-6 are higher than those of the comparative example. Furthermore, the tensile strength, elongation at break and porosity of Examples 3 to 6 are higher than those of Examples 1 to 2.

[0092] In summary, the polyethylene biocomposite membrane prepared by the present invention has the advantages of removing phenolic substances, small loss of activity of sphaerocephala, deep treatment performance and low cost.

[0093] According to the above method, a polyethylene biocomposite membrane for treating phenol-containing wastewater and a preparation method thereof are obtained.

[0094] The above are merely exemplary embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A polyethylene biocomposite membrane for treating phenolic wastewater, characterized in that: The composite film is made of the following substances: polyethylene 1, solvent, polyethylene 2, reinforcing agent, bioactive component and glutaraldehyde; The amounts of polyethylene 1, solvent, polyethylene 2, enhancer, bioactive component and glutaraldehyde added are 5-30 parts by mass, 50-90 parts by mass, 1-20 parts by mass, 0.5-5 parts by mass, 3-10 parts by mass and 0.5-5 parts by mass respectively; The molecular weight of the polyethylene 1 is 1,000,000, and the molecular weight of the polyethylene 2 is 200,000.

2. The polyethylene biocomposite membrane for treating phenolic wastewater according to claim 1, characterized in that: The preferred addition amounts of the polyethylene 1, solvent, polyethylene 2, enhancer, bioactive component and glutaraldehyde are 15-30 parts by mass, 60-90 parts by mass, 10-20 parts by mass, 0.5-2 parts by mass, 6-10 parts by mass and 2-5 parts by mass, respectively.

3. The polyethylene biocomposite membrane for treating phenolic wastewater according to claim 1 or 2, characterized in that: The solvent is a mixture of paraffin oil and white oil; the weight ratio of the paraffin oil to the white oil is 1:

1.

4. The polyethylene biocomposite membrane for treating phenolic wastewater according to claim 1 or 2, characterized in that: The reinforcing agent is one or both of polyvinyl alcohol (PVA) and nano silicon dioxide (SiO2).

5. The polyethylene biocomposite membrane for treating phenolic wastewater according to claim 1 or 2, characterized in that: The biologically active component is Spirulina, which is purchased from Shanghai Ditian Biotechnology Co., Ltd. in a specification of 500 ml suspension culture solution.

6. A method for preparing a polyethylene biocomposite membrane for treating phenol-containing wastewater as claimed in claim 1 or 2, characterized in that: The method includes: S1. Preparation of polyethylene mixed system: polyethylene 1 and polyethylene 2 are mixed evenly, and then dried in a drying oven at 35-100° C. for 1-4 hours to form a polyethylene resin mixed system; S2, reinforcing agent addition: adding solvent and reinforcing agent to the polyethylene resin mixed system described in step S1, and mixing in a stirrer; S3. Preparation of biologically active components: Place Spirulina in a beaker at room temperature, add deionized water using a pipette until the concentration of Spirulina is 1-2 g / L, and obtain a Spirulina suspension; S4, preparing a casting solution: mixing the polyethylene reinforcement system described in step S1 with the Spirulina suspension described in step S3, stirring evenly to form a casting solution; S5, preparing a base film: pouring the casting solution in step S4 into the feed port of a tape casting machine, preparing a base film by tape casting, adjusting the tape casting speed to 1-3 cm / s, and slowly evaporating the solvent at 40-60° C. for 1-2 hours to form a base film; S6, cross-linking and curing: drying the prepared base film, and cross-linking treatment with glutaraldehyde cross-linking agent for 2 to 4 hours to improve the stability and anti-swelling performance of the film; S7. Preparation of composite membrane: The cross-linked and cured membrane is soaked and cleaned with deionized water, and cultured in a nutrient solution for 24 to 48 hours to restore the activity of Spirulina, and finally a polyethylene biocomposite membrane is prepared.

7. The method for preparing a polyethylene biocomposite membrane for treating phenol-containing wastewater according to claim 6, characterized in that: In step S2, the rotation speed of the stirrer is 60-150 rpm, the reaction temperature is 100-180° C., and the reaction time is 20-80 min.

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