An electrospun carrier for rapid biofilm formation, its preparation method and application

Abstract

A fast biofilm-forming electrospinning carrier, and its preparation method and application. The present invention belongs to the field of sewage biological treatment. The purpose of the present invention is to solve the technical problem that the existing methods cannot achieve the sustained release of AHLs by directly adding AHLs or simply fixing AHLs on the carrier surface. The method of the present invention: S1: dissolving a polymer and AHLs in an organic solvent to obtain a mixed solution; S2: electrospinning the mixed solution to obtain an electrospinning carrier with fast biofilm formation. In the obtained electrospinning carrier, AHLs are wrapped or attached to fibers. The present invention can accelerate the formation of biofilms on the carrier surface, promote the enrichment of nitrifying bacteria, and enhance the degradation of nitrogen-containing pollutants in water. Compared with traditional biofilm carriers, the present invention can shorten the biofilm formation and acclimation cycle, so that the sewage treatment unit used can meet the relevant effluent standards earlier.

Description

Technical Field

[0001] The invention belongs to the field of biological sewage treatment, and particularly relates to an electrostatic spinning carrier for rapid biofilm formation, a preparation method and an application thereof. Background Art

[0002] Biofilm treatment is one of the most widely used wastewater treatment methods. Due to the long generation time of nitrifying bacteria and the presence of oxygen concentration gradients within the biofilm, biofilm treatment is particularly advantageous in treating nitrogenous wastewater. However, the long biofilm formation period restricts its application.

[0003] N-acylhomoserine lactones (AHLs) are signaling molecules that promote and regulate nitrification. Existing research suggests that AHLs can increase the biomass of nitrifying bacteria. However, how to rationally utilize AHLs and further maximize their effectiveness is an urgent issue.

[0004] Numerous inventions have been proposed to promote rapid biofilm formation by improving the composition or surface properties of biofilm carriers. However, most of these inventions only improve initial bacterial adsorption and have no significant benefit for nitrifying bacteria. For example, patent CN105923744A discloses efficient utilization of AHLs by directly adding AHLs or simply immobilizing them on the carrier surface. However, the AHLs added by this method are only effective upon addition or sudden release, and cannot achieve sustained release of AHLs. Achieving long-term promoting effects during the biofilm formation period and acclimatization remains an urgent challenge. Summary of the Invention

[0005] In view of the above defects and shortcomings, the present invention provides an electrospinning carrier with rapid film formation, a preparation method and application thereof.

[0006] The technical solutions of the present invention are as follows:

[0007] One of the purposes of the present invention is to provide an electrospinning carrier with rapid film formation, wherein the electrospinning carrier comprises a polymer fiber network obtained by electrospinning and AHLs, wherein the AHLs are wrapped around or attached to the fibers.

[0008] It is further defined that the polymer is one or a mixture of any proportion of polyethylene (PE), polypropylene (PP), polyurethane (PU), polyvinylidene fluoride (PVDF), polyimide (PI), polyamide (PA), and polystyrene (PS).

[0009] It is further defined that the AHLs are one or more of N-butyryl homoserine lactone (C4-HSL), N-hexanoyl homoserine lactone (C6-HSL), N-octanoyl homoserine lactone (C8-HSL), N-decanoyl homoserine lactone (C10-HSL), N-dodecanoyl homoserine lactone (C12-HSL), and N-tetradecanoyl homoserine lactone (C14-HSL), a mixture of any proportions.

[0010] It is further defined that the mass ratio of polymer to AHLs in the electrospinning carrier is (8-25): (0.1-5).

[0011] The second object of the present invention is to provide a method for preparing an electrospinning carrier with rapid film formation, the preparation method being carried out according to the following steps:

[0012] S1: dissolving the polymer and AHLs in an organic solvent to obtain a mixed solution;

[0013] S2: The mixed solution is electrospinned to prepare an electrospinning carrier for rapid film formation.

[0014] It is further defined that the organic solvent in S1 includes one or a mixture of several of N-methylpyrrolidone (NMP), N,N-dimethylformamide (DMF), N,N-dimethylacetamide (DMAC), dimethyl sulfoxide (DMSO), and acetone in any ratio.

[0015] It is further defined that the mass concentration of the polymer in the mixed solution in S1 is 8-25%.

[0016] It is further defined that the mass concentration of AHLs in the mixed solution in S1 is 0.1-5%.

[0017] The S2 electrospinning parameters are further defined as follows: temperature of 20-25°C, humidity of 30-60%, voltage of 15-30 KV, injection speed of 0.005-0.05 mL / min, and nozzle diameter of 0.1-1 mm.

[0018] The third purpose of the present invention is to provide an electrospinning carrier with rapid film formation for use in the field of water treatment.

[0019] A fourth object of the present invention is to provide a biofilm-based sewage biological treatment unit, characterized in that the sewage biological treatment unit uses the above-mentioned electrospinning carrier as a biofilm carrier.

[0020] Compared with the prior art, the present invention has the following advantages:

[0021] (1) The present invention can accelerate the formation of biofilm on the surface of the carrier, promote the enrichment of nitrifying bacteria, and enhance the degradation of nitrogen-containing pollutants in water.

[0022] (2) Compared with traditional biofilm carriers, the present invention can shorten the biofilm formation and acclimation period, so that the sewage treatment unit used can meet the relevant effluent standards earlier.

[0023] (3) The biofilm on the surface of the electrospun carrier of the present invention has a higher biomass content and nitrifying bacteria biomass. In addition, since AHLs are wrapped or attached to the fibers, they are released into the water in a slow release form rather than a sudden release, which has a more lasting promoting effect.

[0024] (4) Through experimental comparison, it was found that the present invention achieved the Class A standard for sewage treatment (COD ≤ 50 mg / L, ammonia nitrogen ≤ 5 mg / L) on the 8th day of the sewage treatment unit, while the commonly used polyurethane carrier achieved the same standard on the 13th day. Analysis of the biofilm on the 15th day found that the abundance of the functional gene amoA in the surface biofilm of the present invention was 275% of that of the polyurethane carrier, and the dry weight of the surface biofilm of the present invention was 166.7% of that of the polyurethane carrier. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 is a scanning electron microscope photograph of the electrospun carrier in Example 1;

[0026] Figure 2 This is a comparison chart of effluent COD and ammonia nitrogen between the experimental group and the control group in the application example;

[0027] Figure 3 This is the C12-HSL concentration diagram of the effluent from the experimental group in the application example;

[0028] Figure 4 This is a comparison chart of the amoA functional gene abundance and dry weight of the biofilms in the experimental and control groups in the application example. DETAILED DESCRIPTION

[0029] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0030] The experimental methods used in the following examples are conventional methods unless otherwise specified. The materials, reagents, methods, and instruments used are conventional in the art and can be obtained commercially by those skilled in the art unless otherwise specified.

[0031] As used in the following examples, the terms "comprising," "including," "having," "containing," or any other variations thereof, are intended to cover a non-exclusive inclusion. For example, a composition, process, method, article, or apparatus that comprises the listed elements is not necessarily limited to only those elements but may include other elements not expressly listed or inherent to such composition, process, method, article, or apparatus.

[0032] When amount, concentration or other value or parameter are represented with the range of scope, preferred range or a series of upper preferred value and lower preferred value limit, this should be understood as specifically disclosing all ranges formed by any pairing of any range upper limit or preferred value and any range lower limit or preferred value, and no matter whether this scope is disclosed separately.For example, when disclosing scope "1 to 5", described scope should be interpreted as including scope "1 to 4", "1 to 3", "1 to 2", "1 to 2 and 4 to 5", "1 to 3 and 5" etc.When numerical range is described in this article, unless otherwise stated, otherwise this scope is intended to include its end value and all integers and fractions within the scope.In this application specification and claims, range limitation can be combined and / or interchanged, and if these ranges are not otherwise stated, include all subranges contained therein.

[0033] The indefinite articles "a" and "an" before the elements or components of the present invention do not limit the quantity requirement (i.e. the number of times they appear). Therefore, "a" or "an" should be interpreted as including one or at least one, and elements or components in the singular also include plural forms, unless the quantity clearly refers to only the singular form.

[0034] Example 1:

[0035] The preparation method of the electrospinning carrier for rapid film formation of this embodiment is carried out according to the following steps:

[0036] S1: Dissolve 12 g of PVDF and 2 g of C12-HSL in 86 g of N-methylpyrrolidone (NMP) to obtain a mixed solution;

[0037] S2: The mixed solution was electrospinned to prepare an electrospinning carrier with rapid membrane formation. The electrospinning parameters were: temperature 25°C, humidity 40%, voltage 20 kV, injection speed 0.01 mL / min, and nozzle diameter 0.8 mm.

[0038] The SEM image of the spinning product obtained under a scanning electron microscope with a magnification of 2000 times is as follows Figure 1 As shown in the figure, it can be seen that the polymer fibers present a three-dimensional cross-network morphology, and C12-HSL is wrapped or attached to the fiber surface.

[0039] Application examples:

[0040] The electrospinning carrier obtained in Example 1 was 2 / m 3 The experimental group and the control group were inoculated with activated sludge containing 3200 mg / L MLSS and 80 mL / g SVI, respectively. The reactor influent COD concentration was 240 mg / L, ammonia nitrogen concentration was 30 mg / L, the residence time was 12 hours, and the dissolved oxygen content was 5 mg / L. Magnetic stirring was applied at 100 rpm at the bottom. The effluent COD, ammonia nitrogen, and C12-HSL concentrations were measured daily. The abundance of amoA functional genes and the dry weight of the biofilm were measured on the 15th day.

[0041] The effluent COD and ammonia nitrogen results of the experimental group and the control group are as follows Figure 2 As shown, the effluent from the experimental group met the Class A standard for sewage treatment (COD ≤ 50 mg / L, ammonia nitrogen ≤ 5 mg / L) on the 8th day, while the commercial polyurethane carrier reached the same standard on the 13th day. After the effluent quality stabilized, the effluent quality of the experimental group was still better than that of the control group.

[0042] The C12-HSL concentration in the effluent of the experimental group was Figure 3 As shown, it can be seen that the concentration of C12-HSL is maintained at a certain level, and the membrane in Example 1 has a sustained release effect.

[0043] The abundance and dry weight of amoA functional genes in biofilms of the experimental and control groups are shown in Figure 2. Figure 4 As shown, from Figure 4 It can be seen that the abundance and dry weight of amoA functional genes in the biofilm of the experimental group were much higher than those in the control group, which were 275% and 166.7% of that of the control group, respectively. This shows that the biomass and nitrifying bacteria biomass in the biofilm of the experimental group were higher, and C12-HSL played a role in the rapid formation of biofilm and rapid enrichment of nitrifying bacteria.

[0044] Example 2:

[0045] The preparation method of the electrospinning carrier for rapid film formation of this embodiment is carried out according to the following steps:

[0046] S1: 20 g of PS and 0.1 g of C6-HSL were dissolved in 79.9 g of N-methylpyrrolidone (NMP) to obtain a mixed solution;

[0047] S2: The mixed solution was electrospun to prepare an electrospinning carrier with rapid membrane formation. The electrospinning parameters were: temperature 25°C, humidity 40%, voltage 20 kV, injection speed 0.05 mL / min, and nozzle diameter 1 mm.

[0048] Example 3:

[0049] The preparation method of the electrospinning carrier for rapid film formation of this embodiment is carried out according to the following steps:

[0050] S1: Dissolve 15 g of PI and 5 g of C6-HSL in 80 g of N-methylpyrrolidone (NMP) to obtain a mixed solution;

[0051] S2: The mixed solution was electrospinned to prepare an electrospinning carrier with rapid membrane formation. The electrospinning parameters were: temperature 25°C, humidity 40%, voltage 20 kV, injection speed 0.005 mL / min, and nozzle diameter 0.2 mm.

[0052] The foregoing are merely preferred embodiments of the present invention. These embodiments are all different implementations based on the overall concept of the present invention. The scope of protection of the present invention is not limited thereto. Any changes or substitutions that can be easily conceived by a person skilled in the art within the technical scope disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be based on the scope of protection of the claims.

Claims

1. A method for preparing a fast-film electrospinning carrier, characterized in that: The invention comprises a polymer fiber network obtained by electrospinning and AHLs, wherein the AHLs are wrapped around or attached to the fibers. The preparation method is carried out according to the following steps: S1: dissolving the polymer and AHLs in an organic solvent to obtain a mixed solution; the mass concentration of the polymer in the mixed solution is 8-25%, and the mass concentration of the AHLs is 0.1-5%; S2: The mixed solution is electrospinned to prepare an electrospinning carrier with rapid film formation. The electrospinning parameters are: temperature 20-25°C, humidity 30-60%, voltage 15-30 KV, injection speed 0.005-0.05 mL / min, and nozzle diameter 0.1-1 mm.

2. The method for preparing an electrospinning carrier according to claim 1, wherein: The polymer is one or more of PE, PP, PU, PVDF, PI, PA, and PS.

3. The method for preparing an electrospinning carrier according to claim 1, wherein: AHLs are one or more of C4-HSL, C6-HSL, C8-HSL, C10-HSL, C12-HSL, and C14-HSL.

4. The method according to claim 1, wherein The organic solvent in S1 includes one or more of NMP, DMF, DMAC, DMSO, and acetone.

5. Application of the electrospinning carrier prepared by the method according to any one of claims 1 to 4 in the field of water treatment.

6. A biological sewage treatment unit based on biofilm, characterized in that: The electrospinning carrier prepared by the method according to any one of claims 1 to 4 is used as the biofilm carrier.

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