Collagen / polyvinyl alcohol enzyme-loaded nanofiber and its preparation method and application

Abstract

The present invention provides a collagen / polyvinyl alcohol-loaded enzyme nanofiber and its preparation method and application, belonging to the technical field of nano-adsorption materials. The present invention first mixes a collagen solution and an enzyme solution with a polyvinyl alcohol solution in sequence to obtain a spinning solution, and then spins the spinning solution to obtain a collagen / polyvinyl alcohol-loaded enzyme nanofiber. The present invention adds an enzyme to the spinning solution to improve the fiber's ability to enrich molecules, promote the formation of a spindle-shaped structure, and improve the adsorption efficiency of the nanofiber. The prepared nanofiber contains abundant hydrogen bonds and has a large specific surface area. In the process of adsorbing nickel ions, both physical adsorption and chemical adsorption exist, and physical adsorption plays a major role. The hydrogen bonding force and van der Waals force generated between the enzyme and the adsorbed ions enhance the adsorption effect, and the adsorption capacity is increased while retaining the enzyme activity.

Description

Technical Field

[0001] The present invention relates to the technical field of nano-adsorption materials, and in particular to a collagen / polyvinyl alcohol enzyme-loaded nanofiber and a preparation method and application thereof. Background Art

[0002] Adsorption is a convenient and simple industrial water purification method. Among them, electrospun nanofiber materials have attracted widespread attention as an efficient adsorption tool. Electrospun nanofibers have a high specific surface area and excellent adsorption properties and have been used as functional materials for heavy metal ion adsorption. At present, there are several options for using electrospun nanofiber materials to develop advanced adsorbent nanomaterials: (1) using functional groups or molecules to modify the fiber surface; (2) adding auxiliary adsorbents such as graphene oxide and dicyclodextrin to the main filamentous polymer matrix during the electrospinning process; (3) developing new electrospun nanofiber materials for direct adsorption. The third option is more directly innovative. The designed material can be used directly, and the adsorption effect generated by the addition of other types of adsorbents can often make the material have better adsorption properties.

[0003] Therefore, providing a collagen / polyvinyl alcohol enzyme-loaded nanofiber and its preparation method and application, so that the obtained collagen / polyvinyl alcohol enzyme-loaded nanofiber has excellent adsorption performance is a problem that those skilled in the art urgently need to solve. Summary of the Invention

[0004] The purpose of the present invention is to provide a collagen / polyvinyl alcohol enzyme-loaded nanofiber and its preparation method and application, so as to solve the technical problem of poor adsorption performance of nanofiber materials in the prior art.

[0005] In order to achieve the above-mentioned object of the invention, the present invention provides the following technical solutions:

[0006] The present invention provides a method for preparing collagen / polyvinyl alcohol-loaded enzyme nanofibers, comprising the following steps:

[0007] (1) mixing the collagen solution, the enzyme solution and the polyvinyl alcohol solution in sequence to obtain a spinning solution;

[0008] (2) The spinning solution is subjected to spinning treatment to obtain collagen / polyvinyl alcohol enzyme-loaded nanofibers.

[0009] Furthermore, in step (1), the concentration of the collagen solution is 5 to 15 wt%.

[0010] Furthermore, in step (1), the concentration of the polyvinyl alcohol solution is 5 to 15 wt%.

[0011] Furthermore, in step (1), the concentration of the enzyme solution is 0.01 to 0.05 g / mL.

[0012] Furthermore, in step (1), the temperature for mixing the collagen solution and the polyvinyl alcohol solution is 15-35° C., the mixing time is 10-20 min, and the mixing speed is 500-600 r / min.

[0013] Furthermore, in step (1), the temperature for mixing the enzyme solution and the polyvinyl alcohol solution is 15-35° C., the mixing time is 0.5-2 h, and the mixing speed is 500-600 r / min.

[0014] Furthermore, in step (1), the volume ratio of the collagen solution, the polyvinyl alcohol solution and the enzyme solution is 0.1-7:3-10:2-10.

[0015] Furthermore, in step (2), the process parameters of the spinning treatment are: the needle diameter of the syringe is 0.7-0.9 mm, the horizontal distance from the receiving device is 10-15 cm, the perfusion speed is 0.5-1.5 mL / h, the time is 8-12 h, and the voltage is 15-25 kV.

[0016] The invention provides a collagen / polyvinyl alcohol enzyme-loaded nanofiber.

[0017] The present invention provides a collagen / polyvinyl alcohol enzyme-loaded nanofiber for adsorbing Ni in wastewater treatment. 2+ application.

[0018] Beneficial effects of the present invention:

[0019] (1) The collagen used in the present invention is a biopolymer and the main component of animal connective tissue. It has good biocompatibility, biodegradability, and biological activity, and is a functional protein with a wide source and the most widespread distribution. Polyvinyl alcohol is a polyhydroxyl environmentally friendly polymer with multiple excellent properties. It is easily soluble in water and has excellent film-forming properties, adhesion, and solvent resistance. Adding enzyme to the above-mentioned collagen / polyvinyl alcohol mixed solution is beneficial to improving the ability of fibers to enrich molecules, promoting the formation of spindle-shaped structures, and thus improving the adsorption efficiency of collagen / polyvinyl alcohol-loaded enzyme nanofibers.

[0020] (2) The preparation method provided by the present invention is simple and convenient, and the nanofibers prepared by the spinning technology are spindle-shaped, contain rich hydrogen bonds, have the advantages of large specific surface area, and adjustable fiber diameter.

[0021] (3) The collagen / polyvinyl alcohol enzyme-loaded nanofibers prepared by the present invention adsorb Ni 2+Both physical adsorption and chemical adsorption exist in the process, and physical adsorption plays a major role in accelerating the adsorption rate. The hydrogen bond force and van der Waals force generated between the enzyme and the adsorbed ions enhance the adsorption effect, increasing the adsorption capacity while retaining the enzyme activity.

[0022] (4) The collagen / polyvinyl alcohol enzyme-loaded nanofibers prepared by the present invention have a very fast adsorption efficiency in the initial stage of adsorption. As the adsorption time increases, the adsorption sites tend to be saturated, the adsorption rate slowly decreases, and the adsorption equilibrium is reached after about 12 hours of adsorption. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 The SEM images of the nanofibers prepared in Examples 1 to 3 and Comparative Example 1 are shown;

[0024] Figure 2 The SEM images of the nanofibers prepared in Examples 1 to 3 before and after adsorption;

[0025] Figure 3 The infrared spectra of the nanofibers prepared in Examples 1 to 3 and Comparative Example 1 are shown;

[0026] Figure 4 This is a test chart of the enzyme activity retention rate of the nanofibers prepared in Examples 1 to 3 and Comparative Example 1;

[0027] Figure 5 This is a comparative curve diagram of the adsorption performance of the nanofibers prepared in Examples 1 to 3 and Comparative Example 1;

[0028] Figure 6 The graph is a comparison of the adsorption performance of the nanofibers prepared in Examples 1 to 3 and Comparative Example 1 at different adsorption times;

[0029] Figure 7 The nanofibers prepared in Examples 1 to 3 and Comparative Example 1 were used to adsorb Ni 2+ Conductivity test diagram of post-ion solution;

[0030] Figure 8 (a) is Ni 2+ Pseudo-first-order adsorption model, (b) Ni 2+ Pesudo-second-order model of adsorption. DETAILED DESCRIPTION

[0031] The present invention provides a method for preparing collagen / polyvinyl alcohol-loaded enzyme nanofibers, comprising the following steps:

[0032] (1) mixing the collagen solution, the enzyme solution and the polyvinyl alcohol solution in sequence to obtain a spinning solution;

[0033] (2) The spinning solution is subjected to spinning treatment to obtain collagen / polyvinyl alcohol enzyme-loaded nanofibers.

[0034] In the present invention, in step (1), the concentration of the collagen solution is 5 to 15 wt%, preferably 6 to 14 wt%, and more preferably 7 to 13 wt%.

[0035] When preparing a collagen solution with a concentration of 5 to 15 wt% in the present invention, it is preferred to add 5 to 15 g of collagen to a certain amount of deionized water and stir. The stirring temperature is 15 to 35° C., preferably 20 to 30° C., and more preferably 25° C.; the stirring time is 0.5 to 1.5 h, preferably 1 h; and the stirring speed is 500 to 600 r / min, preferably 520 to 580 r / min, and more preferably 550 r / min.

[0036] In the present invention, in step (1), the concentration of the polyvinyl alcohol solution is 5 to 15 wt %, preferably 7 to 13 wt %, and more preferably 9 to 11 wt %.

[0037] When preparing a polyvinyl alcohol solution with a concentration of 5 to 15 wt% in the present invention, preferably 5 to 15 g of polyvinyl alcohol is added to a certain amount of deionized water and stirred. The stirring temperature is 75 to 95° C., preferably 80 to 90° C., and more preferably 85° C.; the stirring time is 0.5 to 1.5 h, preferably 1 h; and the stirring speed is 500 to 600 r / min, preferably 520 to 580 r / min, and more preferably 550 r / min.

[0038] In the present invention, in step (1), the concentration of the enzyme solution is 0.01 to 0.05 g / mL, preferably 0.02 to 0.04 g / mL, and more preferably 0.02 g / mL.

[0039] In the present invention, the collagen used is type I collagen produced by Shanghai Yuanye Biotechnology Co., Ltd., and the polyvinyl alcohol is polyvinyl alcohol model 117 produced by Kuraray Co., Ltd. of Japan.

[0040] The present invention does not specifically limit the type of the enzyme, and those skilled in the art can select commercially available oxidoreductases, transferases, hydrolases, isomerases, lyases, and ligases as needed. In the present invention, xylanase is preferably used.

[0041] In the present invention, in step (1), the temperature for mixing the collagen solution and the polyvinyl alcohol solution is 15 to 35°C, preferably 20 to 30°C, and more preferably 25°C; the mixing time is 10 to 20 min, preferably 12 to 18 min, and more preferably 15 min; and the mixing speed is 500 to 600 r / min, preferably 520 to 580 r / min, and more preferably 550 / min.

[0042] In the present invention, in step (1), the temperature for mixing the enzyme solution and the polyvinyl alcohol solution is 15-35°C, preferably 20-30°C, and more preferably 25°C; the mixing time is 0.5-2h, preferably 1-1.5h, and more preferably 1.3h; and the mixing speed is 500-600r / min, preferably 520-580r / min, and more preferably 550r / min.

[0043] In the present invention, in step (1), the volume ratio of the collagen solution, the polyvinyl alcohol solution and the enzyme solution is 0.1-7:3-10:2-10, preferably 1-6:4-9:4-8, and more preferably 2-5:5-8:6.

[0044] In the present invention, in step (2), the process parameters of the spinning treatment are: the needle diameter of the syringe is 0.7 to 0.9 mm, preferably 0.8 mm; the horizontal distance from the receiving device is 10 to 15 cm, preferably 11 to 14 cm, and more preferably 12 to 13 cm; the perfusion speed is 0.5 to 1.5 mL / h, preferably 0.8 to 1.2 mL / h, and more preferably 1 mL / h; the time is 8 to 12 h, preferably 9 to 11 h, and more preferably 10 h; the voltage is 15 to 25 kV, preferably 17 to 23 kV, and more preferably 20 kV.

[0045] The invention provides a collagen / polyvinyl alcohol enzyme-loaded nanofiber.

[0046] The present invention provides a collagen / polyvinyl alcohol enzyme-loaded nanofiber for adsorbing Ni in wastewater treatment. 2+ application.

[0047] The technical solutions provided by the present invention are described in detail below with reference to the embodiments, but they should not be construed as limiting the scope of protection of the present invention.

[0048] Example 1

[0049] 5 mL of a 10 wt% collagen solution and 5 mL of a 10 wt% polyvinyl alcohol solution were mixed at 30° C., at a mixing speed of 550 r / min, and for 10 minutes to obtain a collagen / polyvinyl alcohol mixed solution. 2 mL of a 0.02 g / mL xylanase solution was then added and mixed at 30° C., at a mixing speed of 550 r / min, and for 10 minutes to obtain a spinning solution. The spinning solution was injected into a syringe with a needle diameter of 0.8 mm and excess bubbles were expelled. The syringe was then fixed to a micro-injection pump, a receiving device was installed, and the horizontal distance between the needle and the receiving device was 12 cm. The perfusion rate was 1.0 mL / h for 10 hours, and spinning was performed at a voltage of 20 kV to obtain collagen / polyvinyl alcohol-loaded xylanase nanofibers.

[0050] Example 2

[0051] 7 mL of a 15 wt% collagen solution was mixed with 10 mL of a 5 wt% polyvinyl alcohol solution at 35° C., at a mixing speed of 600 r / min, for 15 minutes to obtain a collagen / polyvinyl alcohol mixed solution. 4 mL of a 0.02 g / mL xylanase solution was then added and mixed at 15° C., at a mixing speed of 500 r / min, for 20 minutes to obtain a spinning solution. The spinning solution was injected into a syringe with a needle diameter of 0.9 mm and excess bubbles were expelled. The syringe was then fixed to a micro-injection pump, a receiving device was installed, the horizontal distance between the needle and the receiving device was 10 cm, the perfusion rate was 1.5 mL / h, the time was 12 hours, and spinning was performed at a voltage of 25 kV to obtain collagen / polyvinyl alcohol loaded xylanase nanofibers.

[0052] Example 3

[0053] 1 mL of a 5 wt% collagen solution was mixed with 3 mL of a 15 wt% polyvinyl alcohol solution at 15° C., at a mixing speed of 500 r / min, for 20 minutes to obtain a collagen / polyvinyl alcohol mixed solution. 6 mL of a 0.02 g / mL xylanase solution was then added and mixed at 20° C., at a mixing speed of 600 r / min, for 15 minutes to obtain a spinning solution. The spinning solution was injected into a syringe with a needle diameter of 0.7 mm and excess bubbles were expelled. The syringe was then fixed to a micro-injection pump, a receiving device was installed, and the horizontal distance between the needle and the receiving device was 15 cm. The perfusion rate was 1.2 mL / h for 8 hours, and spinning was performed at a voltage of 15 kV to obtain collagen / polyvinyl alcohol-loaded xylanase nanofibers.

[0054] Example 4

[0055] 5 mL of a 10 wt% collagen solution and 5 mL of a 10 wt% polyvinyl alcohol solution were mixed at 30° C., at a mixing speed of 550 r / min, and for 10 minutes to obtain a collagen / polyvinyl alcohol mixed solution. 6 mL of a 0.01 g / mL xylanase solution was then added and mixed at 30° C., at a mixing speed of 550 r / min, and for 10 minutes to obtain a spinning solution. The spinning solution was injected into a syringe with a needle diameter of 0.8 mm and excess bubbles were expelled. The syringe was then fixed to a micro-injection pump, a receiving device was installed, and the horizontal distance between the needle and the receiving device was 12 cm. The perfusion rate was 1.0 mL / h for 10 hours, and spinning was performed at a voltage of 20 kV to obtain collagen / polyvinyl alcohol loaded xylanase nanofibers.

[0056] Example 5

[0057] 5 mL of a 10 wt% collagen solution and 5 mL of a 10 wt% polyvinyl alcohol solution were mixed at 30° C., at a mixing speed of 550 r / min, and for 10 minutes to obtain a collagen / polyvinyl alcohol mixed solution. 6 mL of a 0.05 g / mL xylanase solution was then added and mixed at 30° C., at a mixing speed of 550 r / min, and for 10 minutes to obtain a spinning solution. The spinning solution was injected into a syringe with a needle diameter of 0.8 mm and excess bubbles were expelled. The syringe was then fixed to a micro-injection pump, a receiving device was installed, and the horizontal distance between the needle and the receiving device was 12 cm. The perfusion rate was 1.0 mL / h for 10 hours, and spinning was performed at a voltage of 20 kV to obtain collagen / polyvinyl alcohol-loaded xylanase nanofibers.

[0058] Comparative Example 1

[0059] The only difference between Comparative Example 1 and Example 1 is that no xylanase solution was added, and other operations and technical parameters were exactly the same.

[0060] Performance Verification

[0061] 1. Scanning electron microscope test

[0062] First, the nanofibers obtained in Examples 1-3 and Comparative Example 1 were used as samples. Scanning electron microscopy (QuantaFEG2500, manufactured by PEI, USA) was used to observe the fiber structure of the nanofibers and whether there were adhesion, breakage, and beading between the fibers. Then, the nanofibers obtained in Examples 1-3 and Comparative Example 1 were subjected to adsorption (both physical and chemical adsorption occurred, with physical adsorption playing a primary role), freeze-dried, and then observed using a scanning electron microscope (SEM). The specific operation was as follows: the samples were attached to a sample stage with conductive adhesive, spray-coated with gold, and then tested under high vacuum at 10 kV.

[0063] The result is as follows Figure 1 、 2 As shown, Figure 1 a corresponds to the microstructure before adsorption of Example 1, b corresponds to the microstructure before adsorption of Example 1, c corresponds to the microstructure before adsorption of Example 2, and d corresponds to the microstructure before adsorption of Example 3; Figure 2 In the figure, a and d correspond to the microstructure before and after adsorption of Example 1, b and e correspond to the microstructure before and after adsorption of Example 2, and c and f correspond to the microstructure before and after adsorption of Example 3.

[0064] The above results indicate that the addition of xylanase significantly alters the microscopic morphology of the nanofibers, as clearly seen in the pre-adsorption SEM images. The previously smooth fibers become non-uniform, and the nanofibers with varying levels of xylanase exhibit varying degrees of spindle-shaped structures, likely due to the uneven distribution of xylanase within the nanofibers. Xylanase has a certain solubility in water. When dissolved in water, hydrogen bonds may form between the xylanase and polyvinyl alcohol, increasing the fibers' ability to accumulate molecules and resulting in the spindle-shaped structure.

[0065] After the adsorbed nanofibers were freeze-dried, SEM images showed that the adsorbed nanofiber membranes were honeycomb-shaped and the fiber diameters were significantly increased. This was because the collagen / polyvinyl alcohol nanofibers were highly hydrophilic and expanded and thickened after combining with the solvent.

[0066] 2. Fourier transform infrared spectroscopy test

[0067] The nanofibers prepared in Examples 1 to 3 and Comparative Example 1 were used as samples and scanned using a Fourier transform infrared spectrometer (FTIR, NicoletiN10MX, manufactured by Nicolet Instruments, Inc., USA) to study the interactions between functional groups in the samples. The samples were mixed with KBr powder at a mass ratio of 1:100 and then pressed into thin sheets. The spectral range was 4000-400 cm -1 , with a resolution of 4cm -1The result is as follows Figure 3 0 mL corresponds to Example 1, 2 mL corresponds to Example 1, 4 mL corresponds to Example 2, and 6 mL corresponds to Example 3.

[0068] Examples 1 to 3 and Comparative Example 1 were performed at 3200 to 3600 cm -1 The broad peak between the two is the stretching vibration peak of -OH, at 2900 cm -1 The characteristic peak near 1650cm -1 The characteristic peak at 1100 cm-1 may be the bending vibration absorption peak of -OH. -1 The peaks at the top and bottom of the graphite column may be the antisymmetric stretching vibration absorption peak of COC. With the addition of xylanase, the peaks at each location gradually weakened. This may be because the addition of xylanase destroyed the connection between collagen and polyvinyl alcohol, but no new chemical bonds were generated, indicating that the addition of xylanase achieved a good blending effect.

[0069] 3. Enzyme activity test

[0070] The nanofibers prepared in Examples 1 to 3 were used as samples, and the enzyme activity retention rate was tested on the spinning solution (free enzyme) before spinning and the nanofibers (immobilized enzyme) after spinning. The results were as follows: Figure 4 As shown, the 2 mL column corresponds to Example 1, the 4 mL column corresponds to Example 2, and the 6 mL column corresponds to Example 3.

[0071] From the above results, we can know that with the increase of xylanase content, the ability of nanofibers to immobilize it is gradually improved, and the highest enzyme activity retention rate can reach 99.65%. A higher enzyme activity retention rate can improve the immobilization of Ni by nanofibers. 2+ The xylanase-immobilized nanofibers prepared by electrospinning can retain a high enzyme activity. This research can provide certain theoretical guidance and reference significance for the future lightweight storage of enzymes.

[0072] 4. Adsorption performance test

[0073] The ICP-OES instrument was used to test. First, standard solutions of nickel with different gradients of ion concentrations of 0, 20, 40, 60, 80 and 100 mg / g were prepared. After testing them in sequence, a standard curve of nickel ion concentration was obtained. Then, appropriate amounts of the heavy metal solutions to be tested before and after adsorption were taken into a centrifuge tube. Each sample was measured three times in a row and the average value was taken. The results were as follows: Figure 5 、 Figure 6 As shown in Tables 1 and 2.

[0074] At the same time, the adsorbed Ni 2+The conductivity test of the ion solution was carried out using the DDS-307 conductivity meter from Shanghai Yueping Scientific Instrument Co., Ltd. Take an appropriate amount of the adsorbed heavy metal ion solution to be tested into a centrifuge tube, immerse the probe in the liquid so that it covers the probe, and read the reading after the reading stabilizes. After three consecutive measurements, take the average value and obtain the result as shown below. Figure 7 As shown in Tables 1 and 2.

[0075] The adsorption method is as follows: 50 mg of the nanofibers prepared in Examples 1 to 3 and Comparative Example 1 were weighed, respectively, and immersed in 50 mL of a 50 mg / L nickel standard solution. After adsorption at a speed of 200 rpm / min at 25°C for a certain period of time, the concentrations of the nickel standard solution and the test solution were measured by ICP, and the adsorption amount was calculated. 2+ After the concentration was determined, the adsorption capacity of the nanofibers was calculated according to the following formula:

[0076]

[0077] q t (mg / g) is the adsorption amount at any time, C0 (mg / L) is the initial ion concentration, C t (mg / L) is the measured ion concentration, V (L) is the volume of the solution, and m (mg) is the mass of the nanofiber.

[0078] Table 1 Adsorption capacity and nickel ion removal rate of nanofibers with different xylanase contents

[0079]

[0080] Table 2 Adsorption capacity and nickel ion removal rate of nanofibers at different adsorption times

[0081]

[0082] From the above results, we can know that Figure 5 It can be seen that with the increase of xylanase content, the collagen / polyvinyl alcohol loaded xylanase nanofibers have a greater effect on Ni 2+ The adsorption capacity of collagen / polyvinyl alcohol nanofibers on Ni 2+ The adsorption performance of Ni was poor, and after 12 h of adsorption, it was only 16.49 mg / g. With the increase of the amount of xylanase solution added, the adsorption of Ni by collagen / polyvinyl alcohol loaded xylanase nanofibers increased. 2+ The adsorption performance of Ni 2+ The adsorption performance reached the maximum, which was 23.99 mg / g. The adsorption efficiency was 45.48% higher than that of collagen / polyvinyl alcohol nanofibers without xylanase. Figure 6 It can be seen that the adsorption equilibrium was reached after 18 h of adsorption, and the adsorption results of collagen / polyvinyl alcohol loaded xylanase nanofibers prepared by adding 4 ml and 6 ml of xylanase solution were very similar.

[0083] The exploration of the adsorption mechanism involves the genetic recombination process of the enzyme. In this process, the plasmid acts as a carrier of the enzyme, the enzyme is introduced into the plasmid, and then the plasmid is introduced into Escherichia coli, and the Escherichia coli is induced to produce xylanase under certain conditions. The plasmid used in the genetic recombination contains a HIS tag, which will bind to the metal nickel. Therefore, in addition to the chelation effect of the original protein on heavy metals, the collagen / polyvinyl alcohol-loaded xylanase nanofibers prepared by the present invention also have the binding effect of the HIS tag in the plasmid on the enzyme. The two effects synergize with each other to improve the Ni 2+ adsorption performance.

[0084] At the same time, the adsorbed Ni 2+ Conductivity test of ion solution. The conductivity reflects the ability of aqueous solution to conduct electric current and is often used to infer the concentration of ions in water. Figure 7 It can be seen that the conductivity test curve is consistent with Figure 5 、 Figure 6 The adsorption results obtained are basically consistent.

[0085] 5. Kinetic analysis

[0086] The effects of collagen / polyvinyl alcohol nanofibers on Ni 2+ The adsorption test results were fitted by pseudo-first-order and pseudo-second-order equations as shown in Figure 8 The fitting data are shown in Table 3.

[0087] Table 3 Fitting data of nickel ion adsorption results of nanofibers

[0088]

[0089] From the above results, we can know that R2 in the Pseudo-first-order model 2 Greater than R1 2 , indicating that both physical adsorption and chemical adsorption exist in the adsorption process of collagen / polyvinyl alcohol-loaded xylanase nanofibers with different amounts of xylanase added, and chemical adsorption plays a major role.

[0090] By comparing the k1 value of the Pseudo-first-order model, it can be found that the k1 value of the nanofibers with a xylanase solution added in an amount of 2 mL is greater than the k1 value of the nanofibers without xylanase, indicating that the physical adsorption rate is accelerated after the addition of xylanase, and the hydrogen bond force and van der Waals force generated between xylanase and the adsorbed ions enhance the adsorption effect and increase the adsorption capacity.

[0091] The collagen / polyvinyl alcohol loaded xylanase nanofibers prepared in Examples 4 and 5 also have a negative impact on Ni 2+ Has good adsorption effect.

[0092] As can be seen from the above embodiments, the present invention provides a collagen / polyvinyl alcohol loaded enzyme nanofiber and its preparation method and application. The present invention first mixes the collagen solution and the enzyme solution with the polyvinyl alcohol solution in sequence to obtain a spinning solution, and then spins the spinning solution to obtain the collagen / polyvinyl alcohol loaded enzyme nanofiber. The present invention adds enzymes to the spinning solution, which is beneficial to improving the ability of the fiber to enrich molecules, promotes the formation of spindle-shaped structures, and improves the adsorption efficiency of the collagen / polyvinyl alcohol loaded enzyme nanofiber. The obtained spindle-shaped nanofiber contains rich hydrogen bonds, has the advantages of a large specific surface area, and adjustable fiber diameter, and has good adsorption performance in Ni adsorption. 2+ Both physical adsorption and chemical adsorption exist in the process, and physical adsorption plays a major role in accelerating the adsorption rate. The hydrogen bond force and van der Waals force generated between the enzyme and the adsorbed ions enhance the adsorption effect, increasing the adsorption capacity while retaining the enzyme activity.

[0093] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present invention. These improvements and modifications should also be regarded as within the scope of protection of the present invention.

Claims

1. A collagen / polyvinyl alcohol loaded enzyme nanofiber for Ni adsorption in wastewater treatment 2+ The application is characterized in that The preparation method of the collagen / polyvinyl alcohol enzyme-loaded nanofibers comprises the following steps: (1) mixing the collagen solution, the enzyme solution and the polyvinyl alcohol solution in sequence to obtain a spinning solution; (2) spinning the spinning solution to obtain collagen / polyvinyl alcohol-loaded enzyme nanofibers; The enzyme solution is a xylanase solution; In the step (1), the concentration of the enzyme solution is 0.01 to 0.05 g / mL; In the step (1), the volume ratio of the collagen solution, the polyvinyl alcohol solution and the enzyme solution is 0.1-7:3-10:2-10.

2. The collagen / polyvinyl alcohol enzyme-loaded nanofiber according to claim 1 is used to adsorb Ni in wastewater treatment. 2+ The application is characterized in that In the step (1), the concentration of the collagen solution is 5 to 15 wt%.

3. The collagen / polyvinyl alcohol enzyme-loaded nanofiber according to claim 2 is used to adsorb Ni in wastewater treatment. 2+ The application is characterized in that In the step (1), the concentration of the polyvinyl alcohol solution is 5 to 15 wt%.

4. The collagen / polyvinyl alcohol enzyme-loaded nanofiber according to any one of claims 1 to 3 is used to adsorb Ni in wastewater treatment. 2+ The application is characterized in that In the step (1), the temperature for mixing the collagen solution and the polyvinyl alcohol solution is 15 to 35° C., the mixing time is 10 to 20 minutes, and the mixing speed is 500 to 600 r / min.

5. The collagen / polyvinyl alcohol enzyme-loaded nanofiber according to claim 4 is used to adsorb Ni in wastewater treatment. 2+ The application is characterized in that In the step (1), the temperature for mixing the enzyme solution and the polyvinyl alcohol solution is 15-35° C., the mixing time is 0.5-2 h, and the mixing speed is 500-600 r / min.

6. The collagen / polyvinyl alcohol loaded enzyme nanofiber according to claim 1 is used to adsorb Ni in wastewater treatment. 2+ The application is characterized in that In the step (2), the process parameters of the spinning treatment are: the needle diameter of the syringe is 0.7-0.9 mm, the horizontal distance from the receiving device is 10-15 cm, the perfusion speed is 0.5-1.5 mL / h, the time is 8-12 h, and the voltage is 15-25 kV.

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