CN108411401B

CN108411401B - Nano-selenium composite fiber and preparation method thereof

Info

Publication number: CN108411401B
Application number: CN201810282865.XA
Authority: CN
Inventors: 王红艳; 朱光
Original assignee: Suzhou University
Current assignee: Jiangsu Yize Water Supply And Drainage Equipment Co ltd
Priority date: 2018-04-02
Filing date: 2018-04-02
Publication date: 2020-10-16
Anticipated expiration: 2038-04-02
Also published as: CN108411401A

Abstract

The invention discloses a preparation method of nano-selenium composite fiber, which comprises the steps of firstly, adopting sodium alginate as a template agent, and reducing selenious acid by using ascorbic acid as a reducing agent in a water bath to prepare nano-selenium; and then dispersing the nano-selenium into a mixed solution of polyvinyl alcohol and sodium alginate, and preparing the nano-selenium composite fiber by adopting an electrostatic spinning technology. The invention has the advantages that: the method for preparing the nano-selenium has low cost and simple operation and is suitable for popularization; the electrostatic spinning technology can be used for simply and effectively preparing the nano-fiber, and the prepared nano-fiber has large specific surface area, high porosity and strong adsorbability.

Description

Nano-selenium composite fiber and preparation method thereof

Technical Field

The invention relates to the technical field of nano materials, in particular to nano selenium composite fiber and a preparation method thereof.

Background

Selenium (Se) is one of indispensable trace nonmetallic elements of human body, and researches show that the selenium (Se) has wide physiological functions and pharmacological actions such as oxidation resistance, antiviral action, immunologic function, anticancer action and the like. However, selenium is extremely narrow in the range between the nutritional dose and the toxic dose of the human body, and is difficult to be used effectively, so people are keen to develop a safe and efficient selenium product. Selenium is an important semiconductor material, has the characteristics of excellent one-way conductivity, high photoconductivity, high thermoelectric effect, piezoelectric effect and the like, and is widely applied to the photoelectronic fields of pressure sensor production, solar cells, xerographic equipment, photo exposure meters and the like^[7]. Selenium can be roughly divided into two forms of organic selenium and inorganic selenium in nature, both of which can be absorbed and utilized by organisms, but organic selenium is slowly absorbed, and inorganic selenium is poor in safety. In recent research, nano-selenium is found. Compared with other forms of selenium, the nano selenium has the remarkable characteristics of high safety and high biological activity. Because the application of the method in the fields of food, medical treatment and the like is increasingly wide, the exploration of a safe and simple preparation method has important practical significance. The main methods for preparing the nano-selenium at present comprise a surfactant method, a solid phase method, a sol method and the like.

The nano selenium can be used for preparing selenium-containing fiber, and the selenium-containing fiber has wide application prospect and can be applied to the fields of selenium supplement for organisms, photoelectron and the like. Polyvinyl alcohol (PVA) is a non-toxic and pollution-free hydrophilic polymer, has stable chemical properties and good biocompatibility. Sodium Alginate (SA) is a polysaccharide polymer extracted from seaweed, and can form viscous liquid after being dissolved in water, so that a microenvironment with good emulsification, suspension and stabilization effects is formed. The spinning solution can be prepared by mixing the sodium alginate and the polyvinyl alcohol aqueous solution, and electrostatic spinning is carried out. Therefore, the polyvinyl alcohol/sodium alginate/nano-selenium are effectively compounded to prepare the composite material with excellent performance.

Disclosure of Invention

The invention aims to solve the technical problem of providing the nano selenium composite fiber with large specific surface area, high porosity and strong adsorbability and the preparation method thereof, and the preparation method has low cost, simple operation and suitability for popularization.

The invention solves the technical problems through the following technical scheme:

firstly, sodium alginate is used as a template agent, and ascorbic acid is used as a reducing agent in water bath to reduce selenious acid to prepare nano-selenium; then dispersing the nano selenium into a mixed solution of polyvinyl alcohol and sodium alginate, and preparing the polyvinyl alcohol/sodium alginate/nano selenium (PVA/SA/Se) composite fiber by adopting an electrostatic spinning technology, wherein the method specifically comprises the following steps:

(1) preparing nano selenium: dropwise adding a sodium alginate solution into an ascorbic acid solution, uniformly mixing, adding a selenious acid solution, uniformly mixing, heating to 40-70 ℃, preferably 60 ℃, reacting for 30-60 min, preferably 30min, and washing after the reaction is finished to obtain nano-selenium;

(2) preparing a spinning solution: uniformly mixing a polyvinyl alcohol solution and a sodium alginate solution, adding the nano-selenium prepared in the step (1), stirring at room temperature until the nano-selenium is uniform, standing for defoaming, and preparing a spinning solution;

(3) preparing a composite fiber: and (3) processing the spinning solution prepared in the step (2) by using an electrostatic spinning machine to prepare the polyvinyl alcohol/sodium alginate/nano selenium composite fiber.

Preferably, in the step (1), the molar ratio of the ascorbic acid to the selenious acid is 4:1, and 1-500 μ g of sodium alginate is dropwise added to 1mol of the ascorbic acid.

Preferably, in the step (1), the washing process is repeated by using deionized water and absolute ethyl alcohol.

Preferably, in the step (2), the mass of the nano selenium in the spinning solution is 5% to 15%, more preferably 10% of the mass of the water.

Preferably, in the step (2), the mass ratio of the polyvinyl alcohol to the sodium alginate is 1-4: 1.

Preferably, in step (3), the working parameters of the electrostatic spinning machine are: the receiving distance is 15-20 cm, the flow rate is 0.01-0.1 mm/min, and the voltage is 20-25 kV; more preferably, the receiving distance is 17cm, the flow rate is 0.05mm/min and the voltage is 22 kV.

On the other hand, the polyvinyl alcohol/sodium alginate/nano selenium composite fiber prepared by the preparation method is also provided.

Compared with the prior art, the invention has the following advantages: the method uses the ascorbic acid as a reducing agent and the sodium alginate as a template agent, utilizes low-temperature water bath to quickly prepare the nano-selenium, and has the advantages of low cost, simple operation, suitability for popularization and the like; the nano-fiber can be simply and effectively prepared by utilizing the electrostatic spinning technology, and the prepared nano-fiber has large specific surface area, high porosity and strong adsorbability; in addition, the selenium-containing fiber can be widely applied to the fields of selenium supplement for organisms, photoelectron and the like.

Drawings

FIG. 1 is a graph showing the effect of the amount of sodium alginate as a surfactant on the particle size of nano-selenium;

FIG. 2 is a graph showing the effect of reaction time on the particle size of nano-selenium;

FIG. 3 is a graph showing the effect of reaction temperature on the particle size of nano-selenium;

FIG. 4 is a scanning electron micrograph of a nano-selenium composite fiber;

FIG. 5 is an X-ray diffraction pattern of a nano-selenium composite fiber;

FIG. 6 is an infrared spectrum of a nano-selenium composite fiber.

Detailed Description

The following examples are given for the detailed implementation and specific operation of the present invention, but the scope of the present invention is not limited to the following examples.

Instruments and medicines used in the invention are commonly used in laboratories, wherein selenium dioxide (AR, Shanghai Crystal pure science and technology Limited); ascorbic acid (AR, shanghai shoyun chemical ltd); sodium alginate (AR, chemical agents ltd of the national drug group); polyvinyl alcohol (GR, chemical Co., Ltd., national drug group).

Example 1

(1) Preparing nano selenium:

accurately weighing 5.548g of selenium dioxide powder, dissolving in deionized water, and fixing the volume to 500mL to obtain selenious acid solution with the concentration of 0.1 mol/L; weighing 8.800g of ascorbic acid, and fixing the volume to 500mL by deionized water to prepare an ascorbic acid solution with the concentration of 0.1 mol/L; weighing 0.100g of sodium alginate, dissolving with deionized water, magnetically stirring at normal temperature for 30min, and diluting to 200mL to obtain a sodium alginate solution with a concentration of 0.5 g/L.

Sucking 20mL of 0.1mol/L ascorbic acid solution, injecting into a beaker, dropwise adding 1.0mL of 0.5g/L (500 mu g) surfactant sodium alginate solution, shaking uniformly, then adding 5mL of 0.1mol/L selenious acid solution, changing the solution from colorless to red immediately, shaking uniformly, placing in a constant-temperature water bath kettle at 60 ℃ for heating for 30min, reducing the selenic acid by using the ascorbic acid, dispersing the surfactant sodium alginate in the solution as a template agent, and after the reaction is finished, washing the product for multiple times by using deionized water and absolute ethyl alcohol to prepare the nano-selenium.

(2) Preparing a spinning solution:

weighing 1.0g of polyvinyl alcohol (PVA) and adding the PVA into a beaker containing 10mL of deionized water, heating to 90 ℃, mechanically stirring until the PVA is completely dissolved, and preparing into a uniform solution; 0.5g of Sodium Alginate (SA) is weighed into a beaker containing 10mL of deionized water, and stirred at room temperature until the sodium alginate is completely dissolved, so as to prepare a uniform sodium alginate solution.

Mixing 10mL of PVA and 10mL of SA solution, stirring at room temperature until the mixture is uniformly mixed, adding the prepared nano-selenium into the solution to prepare a solution with the nano-selenium mass ratio (mass ratio relative to water) of 10%, stirring at room temperature until the solution is uniform, standing for defoaming, and preparing the spinning solution.

(3) Preparing a composite fiber:

the prepared spinning solution is processed by an electrostatic spinning machine, and the method specifically comprises the steps of using an injector with the capacity of 20mL, quantitatively extracting the prepared spinning solution, connecting and fixing a metal needle head and the injector, connecting the positive pole of a high-voltage power supply with the metal needle head, connecting the negative pole with a receiving device, collecting fibers by using a grounding aluminum foil arranged in front of the needle head, wherein the distance between the aluminum foil and the needle head is 17cm, the injection rate of the electrostatic spinning machine is 0.05mm/min, and the voltage is 22 kV.

Examples 2 to 4

The method of example 1 was used to prepare a polyvinyl alcohol/sodium alginate/nano-selenium composite fiber, with the following differences: respectively dropwise adding 0.5, 1.5 and 2.0mL of 0.5g/L sodium alginate solution as a surfactant to prepare the nano-selenium.

Examples 5 to 6

The method of example 1 was used to prepare a polyvinyl alcohol/sodium alginate/nano-selenium composite fiber, with the following differences: heating in a constant temperature water bath kettle at 60 deg.C for 45min and 60min respectively to obtain nanometer selenium.

Examples 7 to 9

The method of example 1 was used to prepare a polyvinyl alcohol/sodium alginate/nano-selenium composite fiber, with the following differences: heating in 40, 50, and 70 deg.C constant temperature water bath respectively for 30min to obtain nanometer selenium.

Examples 10 to 11

A composite fibre was prepared using the method of example 1, with the only difference that: the mass ratio of the nano-selenium (relative to the mass ratio of water) in the prepared spinning solution is 5 percent and 15 percent respectively.

Comparative example 1

The method of example 1 is used to prepare a polyvinyl alcohol/sodium alginate composite fiber, with the difference that: and dropwise adding 0mL0.5g/L of sodium alginate solution serving as a surfactant to prepare the nano-selenium.

Comparative examples 2 to 3

The method of example 1 was used to prepare a polyvinyl alcohol/sodium alginate/nano-selenium composite fiber, with the following differences: heating in a constant temperature water bath kettle at 60 deg.C for 15min and 75min respectively to obtain nanometer selenium.

Comparative example 4

The method of example 1 was used to prepare a polyvinyl alcohol/sodium alginate/nano-selenium composite fiber, with the following differences: heating in 80 deg.C constant temperature water bath for 30min to obtain nanometer selenium.

Comparative examples 5 to 6

A composite fibre was prepared using the method of example 1, with the only difference that: the mass ratio of the nano-selenium (relative to the mass ratio of water) in the prepared spinning solution is 0% and 20% respectively.

Example 12

Characterization test: performing particle size analysis and detection on the nano-selenium prepared in the above examples 1-9 and comparative examples 1-4 after repeated ultrasonic cleaning, wherein the examples 1-4 and comparative example 1 are the influence of the amount of sodium alginate as a surfactant on the particle size of the nano-selenium, and the result is shown in fig. 1; examples 1, 5-6 and comparative examples 2-3 are the effect of reaction time on the particle size of nano-selenium, and the results are shown in fig. 2; examples 1, 7-9 and comparative example 4 are the effect of reaction temperature on the particle size of nano-selenium, and the results are shown in fig. 3.

The morphology of the nano-selenium composite fibers prepared in example 1 and comparative examples 5 to 6 was observed by using a Scanning Electron Microscope (SEM), and the result is shown in fig. 4; the composite fibers prepared in example 1 and comparative examples 5 to 6 were analyzed for the addition of selenium by X-ray diffraction (XRD), and the results are shown in fig. 5; the infrared spectroscopic analysis was performed on the composite fibers prepared in example 1 and comparative example 5, and the results are shown in FIG. 6.

In comparative example 1, no template agent sodium alginate was added, and the solution turned red after the addition of selenious acid, but the product was very unstable and the red color disappeared quickly; in example 2, 0.5mL of sodium alginate solution is added, sodium alginate is dispersed in the solution and used as a template to control the growth of particles, the product is a red solution, in the preparation process, active groups in the template sodium alginate and molecules of a reactant are contacted and collided with each other, so that the reaction speed is slowed down, selenium with a smaller particle size is obtained, the particle size of nanoparticles is shown in fig. 1(a), the average particle size of nano-selenium is 1.347nm, and the occupied proportion is about 1nm at most; in example 1, 1.0mL of sodium alginate solution was added, the particle size of the nano-selenium particles was as shown in fig. 1(B), the particle size of the nano-selenium particles was increased, the average particle size was 4.021nm, it can be seen that the size of the nanoparticles was relatively uniform, most of them were concentrated around 4nm, because the adsorption and encapsulation effect of the template on the initially formed selenium in the solution was enhanced after the concentration of the template was increased, and the newly formed selenium was forced to deposit on the surface of the original selenium; in example 3, 1.5mL of sodium alginate solution was added, the particle size of the nano-selenium particles was as shown in fig. 1(C), the average particle size was 4.276nm, the nanoparticles were uniform, most of them were concentrated around 4nm, and there was no significant difference from the case of adding 1.0mL of sodium alginate; in example 4, when 2.0mL of sodium alginate solution was added, the particle size of the nano-selenium particles was as shown in FIG. 1(D), the average particle size was 10.295nm, and the proportion of particles having a particle size of about 10nm was large, and it was also seen that the particle size of the nano-selenium particles prepared was significantly increased compared to the previous amount of addition, because the solution viscosity increased due to the increase in sodium alginate concentration and a gel structure appeared.

In comparative example 2, when the reaction time is 15min, the particle size of the nanoparticles is as shown in fig. 2(a), and the average particle size is 0.686nm, it can be seen that the prepared nano-selenium has extremely small particle size, and is not uniformly distributed, and the product is very unstable; in example 1, when the reaction time is 30min, the particle size of the nanoparticles is as shown in fig. 2(B), the average particle size is 4.336nm, and the particle size is larger and more uniform than that of the nano-selenium particles prepared under the condition of 15 min; in example 5, when the reaction time was 45min, the particle size of the nanoparticles was as shown in fig. 2(C), the average particle size was 4.257nm, and the distribution was relatively uniform; in example 6, when the reaction time was 60min, the reaction product turned from red to reddish brown, the particle size of the nanoparticles was as shown in FIG. 2(D), and the average particle size was 4.658 nm; in comparative example 3, when the reaction time was 75min, at which time the color of the product was dark brown, the particle size of the nanoparticles was as shown in fig. 2(E), the average particle size was 12.275nm, and the particle size was significantly increased because the surface energy of the nano-selenium was high and the particles adjacent to each other and in uniform orientation were easily adsorbed to each other after the reaction time was extended.

As can be seen from FIG. 3, the average particle size of the nano-selenium particles obtained at 40 ℃ is 2.499nm (FIG. 3(A)), at 50 ℃ is 2.414.nm (FIG. 3(B)), at 60 ℃ is 2.085nm (FIG. 3(C)), and at 70 ℃ is 3.936nm (FIG. 3(D)), which are similar in particle size, and at 60 ℃ is the most uniform in particle size distribution, and at 80 ℃ is 13.463nm (FIG. 3(E)), which is a significant increase, and at lower temperatures the nano-selenium particles are more uniform in size and less prone to agglomeration; with the rise of the temperature, the color of the solution gradually becomes dark, changes from red to reddish brown and then changes to dark brown, because the reaction rate becomes fast at high temperature, the thermal motion of the molecules destroys the uniform electrostatic attraction among the original molecules, and the irregular directional growth of selenium is induced, so that the selenium is agglomerated.

As can be seen from FIG. 4(A), in comparative example 5, the pure PVA/SA fibers have uniform thickness and diameter of about 2 μm without adding nano-selenium; when the selenium is added by 10 percent, the PVA/SA/Se blended fiber is shown in figure 4(B), and the obvious change of the appearance is clearly seen compared with figure 4(A), the fiber is thinned, beaded fibers begin to appear, and the thickness is more uniform; when the selenium content was 20% by mass, the fibers became very fine and irregular as shown in FIG. 4(C), and many beaded fibers appeared with uneven thickness. The diameter of the fibers decreased with increasing selenium content because the addition of selenium changed the dope concentration, viscosity, and also surface tension and charge density.

As can be seen from FIG. 5, the diffraction peaks changed after the addition of selenium compared to the pure PVA/SA fibers, and the diffraction data was in agreement with that of selenium on JCPDS cards (No:38-0768), thereby judging that the nano-selenium was successfully added to the blended fibers.

As shown in fig. 6, it can be seen that the infrared peak pattern is not significantly changed when 10% selenium is added (fig. 6b) compared with that when no nano-selenium is added (fig. 6a), indicating that no new chemical bond is formed, and the selenium, sodium alginate and polyvinyl alcohol are merely physically mixed without destroying the molecular structure.

The above description is only for the purpose of illustrating the preferred embodiments of the present invention and is not to be construed as limiting the invention, and any modifications, equivalents and improvements made within the spirit and principle of the present invention are intended to be included within the scope of the present invention.

Claims

1. A preparation method of nano-selenium composite fiber is characterized in that firstly sodium alginate is adopted as a template agent, and ascorbic acid is adopted as a reducing agent in a water bath to reduce selenious acid to prepare nano-selenium; then dispersing the nano-selenium into a mixed solution of polyvinyl alcohol and sodium alginate, and preparing the nano-selenium composite fiber by adopting an electrostatic spinning technology, wherein the method specifically comprises the following steps:

(1) preparing nano selenium: dropwise adding a sodium alginate solution into an ascorbic acid solution, uniformly mixing, adding a selenious acid solution, uniformly mixing, heating to 40-70 ℃, reacting for 30-60 min, and washing after the reaction is finished to prepare nano-selenium;

(3) preparing a composite fiber: processing the spinning solution prepared in the step (2) by using an electrostatic spinning machine to prepare nano selenium composite fibers;

in the step (1), the molar ratio of ascorbic acid to selenious acid is 4:1, and 1-500 mug of sodium alginate is dripped into each 1mol of ascorbic acid;

in the step (2), the mass of the nano selenium in the spinning solution is 5-15% of the mass of water;

in the step (2), the mass ratio of the polyvinyl alcohol to the sodium alginate is 1-4: 1.

2. The method of preparing nano-selenium composite fiber according to claim 1, wherein in the step (1), the washing process is multiple washing with deionized water and absolute ethyl alcohol.

3. The method of preparing nano-selenium composite fiber according to claim 1, wherein in the step (3), the working parameters of the electrospinning machine are: the receiving distance is 15-20 cm, the flow rate is 0.01-0.1 mm/min, and the voltage is 20-25 kV.

4. A nano selenium composite fiber prepared by the preparation method of any one of claims 1 to 3.