CN106735292A - A kind of preparation method of starch/silver nanoparticle compound particle - Google Patents

Abstract

The present invention provides a kind of preparation method of starch/silver compound particle, the described method comprises the following steps：(1) silver-colored precursor water solution is provided；(2) starch granules aqueous dispersions are provided；(3) reducing agent aqueous solution is provided；(4) the starch granules aqueous dispersions are well mixed with the silver-colored precursor water solution, and vibrate or stir at least 30 minutes；(5) reducing agent aqueous solution is added to the mixture of gained in step (4), the pH of regulation system to 3~13, and reacted at a temperature of 25~60 DEG C, then obtain starch/silver nanoparticle compound particle solid powder through being centrifuged, washing and dry.The inventive method is that this can further simplify the preparation process of supported silver nano-particle, it is easy to industrialize without carrying out any surface modification, modified and functionalization to starch granules.

Description

A kind of preparation method of starch/silver nanocomposite particle

technical field

The invention belongs to the field of functional organic/inorganic hybrid nanomaterials, and in particular relates to a preparation method of starch/silver composite particles.

technical background

Due to its extremely small size and large specific surface area, silver nanoparticles have completely different physical and chemical properties compared with bulk metallic silver, so they have attracted more and more attention from scientists. In recent years, silver nanoparticles have been widely used in biosensors, catalysis, antibacterial, and surface-enhanced spectroscopy. However, due to the large surface energy, silver nanoparticles are prone to irreversible aggregation and reduce or even lose the relevant activity. In order to solve the above problems, it has become an effective means to fix silver nanoparticles on the carrier and prepare nanocomposites containing silver nanoparticles.

So far, the carriers used to load silver nanoparticles mainly include inorganic substances and synthetic polymers. In recent years, natural polymer carriers with low cost, good biocompatibility and wide sources have attracted extensive attention. Among them, the researchers' attention is mainly focused on the cellulose carrier. Although the successful loading of silver nanoparticles has been achieved, harsh reaction conditions are required in most reactions or surface pretreatment of the cellulose carrier is necessary. In order to effectively improve its dispersion state in the medium to improve the loading of silver nanoparticles.

For example, H. Liu et al. used carboxyl-modified cellulose nanocrystals as a natural polymer carrier, and used electrostatic interaction to make positively charged silver ions adsorb to the surface of the aforementioned carrier, and then used in-situ reduction to make the silver nanoparticles loaded to the surface of cellulose nanocrystals (see "Preparation of silver nanoparticles on cellulose nanocrystals and the application in electrochemical detection of DNA hybridization", Cellulose, 2011, 18, 67–74). In the method of H. Liu et al., the surface carboxylation of cellulose nanocrystals played a crucial role in the successful preparation of cellulose nanocrystals-supported silver nanoparticles.

Another example, Rezayat et al. synthesized cellulose nanocrystalline composite particles supported by silver, palladium and other noble metal nanoparticles in a subcritical-supercritical _CO atmosphere (see "Green one-step synthesis of catalytically active palladium nanoparticles supported on cellulose nanoparticles" , Acs Sustainable Chemistry & Engineering, 2014, 2, 1241-1250). Specifically, silver and palladium noble metal precursors are mixed with cellulose nanocrystals, placed in an autoclave, and CO ₂ is introduced to synthesize silver and palladium nanoparticles-supported cellulose nanocrystal composites in a high-pressure and high-temperature environment. Particles, wherein, the high temperature and high pressure reaction conditions are an important guarantee for silver and palladium nanoparticles to be loaded on cellulose nanocrystals.

Therefore, since the existing synthesis methods for loading silver nanoparticles on natural polymer carriers are relatively cumbersome and the reaction conditions are relatively harsh, it is still necessary to provide a method for loading silver nanoparticles on natural polymer carriers.

Contents of the invention

Therefore, the object of the present invention is to propose a method for preparing starch/silver nanocomposite particles that is simple to operate, low in production cost, and capable of industrial production.

The purpose of the present invention is achieved through the following technical solutions.

The invention provides a kind of preparation method of starch/silver composite particle, described method comprises the following steps:

(1) providing an aqueous silver precursor solution;

(2) provide starch granule aqueous dispersion;

(3) Provide a reducing agent aqueous solution;

(4) Mix the starch granule aqueous dispersion with the silver precursor aqueous solution evenly, and vibrate or stir for at least 30 minutes;

(5) adding the reducing agent aqueous solution to the mixture obtained in step (4), adjusting the pH of the system to 3-13, and reacting at a temperature of 25-60°C, and then centrifuging, washing and drying to obtain starch /Silver nanocomposite particle solid powder.

Without wishing to be limited by theory, it is believed that the surface of the starch granules in the present invention has a negative charge, while the silver ammonium ion in the silver precursor solution such as the silver ammonia solution in step (1) has a positive charge. During the mixing process, based on the electrostatic interaction, silver ammonium ions will be adsorbed to the surface of starch granules. Then, polyvinylpyrrolidone is added for in-situ reduction to obtain starch/silver nanocomposite particles.

In the preparation process of starch/silver nanocomposite particles, no surface modification and functionalization of starch granules is required, the preparation process is simple and controllable, the source of starch granules is wide and the cost is low, and it is suitable for industrial production.

According to the method provided by the present invention, wherein the silver precursor solution is selected from silver nitrate aqueous solution, triethanolamine silver solution, silver acetate aqueous solution and silver ammonia solution and the like. In a preferred embodiment, the silver precursor solution is a silver ammonia solution.

According to the method provided by the present invention, wherein, the concentration of silver ions in the silver precursor solution is generally not higher than 0.5 mol/liter. In some embodiments, the concentration of silver ions in the silver precursor solution is 0.001-0.2 moles/liter, in some embodiments 0.001-0.02 moles/liter, and in some embodiments 0.01-0.02 moles/liter.

In a preferred embodiment, the silver precursor solution in step (1) is silver ammonia solution, and its concentration is not higher than 0.5 mol/liter. In some embodiments, the concentration of the silver ammonia solution ranges from 0.001 to 0.2 moles/liter, in some embodiments from 0.001 to 0.02 moles/liter, and in some embodiments from 0.01 to 0.02 moles/liter.

In the present invention, the starch granules come from a wide range of sources and can be obtained by means of alkali extraction, acid extraction and enzyme extraction.

In a preferred embodiment, the starch granules can be prepared by alkaline extraction from roots and/or stems of green plants such as potatoes, wheat, tomatoes, sweet potatoes and grain amaranths. In some embodiments, the starch granules are obtained from grain amaranth seeds. In addition, the starch granules used in the present invention can also be purchased directly from the market.

According to the preparation method provided by the present invention, the starch granules are not modified in any way, especially not chemically modified.

According to the preparation method provided by the present invention, the amount of the starch granules used is 1 to 200 times the weight of the silver in the silver precursor solution. In some embodiments, the amount of the starch granules is 1 to 50 times the weight of silver in the silver precursor solution; in some embodiments, it is 1.5 to 10 times the weight of silver in the silver precursor solution; and in some specific embodiments It is 1.75-9.5 times the weight of silver in the silver precursor solution.

According to the preparation method provided by the present invention, wherein the concentration of the aqueous dispersion of starch granules in step (2) is generally not higher than 0.1 g/ml. In some embodiments, the concentration of the aqueous dispersion of starch granules in step (2) is 0.002-0.02 g/ml, in some embodiments 0.005-0.015 g/ml, and in some embodiments 0.01 g/ml .

According to the preparation method provided by the present invention, wherein, the average size of the starch granules is 100 nanometers to 2000 nanometers. In some embodiments, the average size of the starch granules is between 500 nanometers and 1000 nanometers, and in some embodiments, the average size of the starch granules is about 900 nanometers.

According to the preparation method provided by the present invention, wherein, the reducing agent is selected from trisodium citrate, sodium borohydride, potassium borohydride, hydroxylamine hydrochloride, formaldehyde, hydrazine, tannic acid, sodium hypophosphite, polyvinylpyrrolidone, methanol, One or more of ethanol, propanol, ascorbic acid and tetrakis hydroxymethyl phosphorus chloride. In some embodiments, the reducing agent is polyvinylpyrrolidone.

According to the preparation method provided by the present invention, the amount of the reducing agent may be 0.6-600 times the weight of the silver precursor. In some embodiments, the reducing agent can be used in an amount of 0.6-60 times the weight of the silver precursor; in some embodiments, 5-10 times; and in some specific embodiments, 6 times.

In some embodiments, the reducing agent solution in step (3) is an ethanol solution of polyvinylpyrrolidone, and its concentration is not higher than 0.5 g/ml. In some embodiments, the ethanol solution of polyvinylpyrrolidone has a concentration ranging from 0.002 to 0.1 g/ml, in some embodiments from 0.01 to 0.1 g/ml, in some embodiments from 0.01 to 0.02 g g/ml, and in some embodiments 0.01 g/ml.

According to the preparation method provided by the present invention, the time for shaking or stirring in step (4) is 1 to 5 hours, preferably 3 hours.

According to the preparation method provided by the present invention, in step (5), the pH of the mixing system is adjusted to a range of 7-13.

According to the preparation method provided by the present invention, the reaction in step (5) is carried out under shaking or stirring. In some embodiments, the reaction in step (5) is carried out in a shaker.

According to the preparation method provided by the present invention, the reaction temperature in step (5) is preferably 50°C.

According to the preparation method provided by the present invention, the reaction time in step (5) is 12 to 48 hours. In some embodiments, the reaction time in step (5) is preferably 24 hours.

The advantages of the present invention include: (1) starch granules are used as a carrier for the first time to load silver nanoparticles to obtain starch/silver nanocomposite particles; (2) the method of the present invention does not need to carry out any surface modification, modification and Functionalization, for this reason, the preparation process of loaded silver nanoparticles can be further simplified, and it is easy to industrialize; (3) the size and loading capacity of silver nanoparticles on the surface of starch granules can be effectively controlled; (4) starch is an environmentally friendly natural Polymer materials widely exist in the tubers and seeds of most plants in nature, and are cheap and easy to get.

detailed description

The present invention will be further described in detail below in conjunction with specific embodiments, and the given examples are only for clarifying the present invention, not for limiting the scope of the present invention.

Example 1

(1) Extract starch granules by alkaline extraction.

Firstly, select amaranthus seeds as raw materials, grind them into powder with a pulverizer, sieve them, and dry them at 40°C. Next, add 50 grams of dried amaranth seed powder into 150 milliliters of n-hexane, stir for 24 hours, filter, wash, and dry to obtain degreased amaranth seed powder. Finally, the degreased amaranth seed powder was added to 2.5 liters of 0.25% sodium hydroxide solution by mass fraction, stirred for 24 hours, and then filtered with 70, 100, 200, 260, 300 and 400 mesh sieves successively, and the filtrate was passed through Centrifugation, washing with water and ethanol, and drying yielded a powder sample of starch granules.

Scanning electron microscope analysis was used, and the results showed that the average size of the obtained starch granules was about 900 nanometers.

(2) Preparation of silver ammonia solution.

At room temperature, add ammonia water dropwise to 10 milliliters of 1×10 ^-2 mol/liter silver nitrate aqueous solution, observe that the white precipitate produced in the solution just disappears completely, and at this time the concentration of 1×10 ^-2 mol/liter is obtained. liters of silver ammonia solution.

(3) Preparation of starch/silver nanocomposite particles.

At room temperature, 10 ml of starch granule aqueous dispersion with a concentration of 0.01 g/ml was added to the silver ammonia solution prepared in step (2), the pH of the system was adjusted to 7, and the mixture was oscillated for 3 hours. Then, 10 ml of ethanol solution of polyvinylpyrrolidone (0.01 g/ml) was added, the temperature was raised to 50° C., and the mixture was reacted for 24 hours. The product is centrifuged, washed and dried to obtain starch/silver nanocomposite particles.

The prepared starch/silver nanocomposite particles were analyzed by transmission electron microscope and scanning electron microscope. The results showed that silver nanoparticles were successfully deposited on the surface of starch granules with a particle size of about 24 nm.

Example 2

(1) The method described in Example 1 was adopted to prepare starch granules.

(2) Adopt the method described in embodiment 1 to prepare silver ammonia solution.

(3) Preparation of starch/silver nanocomposite particles. At room temperature, 10 ml of starch granule aqueous dispersion with a concentration of 0.01 g/ml was added to the silver ammonia solution prepared in step (2), the pH of the system was adjusted to 7, and the mixture was oscillated for 3 hours. Then, 10 ml of ethanol solution of polyvinylpyrrolidone (0.01 g/ml) was added, the temperature was raised to 50° C., and the mixture was reacted for 24 hours. The product is centrifuged, washed and dried to obtain starch/silver nanocomposite particles.

The prepared starch/silver composite particles were analyzed by transmission electron microscope and scanning electron microscope. The results showed that the silver nanoparticles were loaded on the surface of the starch granules, and the particle diameter of the silver nanoparticles was 15 nanometers.

Example 3

(1) The method described in Example 1 was adopted to prepare starch granules.

(2) Adopt the method described in embodiment 1 to prepare silver ammonia solution.

(3) Preparation of starch/silver nanocomposite particles. At room temperature, 10 milliliters of starch granule aqueous dispersion with a concentration of 0.01 g/ml was added to the silver ammonia solution prepared in step (2), the pH of the system was adjusted to 13, and the mixture was oscillated for 3 hours. Then, 10 ml of ethanol solution of polyvinylpyrrolidone (0.01 g/ml) was added, the temperature was raised to 50° C., and the mixture was reacted for 24 hours. The product is centrifuged, washed and dried to obtain starch/silver nanocomposite particles.

The prepared starch/silver composite particles were analyzed by transmission electron microscope and scanning electron microscope. The results showed that the silver nanoparticles were loaded on the surface of the starch granules, and the particle diameter of the silver nanoparticles was 12 nanometers.

Example 4

(1) The method described in Example 1 was adopted to prepare starch granules.

(2) Adopt the method described in embodiment 1 to prepare silver ammonia solution.

(3) Preparation of starch/silver nanocomposite particles. At room temperature, 10 ml of starch granule aqueous dispersion with a concentration of 0.002 g/ml was added to the silver ammonia solution prepared in step (2), the pH of the system was adjusted to 7, and the mixture was oscillated for 3 hours. Then, 10 ml of ethanol solution of polyvinylpyrrolidone (0.01 g/ml) was added, the temperature was raised to 50° C., and the mixture was reacted for 24 hours. The product is centrifuged, washed and dried to obtain starch/silver nanocomposite particles.

The prepared starch/silver composite particles were analyzed by transmission electron microscope and scanning electron microscope. The results showed that the silver nanoparticles were loaded on the surface of the starch granules, and the particle diameter of the silver nanoparticles was 46 nanometers.

Example 5

(1) The method described in Example 1 was adopted to prepare starch granules.

(2) Preparation of silver ammonia solution. At room temperature, add ammonia water dropwise to 10 ml of 1×10 ^-3 mol/L silver nitrate aqueous solution, observe that the white precipitate in the solution just disappears completely, and at this time the concentration is 1×10 ^-3 mol/L of silver ammonia solution.

(3) Preparation of starch/silver nanocomposite particles. At room temperature, 10 ml of starch granule aqueous dispersion with a concentration of 0.01 g/ml was added to the silver ammonia solution prepared in step (2), the pH of the system was adjusted to 7, and the mixture was oscillated for 3 hours. Then, 10 ml of ethanol solution of polyvinylpyrrolidone (0.01 g/ml) was added, the temperature was raised to 50° C., and the mixture was reacted for 24 hours. The product is centrifuged, washed and dried to obtain starch/silver nanocomposite particles.

The prepared starch/silver composite particles were analyzed by transmission electron microscope and scanning electron microscope. The results showed that the silver nanoparticles were loaded on the surface of the starch granules, and the particle diameter of the silver nanoparticles was 10 nanometers.

Example 6

(1) The method described in Example 1 was adopted to prepare starch granules.

(2) Preparation of silver ammonia solution. At room temperature, aqueous ammonia was added dropwise in 50 milliliters of 0.02 mol/liter silver nitrate aqueous solution, and the white precipitate in the observed solution just disappeared completely, at which point a silver ammonia solution with a concentration of 0.02 mol/liter was obtained.

(3) Preparation of starch/silver nanocomposite particles. At room temperature, 50 ml of starch granule aqueous dispersion with a concentration of 0.02 g/ml was added to the silver ammonia solution prepared in step (2), the pH of the system was adjusted to 7, and the mixture was shaken and mixed for 3 hours. Then, 50 ml of ethanol solution of polyvinylpyrrolidone (0.02 g/ml) was added, the temperature was raised to 50° C., and the mixture was reacted for 24 hours. The product is centrifuged, washed and dried to obtain starch/silver nanocomposite particles.

The prepared starch/silver composite particles were analyzed by transmission electron microscope and scanning electron microscope. The results showed that the silver nanoparticles were loaded on the surface of the starch granules, and the particle diameter of the silver nanoparticles was 31 nanometers.

Claims (10)

1. a kind of preparation method of starch/silver compound particle, the described method comprises the following steps：

(1) silver-colored precursor water solution is provided；

(2) starch granules aqueous dispersions are provided；

(3) reducing agent aqueous solution is provided；

(4) the starch granules aqueous dispersions are well mixed with the silver-colored precursor water solution, and are vibrated or stirring at least 30 Minute；

(5) reducing agent aqueous solution is added to the mixture of gained in step (4), the pH of regulation system to 3~13, and Reacted at a temperature of 25~60 DEG C, then obtain starch/silver nanoparticle compound particle solid powder through being centrifuged, washing and dry.

2. preparation method according to claim 1, wherein, the silver-colored precursor solution is selected from silver nitrate aqueous solution, three second Hydramine silver solution, the silver acetate aqueous solution and silver ammino solution；

Preferably, in the silver-colored precursor solution silver ion concentration be 0.001~0.2 mol/L, preferably 0.001~ 0.02 mol/L, more preferably 0.01~0.02 mol/L.

3. preparation method according to claim 1 and 2, wherein, the starch granules be with potato, wheat, tomato, The root and/or stem of sweet potato or Grain Production of Amaranthus are raw material by obtained in alkaline extraction；

Preferably, the consumption of the starch granules is 1~200 times of silver-colored weight in silver-colored precursor solution, preferably 1~50 times, More preferably 1.5~10 times, most preferably 1.75~9.5 times.

4. preparation method according to any one of claim 1 to 3, wherein, starch granules aqueous dispersions in step (2) Concentration is 0.002~0.02 grams per milliliter, more preferably preferably 0.005~0.015 grams per milliliter, 0.01 grams per milliliter；

Preferably, the average-size of the starch granules in step (2) in starch granules aqueous dispersions is received for 100 nanometers~2000 Rice, more preferably preferably 500 nanometers~1000 nanometers, 900 nanometers.

5. preparation method according to any one of claim 1 to 4, wherein, the reducing agent is selected from trisodium citrate, boron Sodium hydride, potassium borohydride, hydroxylamine hydrochloride, formaldehyde, hydrazine, tannic acid, sodium hypophosphite, PVP, methyl alcohol, ethanol, third One or more in alcohol, ascorbic acid and THPC, preferably PVP；

Preferably, the consumption of the reducing agent is 0.6~600 times of silver-colored forerunner's body weight, preferably 0.6~60 times, more preferably It is 5~10 times, and most preferably 6 times.

6. preparation method according to any one of claim 1 to 5, wherein, reductant solution is polyethylene in step (3) The ethanol solution of base pyrrolidones；

Preferably, the concentration of the ethanol solution of PVP be 0.002~0.1 grams per milliliter, preferably 0.01~ 0.1 grams per milliliter, more preferably 0.01~0.02 grams per milliliter, and most preferably 0.01 grams per milliliter.

7. preparation method according to any one of claim 1 to 6, wherein, the time of vibration or stirring is in step (4) 1 to 5 hour, preferably 3 hours.

8. preparation method according to any one of claim 1 to 7, wherein, the model of regulation mixed system pH in step (5) It is 7~13 to enclose, preferably 7；

Preferably, the reaction in step (5) is carried out under vibration or stirring.

9. preparation method according to any one of claim 1 to 8, wherein, reaction temperature is 50 DEG C in step (5).

10. preparation method according to any one of claim 1 to 9, wherein, the reaction time is 12~48 in step (5) Hour, preferably 24 hours.