CN101342600A - A device for continuously preparing nano-silver and a continuous preparation method for nano-silver - Google Patents

Abstract

A device for continuously preparing nano-silver and a continuous preparation method for nano-silver, relating to a continuous preparation method for nano-silver. Provided are a device for continuously preparing nano-silver and a continuous preparation method for nano-silver. Equipped with 2 constant flow pumps or syringe pumps, tee pipe, tubular reactor and heater. One end of the three-way pipe is connected to the inlet end of the tubular reactor, and the other two ends of the three-way pipe are respectively connected to two constant flow pumps or injection pumps, which are used to transport the raw material liquid to the reactor, and the tubular reactor is placed in the heater . Take Lauraceae plants to prepare plant water extracts; prepare silver precursor solution; take equal volumes of plant water extracts and silver precursor solutions, add them to the reaction device for reaction, and the obtained reaction solution is nano-silver sol. The prepared silver nanoparticles are mainly spherical, the average particle diameter is 3-80nm, and the particle dispersibility is good. Moreover, the source of raw materials is extensive, no additional chemical reducing agent is needed, the cost is low, and industrialization is easy to realize.

Description

A device for continuously preparing nano-silver and a continuous preparation method for nano-silver

technical field

The invention relates to a continuous preparation method of nano-silver, in particular to a device for continuously preparing nano-silver by a plant reduction method and the continuous preparation method of nano-silver.

Background technique

Due to its unique physical and chemical properties, nanoscale elemental silver particles have broad application prospects in the fields of antibacterial, catalysis, energy, magnetism, and protective materials. The preparation methods are generally based on physical and chemical methods. Although the research on these two methods is relatively sufficient at home and abroad, and the technology is relatively mature, they have disadvantages such as high production costs and easy pollution of the environment. The bioreduction method is a method developed in recent years for the preparation of metal nanoparticles. This method has many advantages, such as a wide range of raw material biomass sources, environmentally friendly and renewable, mild reduction process conditions, and no additional chemical reducing agent, the stability of the obtained nanoparticles and so on. Bioreduction is further divided into microbial reduction and plant reduction. Although the microbial method can overcome the shortcomings of physical and chemical methods with high production costs and easy pollution of the environment, it has the disadvantages of slow reduction and troublesome acquisition of microorganisms (by fermentation, etc.). The phytoreduction method is more valuable for industrial development because of its wide and simple sources of biomass.

It has been found that silver nanoparticles can be prepared by using plant biomass such as alfalfa, for example, Shankar et al. (Biotechnol.Prog. 2003, 19, 1627-1631) reported the preparation of silver nanoparticles by reducing boiling solution of geranium. Gardea-Torresdey et al. (Langmuir 2003, 19, 1357-1361) reported the use of live plants or biomass of alfalfa for the synthesis of silver nanoparticles. Chandran et al. (Biotechnol. Prog. 2006, 22, 577-583) reported the reduction preparation of silver nanoparticles by using the boiling liquid of Aloe vera. However, most of these existing studies only stay in the batch preparation stage of simple shake flasks. During the batch preparation process, due to the poor mass transfer and heat transfer effects of the macroscopic liquid in the reactor, there are potential disadvantages to the preparation of nanoparticles. Influence, and as the volume of the reactor increases, the uniformity of temperature and concentration in the kettle is more difficult to achieve. Therefore, it is difficult to realize the controllable synthesis and large-scale preparation of high-quality nanocrystals by batch synthesis.

Contents of the invention

The purpose of the present invention is to provide a device for continuously preparing nano-silver and a continuous preparation method for nano-silver. The prepared silver nanoparticles are mainly spherical, the average particle diameter is 3-80nm, and the particle dispersibility is good.

The device for continuously preparing nano-silver is equipped with two constant flow pumps or injection pumps, a three-way pipe, a tubular reactor and a heater. One end of the three-way pipe is connected to the inlet end of the tubular reactor, and the other two ends of the three-way pipe are respectively connected to two constant flow pumps or injection pumps, which are used to transport the raw material liquid to the reactor, and the tubular reactor is placed in the heater .

The three-way pipe can be a Y-shaped or T-shaped three-way pipe, and the inner diameter of the three-way pipe is preferably 0.05-5mm.

The pipe diameter of the tubular reactor is preferably 0.01-5 mm.

The continuous preparation method of described nano-silver comprises the following steps:

1) taking Lauraceae plants to produce plant water extract;

2) preparing silver precursor solution;

3) Take an equal volume of plant water extract and silver precursor solution, add them into the reaction device for reaction, and the obtained reaction solution is nano-silver sol.

The Lauraceae plant can be selected from at least one of camphor, avocado, laurel and the like. Plant water extracts can be prepared by leaching or boiling. The concentration of the plant water extract is preferably 5-100 g/L.

The silver precursor solution is silver nitrate or silver ammonia solution. The concentration of the silver precursor solution is preferably 0.001-0.1 mol/L. The temperature of the reaction is preferably 30-100°C, and the reaction flow rate is preferably 0.01-10.0 mL/min.

In the present invention, the continuous preparation of nanoparticles by applying the tubular reactor to the plant biomass reduction of metal ions can not only solve the shortcomings of difficult control of heat transfer and mass transfer in the batch preparation process, but also is simple to operate, silver nanoparticles Continuous synthesis in a tubular reactor can achieve large-scale production by increasing the number of tubes in the tubular reactor or extending the operating time, effectively avoiding a series of problems in the scale-up process of traditional reactors. Moreover, the source of biomass raw materials is extensive, environmentally friendly and renewable, and the process does not need to add other chemical reducing agents, the cost is low, and it is easy to realize industrialization. The prepared silver nanoparticles are mainly spherical, the average particle size is 3-80nm, and the particle dispersibility is good.

Description of drawings

Fig. 1 is a schematic diagram of the device structure for preparing nano-silver in the embodiment of the present invention.

Fig. 2 is the TEM picture of the nano-silver prepared in Example 1, and the scale bar in the figure is 100nm.

Detailed ways

Below by embodiment the present invention will be further described.

Example 1

Referring to FIG. 1 , the device for preparing nano silver includes two constant flow pumps 1 , a three-way pipe 2 , a tubular reactor 3 and an oil bath heater 4 . One end of the three-way pipe 2 is connected to the inlet end of the tubular reactor 3, and the other two ends are respectively connected to two constant-flow pumps 1 through silicone tubes. In the containers of the extract solution A and the silver precursor solution B, the tubular reactor 3 is placed in the oil bath heater 4 . Existing products can be used for constant flow pumps, tee pipes, tubular reactors and heaters.

The dried cinnamon leaves are pulverized and passed through a 20-mesh sieve to obtain cinnamon leaf dry powder. Weigh 4g of Cinnamomum camphora leaf dry powder, add 200mL of water, place it in a shaker (30°C, 150rpm) and vibrate for 1h, take it out, filter with filter paper, and the obtained filtrate is the Cinnamomum camphora water extract with a concentration of 20g/L. Take 200mL of Cinnamomum camphora water extract and 200mL of silver ammonia solution (0.001mol/L) and put them in containers A and B respectively, and continuously transport these two solutions to the T-shaped tee at a flow rate of 0.5mL/min through a constant flow pump After being mixed in a tube (0.05mm inner diameter), it enters into a stainless steel tubular reactor (0.5mm inner diameter) for reaction, and the reaction temperature is controlled at 60°C. The reaction solution C is collected at the outlet of the tubular reactor, and the resulting reaction solution is nano-silver sol. Utilize the electron microscope to observe the particle size and appearance of the obtained nano-silver, the observation result (referring to Fig. 2) shows that the obtained nano-silver particle is nearly spherical, uniform in size, and the particle diameter is mainly distributed in 3.3～5.7nm, and the average particle diameter 4.3nm.

Example 2

Adopt the camphora water extract in embodiment 1 and 200mL silver nitrate solution (0.001mol/L), these two kinds of solutions are continuously delivered to the Y-type tee pipe (inner diameter 5mm) with the flow velocity of 0.5mL/min by constant flow pump ) into a glass tube reactor (with an inner diameter of 5mm) for reaction at a temperature of 40°C. The obtained nanoparticles are all nearly spherical, the particle diameters are mainly distributed in the range of 19-40nm, and the average particle diameter is 30.7nm.

Example 3

Adopt the camphora water extract in the embodiment 1 and 200mL silver nitrate solution (0.001mol/L), these two kinds of solutions are continuously delivered to the Y-type tee pipe (inner diameter 5mm) with the flow rate of 0.5mL/min by the constant flow pump ) into a glass tube reactor (inner diameter 5mm) for reaction, and the reaction temperature is 60°C. The obtained nanoparticles are all nearly spherical, the particle diameters are mainly distributed in the range of 20-80nm, and the average particle diameter is 42.2nm.

Example 4

Adopt the camphora water extract in the embodiment 1 and 200mL silver nitrate solution (0.001mol/L), these two kinds of solutions are continuously delivered to the Y-type tee pipe (inside diameter 3mm) with the flow rate of 0.5mL/min by the constant flow pump ) into the glass tube reactor (inner diameter 3mm) after mixing, and the reaction temperature is 90°C. The obtained nanoparticles are all nearly spherical, the particle diameters are mainly distributed in the range of 5-26nm, and the average particle diameter is 16.0nm.

Example 5

Adopt the camphora water extract in embodiment 1 and 200mL silver nitrate solution (0.001mol/L), these two kinds of solutions are continuously transported in the silica gel tube with the flow rate of 0.1mL/min by constant flow pump, both in Y-shaped tee tube (inner diameter: 3mm, material: glass) is mixed and then enters the glass tube for reaction (inner diameter: 3mm), and the reaction temperature is 90°C. The obtained nanoparticles are all nearly spherical, the particle diameters are mainly distributed in the range of 23-39nm, and the average particle diameter is 26.4nm.

Example 6

Adopt the equal volume of cinnamon camphora water extract in embodiment 1 and 200mL silver nitrate solution (0.001mol/L) by constant flow pump these two kinds of solutions are continuously delivered to Y-shaped three-way pipe (internal diameter) with the flow velocity of 5.0mL/min 3mm) and mixed in a glass tube reactor (inner diameter 3mm), the reaction temperature is 90°C. The obtained nanoparticles are all nearly spherical, the particle diameters are mainly distributed in the range of 24-46nm, and the average particle diameter is 32.2nm.

Example 7

Adopt the equal volume of the cinnamon camphora water extract in the embodiment 1 and 200mL silver nitrate solution (0.001mol/L) by constant flow pump these two kinds of solutions are continuously delivered in the silica gel tube with the flow rate of 10.0mL/min, both After mixing in a Y-shaped tee tube (inner diameter: 3mm), it enters into a glass tube for reaction (inner diameter: 3mm), and the reaction temperature is 90°C. The obtained nanoparticles are all nearly spherical, the particle diameters are mainly distributed in the range of 20-50nm, and the average particle diameter is 28.8nm.

Example 8

Adopt the equal volume of linoleum camphora water extract in embodiment 1 and 200mL silver nitrate solution (0.001mol/L) by constant flow pump these two kinds of solutions are continuously delivered to Y type tee pipe (inner diameter) with the flow rate of 0.5mL/min 3mm) and mixed in a polytetrafluoroethylene tubular reactor (inner diameter 2.5mm), the reaction temperature is 90°C. The obtained nanoparticles are all nearly spherical, the particle diameters are mainly distributed in the range of 40-77nm, and the average particle diameter is 51.2nm.

Example 9

Extract concentration by the method among the embodiment 1 and be the camphora water extract of 100g/L. Take 200mL of Cinnamomum camphora water extract and 200mL of silver nitrate solution (0.01mol/L), and continuously transport the above two solutions at a flow rate of 0.5mL/min to a Y-shaped three-way pipe (inner diameter 3mm) through a constant flow pump and mix them. Enter into a glass tube reactor (inner diameter 3mm) for reaction, and the reaction temperature is 90°C. The obtained nanoparticles are all nearly spherical, the particle diameters are mainly distributed in the range of 25-54nm, and the average particle diameter is 36.4nm.

Example 10

The dried avocado leaves are pulverized and passed through a 20-mesh sieve to obtain avocado dry powder. Weigh 4g of avocado dry powder, add 200mL of water, filter with filter paper after boiling for 5min, and the obtained filtrate is the water extract with a concentration of 20g/L. Take 200mL of water extract and 200mL of silver nitrate solution (0.001mol/L), and continuously transport these two solutions to a Y-shaped tee (inner diameter 3mm) through a constant flow pump at a flow rate of 0.5mL/min. To react in a glass tube reactor (3mm inner diameter), the reaction temperature is 90°C. The obtained nanoparticles are all nearly spherical, the particle diameters are mainly distributed in the range of 14-23nm, and the average particle diameter is 18.8nm.

Example 11

The dried Tianzhugui was crushed and passed through a 20-mesh sieve to obtain Tianzhugui dry powder. Weigh 4g of Tianzhu Gui dry powder, add 200mL of water, place in a shaker (30°C, 150rpm) and vibrate for 1 hour, then filter with filter paper, and the obtained filtrate is a water extract with a concentration of 20g/L. Take 200mL of water extract and 200mL of silver nitrate solution (0.001mol/L), and continuously transport these two solutions to a Y-shaped tee (inner diameter 3mm) through a constant flow pump at a flow rate of 0.5mL/min. To react in a glass tube reactor (3mm inner diameter), the reaction temperature is 90°C. The obtained nanoparticles are all nearly spherical, the particle diameters are mainly distributed in the range of 20-32nm, and the average particle diameter is 27.1nm.

Claims (10)

1. continuous device of preparation Nano Silver, it is characterized in that being provided with 2 constant flow pumps or syringe pump, three-way pipe, tubular reactor and heater, one end of three-way pipe connects the entrance point of tubular reactor, two ends in addition of three-way pipe connect 2 constant flow pumps or syringe pump respectively, be used for transferring raw material liquid to reactor, tubular reactor places heater.

2. the device of a kind of continuous preparation Nano Silver as claimed in claim 1 is characterized in that three-way pipe is Y type or T type three-way pipe.

3. the device of a kind of continuous preparation Nano Silver as claimed in claim 1, the internal diameter that it is characterized in that three-way pipe is 0.05～5mm.

4. the device of a kind of continuous preparation Nano Silver as claimed in claim 1 is characterized in that the tubular reactor caliber is 0.01～5mm.

5. the continuous preparation method of Nano Silver is characterized in that may further comprise the steps:

1) gets canella and produce the vegetation water extract;

2) prepare silver-colored precursor solution;

3) get the vegetation water extract and the silver-colored precursor solution of equating volume, join in the reaction unit and react, the gained reactant liquor is a nano silver colloidal sol.

6. the continuous preparation method of Nano Silver as claimed in claim 5 is characterized in that described canella is selected from least a in fragrant camphor tree, avocado, the cinnamomum japonicum.

7. the continuous preparation method of Nano Silver as claimed in claim 5 is characterized in that producing of vegetation water extract adopt leaching method or hot cooking method.

8. as the continuous preparation method of claim 5 or 7 described Nano Silvers, the concentration that it is characterized in that the vegetation water extract is 5～100g/L.

9. the continuous preparation method of Nano Silver as claimed in claim 5 is characterized in that described silver-colored precursor solution is silver nitrate or silver ammino solution, and the concentration of silver-colored precursor solution is 0.001～0.1mol/L.

10. the continuous preparation method of Nano Silver as claimed in claim 5, the temperature that it is characterized in that described reaction is 30～100 ℃, the reaction flow velocity is 0.01～10.0mL/min.

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