CN109012059A - A kind of preparation method of the Modified Iron dried bean noodles drying prescription based on multilayer carbon nanotube - Google Patents

Abstract

The present invention relates to gas sensor fields, disclose a kind of preparation method of Modified Iron dried bean noodles drying prescription based on multilayer carbon nanotube, include: that croci, powdered graphite 1) are respectively put into ball mill, is crushed under dry air atmosphere and obtain nanoscale ferric oxide particles and graphite particle；2) obtained hybrid particles are put into room temperature in ball mill with adhesive to mix, modified electrode is made in molding；3) in the closed joint sealing full of argon gas, modified electrode is placed in one, electric arc is inspired between the two poles of the earth using 220V normal voltage, reacts generate iron and carbon nanotube at high temperature；4) gas natural cooling on remaining electrode surface forms the iron solid particle using carbon nanotube as matrix.The iron powder desiccant modified based on multilayer carbon nanotube can quickly be prepared environmentally friendlyly through the invention, provide new method for the preparation of novel drier, there is very important realistic meaning to the development of China's desiccant preparation industry.

Description

A kind of preparation method of modified iron powder desiccant based on multilayer carbon nanotube

technical field

The invention relates to the field of desiccant preparation, in particular to a preparation method of a modified iron powder desiccant based on multilayer carbon nanotubes.

Background technique

Carbon nanotubes (also known as bucky tubes) are one-dimensional quantum materials with a special structure (the radial dimension is on the order of nanometers, the axial dimension is on the order of micrometers, and both ends of the tube are basically sealed). This material can be regarded as a single-layer graphene rolled into a tubular material. This unique structure makes carbon nanotubes have completely different properties from general carbon materials, including super toughness, ultra-high temperature resistance, superconductivity, good Thermal conductivity and unique optical properties. Research on the application of carbon nanotubes is now a hot spot in the field of materials.

Under a certain humidity and temperature, bacteria and mold in food will multiply at a high speed, causing food to spoil; if the humidity is too high, electronic products will cause electrochemical corrosion due to the formation of batteries, resulting in poor contact; even polymer materials such as plastics and rubber It is not afraid of corrosion, and its yield rate is also closely related to the moisture in the air. Therefore, humidity regulation is very important in our life. Desiccants have emerged to solve this problem.

In general, solid desiccants are mainly composed of quicklime. Compared with quicklime desiccant which can only absorb H ₂ O, iron powder desiccant can absorb H ₂ O and oxygen at the same time, and has a wider range of applications. However, iron powder desiccants react relatively slowly and cannot quickly absorb large amounts of water. People need an iron powder desiccant with better performance and wider application range.

Contents of the invention

In order to solve the above technical problems, the present invention provides a method for preparing a modified iron powder desiccant based on multilayer carbon nanotubes. In the invention, iron oxide is reduced to iron through the high temperature brought by electric arc action, and graphite becomes multi-layered carbon nanotubes, and finally an iron solid particle material with carbon nanotubes as a matrix is prepared.

The specific technical scheme of the present invention is: a kind of preparation method of the modified iron powder desiccant based on multilayer carbon nanotube, in g, comprises the following steps:

1) Put 280-300g of iron oxide powder and 80-100g of graphite powder into a ball mill respectively, and pulverize in a dry air atmosphere to obtain nanoscale mixed particles.

The present invention uses iron oxide particles and graphite particles in step 1), the mechanical force of the ball mill activates metal oxides and carbon simple substances, activates polar groups on the surface of graphite, forms ionic bonds with iron oxide, and pulverizes them into nanoscale , which is beneficial for the next reaction.

2) Put the mixed particles obtained in step 1) and 20-35g of adhesive into a ball mill, mix them at room temperature, and mold them to form a modified electrode.

In the present invention, in the step 2), the adhesive is used to bind the mixed particles into a solid through compression molding, and the electrodes are made without changing the properties of the materials.

3) Place the modified electrode in a sealed box filled with argon, and use a standard voltage of 220V to excite an arc between the two electrodes, intermittently; the heat brought by the arc makes the temperature of the material reach 3500-3900°C, At this temperature, the graphite in the electrode turns into carbon vapor; the iron oxide in the electrode turns into iron oxide vapor; iron oxide vapor and carbon vapor undergo a reduction reaction at high temperature to form iron and carbon dioxide; Carbon nanotubes are formed under the influence of iron oxide in which the remaining iron oxide acts as a catalyst.

The present invention prepares iron single substance and multilayer carbon nanotubes by arc discharge in step 3), during which iron oxide and graphite promote and interact with each other: high temperature makes the two solids sublime into gas, iron oxide is reduced to iron by graphite, forming Carbon dioxide; carbon dioxide and graphite form multilayer carbon nanotubes under high temperature, and iron oxide is used as a catalyst to promote this process; the whole process goes through multiple cycles, and the purity of iron and multilayer carbon nanotubes gradually increases.

4) After step 3), the gas is naturally cooled on the surface of the remaining iron oxide to form a modified iron powder desiccant based on multilayer carbon nanotubes.

In step 4) of the present invention, the iron element and the multilayer carbon nanotubes are naturally cooled and condensed into solids, and the nanoscale iron element is attached to the multilayer carbon nanotubes, finally forming a multilayer carbon nanotube rich in iron element nanoparticles. Tube carrier.

Compared with ordinary carbon simple substances, carbon nanotubes have unique advantages in electrical properties, mechanical properties and thermodynamic properties: first, multilayer carbon nanotubes form defects between layers, which become potential wells. It is easy to capture polar groups and ionized groups in the air, including water vapor, carbon dioxide, charged dust, etc., and form a synergistic effect with iron powder; secondly, p electrons in multilayer carbon nanotubes form delocalized large π bonds, The carbon nanotubes have the superconductivity and conjugation effect that ordinary carbon simple substances do not have. Electrons can quickly flow between carbon nanotubes and iron atoms, accelerating the bond combination, and the carbon nanotubes and iron simple substances are more closely combined to improve drying. The stability of the desiccant prolongs the life of the desiccant; secondly, carbon nanotubes have a very high melting and boiling point, even if the temperature reaches 3000 ° C, the carbon nanotubes will not melt, making the working temperature of this modified desiccant The scope is further expanded; finally, carbon nanotubes have extremely high modulus and strength, and are even called superfibers, which makes this substance not only in the form of lumps or granules like ordinary materials, but also in the form of fibers , and finally woven into a cloth material or a mesh material, which can be used as an auxiliary additive to other materials to improve the oxidation resistance, moisture resistance, oxidation resistance and toughness of functional materials, and can also be used alone to become carbon cloth And carbon film, are applied to daily life, greatly improving the applicability of the material. It can be said that carbon nanotubes have the dual advantages of activated carbon and carbon fiber, which can greatly improve the performance of iron powder desiccant.

Preferably, in step 1), the material is pulverized for 10-15 minutes, and the rotating speed of the ball mill is 220-250 r/min.

As a preference, in step 2), mixing at room temperature for 5-8min, and the ball mill rotating speed is 150-200r/min.

Preferably, in step 3), the electrode is in a sealed box filled with argon, and the arc is intermittently excited for 15-28 minutes, each time lasting 15-25 seconds, with an interval of 2-7 seconds.

Preferably, in step 2), the adhesive is any one of aluminum oxide, zinc oxide or tungsten oxide.

Compared with prior art, the beneficial effect of the present invention is:

1. The operation process is simple, convenient and fast, and can quickly produce a large amount of modified desiccant, which is suitable for large-scale industrial production.

2. In the preparation process of the present invention, there are only metal oxides, metal elements and carbon elements in the gas, no toxic and harmful gases appear, and the raw materials are in a completely closed space during the reaction, and there will be no gas escaping to cause pollution, which is in line with the thinking of green preparation .

3. The desiccant prepared by the present invention belongs to nanomaterials and has a higher surface area; iron can react with oxygen and H ₂ O, and multilayer carbon nanotubes can react with carbon monoxide, so the scope of application is wider. Multilayer carbon nanotubes The hollow structure is more conducive to the entry of oxygen and H ₂ O; the good thermal conductivity of multi-layer carbon nanotubes is conducive to controlling the discharge of heat when iron powder reacts; the combination of multi-layer carbon nanotubes and iron strengthens the electronic flow to increase the reaction rate; iron is loaded on multilayer carbon nanotubes, which can be prepared into solids of various shapes without affecting the performance of the desiccant; iron powder desiccants with carbon nanotubes as the carrier have stronger environmental adaptability Capability and mechanical properties, higher stability and longer life.

4. Generally speaking, people need single-layer carbon nanotubes more, and the preparation of carbon nanotubes often produces impurities of multilayer carbon nanotubes and fullerenes. However, in the present invention, the purity requirements of carbon nanotubes It is not high, whether it is multi-layer carbon nanotubes, single-layer carbon nanotubes or fullerenes can play the role of adsorbing impurities, even compared to single-layer carbon nanotubes, multi-layer carbon nanotubes are more popular, secondly, in Under the catalysis and influence of iron powder, the reaction tends to form multilayer carbon nanotubes with more active surface, and the purity is much higher than that of carbon nanotubes prepared by simple arc discharge.

Detailed ways

The present invention will be further described below in conjunction with embodiment.

Example 1:

A preparation method of a modified iron powder desiccant based on multilayer carbon nanotubes, comprising the steps of:

1) Put 280g of iron oxide powder and 80g of graphite powder into a ball mill respectively, and pulverize them in a dry air atmosphere for 10min at a speed of 220r/min to obtain nanoscale iron oxide particles and graphite particles;

2) Put the mixed particles obtained in step 1) and 20g of adhesive (aluminum oxide) into a ball mill, mix at room temperature for 5min at a speed of 150r/min, and mold into a modified electrode;

3) Place the modified electrode in a sealed box filled with argon, and use a standard voltage of 220V to excite an arc between the two electrodes. The arc is intermittently excited for 15 minutes, each time lasting 15 seconds, with an interval of 2 seconds;

The heat brought by the arc makes the temperature of the material reach 3500°C. At this temperature, the graphite in the electrode evaporates to generate carbon vapor; the iron oxide in the electrode evaporates to generate iron oxide vapor;

The iron oxide in the gas and the carbon element undergo a reduction reaction at high temperature to form iron and carbon dioxide; the carbon element and carbon dioxide in the gas form carbon nanotubes under the action of the arc, and the iron oxide acts as a catalyst to promote this process;

4) After step 3), the gas is naturally cooled on the surface of the remaining iron oxide to form iron solid particles with carbon nanotubes as the matrix.

Example 2:

A preparation method of a modified iron powder desiccant based on multilayer carbon nanotubes, comprising the steps of:

1) Put 300g of iron oxide powder and 100g of graphite powder into a ball mill respectively, and pulverize them for 15 minutes in a dry air atmosphere at a speed of 250r/min to obtain nanoscale iron oxide particles and graphite particles;

2) Put the mixed particles obtained in step 1) and 35g of adhesive (zinc oxide) into a ball mill, mix them at room temperature for 8 minutes, and rotate at 200r/min, and mold them into a modified electrode;

3) Place the modified electrode in a sealed box filled with argon, and use a standard voltage of 220V to excite an arc between the two electrodes. The arc is intermittently excited for 28 minutes, each time lasting 25s, with an interval of 7s;

The heat brought by the arc makes the temperature of the material reach 3900°C. At this temperature, the graphite in the electrode evaporates to generate carbon vapor; the iron oxide in the electrode evaporates to generate iron oxide vapor;

The iron oxide in the gas and the carbon element undergo a reduction reaction at high temperature to form iron and carbon dioxide; the carbon element and carbon dioxide in the gas form carbon nanotubes under the action of the arc, and the iron oxide acts as a catalyst to promote this process;

4) After step 3), the gas is naturally cooled on the surface of the remaining iron oxide to form iron solid particles with carbon nanotubes as the matrix.

Example 3:

A preparation method of a modified iron powder desiccant based on multilayer carbon nanotubes, comprising the steps of:

1) 275g of iron oxide powder and 85g of graphite powder were put into a ball mill respectively, and pulverized in a dry air atmosphere for 12min at a speed of 230r/min to obtain nanoscale iron oxide particles and graphite particles;

2) Put the mixed particles obtained in step 1) and 25g of adhesive (tungsten oxide) into a ball mill, mix them at room temperature for 6 minutes at a speed of 170r/min, and mold them into a modified electrode;

3) Place the modified electrode in a sealed box filled with argon, and use a standard voltage of 220V to excite an arc between the two electrodes. The arc is intermittently excited for 19 minutes, each time lasting 19 seconds, with an interval of 4 seconds;

The heat brought by the arc makes the temperature of the material reach 3600°C. At this temperature, the graphite in the electrode evaporates to generate carbon vapor; the iron oxide in the electrode evaporates to generate iron oxide vapor;

The iron oxide in the gas and the carbon element undergo a reduction reaction at high temperature to form iron and carbon dioxide; the carbon element and carbon dioxide in the gas form carbon nanotubes under the action of the arc, and the iron oxide acts as a catalyst to promote this process;

4) After step 3), the gas is naturally cooled on the surface of the remaining iron oxide to form iron solid particles with carbon nanotubes as the matrix.

Example 4:

A preparation method of a modified iron powder desiccant based on multilayer carbon nanotubes, comprising the steps of:

1) 295g of iron oxide powder and 95g of graphite powder were put into a ball mill respectively, and pulverized in a dry air atmosphere for 14min at a speed of 240r/min to obtain nanoscale iron oxide particles and graphite particles;

2) Put the mixed particles obtained in step 1) and 35g of adhesive (aluminum oxide) into a ball mill, mix at room temperature for 7min at a speed of 190r/min, and mold into a modified electrode;

3) Place the modified electrode in a sealed box filled with argon, and use a standard voltage of 220V to excite an arc between the two electrodes, intermittent excitation for 27min, each time lasting 20s, with an interval of 5s;

The heat brought by the arc makes the temperature of the material reach 3850°C. At this temperature, the graphite in the electrode evaporates to generate carbon vapor; the iron oxide in the electrode evaporates to generate iron oxide vapor;

The iron oxide in the gas and the carbon element undergo a reduction reaction at high temperature to form iron and carbon dioxide; the carbon element and carbon dioxide in the gas form carbon nanotubes under the action of the arc, and the iron oxide acts as a catalyst to promote this process;

4) After step 3), the gas is naturally cooled on the surface of the remaining iron oxide to form iron solid particles with carbon nanotubes as the matrix.

Example 5:

A preparation method of a modified iron powder desiccant based on multilayer carbon nanotubes, comprising the steps of:

1) 300g of iron oxide powder and 85g of graphite powder were put into a ball mill respectively, and pulverized in a dry air atmosphere for 15min at a speed of 220r/min to obtain nanoscale iron oxide particles and graphite particles;

2) Put the mixed particles obtained in step 1) and 30g of adhesive (aluminum oxide) into a ball mill, mix them at room temperature for 7 minutes at a speed of 190r/min, and mold them into a modified electrode;

3) Place the modified electrode in a sealed box filled with argon, and use a standard voltage of 220V to excite an arc between the two electrodes, intermittently exciting for 25min, each time lasting 22s, with an interval of 6s;

The heat brought by the arc makes the temperature of the material reach 3800°C. At this temperature, the graphite in the electrode evaporates to generate carbon vapor; the iron oxide in the electrode evaporates to generate iron oxide vapor;

The iron oxide in the gas and the carbon element undergo a reduction reaction at high temperature to form iron and carbon dioxide; the carbon element and carbon dioxide in the gas form carbon nanotubes under the action of the arc, and the iron oxide acts as a catalyst to promote this process;

4) After step 3), the gas is naturally cooled on the surface of the remaining iron oxide to form iron solid particles with carbon nanotubes as the matrix.

The following is a performance comparison between the five cases and conventional iron powder desiccants. It can be clearly seen from the table that the iron powder desiccant modified by multi-layer carbon nanotubes not only greatly increases the mechanical properties, thermodynamic properties and stability, but also greatly improves the adsorption performance of water vapor.

Raw materials used in the present invention, equipment, if not specified, are commonly used raw materials, equipment in this area; Method used in the present invention, if not specified, are conventional methods in this area.

The above are only preferred embodiments of the present invention, and do not limit the present invention in any way. All simple modifications, changes and equivalent transformations made to the above embodiments according to the technical essence of the present invention still belong to the technical solution of the present invention. scope of protection.

Claims (5)

1. a preparation method of modified iron powder desiccant based on multilayer carbon nanotubes, in g, is characterized in that comprising the following steps: 1) Put 280-300g of iron oxide powder and 80-100g of graphite powder into a ball mill respectively, and pulverize in a dry air atmosphere to obtain nano-scale mixed particles; 2) Put the mixed particles obtained in step 1) and 20-35g of adhesive into a ball mill, mix them at room temperature, and mold them to make a modified electrode; 3) Put the modified electrode in a sealed box filled with argon, and use a standard voltage of 220V to excite an arc between the two poles, intermittently; the heat brought by the arc makes the material temperature reach 3500-3900°C, At this temperature, the graphite in the electrode turns into carbon vapor; the iron oxide in the electrode turns into iron oxide vapor; iron oxide vapor and carbon vapor undergo a reduction reaction at high temperature to form iron and carbon dioxide; Formation of carbon nanotubes under the action of which the remaining iron oxide acts as a catalyst; 4) After step 3), the gas is naturally cooled on the remaining iron oxide surface to form a modified iron powder desiccant based on multilayer carbon nanotubes. 2. The preparation method of a modified iron powder desiccant based on multilayer carbon nanotubes as claimed in claim 1, characterized in that, in step 1), the material is pulverized for 10-15min, and the speed of the ball mill is 220-250r/ min. 3. The preparation method of a modified iron powder desiccant based on multilayer carbon nanotubes as claimed in claim 1, characterized in that, in step 2), mixing at room temperature for 5-8min, ball mill speed is 150-200r/ min. 4. The preparation method of a modified iron powder desiccant based on multi-layer carbon nanotubes as claimed in claim 1, characterized in that, in step 3), the electrode is in a sealed box filled with argon, and the arc is intermittent Stimulate for 15-28min, last for 15-25s each time, with an interval of 2-7s. 5. The method for preparing a modified iron powder desiccant based on multilayer carbon nanotubes as claimed in claim 1, wherein in step 2), the adhesive is aluminum oxide, zinc oxide or oxide Any kind of tungsten.