WO2012144679A1 - Method for manufacturing a nanofluid containing carbon nanoparticles treated with metal - Google Patents

Abstract

The present invention relates to a method for manufacturing a nanofluid containing carbon nanoparticles treated with metal, said nanofluid being useful for heat-exchangers and all industries in which lubricating properties are required. The method for manufacturing the nanofluid containing carbon nanoparticles treated with metal includes: a step of milling a carbonaceous material; a step of acidizing the surfaces of the carbon nanoparticles resulting from the milling step; a step of drying the carbon nanoparticles resulting from the acidizing step; a step of heat-treating the carbon nanoparticles resulting from the drying step; and a step of mixing the carbon nanoparticles resulting from the heat-treatment using a metal hydroxide solution, and irradiating the carbon nanoparticles with ultrasonic waves.

Description

Method for preparing nanofluid containing metal treated carbon nanoparticles

The present invention relates to a method for producing a nanofluid, and more particularly, to a method for producing a nanofluid containing metal-treated carbon nanoparticles exhibiting properties that can be used throughout the industry requiring coolers, heat exchangers and lubricity. .

The present invention relates to a method for producing a nanofluid, and more particularly, to a method for producing a nanofluid containing metal-treated carbon nanoparticles exhibiting properties that can be used throughout the industry requiring coolers, heat exchangers and lubricity. .

Currently, Korea's nanotechnology level is estimated to have improved from about 25% in 2001 to 66% in 2005, compared to developed countries, and the number of SCI papers and patents is ranked 5th in the world. It is rated as the 4th power in the world.

Research on nanofluids has been carried out mainly on nanofluids in which CuO and Al2O3 particles are dispersed, and studies on CNTs have been reported, and the thermal conductivity of 10 to 150% is increased depending on the basic fluid and particle fraction. In addition, several researchers, such as Xuan and Ding, have published experimental results on the convective heat transfer synergistic effects of these nanofluids, and reported that the application of nanofluids to convective heat transfer increases several times to tens of times.

This is presumed to be due to the heat transfer increase due to the increase of nanofluid heat transfer by the particles, as well as the additional heat transfer increase effect due to the particle movement in the fluid and the thermal boundary layer disturbance.

In Korea, energy dependence abroad is very high, with 97% dependence on energy overseas. Therefore, there is a need for a high efficiency heat exchanger that can dramatically improve energy utilization efficiency. Also, with the adoption and official entry into force of the Climate Change Convention to reduce greenhouse gases, there is an urgent need to secure domestic unique technologies that can reduce emissions such as carbon dioxide by reducing the use of fossil fuels. Therefore, until the stage where the energy source can be developed by itself, it is necessary to maximize the efficiency of the device so as to reduce the energy consumption of the existing facilities as much as possible. In view of this, the nanofluid developed in this study can be applied to various heat exchangers to reduce energy consumption and significantly reduce energy costs.

This reduction in energy use not only provides financial benefits, but also contributes to solving environmental problems by reducing air pollution and greenhouse gas emissions caused by the use of energy sources.

An object of the present invention is to provide a method for producing nanofluids containing metal-treated carbon nanoparticles having excellent cooling, heat exchange and lubricity.

An object of the present invention is a milling step of milling a carbonaceous material, an acid treatment step of treating the surface of the carbon nanoparticles subjected to the milling step with an acid, a drying step of drying the carbon nanoparticles subjected to the acid treatment step, the drying Nano-contained metal-treated carbon nanoparticles comprising a heat treatment step of heat-treating the carbon nanoparticles, and the water dispersion step of mixing the carbon nanoparticles undergoing the heat treatment step with an aqueous metal hydroxide solution and irradiating ultrasonic waves By providing a method of making the fluid.

According to a preferred feature of the invention, the carbonaceous material is made of one or more selected from the group consisting of activated carbon, activated carbon fiber, carbon black and graphene.

According to a further preferred feature of the invention, the milling step is to be made by milling the carbonaceous material with a tumbling ball mill and a mono planner mill for 48 hours.

According to a more preferred feature of the invention, the acid is to be made of one selected from the group consisting of m-chloroperbenzoic acid, hydrochloric acid and sulfuric acid.

According to a further preferred feature of the invention, the heat treatment step is to be made by heating the carbon nanoparticles undergoing the drying step to a temperature of 400 to 500 ℃.

According to a further preferred feature of the invention, the water dispersion step is to be made by mixing 4 to 7 parts by weight of the carbon nanoparticles subjected to the heat treatment step with 93 to 97 parts by weight of the metal hydroxide and irradiated with ultrasonic waves for 1 hour.

According to an even more preferable feature of the present invention, the aqueous metal hydroxide solution is 200 ml of a metal hydroxide 0.05 to 0.2 mol consisting of at least one selected from the group consisting of lithium hydroxide, aluminum hydroxide, sodium hydrogen carbonate, iron hydroxide, lead hydroxide and molybdenum hydroxide It shall be mixed with purified water.

According to a still further preferred feature of the invention, the ultrasonic wave is said to have a frequency of 20 kHz and an amplitude of 48.8 micrometers.

The method for preparing nanofluids containing metal-treated carbon nanoparticles according to the present invention exhibits an excellent effect of providing nanofluids containing metal-treated carbon nanoparticles having excellent cooling, heat exchange and lubricity.

1 is a flow chart showing a method for producing a nanofluid containing carbon nanoparticles according to the present invention.

In the following, preferred embodiments of the present invention and the physical properties of each component will be described in detail, which is intended to explain in detail enough to be able to easily carry out the invention by one of ordinary skill in the art, This does not mean that the technical spirit and scope of the present invention is limited.

Method for producing a nanofluid containing the metal-treated carbon nanoparticles according to the present invention is a milling step (S101) of milling the carbonaceous material, the acid treatment of the surface of the carbon nanoparticles after the milling step (S101) with acid Treatment step (S103), drying step of drying the carbon nanoparticles subjected to the acid treatment step (S103) (S105), heat treatment step (S107) and the heat treatment step of heat treating the carbon nanoparticles subjected to the drying step (S105) (S107) is made of a water dispersion step (S109) of mixing the carbon nanoparticles with the aqueous metal hydroxide solution and irradiating ultrasonic waves.

The above-described milling step (S101) is a step of milling a carbonaceous material by milling a carbonaceous material consisting of at least one selected from the group consisting of activated carbon, activated carbon fiber, carbon black and graphene with a tumbling ball mill and a mono planner mill for 48 hours. In this milling step (S101), the particles of carbonaceous material are pulverized to nano size.

The above-described acid treatment step (S103) is a step of treating the surface of the carbon nanoparticles prepared through the aforementioned milling step (S101) with an acid, and m- the carbon nanoparticles prepared through the aforementioned milling step (S101). It is impregnated with an acid solution selected from the group consisting of chloroperbenzoic acid, hydrochloric acid and sulfuric acid to form a functional group on the surface of the carbon nanopowder. In operation S109, the surface is combined with the metallic material to provide the carbon nanoparticles having the surface treated with the metal.

In the above-described acid treatment step (S103), other oxidants may be used in addition to the above-described acid.

The above-mentioned drying step (S105) is a step of drying the carbon nanoparticles subjected to the above-described acid treatment step (S103), and drying the acid component applied to the surface of the carbon nanoparticles through the above-described acid treatment step (S103). Step.

At this time, the drying step (S105) is made by heating the carbon nanoparticles subjected to the acid treatment step (S103) to a temperature of 50 to 90 ℃, the above-described heating temperature is not particularly limited, remaining on the surface of the carbon nanoparticles Any temperature range is possible so long as it can remove the acid component.

The above-described heat treatment step (S107) is a step of heat-treating the carbon nanoparticles passed through the drying step (S105) described above, by heating the carbon nanoparticles prepared through the drying step (S105) described above to a temperature of 400 to 500 ℃ Although the heat treatment step (S107) described above is made, volatile impurities and the like contained in the carbon nanoparticles are removed to provide high-purity carbon nanoparticles.

The above-described water dispersion step (S109) is a step of mixing the carbon nanoparticles undergoing the above-described heat treatment step (S107) with a metal hydroxide aqueous solution and irradiating ultrasonic waves, 4 to 7 parts by weight of the carbon nanoparticles 93 to 97 weight It is made by mixing ultrasonic waves with a frequency of 20 kHz and an amplitude of 48.8 micrometers for 1 hour, and the nanofluid containing the metal-treated carbon nanoparticles having improved water dispersibility is produced through the above-mentioned ultrasonic waves. .

At this time, the above-described metal hydroxide aqueous solution is made by mixing 0.05 to 2 mol of a metal hydroxide consisting of at least one selected from the group consisting of lithium hydroxide, aluminum hydroxide, sodium hydrogen carbonate, iron hydroxide, lead hydroxide and molybdenum hydroxide with 200 ml of purified water.

Hereinafter, the production method and physical properties of the nanofluid containing the metal-treated carbon nanoparticles according to the present invention will be described with reference to Examples.

<Example 1>

Activated carbon was milled for 48 hours using a tumbling ball mill and a mono planner mill to pulverize the nano-sized, surface-treated by immersing the pulverized carbon nanoparticles in M-chloroperbenzoic acid, and the immersed carbon nanoparticles were separated at 60 ° C. The dried carbon nanoparticles were heated to a temperature of 500 ° C. and heat-treated, and 5 parts by weight of the heat-treated carbon nanoparticles were mixed with 95 parts by weight of an aqueous solution in which 0.05 mol of sodium hydrogen carbonate was mixed with 200 ml of purified water, Was 20 kHz, and an ultrasonic wave having an amplitude of 48.8 micrometers was irradiated for 1 hour to prepare a nanofluid containing carbonized carbon nanoparticles.

<Example 2>

Proceed in the same manner as in Example 1, using a nano hydroxide instead of sodium hydrogen carbonate to prepare a nano-fluid containing the metal-treated carbon nanoparticles.

<Example 3>

Proceed in the same manner as in Example 1, using lithium hydroxide instead of sodium hydrogen carbonate to prepare a nanofluid containing metal-treated carbon nanoparticles.

<Example 4>

Proceed in the same manner as in Example 1, using activated carbon fibers instead of activated carbon to prepare a nanofluid containing metal treated carbon nanoparticles.

Example 5

Proceed in the same manner as in Example 2, using activated carbon fibers instead of activated carbon to prepare a nanofluid containing metal-treated carbon nanoparticles.

<Example 6>

Proceed in the same manner as in Example 3, using activated carbon fibers instead of activated carbon to prepare a nanofluid containing metal-treated carbon nanoparticles.

<Example 7>

Proceed in the same manner as in Example 1, using carbon black instead of activated carbon to prepare a nanofluid containing metal-treated carbon nanoparticles.

<Example 8>

Proceed in the same manner as in Example 2, using carbon black instead of activated carbon to prepare a nanofluid containing metal-treated carbon nanoparticles.

Example 9

Proceed in the same manner as in Example 3, using carbon black instead of activated carbon to prepare a nanofluid containing metal treated carbon nanoparticles.

<Example 10>

Proceed in the same manner as in Example 1, using graphene instead of activated carbon, using lead hydroxide instead of sodium hydrogen carbonate to prepare a nanofluid containing metal-treated carbon nanoparticles.

<Example 11>

Proceed in the same manner as in Example 1, but using graphene instead of activated carbon, using iron hydroxide instead of sodium hydrogen carbonate to prepare a nanofluid containing metal-treated carbon nanoparticles.

<Example 12>

Proceed in the same manner as in Example 1, but using graphene instead of activated carbon, using molybdenum hydroxide instead of sodium hydrogen carbonate to prepare a nanofluid containing carbon-treated carbon nanoparticles.

Comparative Example 1

The activated carbon was milled for 48 hours using a tumbling ball mill and a mono planner mill to be pulverized to nanosize, and 5 parts by weight of the nanoscale pulverized carbon nanoparticles were mixed with 95 parts by weight of purified water to prepare a nanofluid containing carbon nanoparticles.

Comparative Example 2

Activated carbon was milled for 48 hours with a tumbling ball mill and a mono planner mill, pulverized to nano size, immersed in M-chloroperbenzoic acid, and then mixed with 5 parts by weight of dry carbon nanoparticles with 95 parts by weight of purified water to contain carbon nanoparticles. Nanofluids were prepared.

Comparative Example 3

Proceed in the same manner as in Comparative Example 1, using carbon nanoparticles instead of activated carbon to prepare a nanofluid containing the carbon nanoparticles.

<Comparative Example 4>

Proceed in the same manner as in Comparative Example 2, using carbon nanoparticles instead of activated carbon to prepare a nanofluid containing the carbon nanoparticles.

Comparative Example 5

Proceed in the same manner as in Comparative Example 1, using carbon black instead of activated carbon to prepare a nanofluid containing carbon nanoparticles.

Comparative Example 6

Proceed in the same manner as in Comparative Example 2, using carbon black instead of activated carbon to prepare a nanofluid containing the carbon nanoparticles.

The thermal diffusion and electrical conductivity of the nanofluids containing the metal-treated carbon nanoparticles and the nanofluids containing the carbon nanoparticles prepared through the above Examples 1 to 12 and Comparative Examples 1 to 6 were measured. Indicated.

(However, the thermal diffusion coefficient was measured by a thermal diffusion coefficient measuring device using a thermal diffusion coefficient measuring method of α = k / (ρ × c), and the electrical conductivity was measured by the WalkLAB Digital Conductivity Pro meter of Trans Instruments.

TABLE 1

As shown in Table 1 above, the nanofluid containing the metal-treated carbon nanoparticles prepared through Examples 1 to 12 of the present invention is thermally diffused compared to the nanofluid containing the carbon nanoparticles prepared through Comparative Examples 1 to 6. It can be seen that the performance and electrical conductivity are greatly improved.

The present invention provides a method for producing nanofluids containing metal-treated carbon nanoparticles having excellent cooling, heat exchange and lubricity, and the nanofluids prepared according to the method are used in coolers, heat exchangers, and industries requiring lubricity. Can be used

Claims (8)

1. Milling the carbonaceous material;

   An acid treatment step of treating the surface of the carbon nanoparticles subjected to the milling step with an acid;

   A drying step of drying the carbon nanoparticles subjected to the acid treatment step;

   A heat treatment step of heat-treating the carbon nanoparticles subjected to the drying step; And

   And a water dispersion step of mixing the carbon nanoparticles subjected to the heat treatment step with an aqueous solution of metal hydroxide and irradiating ultrasonic waves.
2. The method according to claim 1,

   The carbonaceous material is a method for producing a nanofluid containing metal-treated carbon nanoparticles, characterized in that at least one selected from the group consisting of activated carbon, activated carbon fiber, carbon black and graphene.
3. The method according to claim 1,

   The milling step is a method for producing a composition containing metal-treated carbon nanoparticles, characterized in that the carbonaceous material is milled for 48 hours with a tumbling ball mill and a mono planner mill.
4. The method according to claim 1,

   Wherein said acid is one selected from the group consisting of m-chloroperbenzoic acid, hydrochloric acid and sulfuric acid.
5. The method according to claim 1,

   The heat treatment step is a method of producing a nanofluid containing metal-treated carbon nanoparticles, characterized in that the drying is performed by heating the carbon nanoparticles to a temperature of 400 to 500 ℃.
6. The method according to claim 1,

   The water dispersion step is 4 to 7 parts by weight of the carbon nanoparticles subjected to the heat treatment step is mixed with 93 to 97 parts by weight of a metal hydroxide aqueous solution, and the metal-treated carbon nanoparticles, characterized in that the irradiation is performed for 1 hour Method of preparing nanofluids.
7. The method according to claim 1 or 6,

   The metal hydroxide aqueous solution is a metal treatment, characterized in that by mixing with a 200 ml of purified water of 0.05 to 2 mol of a metal hydroxide consisting of at least one selected from the group consisting of lithium hydroxide, aluminum hydroxide, sodium hydrogen carbonate, iron hydroxide, lead hydroxide and molybdenum hydroxide Of a nanofluid containing the carbon nanoparticles.
8. The method according to claim 1 or 6,

   The ultrasonic wave has a frequency of 20 kHz, the amplitude of 48.8 micrometers, characterized in that the nanofluid containing the carbon-treated carbon nanoparticles manufacturing method.

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