KR20150015151A - Manufacturing method of zinc oxide/reduced graphite oxide composite using microwave - Google Patents

Abstract

The present invention relates to a manufacturing method of zinc oxide chemically connected to graphene oxide as a desulfurizing agent and, more specifically, a manufacturing method of zinc oxide/reduced graphene oxide compounds, which increases desulfurizing efficiency by using microwaves, comprising the steps of preparing a graphene oxide manufactured by which graphite oxidizes with use of an acid and an oxidizing agent and is peeled; mixing ethylene glycol with the graphene oxide and firstly distributing the same by using ultrasonic vibrations; mixing the mixture from the first distribution step with a sodium hydroxide (NaOH) solution and secondly distributing the same by using the ultrasonic vibrations; adding a zinc acetate (ZnAc) solution to the mixture from the second distribution step and mixing the same by using ultrasonic vibrations; adding a reducing agent to the mixture from the mixing step by using ultrasonic waves and making the same reduction through heat treatment with use of microwaves; cooling the mixture from the step of reduction via the heat treatment, washing the same with distilled water and drying the same in a frozen vacuum dryer, thereby preventing aggregation of zinc oxide generated at high temperatures and making the surface area of the zinc oxide particles become larger, leading to maximum adsorption rate of hydrogen sulfide.

Description

[0001] The present invention relates to a zinc oxide / reduced graphene oxide compound,

The present invention relates to a method for producing zinc oxide chemically bonded to graphene oxide as a desulfurizing agent, and more particularly to a method for producing desulfurization using microwave.

Hydrogen sulfide (H ₂ S) is one of the most common materials containing sulfur from all gases. In particular, hydrogen sulfide is a toxic gas and a major source of acid rain. Increasingly stringent environmental regulations and efforts to protect the separation / refinement process are requiring less and less hydrogen sulfide emissions. One effective method for removing such hydrogen sulfide is the adsorption method. Adsorption refers to the phenomenon that a fluid powder is attached to a solid surface in contact with it. Physical adsorption and chemical bonding (adsorption) by physical forces such as van der waals' force between the interface and a specific component And adsorbed by chemical adsorption (chemical adsorption). Physical adsorbents include activated carbon, zeolite, and the like, and metal oxides such as a chemical adsorbent. Activated carbon is carbon with various pore structure, and removes organic substances by the pulling force and adsorption force of the active surface. Zeolite is a kind of natural minerals. Due to its unique adsorption properties and ion exchange ability, it has a wide range of applications such as desiccants, detergents and catalysts. Metal oxides are various metal compounds combined with oxygen to adsorb sulfur by utilizing the property of interacting with the metal or oxygen of sulfur. The interaction is formed by the transfer of electrons from the hydrogen sulphide orbital to the orbitals of the unoccupied metal.

Based on the results of various desulfurization tests conducted by various research institutes until the early 1980s, Westmoreland and Harrison systematically conducted desulfurization experiments using 28 elements. Ten useful elements (Fe, Zn, Mo , Mn, V, Ca, Sr, Ba, Cu, and W) are suitable for desulfurization in the temperature range of 400 to 1200 ° C. 25, 429-437), which is an example of a mixed-oxide sorbent for high-temperature removal of hydrogensulfuric acid (Tamhankar, S., Bagajewicz, M. and Gavalas, G. R.,

Among these, zinc oxide (ZnO), which is a metal oxide oxidized with zinc (Zn), generates water vapor accompanied by zinc sulfide (ZnS) by reaction with hydrogen sulfide, so that hydrogen sulfide is very effectively removed. This reaction produces a metal sulfide and is shown in the following equation.

Formula 1

ZnO _(s) + H ₂ S _(g) ZnS _(s) + H ₂ O _(g)

This hydrogen sulfide adsorption mechanism is introduced with the fact that H ₂ S is separated into H ⁺ and HS ^- from early on, and it is accompanied by HS ^- diffusion into the oxide lattice structure.

In order to achieve a higher desulfurization effect, zinc oxide, which is a chemisorbing agent, is dispersed in reduced graphene oxide, which is a physical adsorbent and activated carbon, such as activated carbon, so that zinc oxide and zinc oxide Reduced graphene oxide compounds have been studied.

Korean Patent Publication No. 2009-0067856 discloses "a method for producing a zinc ferrite catalyst for removing hydrogen sulfide contained in a coke oven gas ", wherein hydrogen sulfide contained in the coke oven gas is mixed with iron oxide (Fe ₂ O ₃ ) produced in the iron- Zinc oxide (ZnO) were mixed and reacted to prepare a catalyst of zinc ferrite (Zn-ferrite) crystal. However, pellets prepared by mixing iron oxide powder and zinc oxide powder with sodium carbonate (Na ₂ CO ₃ ) powder should be heat treated at a high temperature of 950 ~ 1050 ° C in a nitrogen atmosphere. Of the various metal oxides for desulfurization in general, zinc oxide is most widely used for adsorbing hydrogen sulfide, and many nanoparticles are being produced to increase the surface area and increase the desulfurization efficiency. However, existing metal oxides such as zinc oxide require a somewhat higher temperature condition, and the efficiency is lowered because zinc oxide nanoparticles aggregate with each other at a high temperature to reduce the surface area of the adsorbent.

Republic of Korea public patent 2009-0067856

Tamhankar, S. S., Bagajewicz, Ind. Eng. Chem. Process Des. Dev., 25, 429-437

SUMMARY OF THE INVENTION The present invention has been devised to solve the problems described above, and it is an object of the present invention to provide a method of manufacturing a zinc oxide / reduced graphene oxide compound that prevents the aggregation of zinc oxide nanoparticles at high temperatures through a short heat treatment using microwaves .

In order to solve the above-described problems, it is an object of the present invention to provide a zinc oxide / reduced graphene oxide compound which is capable of preventing the aggregation of zinc oxide at high temperatures through rapid and short heat treatment using microwaves during the process of reducing graphene oxide, The present invention has been accomplished by maximizing the desulfurizing effect of the compound.

The present invention provides a method for producing graphite oxide, comprising: preparing graphene oxide obtained by oxidizing graphite with an acid and an oxidizing agent; A first dispersion step using ultrasonic vibration after mixing ethylene glycol in the graphene oxide; A second dispersion step using an ultrasonic vibration after mixing the mixed solution having undergone the first dispersion step with an aqueous solution of sodium hydroxide (NaOH); Adding an aqueous solution of zinc acetate (ZnAc) to the mixed solution obtained through the secondary dispersion step, and mixing with an ultrasonic vibrator; Adding a reducing agent to the mixed solution obtained through mixing with the ultrasonic vibrator, and heat-treating the mixed solution by microwave heating; And a step of cooling the mixed solution through the heat treatment and reducing step, washing with distilled water, and drying in a freeze-drier. The present invention also provides a method for producing a zinc oxide / reduced graphene oxide compound.

The invention also, the acid is hydrogen chloride (HCl), sulfuric acid (H ₂ SO _4), nitric acid (HNO _3), phosphoric acid (H ₃ PO ₄₎ one or more, the production method of the zinc oxide / the reduced graphene oxide compound of to provide.

The present invention also provides a process for preparing a zinc oxide / reduced graphene oxide compound wherein the oxidant is one of sodium nitrate (NaNO ₃ ), potassium permanganate (KMnO ₄ ).

The present invention also provides a method for producing a zinc oxide / reduced graphene oxide compound, wherein the time for dispersing using the ultrasonic vibration is 20 minutes to 40 minutes.

The present invention also provides a process for preparing a zinc oxide / reduced graphene oxide compound wherein the zinc acetate aqueous solution has a molar concentration of 0.05M to 0.09M.

The present invention also relates to a process for producing a magnetic material, wherein the mixing time with the magnetic stirrer is 20 minutes to 40 minutes,

Zinc oxide / reduced graphene oxide compound.

The present invention also provides a process for preparing a zinc oxide / reduced graphene oxide compound, wherein the reducing agent is one of sodium borohydride (NaBH ₄ ), hydrazine.

The present invention also provides a method for producing a zinc oxide / reduced graphene oxide compound by repeating the step of heating the microwave for 40 seconds to 80 seconds and then waiting for the heating time twice to four times .

The zinc oxide / reduced graphene oxide compound manufacturing method of the present invention prevents micronized zinc oxide particles from aggregating at high temperatures and maximizes the adsorption rate of hydrogen sulfide by enlarging the surface area of the zinc oxide particles.

1 is a schematic view of a process for producing graphene oxide used in the present invention.
FIG. 2 is a graph showing the relationship between the amount of zinc oxide / reduction (A) and the amount of zinc oxide / reduction (B) using graphene oxide, (B) reduced graphene oxide using the reflux method, (C) reduced graphene oxide using microwave, (E) X-ray diffraction pattern of zinc oxide / reduced graphene oxide compound using microwave.
FIG. 3 is a graph showing the results of (A) graphite oxide, (B) reduced graphene oxide using the reflux method, (C) reduced graphene oxide using microwave, (D) zinc oxide / reduced graphene (E) an FT-IR spectrum of a zinc oxide / reduced graphene oxide compound using a microwave.
4A is a scanning electron microscope (SEM) photograph of zinc oxide / reduced graphene oxide using a reflux method.
FIG. 4B is an electric scanning microscope (SEM) photograph of zinc oxide / reduced graphene oxide using a microwave.
5A is a transmission electron microscope (TEM) photograph of zinc oxide / reduced graphene oxide using a reflux method.
5B is a transmission electron microscope (TEM) photograph of zinc oxide / reduced graphene oxide using a microwave.
FIG. 6 is a graph showing the relationship between zinc oxide / carbon nanotube compound (A) and zinc oxide / carbon nanotube compound using (B) reflux method, (C) zinc oxide / carbon nanotube compound using microwave, (E) Microwave-assisted zinc oxide / reduced graphene oxide compound adsorbed to hydrogen sulfide.
Fig. 7 is a schematic diagram of an experimental apparatus in which hydrogen sulfide adsorption experiments were conducted under the same conditions for all compounds.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

Prior to the detailed description of the present invention, terms and words used in the present specification and claims should not be construed as limited to ordinary or dictionary terms. Therefore, the embodiments described in this specification and the configurations shown in the drawings are merely the most preferred embodiments of the present invention and do not represent all the technical ideas of the present invention. Therefore, It is to be understood that equivalents and modifications are possible.

Here, in the entire drawings for explaining the embodiments of the present application, those having the same functions are denoted by the same reference numerals, and a detailed description thereof will be omitted.

The present invention relates to a process for preparing zinc oxide / reduced graphene oxide compounds using microwaves. In order to achieve a higher desulfurization effect as a desulfurizing agent, zinc oxide, which is a chemical adsorbent, is dispersed in reduced graphene oxide, which is a physical adsorbent and carbon such as activated carbon, Zinc and reduced graphene oxide compounds are being studied.

Graphene is a two-dimensional material made of carbon atoms. It has a honeycomb structure. When it is stacked in three dimensions, it becomes graphite. In one dimension, carbon nanotube becomes a carbon nanotube. When it is made into a ball, it becomes a fullerene. Material. It is very stable in structure and chemistry, has a charge mobility more than 100 times higher than silicon, and has a very high transparency and excellent thermal / mechanical properties because it is only one carbon atom (0.35 nm) thick. In 2004, the University of Manchester's Geim group succeeded in separating graphene from graphite for the first time, resulting in high charge mobility, high current density, excellent thermal conductivity and low calorific value, chemical and high mechanical strength, chemical A variety of reactions, simple patterning processes, flexibility, and stretchability. Recently, new graphene synthesis methods for large-area / high-volume production have been developed and the applicability as various electronic devices has further increased.

Graphene is synthesized by Scotch tape method, chemical synthesis method, CVD growth method, epitaxy synthesis method and the like. The Scotch tape method is a method of obtaining multiple layers of graphene by repeatedly folding and folding the graphite several times on a Scotch tape. Although it is a very simple method, the graphene produced by this method can not control the size and shape, and thus it is difficult to apply the graphene to the device. The chemical synthesis method is a method of separating and reducing graphite to obtain graphene. Graphite oxidized with an acid and an oxidizing agent has strong hydrophilicity and it is easy to insert the water molecule between the surface and the surface. As a result, the interval between the surfaces increases to 6 ~ 12 Å and can be easily peeled off by using a long stirring or an ultrasonic mill. The graphene oxide (oxidized graphene) obtained in this way exists in the form of a hydroxyl group and an epoxy group on the surface and a carboxyl group on the edge, so that most of the inherent properties of graphene are lost. However, when the graphene oxide is reduced again by liquid or vapor hydrazine, most functional groups are removed to obtain graphene, and the graphene produced by this method is called reduced graphene oxide. The chemical graphene synthesis method has a disadvantage in that the physical properties of graphene are lower than those of other methods, but it has a great advantage that it can be easily functionalized, mass-produced and large-sized, and is not limited by the type and structure of the substrate. Researches are being actively pursued. The CVD growth method uses a transition metal that absorbs carbon well as a catalyst layer. When the carbon in the mixed gas of CH ₄ , H ₂ and Ar injected at a high temperature of 1,000 ° C. or higher reacts with the catalyst layer and then quenched, And growing graphene on the surface. The epitaxy synthesis method is a method of growing a graphene layer by growing carbon on the surface by heat treatment of a material in which carbon is adsorbed or contained in the crystal, such as silicon carbide (SiC), in a high temperature atmosphere at about 1,500 ° C.

Among them, the present invention produced a zinc oxide / reduced graphene oxide compound by applying a chemical synthesis method which is the closest to the goal of large area / mass production of graphene. In the process of reducing zinc oxide / reduced graphene oxide compounds, the rapid and short heat treatment using microwaves in the process of reducing graphene oxide leaves a large number of oxygen functional groups on the surface that serve to fix nano-sized zinc oxide particles. , It is possible to prevent aggregation of zinc oxide at high temperatures, thereby maximizing the desulfurization effect of the compound.

A method for producing zinc oxide and a reduced graphene oxide compound using microwave is as follows. The present invention relates to a method for producing graphene oxide by oxidizing graphite with an acid and an oxidizing agent, A first dispersion step using ultrasonic vibration after mixing ethylene glycol in the graphene oxide; A second dispersion step using an ultrasonic vibration after mixing the mixed solution having undergone the first dispersion step with an aqueous solution of sodium hydroxide (NaOH); Adding an aqueous solution of zinc acetate (ZnAc) to the mixed solution obtained through the secondary dispersion step, and mixing with an ultrasonic vibrator; Adding a reducing agent to the mixed solution obtained through mixing with the ultrasonic vibrator, and heat-treating the mixed solution by microwave heating; And a step of cooling the mixed solution through the heat treatment and reducing step, washing with distilled water, and drying in a freeze-drier. The present invention also provides a method for producing a zinc oxide / reduced graphene oxide compound.

1 is a schematic view of a process for producing graphene oxide used in the present invention. The graphene oxide is prepared by oxidizing graphite with an acid and an oxidizing agent and then peeling the graphite oxide. In one embodiment of the present invention, the acid may use at least one of hydrogen chloride (HCl), sulfuric acid (H ₂ SO ₄ ), nitric acid (HNO ₃ ), phosphoric acid (H ₃ PO ₄ ) ₃ ), and potassium permanganate (KMnO ₄ ). The prepared graphene oxide was mixed with ethylene glycol and dispersed using ultrasonic vibration for 20 to 40 minutes. Then, the mixture was mixed with an aqueous solution of sodium hydroxide (NaOH), and ultrasonic vibration was applied thereto for 20 minutes To 40 minutes. The aqueous solution of zinc acetate is added to the mixed solution and mixed with an ultrasonic vibrator. In one embodiment of the present invention, the molar concentration of the zinc acetate aqueous solution is 0.05M to 0.09M, and the mixing time with the ultrasonic vibrator is 20 minutes to 40 minutes. The mixture that has been mixed with the ultrasonic vibrator is added with a reducing agent. And then subjected to a step of heat treatment by microwave and reduction. In one embodiment of the present invention, the reducing agent is at least one selected from the group consisting of sodium borohydride (NaBH ₄ ) and hydrazine, and the heating process using the microwave is performed for 40 seconds to 80 seconds, Is repeated two to four times.

The microwave-assisted reduction method has a faster heating rate than the reflux heating method using a reflux apparatus, and the entire solution is uniformly heated to shorten the reaction time, thereby reducing the particle size of the zinc oxide and increasing the surface area capable of adsorbing hydrogen sulfide There are advantages. Using microwaves, graphene oxide reduces the oxygen functionality on the surface of graphene oxide more than the conventional reflux method. The oxygen functional groups uniformly disperse zinc oxide on the surface of the reduced graphene oxide to prevent aggregation of zinc oxide particles at high temperatures. The mixed solution having been subjected to the heat treatment and reduction step is cooled, washed with distilled water, and then dried in a freeze dryer to prepare zinc oxide / reduced graphene oxide compound.

Hereinafter, embodiments are provided to facilitate understanding of the present invention. However, the following examples are provided only for the purpose of easier understanding of the present invention, and the present invention is not limited to the following examples.

[Example 1] Production of zinc oxide / reduced graphene oxide (ZnO / rGO-M) using microwave

400 mg of graphene oxide was added to 200 ml of ethylene glycol, and the mixture was first dispersed in an ultrasonic vibrator for 30 minutes. Then, the mixture was mixed with 100 ml of an aqueous solution of 0.1 M sodium hydroxide, and the mixture was stirred with a spoon and dispersed for 30 minutes in an ultrasonic vibrator. A 0.07M zinc acetate aqueous solution was added to the mixed solution after the dispersion process, and the mixture was mixed with an ultrasonic vibrator for 30 minutes. After mixing, zinc hydroxide (Zn (OH) ₂ ) was produced, resulting in an opacifying solution. In order to obtain a stronger reducing environment, hydrazine (300 μl) was added to the solution and stirred. And heated. To prevent the temperature rise too fast, 1 minute heating and 1 minute maintenance were repeated 3 times. After the last heating, at very high temperatures, the precipitate floated to the surface of the water, but after cooling for a sufficient time, all of the precipitate sank to the bottom. The mixed solution, in which the precipitate was deposited, was washed twice with distilled water and filtered, and then dried with a freeze dryer to prepare zinc oxide / reduced graphene oxide using microwave.

[Comparative Example 1] Production of zinc oxide / reduced graphene oxide (ZnO / rGO-R) using a reflux method

400 mg of graphene oxide was added to 200 ml of ethylene glycol, and the mixture was first dispersed in an ultrasonic vibrator for 30 minutes. Then, the mixture was mixed with 100 ml of an aqueous solution of 0.1 M sodium hydroxide, and the mixture was stirred with a spoon and dispersed for 30 minutes in an ultrasonic vibrator. A 0.07M zinc acetate aqueous solution was added to the mixed solution after the dispersion process, and the mixture was mixed with an ultrasonic vibrator for 30 minutes. After mixing, zinc hydroxide (Zn (OH) ₂ ) was formed as a cloudy solution, and 300 μl of hydrazine was mixed for a stronger reducing environment. Then, Lt; / RTI > for 24 hours. The reduced mixed solution was rinsed with distilled water and filtered twice, and then dried with a freeze drier to prepare zinc oxide / reduced graphene oxide using a reflux method.

[Comparative Example 2] Production of zinc oxide / reduced carbon nanotube (ZnO / CNT-M) using microwave

In place of the graphene oxide of Example 1, 200 ml of ethylene glycol was added to the carbon nanotubes, and the mixture was first dispersed in an ultrasonic vibrator for 30 minutes. Then, the mixture was mixed with 100 ml of an aqueous solution of sodium hydroxide 0.1 M and then stirred with a spoon. Lt; / RTI > A 0.07M zinc acetate aqueous solution was added to the mixed solution after the dispersion process, and the mixture was mixed with an ultrasonic vibrator for 30 minutes. After mixing, zinc hydroxide (Zn (OH) ₂ ) was produced, resulting in an opacifying solution. In order to obtain a stronger reducing environment, hydrazine (300 μl) was added to the solution and stirred. And heated. To prevent the temperature rise too fast, 1 minute heating and 1 minute maintenance were repeated 3 times. After the last heating, at very high temperatures, the precipitate floated to the surface of the water, but after cooling for a sufficient time, all of the precipitate sank to the bottom. The mixed solution, in which the precipitate was deposited, was washed twice with distilled water and filtered, and then dried with a freeze dryer to prepare zinc oxide / reduced carbon nanotubes by microwave irradiation.

[Comparative Example 3] Production of zinc oxide / reduced carbon nanotube (ZnO / CNT-R) using a reflux method

In place of the graphene oxide of Comparative Example 1, carbon nanotubes were firstly dispersed in 200 ml of ethylene glycol by an ultrasonic vibrator for 30 minutes, mixed with 100 ml of 0.1 M aqueous sodium hydroxide solution, stirred with a spoon, Lt; / RTI > A 0.07M zinc acetate aqueous solution was added to the mixed solution after the dispersion process, and the mixture was mixed with an ultrasonic vibrator for 30 minutes. After mixing, zinc hydroxide (Zn (OH) ₂ ) was formed as a cloudy solution, and 300 μl of hydrazine was mixed for a stronger reducing environment. Then, Lt; / RTI > for 24 hours. Reduced mixed solution was washed with distilled water and filtered twice and dried with a freeze dryer to prepare zinc oxide / reduced carbon nanotubes by a reflux method.

[Comparative Example 4] Production of zinc oxide (ZnO)

200 ml of a 0.1 M aqueous solution of zinc acetate and 200 ml of a 0.7 M aqueous solution of sodium hydroxide were mixed to produce opaque precipitates as zinc hydroxide was formed. The mixture was aged for 24 hours for sufficient reaction. washed with distilled water until the pH was neutral and dried in a vacuum dryer. The dried zinc hydroxide was fired at 550 DEG C for 2 hours to prepare zinc oxide (ZnO).

FIG. 2 is a graph showing the relation between the amount of zinc oxide / reduced graphene (A) and the amount of zinc oxide / reduced graphene (A) by using graphene oxide, (B) reduced graphene oxide using the reflux method, (C) reduced graphene oxide using microwave, Oxide compound, and (E) a microwave-assisted zinc oxide / reduced graphene oxide compound. As shown in the graphs (D) and (E), in which (A) the graphene oxide was reduced and the crystal structure peak disappeared and the zinc oxide was added to the reduced graphene oxide, the zinc oxide particles successfully rose to the reduced graphene surface Respectively.

FIG. 3 is a graph showing the results of (A) graphite oxide, (B) reduced graphene oxide using the reflux method, (C) reduced graphene oxide using microwave, (D) zinc oxide / reduced graphene Oxide compound, and (E) microwave-assisted zinc oxide / reduced graphene oxide compound. It can be confirmed that oxygen functional groups are attached to the surface of the reduced graphene oxide through the FT-IR spectrum.

4A is an SEM photograph of zinc oxide / reduced graphene oxide using reflux method and FIG. 4B is an SEM photograph of zinc oxide / reduced graphene oxide using microwave. 5A is a transmission electron microscope (TEM) photograph of zinc oxide / reduced graphene oxide using a reflux method, and FIG. 5B is a transmission electron microscope (TEM) photograph of zinc oxide / reduced graphene oxide using microwave. The scanning electron microscope (SEM) and transmission electron microscope (TEM) photographs show that the zinc oxide particles of the compound using the microwave are smaller than the reflux method. The smaller the particles of zinc oxide, the wider the surface area that can be adsorbed and the higher the desulfurization efficiency.

FIG. 6 is a graph showing the relationship between zinc oxide / carbon nanotube compound (A) and zinc oxide / carbon nanotube compound using (B) reflux method, (C) zinc oxide / carbon nanotube compound using microwave, (E) Microwave-assisted zinc oxide / reduced graphene oxide compound adsorbed to hydrogen sulfide. Breakthrough time means the time from the introduction of hydrogen sulfide to the adsorption of the adsorbent to the adsorption of hydrogen sulfide after the adsorption of the maximum amount of hydrogen sulfide. The longer the breakthrough time, the more the adsorbent adsorbs the hydrogen sulfide. In the hydrogen sulfide adsorption test, the compound was filled in a fixed bed reactor at a volume of 1 cm ³ and the upper and lower portions were fixed with glass wool. The gases were dry air and nitrogen and 3.01% hydrogen sulphide. In order to create an environment similar to the general desulfurization process, a bubbler was placed in the middle of the pipe through which the air was introduced to make dry air into saturated air. Because only air and hydrogen sulphide are poured into the reactor, the sulfur level is very high and diluted with nitrogen to a concentration that can be analyzed by sulfur analyzer. Aluminum oxide (alumina) was mixed together to prevent drift. Further, in order to prevent the sample from mixing due to a sudden change in flow rate of the gas and prevent the drift, the above compounds were sufficiently mixed in the reactor and the upper part was fixed with glass wool. FIG. 7 shows a schematic diagram of the experimental equipment in which the hydrogen sulfide adsorption test was performed. As a result of the hydrogen sulfide adsorption experiment, microwave - assisted zinc oxide / reduced graphene oxide adsorbed the most sulfur, while zinc oxide adsorbed the least sulfur. The difference in the sulfur adsorption amount between zinc oxide / reduced graphene oxide and zinc oxide using microwave was more than 10 times. Also, zinc oxide / reduced graphene oxide prepared by microwave adsorbed more than twice as much sulfur as zinc oxide / reduced graphene oxide prepared by the reflux method.

Claims (7)

Preparing graphene oxide by oxidizing graphite with an acid and an oxidizing agent and then peeling off;
A first dispersion step using ultrasonic vibration after mixing ethylene glycol in the graphene oxide;
A second dispersion step using an ultrasonic vibration after mixing the mixed solution having undergone the first dispersion step with an aqueous solution of sodium hydroxide (NaOH);
Adding an aqueous solution of zinc acetate (ZnAc) to the mixed solution obtained through the secondary dispersion step, and mixing with an ultrasonic vibrator;
Adding a reducing agent to the mixed solution obtained through mixing with the ultrasonic vibrator, and heat-treating the mixed solution by microwave heating;
And cooling the mixed solution through the heat treatment and reduction step, washing with distilled water, and drying in a freeze-drier.
Process for producing zinc oxide / reduced graphene oxide compound
The method according to claim 1,
One of the acid is hydrogen chloride (HCl), sulfuric acid (H ₂ SO _4), nitric acid (HNO _3), phosphoric acid (H ₃ PO ₄₎ or more,
Process for producing zinc oxide / reduced graphene oxide compound
The method according to claim 1,
The oxidant may be one of sodium nitrate (NaNO ₃ ), potassium permanganate (KMnO ₄ )
Process for producing zinc oxide / reduced graphene oxide compound
The method according to claim 1,
Wherein the primary dispersion using the ultrasonic vibration, the secondary dispersion time and the mixing time are 20 minutes to 40 minutes,
Process for producing zinc oxide / reduced graphene oxide compound
The method according to claim 1,
Wherein the molar concentration of the zinc acetate aqueous solution is 0.05 M to 0.09 M,
Process for producing zinc oxide / reduced graphene oxide compound
The method according to claim 1,
Wherein the reducing agent is one of sodium borohydride (NaBH ₄ ), hydrazine,
Process for producing zinc oxide / reduced graphene oxide compound
The method according to claim 1,
The heat treatment using microwaves is repeated 40 seconds to 80 seconds and then the process of waiting for the heating time is repeated 2 to 4 times,
Process for producing zinc oxide / reduced graphene oxide compound

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