KR101394016B1 - Manufacturing method of metal oxide-carbon composite and composite and electrode thereby - Google Patents

Abstract

The present invention relates to a process for producing a complex of a metal oxide and a carbonaceous material, a complex thereof and a storage water treatment electrode using the complex, wherein a fatty acid solution in which ethanol is dispersed is prepared and then a substance for saponification reaction is added and dissolved A solution preparation step (S10) of adding metal oxide particles and stirring; A saponification reaction step (S20) in which the saponification reaction proceeds in the solution by the saponification reaction material; A sintering step (S30) of producing a composite material by synthesizing a metal oxide and a carbonaceous material by firing a solution in which the saponification reaction proceeds within a range of a predetermined temperature and time; And a water washing and drying step (S40) of filtering the composite material solidified by the firing step to remove unreacted materials and drying the composite material to form a carbon material on the surface of the metal oxide (S40) And the electrode is used as an anion and a cation removing electrode in the CDI process, there is an effect of increasing the electrostatic capacitance and improving the ion removal rate compared to the electrode using only the activated carbon in the related art .

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a composite material of metal oxide and carbonaceous material,

TECHNICAL FIELD The present invention relates to a method for producing a composite of metal oxide and carbonaceous material, a composite thereof and a storage water treatment electrode using the composite, and more particularly to an additive for efficiently removing ions contained in raw water for the purpose of water treatment A composite of the metal oxide and the carbonaceous material to be used, and a composite made therefrom, and an electrode manufactured using the composite. That is, a composite in which a carbon material is formed on the surface of a metal oxide is manufactured, and then an electrode using a composite of the metal oxide and the carbonaceous material as a main active material is manufactured, and ions are adsorbed Thereby efficiently removing the ions contained in the raw water, and a composite and an electrode manufactured using the composite.

As an background of the present invention, an electrode is manufactured using activated carbon having a specific surface area of 1,500 to 2,500 m < 2 > g < ^{-1 &} gt ;, and an external power source is applied to a symmetrical electrode to adsorb ions contained in the raw water to the activated carbon There is a capacitive ion removal device which uses a method of removing the ions.

However, the characteristics of the carbonaceous material, which is the main material of the activated carbon, can not be stably impregnated with the electrolyte solution in the aqueous solution, and thus, the available capacity of the activated carbon is not fully utilized.

Korean Patent Registration No. 10-1020729 Korean Patent Registration No. 10-0622737 Korean Patent Publication No. 10-2011-0033733

The object of the present invention is to improve the impregnation characteristics between the carbon material and the electrolytic solution and to increase the ion removal rate of the raw water in the water treatment process. And a method for producing a composite of a metal oxide and a carbonaceous material, which is produced by forming a carbonaceous material by using the carbonaceous material.

Another object of the present invention is to provide a storage water treatment electrode prepared by applying a composite prepared by the above production method, and a mixed material obtained by mixing the composite with a binder, a solvent and an activated carbon as an additive, and pressing the mixture.

Another object of the present invention is to provide a storage water treatment electrode in which a storage water treatment electrode manufactured using the composite as an additive is applied to a flat cell for water treatment so as to be used in a condensation deionization (CDI) process.

In order to accomplish the above object, the present invention provides a method for producing a composite of metal oxide and carbonaceous material, which comprises preparing a fatty acid solution in which ethanol is dispersed, adding a substance for saponification reaction and dissolving the metal oxide particle, Stirring solution preparation step (S10); A saponification reaction step (S20) in which the saponification reaction proceeds in the solution by the saponification reaction material; A sintering step (S30) of producing a composite material by synthesizing a metal oxide and a carbonaceous material by firing a solution in which the saponification reaction proceeds within a range of a predetermined temperature and time; And a water washing and drying step (S40) of filtering the composite material solidified by the firing step to remove unreacted materials and then drying to form a composite material having a carbon material on the surface of the metal oxide.

It is preferable that the metal oxide is any one of titanium oxide, zinc oxide, manganese oxide and iron oxide.

In the firing step (S30), the temperature is preferably in the range of 400 to 500 DEG C, and the period of time is preferably 2 to 6 hours.

When the metal oxide is a manganese oxide, the manganese oxide is synthesized as a manganese oxide in an? -Phase under a firing condition in a range of 400 to 500 占 폚.

It is preferable that the fatty acid is a fatty acid containing a monovalent carboxyl group in the range of C ₁₂ to C ₁₈ .

It is also preferable to induce a saponification reaction on the surface of the metal oxide to synthesize a fatty acid in the form of a macromolecule or macromolecule.

The content of the carbon material formed on the surface of the metal oxide is preferably 5 to 20 wt%.

A composite of a metal oxide and a carbonaceous material produced by the manufacturing method of any one of claims 1 to 7

In addition, a composite of a metal oxide and a carbonaceous material within a range of 5 to 20 wt% is used as an additive, active carbon as an active material and the composite are added as an additive to a mixed solution of a binder and a solvent, The primary electrode coated by coating is compressed and then cut to a predetermined size to complete the secondary electrode and use it as an electrode.

When an electrolytic water treatment electrode is used to construct an asymmetrically structured flat plate cell for use in a capacitor deionization (CDI) process, an electrode to which manganese oxide is added as an anion removal electrode, an activated carbon electrode or a titanium Another feature is the use of an oxide-doped electrode.

The method for producing the composite of the metal oxide and the carbonaceous material of the present invention and the composite thereof and the capacitor water treatment electrode using the composite have the following two effects.

Results of electrochemical characterization

As a result of evaluating the electrostatic capacity by the three electrode method for evaluating the electrochemical characteristics using the manufactured accumulative water treatment electrode, as shown in FIG. 6, it was found that the electrode having a capacity of 80 F / g or less in the positive electrode potential region The increase in capacitance of 30 F / g can be confirmed, and the capacitance increase of 40 F / g at the negative electrode potential is effective.

celebration Deionization ( capacitive deionization , CDI ) Application Effectiveness of Process

As a result of evaluating the characteristics after applying to the CDI process as shown in the schematic diagram of FIG. 6 using the storage water treatment electrode prepared above, it was found that, in the case of an electrode containing 10 wt% of a composite of manganese oxide and carbonaceous material, The ion removal rate is increased by 20%, which can be confirmed from FIG. 7 and FIG. 8.

FIG. 1 is a flowchart illustrating a process for manufacturing a capacitor-based water-treatment electrode using the composite of the metal oxide and the carbonaceous material according to the present invention, and a CDI process
FIG. 2 is a photograph of a composite of a metal oxide and a carbonaceous material using SEM, wherein (a) is an SEM image of manganese oxide, and (b) is a SEM image of a composite of manganese oxide and carbonaceous material
Fig. 3 is a graph showing the results of analysis of carbon content by thermogravimetric analysis (TGA)
FIG. 4 is a result of the capacitance evaluation using the cyclic voltammetry, in which (a) shows the results for the cathode potential region, (b) shows the results for the anode potential region
FIG. 5 shows the results of the electrostatic capacity evaluation according to the content ratio of MnO ₂ / C, wherein (a) shows the result for the cathode potential region, (b)
6 is a schematic diagram according to the CDI process application
FIG. 7 is a graph showing the results of comparative evaluation according to the result of raw water treatment using the electrolytic water treatment electrode according to the present invention
FIG. 8 is a graph showing the results of cycle performance evaluation according to the result of raw water treatment using the storage water treatment electrode according to the present invention

Hereinafter, a method of manufacturing a composite of a metal oxide and a carbonaceous material according to the present invention, a composite material thereof, and a capacitor water treatment electrode using the composite material will be described in detail with reference to the accompanying drawings. It is to be understood that the present invention is not limited to the disclosed embodiments, but may be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, It is provided to inform.

In the present invention, a composite in which a manganese oxide is selected as a metal oxide to synthesize the manganese oxide and a carbonaceous material, and a storage water treatment electrode manufactured using the composite as an additive are manufactured through the following steps with reference to FIG. 1 and evaluated do.

Solution preparation step ( S10  step)

Preparing a fatty acid solution for the purpose of forming a carbonaceous material on the manganese oxide surface as a (step S10), sikimyeo is dispersed enthanol the fatty acid solution, a fatty acid can be applied is _{Lauric acid (C 12 H 24 O} 2), Myristic acid ( _{C 14 H 28 O 2),} Palmitic acid (C 16 H 32 O 2), Stearic acid (C 18 H 36 O 2), with Carboxy group (-OOH) Oleic acid ( C 18 H 34 O 2) is 1 It is possible to apply saturated or unsaturated fatty acids.

When the carbonaceous material is formed on the surface of the manganese oxide, the carbonaceous material is not synthesized on the surface of the manganese oxide, and only the fatty acids are synthesized during the following saponification reaction. The content of the carbonaceous material synthesized on the surface is decreased.

In addition, sodium hydroxide (NaOH) is added in accordance with the equivalent ratio of the fatty acid to be added and dissolved. Thereafter, manganese oxide particles are added to prepare a solution, followed by stirring for 2 hours or more.

The metal oxide may be selected from titanium oxide, zinc oxide and iron oxide in addition to manganese oxide.

Saponification  The reaction step ( S20  step)

The saponification reaction proceeds in the solution by sodium hydroxide (NaOH) added in the solution preparation step (S10), so that the fatty acid in the solution has a characteristic of a large fatty acid having a long carbon chain. At this time, adsorption of macro-fatty acids occurs on the surface of the manganese oxide in the solution.

Firing step ( S30  step)

The solution having undergone the saponification reaction in the calcination step is calcined at a temperature of 400 to 500 ° C for 2 to 6 hours to prepare a composite material of manganese oxide and carbonaceous material. In this process, aimed α-MnO ₂ can not be obtained under conditions of 400 ° C. or lower, and phase change of MnO ₂ proceeds under conditions of 500 ° C. or higher. Also, the content of carbon formed on the surface of the manganese oxide is small under the firing condition of 2 hours or less, and the content of carbon formed on the surface of the manganese oxide under the condition of 6 hours or more causes a problem of suppressing the characteristic of the MnO ₂ .

Washing and drying step ( S40  step)

After the sintering step (S30), the composite material of manganese oxide and carbonaceous material is solidified, filtered, and then, unreacted material is removed by washing with alcohol and acetone. The composite of the manganese oxide and the carbonaceous material of the present invention is then granulated through a drying step of removing the solution in the composite material at about 80 ° C. The carbon material is formed or coated on the surface of the manganese oxide by the synthesis of the manganese oxide and the carbon material.

Synthesis of manganese oxide and carbonaceous material

The carbon content of the manganese oxide is about 10% through the synthesis of the manganese oxide and the carbonaceous material. The result is shown in FIG. The composite of the synthesized manganese oxide and the carbonaceous material has a spherical shape. The size of the composite is shown in FIG. 2 as a result of SEM analysis. As a result, a particle characteristic of about 500 to 700 nm is obtained.

Next, a capacitor water treatment electrode was prepared using a composite of manganese oxide and carbonaceous material as an additive, and evaluated by an electrochemical evaluation method.

Electrode fabrication and electrochemical evaluation steps ( S50  step)

PvDF (polyvinylidene fluoride), a binder, is dissolved in NMP (n-methyl-pyrrolidone) as a solvent. In the mass ratio, the binder is added so that the solid content ratio does not exceed 5 wt%. In the case of NMP, it is added in an amount of 70% or less based on the total mass. As the content of the binder increases, the resistance increases. As the amount of NMP increases, the density of the slurry decreases, which causes the reduction of the electrode density.

In the mixed solution prepared by the binder and the solvent, activated carbon, which is an active material, is prepared in a predetermined ratio of 75 to 95 wt%, and a composite of the prepared manganese oxide and carbonaceous material is added in an amount of 5 to 20 wt% A capacitor water treatment electrode of the present invention is manufactured by using a doctor blade method as a mixed solution. That is, the mixed solution, in which an active material and a complex are added to a graphite foil as a current collector, is coated to a predetermined thickness by the doctor blade method to produce a primary electrode. Then, the primary electrode coated with the composite on the graphite foil was dried in a drier at about 80 ° C, pressed using a roll-press, cut into a predetermined size, , The secondary electrode is used as a storage water treatment electrode using a composite of manganese oxide and carbonaceous material according to the present invention.

The electrochemical evaluation method of the storage water treatment electrode according to the present invention uses Ag / AgCl as a reference electrode and Pt electrode as a counter electrode using a three-electrode method using the electrode of the present invention manufactured to a size of 1 × 1 cm 2 . The measurement potential is measured in the region of the positive electrode potential of 0 to 0.8 V (vs. Ag / AgCl) and the potential of the negative electrode of 0 to -0.8 V (vs. Ag / AgCl). In the measurement process, the potential velocity is applied at 10 mVs ^-1 .

As shown in FIG. 4 and FIG. 5, a capacitance increase of 30 F / g can be confirmed at 80 F / g or less in the positive electrode potential region compared with the electrode using only the activated carbon in the related art. .

celebration Deionization ( capacitive deionization  : CDI ) Application step of process ( S60  step)

In the application of the capacitor deionization (CDI) process of the storage water treatment electrode according to the schematic diagram of FIG. 6, the electrode manufactured in the flat cell is inserted and the counter electrode is inserted in a symmetrical structure or asymmetric structure. Then, while the electrolyte was being supplied at a constant flow rate, the voltage was applied at 1.5 V using an external power supply, and the ion removal rate was observed by observing the change in the TDS (Total Dissoived Solid) formed at this time.

As a result, as shown in FIGS. 7 and 8, the ion removal rate by observing the change in the mineral concentration (TDS) was increased by more than 20% as compared with the electrode using only the activated carbon.

Although the present invention has been described with reference to exemplary embodiments thereof, those skilled in the art will appreciate that various modifications, additions and substitutions are possible, without departing from the scope and spirit of the invention as disclosed in the accompanying drawings. It will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the scope of the present invention.

Claims (10)

(S10) of preparing a fatty acid solution in which ethanol is dispersed, adding a substance for saponification and dissolving, adding metal oxide particles and stirring the mixture;
A saponification reaction step (S20) in which the saponification reaction proceeds in the solution by the saponification reaction material;
A sintering step (S30) of producing a composite material by synthesizing a metal oxide and a carbonaceous material by firing a solution in which the saponification reaction proceeds within a range of a predetermined temperature and time; And
(S40) of filtering the composite material solidified by the sintering step to remove unreacted materials and then drying to prepare a composite having a carbon material formed on the surface of the metal oxide (S40) And a primary electrode is prepared by applying active carbon as an additive to a mixed solution of a binder and a solvent as an additive and then applying it to the current collector to a predetermined thickness to form the primary electrode coated by coating And then cut to a predetermined size to complete a secondary electrode and use it as an electrode. The method of manufacturing a composite water-treatment electrode according to claim 1, The method according to claim 1,
Wherein the metal oxide is any one of titanium oxide, zinc oxide, manganese oxide, and iron oxide. 3. The method of claim 2,
Wherein the predetermined temperature range in the sintering step (S30) is in a range of 400 to 500 DEG C, and the predetermined time range is 2 to 6 hours. The method of claim 3,
Wherein when the metal oxide is a manganese oxide, the manganese oxide is synthesized as a-phase manganese oxide under a sintering condition in a range of 400 to 500 ° C. The method of manufacturing a composite oxide of metal oxide and carbonaceous material according to claim 1, . The method according to claim 1,
Wherein the fatty acid is a fatty acid containing a monovalent carboxyl group in the range of _{C12 to C18} . ≪ RTI ID = 0.0 > 11. < / RTI > 6. The method of claim 5,
Wherein the fatty acid is synthesized in the form of a macromolecule or macromolecule by inducing a saponification reaction on the surface of the metal oxide. The method according to claim 1,
Wherein the carbonaceous material formed on the surface of the metal oxide has a content of 5 to 20 wt%. delete delete The method according to claim 1,
When an asymmetrically structured flat cell for water treatment is formed by the storage water treatment electrode as an electrode for a capacitor deionization (CDI) process, an electrode to which manganese oxide is added as an anion removal electrode, an activated carbon electrode or titanium oxide as a cation removal electrode Characterized in that an electrode is used as the electrode.

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