KR20150093397A - Electrode for wastewater treatment combined diamond coating boron and preparation method thereof - Google Patents

Abstract

The present invention relates to an electrode for treating waste water combined with a boron coating diamond, and a manufacturing method thereof. According to the present invention, the electrode has quite the wide specific surface area. Therefore, an effect of treating the waste water is significantly improved when treating the waste water using the electrode for treating the waste water. Especially, a water pollution measurement index such as TOC, COD, etc is remarkably improved compared to an existing electrode used in the past.

Description

TECHNICAL FIELD [0001] The present invention relates to an electrode for treating a wastewater containing boron-coated diamond and an electrode for treating the same,

The present invention relates to an electrode for treating wastewater to which boron-coated diamond is bound and a method for producing the same.

Currently, industrial wastewater treatment and disposal uses chemical treatments, which rely on toxic chemicals. Thus, these chemical treatment methods inevitably cause environmental pollution problems. Electrochemical treatment methods are emerging as an alternative to such environmental pollution problems.

Such an electrochemical treatment method causes a chemical reaction while supplying electricity through an electrode made of a metal material as an electrode material to treat wastewater. At present, gold, platinum, or metal oxides are mainly used as electrode materials. However, there is a problem that these materials exhibit unstable characteristics in the process of electrochemically treating wastewater. There is a problem that the specific surface area is low and the manufacturing cost is high.

Therefore, researches on electrodes using boron-doped diamond (BDD) as an electrode material to solve these problems have been actively conducted, and it is now in the commercialization stage. However, previous studies have used boron-coated diamond as a thin film and used it as an electrode. When the electrode is fabricated in this thin film form, there is still a problem in that it has a limited specific surface area and thus has a limitation in efficient wastewater treatment. Thus, although it is necessary to fabricate nanostructures instead of thin films and have a larger specific surface area, such studies are in short supply.

Korean Patent Laid-Open No. 10-2012-0065998 (Patent Document 1) is disclosed as a prior art document related thereto. Patent Document 1 discloses a technique relating to an electrochemical wastewater treatment apparatus and method including an electric coagulating unit having one negative electrode and a positive electrode for removing contaminants and an electro oxidation unit for oxidizing contaminants.

Patent Document 1. Korean Patent Laid-Open No. 10-2012-0065998

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and an object of the present invention is to improve the specific surface area while using boron-coated diamond as an electrode material, thereby enabling wastewater treatment with higher efficiency. It is another object of the present invention to provide a method of manufacturing an electrode material in which boron-coated diamond is bonded as a material of an electrode used for treating wastewater with excellent efficiency.

According to an aspect of the present invention, there is provided an electrode for treating wastewater,

A positive charge and a negative charge are introduced onto a substrate including a plurality of nanostructures,

And boron-coated diamond particles are bonded between the plurality of nanostructures by the introduced positive and negative charges.

According to another aspect of the present invention, there is provided a method of manufacturing an electrode for treating wastewater,

1) forming a plurality of nanostructures on a substrate;

2) introducing a positive charge onto the substrate on which the plurality of nanostructures are formed;

3) bonding the diamond particles while introducing a negative charge onto the substrate; And

4) coating the diamond particles with boron by chemical vapor deposition;

.

The electrode for treating wastewater to which the boron-coated diamond is bonded according to the present invention and the electrode manufactured by the method for producing the same have a larger specific surface area. Therefore, if the wastewater treatment using the electrode for treating wastewater according to the present invention is performed, the efficacy of wastewater treatment is greatly improved. Particularly, the measurement index of water pollution such as TOC and COD is significantly improved compared to the electrode used in the past.

1 is a diagram illustrating a process of manufacturing an electrode for wastewater treatment according to an embodiment of the present invention.
FIG. 2 is a view showing an example of a shape used as a nanostructure formed on a substrate in the embodiment. FIG.
3 is a schematic diagram of an apparatus for treating wastewater using an electrode for treating wastewater produced according to an embodiment.
FIG. 4 shows a result of measurement of cyclic volammetry of an electrode for wastewater treatment according to an embodiment.
FIG. 5 is a view showing a TOC measurement result of the electrode for treating wastewater produced according to the embodiment. FIG.
6 is a graph showing a result of COD measurement of the electrode for wastewater treatment according to the embodiment.

Therefore, the inventors of the present invention have made extensive efforts to develop an electrode for treating wastewater having a wide specific surface area and an efficiency of wastewater treatment and a method for producing the electrode. As a result, it has been found that the electrode for treating wastewater to which boron- And completed the present invention.

Specifically, the electrode for treating wastewater according to the present invention is characterized in that a positive charge and a negative charge are introduced onto a substrate including a plurality of nanostructures, and diamond particles doped with boron by the introduced positive and negative charges are injected between the plurality of nanostructures Coating.

When a plurality of nanostructures are included on the substrate, the surface is not rough and bonded uniformly and thinly than when boron-doped diamond particles are bonded without a nanostructure. That is, the boron-doped nano-diamond particles are coated between positive and negative charges introduced into the substrate and the nanostructure is located. It has been known that a substrate not containing such a nanostructure is preferable when electrodes are formed by other methods. However, if the electrode for treating wastewater according to the present invention does not contain the nanostructure, the surface becomes rough and it is difficult to sufficiently achieve the effect of the wastewater treatment to be achieved in the present invention. In addition, in order to coat boron-doped diamond particles by the electrostatic self-assembly method according to the present invention, it is preferable to include a nanostructure on a substrate because a uniform and thin electrode film can be formed as compared with a case where the nanostructure is not coated.

The average diameter of the nanostructures is not particularly limited, but is preferably 50-500 nm. When the average diameter of the nanostructures is less than 50 nm, it is difficult to firmly bond the diamond particles coated with boron. When the average diameter of the nanostructures exceeds 500 nm, the nanostructures are too large to be doped with boron It is difficult to join the diamond particles to each other between the nanostructures.

The shape of the nanostructure is not particularly limited, but any one or more selected from the group consisting of a quadratic pole, a cylinder, a nanowire, a quadrangular pyramid, a nanowire, and a cylindrical shape can better coat the boron-doped diamond particles desirable.

Bonding of the boron-doped diamond particles due to the introduction of positive and negative charges onto the substrate including the plurality of nanostructures can be more excellent. That is, when the positive and negative charges are introduced on the substrate, attraction between the positive and negative charges is generated, and the boron-doped diamond particles can be coated more tightly due to the attractive force. In the present invention, the process of bonding the boron-doped diamond particles with a coating using the positive and negative charges is called electrostatic self-assembly. Electrodes for wastewater treatment, in which boron-doped diamond particles are coated by the electrostatic self-assembly method, are preferable because uniform and thin electrode films are formed as compared with the conventional ultrasonication method.

The positively charged polymer is a polymer having a polarity such as poly (di-dimethyl ammonium chloride) (PDDA, poly (styrene 4-sulfonate)), poly (styrene sulfonate) (PEI, poly (ethyleneimine)), poly S-119 (PS-119), polyaniline (PA, Polyaniline) and NAFION The boron-doped diamond particles can be coated with a strong bonding force by a force. Further, it is preferable that the negative charge is introduced from poly (styrene 4-sulfonate) (PSS) because the boron-doped diamond particles can be coated with a strong binding force with a higher binding force.

The size of the boron-doped diamond particles is preferably 1-50 nm. When the size of the boron-doped diamond particles is less than 1 nm, the size of the boron-doped diamond particles is too small to achieve a sufficient wastewater treatment effect. If the size of the boron-doped diamond particles exceeds 50 nm Its size is too large to be bonded between the plurality of nanostructures, which is not preferable.

The doping of boron is not particularly limited as long as it is a gas containing boron, and it is preferable to perform doping by chemical vapor deposition while injecting such a gas. When such a chemical vapor deposition and doping is performed, the diamond particles are used as a deposition nuclei and boron is doped and grown. It is preferable that the flow rate at this time is 50-200 sccm.

The substrate is not particularly limited, but is preferably at least one selected from the group consisting of a silicon wafer (Si wafer), stainless steel, and a titanium substrate.

When the wastewater is treated using the electrode for wastewater treatment according to the present invention, it is possible to treat the wastewater with higher efficiency than electrodes prepared by applying boron-doped diamond in a thin film form or ultrasonication method.

The decomposition of pollutants by the electrode for treating wastewater according to the present invention can be decomposed by the following reaction formula.

According to another aspect of the present invention, there is provided a method of manufacturing an electrode for treating wastewater,

1) forming a plurality of nanostructures on a substrate;

2) introducing a positive charge onto the substrate on which the plurality of nanostructures are formed;

3) bonding the diamond particles while introducing a negative charge onto the substrate; And

4) doping the diamond particles with boron by chemical vapor deposition;

.

In order to bond the diamond particles doped with boron by the electrostatic self-assembly method according to the present invention in the step 1), it is preferable that the nanostructure is formed on the substrate to form a uniform and thin electrode film, Do. When a plurality of nanostructures are included on the substrate, the surface is not rough and bonded uniformly and thinly than when boron-doped diamond particles are bonded without a nanostructure. That is, boron-doped diamond exists between the plurality of nanostructures to form the nanostructure.

The positively charged polymer is a polymer having a polarity such as poly (di-dimethyl ammonium chloride) (PDDA, poly (styrene 4-sulfonate)), poly (styrene sulfonate) (PEI, poly (ethyleneimine)), poly-S-119 (PS-119), polyaniline (PA, Polyaniline) and NAFION. The negative charge is preferably introduced from poly (styrene 4-sulfonate) (PSS).

Meanwhile, in the manufacturing method according to the present invention, it is preferable to bond boron-doped diamond particles by an electrostatic self-assembly method. Such an electrostatic self-assembly method can introduce positive and negative charges into a substrate on which a plurality of nanostructures are formed, and bind boron-doped diamond particles through the attraction force generated thereby.

It is possible to simultaneously bind the diamond particles in the step 3) by introducing a negative charge after introducing the positive charge.

It is preferable that the chemical vapor deposition is performed by injecting gas at a pressure of 50-100 torr. If the pressure is less than 50 torr, it is difficult to supply gas smoothly. If the pressure exceeds 100 torr A large amount of gas is injected more than necessary, which is not economical and it is difficult to expect sufficient growth of diamond particles through doping of boron.

When the chemical vapor deposition is performed by step 4), boron can be doped to the diamond particles. When the size of the diamond grains is less than 0.8 nm, it is difficult to firmly bond the grains to the nanostructures. Therefore, when the size of the diamond grains is less than 0.8 nm, When the thickness is more than 20 nm, the size is too large to easily interfere with the nanostructures, and bonding is not easy, which is not preferable.

When the wastewater is treated by using the electrode manufactured by the method of manufacturing an electrode for wastewater treatment according to the present invention, the electrode manufactured by attaching the boron-coated diamond in the form of thin film or the electrode manufactured by ultrasonication It is possible to treat wastewater with improved efficiency.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. The present invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein.

Example

A cylindrical nano structure was formed on the silicon wafer substrate through selective etching of the substrate.

The substrate on which the nanostructure is formed is immersed in a 10% by volume solution of positively charged PDDA (Poly Diallyl Ammonium Chloride, Sigma-Aldrich) for 30 minutes. Then, it was taken out of the solution and dried with nitrogen gas to produce a PDDA monolayer film of approximately 2 nm thickness on the surface of the substrate.

The substrate coated with the PDDA monolayer was immersed for 24 hours in a mixed solution of PSS (polystyrene sulfonate, sigma-aldrich) and nano diamond (JinGangYuan New Material Development Co., LTD. Thereby forming a uniformly coated multi-layer film structure.

Then, boron was coated on the surface of the diamond using HFCVD (Chemical Vapor Deposition) as a chemical vapor deposition to grow diamond particles. B2H6, CH4, and H2 gas mixture were injected at a pressure of 80 torr for 10 hours Respectively. Thus, an electrode for treating wastewater to which boron-coated diamond particles according to the present invention are bonded was finally obtained.

FIG. 1 is a diagram illustrating the above process, and FIGS. 2 (a), 2 (b) and 2 (c) illustrate examples of shapes used as the nanostructure. Particularly, FIG. 2 (a) is a triangular pyramid, FIG. 2 (b) is a nanowire shape, and FIG. 2 (c) is a columnar shape. 3 is a schematic view of an apparatus for treating wastewater using electrodes for treating wastewater. The apparatus includes a flow electrolytic cell equipped with an electrode for removing contaminants by using the electrode for treating wastewater according to the embodiment, The flow electrolytic cell consists of a micropump that can regulate the flow rate of the electrode part and the wastewater, a circulating solution reservoir and a current supply device which supplies a constant current.

Comparative Example

The electrode for treating wastewater produced by adhering a diamond thin film coated with boron was used as Comparative Example 1 (thin film type).

Experimental Example

Experimental Example  One: Specific surface area  Measure

Experiments were conducted to measure the specific surface area of the electrode for wastewater treatment according to the example and the electrode for wastewater treatment according to the comparative example. The cyclic volummetry was also measured (Fig. 4). As a result, the effective surface area was found to be 1.10829 cm 2 in the case of the present invention, and 0.41728 cm 2 in the case of the comparative example, while the reaction area was larger than that of the comparative example. And it was confirmed that it came out more widely.

Experimental Example  2: Total carbon monoxide ( TOC , total organic carbon ) Measure

Experiments were conducted to measure the total organic carbon (TOC) after treating wastewater by using the electrode for treating wastewater according to the example and the electrode for treating wastewater according to the comparative example. The results are shown in FIG. On the other hand, the TOC refers to the amount of carbon present in an organic state in the wastewater, which is used as a contaminated indicator of water, and the lower the measured value, the greater the degree of contamination.

As can be seen from FIG. 5, it was confirmed that the TOC measurement values of the Examples were lower than those of the Comparative Examples, and the widening of the gaps was observed over time.

Experimental Example 3: Chemical Oxygen Demand ( COD , chemical oxygen demand )

Experiments were carried out to measure the chemical oxygen demand (COD) after treating wastewater using electrodes for wastewater treatment according to the examples and wastewater treatment electrodes according to the comparative examples. The results are shown in FIG. On the other hand, the COD indicates the amount of oxygen consumed for purification by oxidizing and decomposing pollutants such as organic substances into oxidants in ppm or the like, and the greater the COD, the more contaminated water is.

As can be seen from FIG. 6, the measured value of COD was not larger than that of Comparative Example 1 in the case of the embodiment, and it was confirmed that the gaps became wider as time passed.

According to the results of Experiments 2 to 4, boron-coated diamond was bonded to a substrate including a nanostructure according to the present invention to manufacture an electrode to treat wastewater. It was confirmed that the efficiency of the wastewater treatment was significantly improved as compared with the case using the ultrasonication method (Comparative Example 2).

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is to be understood that the invention is not limited to the disclosed exemplary embodiments, but, on the contrary, is intended to cover various modifications and equivalent arrangements included within the spirit and scope of the appended claims. It is natural.

Claims (15)

A positive charge and a negative charge are introduced onto a substrate including a plurality of nanostructures,
Wherein diamond particles doped with boron by the positive and negative charges introduced are coated between the plurality of nanostructures.
The method according to claim 1,
The positive charge may be selected from the group consisting of poly (diallyl dimethyl ammonium chloride), poly (styrene 4-sulfonate) (PSS), poly (ethyleneimine) (PEI , poly (ethyleneimine), poly-S-119 (PS-119), polyaniline (PA), and NAFION.
The method according to claim 1,
Wherein the negative charge is introduced from poly (styrene 4-sulfonate) (PSS).
The method according to claim 1,
Wherein the boron-doped diamond particles have a size of 1-50 nm.
The method according to claim 1,
Wherein the nanostructure has an average diameter of 50 to 500 nm.
The method according to claim 1,
Wherein the shape of the nanostructure is at least one selected from the group consisting of a square column, a cylinder, a nanowire, a quadrangular pyramid, a nanowire, and a cylinder.
The method according to claim 1,
Wherein the substrate is at least one selected from the group consisting of a silicon wafer, stainless steel, and a titanium substrate.
1) forming a plurality of nanostructures on a substrate;
2) introducing a positive charge onto the substrate on which the plurality of nanostructures are formed;
3) bonding the diamond particles while introducing a negative charge onto the substrate; And
4) coating the diamond particles with boron by chemical vapor deposition;
Wherein the electrode is made of a metal.
9. The method of claim 8,
The positive charge may be selected from the group consisting of poly (diallyl dimethyl ammonium chloride), poly (styrene 4-sulfonate) (PSS), poly (ethyleneimine) (PEI , poly (ethyleneimine), poly S-119 (PS-119), polyaniline (PA, Polyaniline) and NAFION Gt;
9. The method of claim 8,
Wherein the negative charge is introduced from poly (styrene 4-sulfonate) (PSS).
9. The method of claim 8,
Wherein the diamond particle size before boron doping is 0.8-20 nm, and the boron-doped diamond particle size is 1-50 nm.
9. The method of claim 8,
Wherein the nanostructure has an average diameter of 50 to 500 nm.
9. The method of claim 8,
Wherein the shape of the nanostructure is at least one selected from the group consisting of a square column, a cylinder, a nanowire, a quadrangular pyramid, a nanowire, and a cylindrical shape.
9. The method of claim 8,
Wherein the substrate is at least one selected from the group consisting of a silicon wafer, stainless steel, and a titanium substrate.
9. The method of claim 8,
Wherein the chemical vapor deposition is performed by injecting gas at a pressure of 50-100 torr.

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