WO2018043773A1

WO2018043773A1 - Technique for removing and controlling heavy metal by means of electrolysis

Info

Publication number: WO2018043773A1
Application number: PCT/KR2016/009671
Authority: WO
Inventors: 원종일; 정원영; 서영록
Original assignee: 동국대학교 경주캠퍼스 산학협력단; 동국대학교 산학협력단
Priority date: 2016-08-29
Filing date: 2016-08-30
Publication date: 2018-03-08

Abstract

The present invention relates to a method for removing heavy metal by means of electrolysis, the method comprising the steps of: (a) inserting electrodes into a solution containing heavy metal; (b) applying current density to the solution; and (c) removing precipitated heavy metal powder, the heavy metal in the solution having been precipitated into powder.

Description

Heavy metal removal and control technology using electrolysis technology

The present invention relates to a technique for removing and controlling heavy metals using electrolysis technology.

The problem of proper disposal of waste generated with industrial development is becoming a serious problem as the economy grows. Since heavy metals in various wastewaters released into nature can adversely affect not only animals and plants, but also humans, the removal of these heavy metals is essential.

Heavy metal refers to a heavy metal element having a specific gravity of 4 or more mainly located below the periodic table such as arsenic, lead, mercury, cadmium, chromium, and copper. On the other hand, when the heavy metal is eluted in water and discharged into the environment, it is essential to have a technology for preventing environmental pollution by heavy metal because it moves to humans along the food chain while circulating in the biosphere.

Meanwhile, groundwater, mine wastewater, landfill wastewater, and the like may contain heavy metals, and there are many difficulties in treating such heavy metals.

Conventionally, various methods using chemicals, adsorbents, etc. have been used as a method for removing heavy metals from liquids (contaminated water, etc.) containing such heavy metals.

However, this method is not environmentally friendly, and since heavy metals in a liquid cannot be removed in a short time, heavy metals cannot be efficiently removed, and many problems are exposed.

The present invention relates to a technology capable of easily removing and controlling heavy metals contained in an electrolyte solution using electrolysis technology, and to provide a method for removing heavy metals using electrolysis.

The present invention includes the steps of (a) charging the electrode in a solution containing heavy metal; (b) applying a current density to the solution; And (c) depositing the heavy metal in the solution into a powder to remove the precipitated heavy metal powder; It provides a method for removing heavy metals using electrolysis comprising a.

According to the method for removing heavy metals using electrolysis of the present invention, by applying an appropriate current density in a solution containing heavy metals using electrolysis, the heavy metals in the solution can be powdered, thereby easily removing the powdered heavy metals. It can work.

According to the method for removing heavy metals using the electrolysis of the present invention, there is an effect that the heavy metal in the solution containing the heavy metal can be easily removed in a short time at low cost.

1 is a view showing a schematic diagram of an electrolysis cell for removing heavy metals according to an embodiment of the present invention.

2 is a view showing an electrode of an electrolytic cell according to an embodiment of the present invention ((a) anode, (b) cathode).

3 is a photograph showing the color change of the electrolyte solution with time during the electrolysis process according to an embodiment of the present invention.

4 is a graph showing the amount of change in cadmium in the embodiment of the present invention.

Figure 5 is a graph showing the amount of lead content change in the embodiment of the present invention.

Figure 6 is a graph showing the amount of chromium content change in the embodiment of the present invention.

7 is a graph showing the amount of change in mercury content in an embodiment of the present invention.

The present invention relates to a method for removing heavy metals using electrolysis.

More specifically, the method for removing heavy metals using the electrolysis of the present invention comprises the steps of (a) charging an electrode in a solution containing heavy metals, (b) applying a current density to the solution, and (c) the solution. And depositing the heavy metal in the powder, thereby removing the precipitated heavy metal powder.

On the other hand, according to the method for removing heavy metals using the electrolysis of the present invention, it is possible to simply remove the heavy metals in a solution containing heavy metals, such as pickling waste liquid at low cost, accordingly the heavy metals using the electrolytic solution from which the heavy metals are removed There is an effect that can be applied to various IT products and eco-friendly products that do not pose a risk to humans.

Hereinafter, a method for removing heavy metals using the electrolysis of the present invention will be described in detail.

As used herein, the term “heavy metal” is mainly located below the periodic table such as arsenic, antimony, lead, mercury, cadmium, chromium, tin, zinc, barium, bismuth, nickel, cobalt, manganese, vanadium, and selenium. It means a heavy metal element having a specific gravity of 4 or more, in one embodiment of the present invention may mean a heavy metal contained in the pickling waste liquid.

As used herein, the term "current density" refers to I / S obtained by dividing the current I flowing through a conductor by the cross-sectional area S in a direction perpendicular to the streamline. It may mean that the size is expressed per unit area.

Method for removing heavy metals using electrolysis according to the present invention comprises the steps of (a) charging the electrode in a solution containing heavy metal, (b) applying a current density to the solution and (c) the heavy metal in the solution powder Precipitating to, including the step of removing the precipitated heavy metal powder.

Here, the “heavy metal-containing solution” may refer to any solution containing heavy metals, and may refer to an electrolyte that is dissolved in a solvent such as water and dissociated into ions to flow a current. For example, it may be pickling waste liquid discharged from the metal smelting industry.

First, the electrode in step (a) may be composed of a positive electrode and a negative electrode, more specifically, the electrode may be at least two selected from the group consisting of iron, stainless steel, zinc, copper, platinum, for example, the positive electrode As a high purity iron, a high purity stainless steel can be used as the cathode.

In addition, it is possible to use a larger area of the cathode than the area of the anode in the electrolytic cell.

In particular, in the step (b), the current density may be appropriately applied in consideration of the area of the cathode, which is a general thin film plating condition in order to grow heavy metal to be removed from the electrode of the electrolytic cell in the form of powder rather than a thin film. More overcurrent can be applied.

On the other hand, as the current density increases, the size of the heavy metal powder increases, because the higher the current density, the better the growth of the particles and the larger the crystal grains.

In addition, in the step (b), it is possible to control the current density, the application time of the current density, the temperature of the solution and the hydrogen ion index (pH).

In certain embodiments, the current density may be 20 to 200 mA / cm ² . More specifically, when the current density is less than 20 mA / cm ² , a long time is required for heavy metal removal, and when the current density exceeds 200 mA / cm ² , the current density applied to the electrolytic cell is increased due to an increase in heavy metal removal cost. To 200 mA / cm ² is preferred.

Meanwhile, the higher the current density applied to the solution, the more effectively the heavy metal can be removed, but it can be changed according to experimental conditions such as the area of the cathode electrode, the capacity of the solution and the type of heavy metal to be removed.

In addition, in step (b), the current density may be applied for 1 to 240 hours, and more specifically, within 24 hours. In the example of the present invention, when 50 mA / cm ² was applied to the pickling liquor, lead was removed in 12 hours, and it took 6 hours to remove 100% of chromium and mercury.

On the other hand, the temperature of the solution in step (b) may be 15 to 80 ° C, heavy metal removal can be carried out at room temperature. On the other hand, when the temperature of the solution exceeds 80 ℃ can evaporate the solution may cause a phenomenon that the electrolyte is insufficient.

In addition, the hydrogen ion index of the above-described solution may be controlled to pH0.01 to pH10. For example, the solution may be removed using a strong acid pickling solution of a strong acid to remove heavy metals in the pickling solution.

Next, (c) the heavy metal in the electrolyte solution may be precipitated as a powder to remove the precipitated heavy metal powder. More specifically, the step (c) may be removed by filtering or separating from the solution containing the precipitated heavy metal powder to extract the heavy metal.

Hereinafter, preferred examples are provided to aid in understanding the present invention. However, the following examples are merely provided to more easily understand the present invention, and the contents of the present invention are not limited by the examples.

<실시예> <Example>

실시예 1. 전기분해기술을 이용한 산세폐액 내의 중금속 제거Example 1 Removal of Heavy Metals in Pickling Waste Using Electrolysis Technique

In this embodiment, the heavy metal in the pickling waste liquid was removed by using an electrolysis technique.

Figure 1 shows an electrolytic cell for removing heavy metals in the pickling waste liquid by the electrolysis technique.

As shown in FIG. 1, an electrolytic cell was formed, and an pickling waste liquid from which impurities were removed was used as an electrolyte solution. On the other hand, in the electrolytic cell, the positive electrode used high purity iron, and the negative electrode to which the heavy metal to be removed is adsorbed and / or precipitated substantially used stainless steel of high purity.

One of the experimental conditions, the current density was applied by calculating the area of the cathode and the experiment was performed.

2 is a view showing the electrode of the electrolytic cell according to an embodiment of the present invention ((a) anode, (b) cathode), referring to Figure 2, it can be seen that the area of the cathode is larger than the area of the anode. .

First, the pickling waste solution was repeatedly filtered through an filter paper to remove impurities, and the pH of the electrolyte solution was adjusted using hydrochloric acid (HCl) and sodium hydroxide (NaOH).

A current density of 50 mA / cm ² was applied to the electrolyte of the pickling waste liquid from which impurities were removed, and the amount of change of heavy metals was changed by changing the application time of the current density to 3 hours, 6 hours, 9 hours, 12 hours, 24 hours, and 48 hours. Measured.

3 is a photograph showing a color change for electrolysis with time in the process of electrolysis according to an embodiment of the present invention.

Referring to FIG. 3, the color of the electrolyte solution was changed as the application time was increased. This means that, in accordance with the principle of electrolysis technology, various metal components together with heavy metals in pickling waste used as electrolytes were adsorbed on the surface of stainless steel, which is a cathode, or precipitated as powders in electrolytes.

Thereafter, the powdered heavy metal was separated and removed in the electrolyte solution.

실시예 2. 전해액 내의 중금속의 함량 변화량Example 2 Content Change of Heavy Metal in Electrolyte

The color change of the electrolyte in Example 1 was analyzed by an Inductively Coupled Plasma Optical Emission Spectrometer (ICP-OES), and the results are shown in FIGS. 4 to 7.

According to the ICP-OES analysis results, as the application time increases to a constant current density (50 mA / cm ² ), the major heavy metals in pickling liquor are cadmium (Cd), lead (Pb), chromium (Cr) and mercury (Hg). It was confirmed that the content of) decreased.

In particular, it was confirmed that almost all heavy metals were removed 100% within the current density application time within 6 hours to 24 hours.

As described above, the preferred embodiments of the present invention have been described, and the fact that the present invention can be embodied in other specific forms in addition to the above-described embodiments without departing from the spirit or scope thereof has ordinary skill in the art. It is obvious to them. Therefore, the above-described embodiments should be regarded as illustrative rather than restrictive, and thus, the present invention is not limited to the above description and may be modified within the scope of the appended claims and their equivalents.

Claims

(a) charging the electrode into a solution containing heavy metals;

(b) applying a current density to the solution; And

(c) depositing the heavy metal in the solution into a powder to remove the precipitated heavy metal powder; Method for removing heavy metals using electrolysis comprising a.
The method of claim 1,

The electrode of step (a) is iron, stainless steel, zinc, copper, platinum is a method for removing heavy metals using electrolysis, characterized in that at least two selected from the group consisting of.
The method of claim 1,

Step (b) is

The method of removing heavy metals using electrolysis, characterized in that for controlling the current density, the application time of the current density, the temperature of the solution and the hydrogen ion index (pH).
The method of claim 3,

The application time of the current density is

Method for removing heavy metals using electrolysis, characterized in that for 1 to 240 hours the current density is applied.
The method of claim 3,

The temperature of the solution

Method for removing heavy metals using electrolysis, characterized in that the control at 15 to 80 ℃.
The method of claim 3,

The hydrogen ion index of the solution

Method for removing heavy metals using electrolysis, characterized in that the pH is controlled to 0.01 to 10.
The method of claim 1,

Step (c) is

The method of removing heavy metals using electrolysis, characterized in that the heavy metals are extracted and removed by filtration or separation from the solution containing the precipitated heavy metal powders.
The method of claim 1,

The heavy metal is

Arsenic (As), Antimony (Sb), Lead (Pb), Mercury (Hg), Cadmium (Cd), Chromium (Cr), Tin (Sn), Zinc (Zn), Barium (Ba), Bismuth (Bi) And nickel (Ni), cobalt (Co), manganese (Mn), vanadium (V) and selenium (Se) at least one selected from the group consisting of heavy metals using electrolysis.