KR101745115B1 - Method for power generation and removing heavy metals from wastewater using fuel cell and System for treating wastewater using the same - Google Patents

Abstract

The present invention relates to a method for removing heavy metals and a wastewater treatment system using a fuel cell, while simultaneously producing power by treating wastewater containing heavy metals with a fuel cell including a negative electrode, a positive electrode and a catalyst layer provided between the two electrodes .
According to the present invention, it is possible to produce electric power at the same time as heavy metal removal, which can solve the power consumption problem of the conventional electrophoretic agglomeration reaction. Since the microorganism is not used, the heavy metal removal rate is high and the performance is not deteriorated even if it is continuously used.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fuel cell and a method for removing wastewater from a wastewater using the fuel cell,

The present invention relates to a method for removing heavy metals while generating electric power from wastewater containing heavy metals by using a fuel cell, and a wastewater treatment system using fuel cells.

In recent years, domestic sewage, livestock wastewater and industrial wastewater due to industrialization have caused pollution of water quality such as inland water and inland waters of public lakes and urban small and medium rivers.

Meanwhile, contaminants such as domestic wastewater, livestock wastewater and industrial wastewater that are generated in the past are organic matter which can be decomposed by certain microorganisms, but recently, due to the rapid industrial development, population increase and urban population concentration, The proportion of inorganic components in wastewater is increasing. For example, wastewater from livestock facilities, wastewater from leather factories, wastewater from dyeing factories, acidic mine drainage, and the like, especially acidic mine drainage, can be discharged through a pile of mine waste or mine tailings, Which contains pyrite and is acidic and occasionally contains large quantities of iron, aluminum and some toxic heavy metals. Since the drainage of 1 to 5 m ³ / min in ordinary mines and 10 m ³ / min in many places is discharged, the pollution degree of the area where acidic mine drainage is discharged is getting worse.

Heavy metals contained in various wastewaters including acid mine drainage refer to heavy metal elements such as lead, zinc, arsenic, copper, manganese, cadmium, selenium, hexavalent chromium, nickel and antimony. These heavy metals, even in trace amounts, adversely affect the aquatic ecosystem and human health and living environment when they enter the soil, rivers and groundwater. Therefore, various methods for efficiently removing heavy metals contained in wastewater have been studied.

As a method for removing the heavy metal, a method of adding a chemical agent or a method using a lime lime is mainly used. In addition to the above methods, a microbial fuel cell (MFC) is used to remove heavy metals, A method of producing a polypropylene resin is used.

Microbial fuel cells are used to purify contaminants such as wastewater and sediments by generating electrons by transferring electrons generated when microorganisms in the cathode part decompose an organic material as a substrate to the anode part. For example, Korean Patent Laid-Open No. 10-2003-0038240 (2003. 05. 16) discloses a fuel cell type biochemical oxygen demand measuring device using a low-nutrient electrochemically active microorganism and a method for measuring biochemical low-concentration oxygen demand using the same. And in Korean Patent Laid-Open No. 10-2008-0066460 (2008. 07. 16), the energy from the decomposition of the organic matter of the wastewater by the microorganisms in the microbial fuel cell reaction tank is converted into electric energy, Thereby decreasing the sludge production amount accordingly. In addition, domestic patent application No. 2012-0124529 (Nov. 14, 2012) discloses a method for removing heavy metals or recovering precious metals by using a microbial fuel cell (MFC) equipped with anaerobic microorganisms from waste water containing heavy metals or precious metals / RTI > However, when the microbial fuel cell is used, the removal efficiency of heavy metals may be low and thus the quality of the effluent water may be a problem. Therefore, an additional post-treatment process such as a secondary settler is required and pH difference between the positive electrode and the negative electrode causes microbial fuel cell There is a problem that the system performance of the system is degraded.

Meanwhile, a wastewater treatment technique using an electrochemical agglomeration reaction, which has been conventionally widely used, generally includes a reaction chamber having an inlet through which wastewater flows and an outlet through which reaction treatment water is discharged, an electrode plate And a power supply unit for supplying power to the electrode plate. The reaction with the wastewater flowing from the surface of the electrode plate through the supply of power is performed to aggregate impurities such as heavy metals, So that the treated water can be discharged. However, the wastewater treatment technique using such an electrocoagulation reaction has a limitation in its use because much power is consumed to remove heavy metals.

Therefore, there is a need to develop a new wastewater treatment technology for solving the problem of low heavy metal removal rate and performance deterioration of conventional microbial fuel cells and solving the power consumption problem of the electrocoagulation reaction.

SUMMARY OF THE INVENTION An object of the present invention is to provide a method of removing heavy metals while generating electric power from wastewater containing heavy metals by using a fuel cell and a wastewater treatment system using the fuel cell.

In order to accomplish the above object, the present invention provides a method for producing heavy metals and removing power from wastewater containing heavy metals, which can use a fuel cell including a negative electrode, a positive electrode, and a catalyst layer provided between the two electrodes.

The negative electrode may be exposed to the atmosphere, and the negative electrode may be a carbon cloth.

The positive electrode may be iron, stainless steel, aluminum, an aluminum alloy, zinc, a zinc alloy, magnesium, a magnesium alloy, or a mixture thereof.

A cation exchange membrane, an anion exchange membrane, and a separation membrane having a pore size of 10 nm to 10 m may be further provided between the catalyst layer and the positive electrode.

One kind selected from the group consisting of the cation exchange membrane, the anion exchange membrane and the separation membrane is in contact with the catalyst layer to prevent the catalyst layer from being contaminated by the wastewater, thereby preventing the cathode electrode contacting the catalyst layer from being contaminated by the wastewater. (FIG. 1A) or spaced apart (FIG. 1B).

And a metal ball may be further provided between the positive electrode and one selected from the group consisting of the cation exchange membrane, the anion exchange membrane, and the separation membrane.

The heavy metal may be at least one selected from the group consisting of lead, zinc, arsenic, copper, manganese, cadmium, selenium, hexavalent chromium, nickel and antimony.

The pH of the wastewater may be adjusted to 2 to 10 to produce power, and the maximum power density obtained through the method of the present invention may be 2200 to 6000 mW / m < 2 >.

The positive electrode may be iron, stainless steel or a mixture thereof. The pH of the wastewater may be adjusted to 5 to 9 to produce a magnetic iron compound. When the magnetic iron compound is produced in the fuel cell, 10 to 200 OMEGA.

The magnetic iron compound may be magnetite (Fe ₃ O ₄ ).

The method may be performed by connecting a plurality of the fuel cells in series.

The present invention also relates to a wastewater inflow section into which wastewater containing heavy metals flows;

An electrocoagulation reaction unit having a fuel cell including a negative electrode, a positive electrode, and a catalyst layer provided between the two electrodes, the wastewater discharged from the wastewater inflow portion;

And a treatment water discharging portion through which the wastewater having undergone the reaction in the electrocoagulation reaction portion is discharged,

Wherein the fuel cell of the electrocoagulation reaction unit generates electric power from wastewater containing heavy metals and removes heavy metals.

At this time, the fuel cell may be a plurality of the same fuel cells connected in series.

Conventional wastewater treatment using an electrocoagulation reaction consumes a lot of power for removing heavy metals, while the method using the fuel cell and the wastewater treatment system of the present invention can remove heavy metals while generating electric power. This can be achieved by using carbon cloth as the negative electrode and by using iron, stainless steel, aluminum, aluminum alloy, zinc, zinc alloy, magnesium, magnesium alloy or a mixture thereof as the positive electrode.

Also, since the method using the fuel cell and the wastewater treatment system of the present invention do not use microorganisms, the removal rate of the heavy metal is high and the performance is not deteriorated even if it is continuously used.

1A is a view illustrating a fuel cell according to an embodiment of the present invention.
1B is a view showing a fuel cell according to another embodiment of the present invention.
2 is a view showing a reaction mechanism when wastewater is charged into a fuel cell according to an embodiment of the present invention.
3 is a view showing a detailed configuration of a fuel cell according to an embodiment of the present invention.
4 is a schematic diagram of a wastewater treatment system in accordance with an embodiment of the present invention.
FIG. 5 is a graph illustrating power produced when a wastewater is injected into a fuel cell according to an embodiment of the present invention.
FIG. 6 is a graph showing the maximum power density of a fuel cell according to an exemplary embodiment of the present invention, which is a voltage and a current generated when a wastewater is introduced into the fuel cell, and an average value of the voltage and current.
FIG. 7A is a graph showing Raman spectrum of a magnetic iron compound produced when a wastewater is introduced into a fuel cell according to an embodiment of the present invention. FIG.
7B is a graph showing magnetite in Raman spectrum.
FIG. 8 is a graph showing a change in maximum power density according to the concentration of an electrolyte used when a wastewater is introduced into a fuel cell according to an embodiment of the present invention.
FIG. 9 is a graph showing the maximum power density of a fuel cell having an anion-exchange membrane according to an embodiment of the present invention, which is calculated as an average value of a voltage and a current, and a voltage and a current generated when a reaction is performed.
FIG. 10 is a graph showing the maximum power density of a fuel cell having a cation exchange membrane according to an embodiment of the present invention, wherein a voltage and a current generated when a wastewater is introduced into the fuel cell, and a voltage and a current are calculated as an average value.

Hereinafter, the present invention will be described in detail.

Conventional microbial fuel cell-based wastewater treatment technology has a problem in that the water quality of the effluent may be low due to the low removal rate of heavy metals, which necessitates an additional post-treatment process such as a secondary settler and the pH difference between the positive electrode and negative electrode Thereby deteriorating system performance of the microbial fuel cell.

In addition, a wastewater treatment technique using an electrocoagulation reaction that has been conventionally widely used generally includes a reaction chamber having an inlet through which wastewater flows and an outlet through which reaction treatment water is discharged, an electrode And a power supply unit for supplying power to the plate and the electrode plate. The reaction with the wastewater flowing from the surface of the electrode plate through the supply of power is performed to coagulate the impurities including the heavy metal, So that the treated water in the state can be discharged. However, the wastewater treatment technique using such an electrocoagulation reaction has a limitation in its use because much power is consumed to remove heavy metals.

Accordingly, the present invention uses a new fuel cell composed of a positive electrode made of a metal having a relatively low reduction potential and a negative electrode using oxygen in the atmosphere having a high reduction potential, so that wastewater containing a heavy metal is used as an electrolyte A new method for solving the problem of low heavy metal removal and performance degradation of conventional microbial fuel cells and solving the power consumption problem of the electrocoagulation reaction and the wastewater treatment system using the fuel cell to provide.

FIG. 1 is a view showing a fuel cell according to the present invention, FIG. 2 is a schematic view illustrating the operation principle of the fuel cell according to the present invention, and FIG. 3 is a view showing a detailed configuration of a fuel cell according to the present invention.

1 to 3, the fuel cell used in the present invention includes a negative electrode, a positive electrode, and a catalyst layer provided between the two electrodes.

At this time, the negative electrode is preferably a carbon electrode exposed to the atmosphere, and a carbon cloth is preferably used as a material of the carbon electrode. The positive electrode is preferably made of iron, stainless steel, aluminum, an aluminum alloy, zinc, a zinc alloy, magnesium, a magnesium alloy or a mixture thereof.

When the wastewater is treated using the fuel cell according to the present invention, electric power is produced by the difference in reduction potential between the positive electrode and the negative electrode, and the heavy metal is removed by the electro-coagulation of the metal oxide and the heavy metal contained in the wastewater . More specifically, a reaction formula for producing heavy metals from electric power generated from the wastewater by using the fuel cell according to the present invention can be expressed as follows. The following reaction formula is a reaction formula when iron is used as a positive electrode, As described above, the positive electrode may be made of iron, stainless steel, aluminum, an aluminum alloy, zinc, a zinc alloy, magnesium, a magnesium alloy, or a mixture thereof. It is not.

Fe ^{2 +} + 3H ₂ O? Fe (OH) ₃ (s) + 3H ⁺ + e ^- (positive electrode)

1 / 4O ₂ + H ⁺ + e ^- → 1 / 2H ₂ O (negative electrode) [Reaction Scheme 2]

1 / 4O ₂ + 1 / 2H ₂ O + e ^{- -} OH ^- (negative electrode) [Reaction Scheme 3]

Fe ^{3 +} + OH ^- > Fe (OH) ₃ (s) (near the negative electrode)

Fe (OH) ₃ + H ⁺ + e ^- ? Fe ₃ O ₄ (s) + 5H ₂ O (near the negative electrode)

As shown in FIG. 1A, when wastewater is fed into a fuel cell having no space between a cathode and a separator (one cell), oxygen having a high reduction potential is reduced in the cathode exposed to the atmosphere, and bivalent iron ions Iron is oxidized to on. In this process, iron is precipitated as an oxide (Fe (OH) ₃ ) to generate electric power, and the iron oxide (Fe (OH) ₃ ) is converted into a magnetic iron compound such as magnetite (Fe ₃ O ₄ ) (Scheme 1 to Scheme 5).

At this time, at least one heavy metal selected from the group consisting of lead, zinc, arsenic, copper, manganese, cadmium, selenium, hexavalent chromium, nickel and antimony is adsorbed on the surface of the magnetic iron compound or enters the crystal structure of the magnetic iron compound Heavy metals are removed from the wastewater. When the material used as the positive electrode is a metal such as aluminum, aluminum alloy, zinc, zinc alloy, magnesium, magnesium alloy or a mixture thereof, metal oxides such as Al (OH) ₃ , ZnO, Zn (OH) ₂ , MgO, Mg (OH) ₂ ) to generate electric power. Since the magnetic iron compound can not be generated, the heavy metal is adsorbed on the surface of the metal oxide or enters the crystal structure to remove heavy metals from the waste water. A centrifugal separation, a belt pressure treatment or the like is required to remove the water.

In addition, as shown in FIG. 1B, when wastewater is injected into a fuel cell in which a cathode and a cathode are separated by a separator, oxygen having a high reduction potential is reduced in the cathode exposed to the atmosphere, and bivalent iron is converted into trivalent iron In this process, iron is precipitated as oxide (Fe (OH) ₃ ) to generate electric power ([Reaction 1] to [Reaction 4]). Since the iron oxide can adsorb on the iron oxide surface or enter the crystal structure and remove the heavy metal from the wastewater, the iron oxide can not generate a magnetic iron compound. Therefore, the iron oxide may be subjected to separate precipitation, A process by a belt pressure or the like is required. Like mentioned before, at this time, the case material is a metal such as aluminum, aluminum alloy, zinc, zinc alloy, magnesium, magnesium alloy, or a mixture thereof, the metal oxide (for example, used as the positive electrode: Al (OH) _3, (OH) ₂ , MgO, and Mg (OH) ₂ ) to generate electric power. Since the magnetic iron compound can not be generated, the heavy metal is adsorbed on the surface of the metal oxide or enters the crystal structure, And the treatment with a needle press, centrifugal separation, belt press or the like is necessary in order to remove the metal oxide.

The fuel cell having the structure as shown in FIG. 1A does not matter whether the wastewater is introduced into the negative electrode or the positive electrode. In the fuel cell having the structure shown in FIG. 1B, the dihydric It is preferable to supply the wastewater to the positive electrode in order to generate electrons generated by the oxidation along the electric wire and to be transmitted to the oxygen on the surface of the negative electrode to be reduced to water to form iron oxide and generate electric power.

When iron ion is not contained in the wastewater fed to the fuel cell, the positive electrode is formed of iron, stainless steel, or an electrode made of a mixture thereof, to produce a dihydric iron ion as shown in Reaction Scheme 6 below. The produced bivalent iron ions produce electric power according to the same procedures as in the above Reaction Schemes 1 to 5, and simultaneously produce a magnetic iron compound and remove heavy metals (in the case of FIG. 1A). In addition, it is also possible to produce iron oxide and remove heavy metals (in the case of FIG. 1B) by generating electric power according to the same procedure as the above-mentioned Reaction Schemes 1 to 4.

Fe (0) - > Fe ^{2 +} + 2 e ^- [Reaction Scheme 6]

At this time, it is preferable to use a carbon cloth as a material of the negative electrode in order to allow the oxygen to pass through the negative electrode and allow the reduction reaction of oxygen to occur smoothly to improve reactivity.

The catalyst layer is not particularly limited as long as it can minimize the contact resistance and the mass transfer resistance. However, it is preferable that the catalyst layer contains at least one metal selected from the group consisting of platinum (Pt), nickel (Ni), cobalt (Co), iridium (Ir) Is coated with a fluororesin (PTFE) is preferably used. Since the catalyst layer is desirably provided so as to be in contact with the negative electrode, the surface on which oxygen is introduced may be coated with fluororesin (PTFE) repeatedly to minimize contact resistance and mass transfer resistance.

Further, when one electrolytic water tank is used as the fuel cell, one kind selected from the group consisting of a cation exchange membrane, anion exchange membrane and separation membrane may be further provided between the catalyst layer and the anode. It is preferable that the separation membrane is formed with a plurality of pores having a pore size of 10 nm to 10 m in order to adsorb or filter suspended matters of wastewater. In the case where the porous membrane having the pores is not used, the suspension or the like may interfere with the reaction of the above-mentioned Reaction Schemes 1 to 5 to produce a large amount of electric power and fail to produce a magnetic iron compound Occation).

In addition, a metal ball may be additionally provided between the positive electrode and one selected from the group consisting of the cation exchange membrane, the anion exchange membrane and the separation membrane. The metal ball increases the surface area of the reaction with the input wastewater to increase the efficiency of wastewater treatment by improving the reaction efficiency and shortens the distance between the cathode and the anode by acting as a bridge when electrons and ions move, So that the power efficiency can be improved. At this time, the diameter of the metal ball is preferably 0.1 mm to 1 cm.

The present invention can maintain the cell voltage of 0.7 to 0.9 V for 20 to 40 hours by controlling the pH of the wastewater to 2 to 10, preferably 4 to 8, as can be seen from the results of the following examples, The maximum power density obtained by averaging the voltage and current generated during 6 hours is 2200 to 2500 mW / m < 2 >. The maximum power density may vary slightly depending on the pH of the wastewater.

In addition, the present invention can produce a magnetic iron compound by adjusting the pH of the wastewater to 5 to 9, preferably 7 to 8, as can be seen from the results of the following examples. When the pH of the wastewater is out of the above range, no magnetic iron compound is produced.

In addition, when the magnetic iron compound is produced in the fuel cell, it is preferable that the external resistance is 10 Ω or more. The lower the external resistance, the higher the effluent treatment efficiency. The higher the external resistance, the higher the power efficiency. It is most preferable that the external resistance is 10 to 200 OMEGA.

In addition, as can be seen from the results of the following examples, the present invention can remove at least 98% of heavy metals including arsenic, lead and copper by adjusting the pH of the wastewater to 4 to 8.5, and the concentration of the electrolyte is 0.06 To 0.6 M, it is possible to control the maximum power density as well as to produce a power of 0.56 M at the electrolyte and 4500 mW / m at the maximum.

Further, the present invention can produce a power of about 6000 mW / m 2 by further providing a cation exchange membrane or an anion exchange membrane between the catalyst layer and the positive electrode, as can be seen from the results of the following examples.

Further, in order to increase the power production efficiency, the method according to the present invention is preferably performed by connecting a plurality of the fuel cells in series.

The present invention also relates to a wastewater inflow section into which wastewater containing heavy metals flows;

An electrocoagulation reaction unit having a fuel cell including a negative electrode, a positive electrode, and a catalyst layer provided between the two electrodes, the wastewater discharged from the wastewater inflow portion;

And a treatment water discharging portion through which the wastewater having undergone the reaction in the electrocoagulation reaction portion is discharged,

Wherein the fuel cell of the electrocoagulation reaction unit generates electric power from wastewater containing heavy metals and removes heavy metals.

At this time, in order to increase the power production efficiency of the wastewater treatment system, it is preferable that a plurality of the fuel cells are connected in series.

Hereinafter, the present invention will be described in more detail with reference to preferred embodiments and the like. It will be apparent to those skilled in the art, however, that these examples are provided for further illustrating the present invention and that the scope of the present invention is not limited thereto.

< Example >

Example  1 to 5.

A fuel cell having the same structure as in FIG. 1A, for example, a fuel cell having a diffusion layer, a cathode electrode, a catalyst layer, and a separation membrane formed in order from the outermost side (the side directly in contact with the atmosphere) 7 mM FeSO ₄ (artificial wastewater) of 5 (Example 2), 6 (Example 3), 7.5 (Example 4) and 8.5 (Example 5), respectively.

Example  6 to 7.

7 mM FeSO ₄ (artificial wastewater) was added to the fuel cell in which a fuel cell having the same structure as in FIG. 1B was used, in which a cation exchange membrane (Example 6) or an anion exchange membrane (Example 7) was formed between the catalyst layer and the positive electrode.

< Test Example >

Test Example  One. Cell voltage (V) measurement

As shown in FIG. 5, after the artificial wastewater having different pH values was injected into the fuel cell, the electric power produced by the fuel cell was measured by a voltage regulator VR-71 (T & D COPORATION).

As shown in FIG. 5, it was confirmed that cell voltages of 0.75 to 0.9 V were maintained for at least 20 hours when using artificial wastewater having pHs of 4, 5, 6 and 7.5, respectively. The external resistance at this time is 1000 Ω.

Test Example  2. Measurement of maximum power density

As in Example 1, the maximum power density obtained by calculating the voltage and current generated during 6 hours after the artificial wastewater having the pH of 4 to the fuel cell and the voltage and current were calculated as an average value is shown in FIG.

As shown in FIG. 6, the voltage and current generated during 6 hours were averaged to find that the maximum power density was 2300 mW / m 2.

Accordingly, it has been confirmed that when the wastewater is supplied to the fuel cell according to the present invention and the reaction is performed, high-density power is produced.

Test Example  3. Magnetic Iron compound  Confirm creation

As in Example 4, the artificial wastewater having a pH of 7.5 was charged into the fuel cell, and the solid material produced by the operation with an external resistance of 100 Ω for 24 hours was analyzed by the Raman spectrum and shown in FIG. 7A.

As shown in FIG. 7A, the resultant solid material was analyzed by a Raman spectrum. As a result, the major peak of the generated solid material was very similar to the intrinsic peak (670 cm ^-1 ) (FIG. 7B) possessed by the standard magnetite Respectively.

Accordingly, it has been confirmed that magnetic iron compounds such as magnetite can be obtained by introducing wastewater into the fuel cell according to the present invention and performing the reaction. Further, the magnetic iron compound is obtained as a solid, and since it has magnetism, it can be easily separated from water by magnetic force.

Test Example  4. Confirm removal efficiency of heavy metals

(1) Measurement of removal efficiency of arsenic

As in Examples 1 to 5, the external water tank having 20 L of artificial wastewater having different pH was connected to the fuel cell water tank by a hose, and the artificial wastewater was circulated by a pump to operate for 24 hours to produce As (V) Were measured and shown in the following Table 1, in which 0.05 M NaCl and 0.06 M NaHCO ₃ were used as electrolytes.

Also, as in the case of Examples 6 to 7, a fuel cell water tank having a cation exchange membrane or anion exchange membrane and an external water tank having 20 liters of artificial wastewater having a pH of 5 were connected by a hose, the artificial wastewater was circulated by a pump, The removal rate of As (V) 5 was measured and shown in Table 2 below. In this case, the electrolyte of the positive electrode was 0.1 M NaHCO ₃ and the electrolyte of the negative electrode was 0.1 M HCl.

Initial pH External Resistance (Ω) Initial contamination concentration (ppm) Arsenic concentration (ppm) 6 hours 9 hours 24 hours 4 100 One N.D. (not detect) N.D. N.D. 200 0.438 0.01 0.005 1000 One N.D. N.D. N.D. 200 11.834 8.492 0.009 5 100 One N.D. N.D. N.D. 200 2.031 0.006 0.004 1000 One N.D. N.D. N.D. 200 13.236 11.389 0.169 6 100 One N.D. N.D. N.D. 200 0.039 0.005 0.003 1000 One N.D. N.D. N.D. 200 13.088 11.182 2.570 7.5 100 One N.D. N.D. N.D. 200 10.986 4.372 0.055 1000 One 0.05 0.048 0.048 200 14.058 11.173 1.610 8.5 100 One 0.42 0.45 0.46 200 10.395 2.246 7.989 1000 One One One One 200 20.016 12.969 14.832

As shown in Table 1, when the initial arsenic concentration was 1 ppm in the pH range of 4 to 7.5, it was confirmed that the arsenic was completely removed after 6 hours regardless of the external resistance, and the initial arsenic concentration was 200 ppm, it was confirmed that 98% or more of arsenic was removed after 24 hours, and it was confirmed that maintaining the pH of the wastewater in the range of 4 to 7.5 is effective for arsenic removal.

Initial pH Type of diaphragm External Resistance (Ω) Initial contamination concentration (ppm) Arsenic concentration (ppm) 1 hours 2 hours 4 hours 8 hours 24 hours 5 Cation exchange membrane  20 One 0.22 0.005 N.D. N.D. N.D. Anion exchange membrane One 0.475 0.1 0.015 N.D. N.D.

As shown in Table 2, it was confirmed that arsenic was completely removed when a cation exchange membrane or anion exchange membrane was used. In particular, when anion exchange membrane was used, arsenic was completely removed in a shorter time than a cation exchange membrane.

(2) Measurement of lead removal efficiency

As in the case of Examples 1 to 5, the removal efficiency of lead (Pb) was measured by circulating artificial wastewater through a hose connecting an external water tank storing 20 L of artificial wastewater having different pH and a fuel cell water tank for 24 hours The results are shown in Table 3, in which 0.05 M NaCl and 0.06 M NaHCO ₃ were used as electrolytes.

Initial pH External Resistance (Ω) Initial contamination concentration (ppm) Residual lead concentration (ppm) 6 hours 9 hours 24 hours 4 20 One N.D. N.D. N.D. 200 0.36 0.05 N.D. 100 One N.D. N.D. N.D. 200 0.8 0.15 N.D. 5 20 One N.D. N.D. N.D. 200 1.4 0.5 0.006 100 One N.D. N.D. N.D. 200 3.15 1.2 0.01 6 20 One N.D. N.D. N.D. 200 1.72 0.65 0.0005 100 One N.D. N.D. N.D. 200 3.3 1.15 0.003 7.5 20 One N.D. N.D. N.D. 200 1.54 0.045 0.001 100 One N.D. N.D. N.D. 200 2.13 0.091 0.0007 8.5 20 One N.D. N.D. N.D. 200 1.31 0.038 0.0001 100 One N.D. N.D. N.D. 200 2.01 0.064 0.0002

As shown in Table 3, it was confirmed that at least 98% of the lead was removed after 24 hours regardless of the initial lead concentration in the pH range of 4 to 8.5.

(3) Measurement of removal efficiency of copper

As in the case of Examples 1 to 5, the removal efficiency of copper (Cu) was measured by circulating artificial wastewater through a hose connecting an external water tank containing 20 L of artificial wastewater having different pH and a fuel cell water tank for 24 hours In Table 4 below, 0.05 M NaCl and 0.06 M NaHCO ₃ were used as electrolytes.

Initial pH External Resistance (Ω) Initial contamination concentration (ppm) Residual copper concentration (ppm) 6 hours 9 hours 24 hours 4 20 One N.D. N.D. N.D. 200 0.23 0.02 N.D. 100 One N.D. N.D. N.D. 200 0.71 0.095 N.D. 5 20 One N.D. N.D. N.D. 200 1.29 0.35 0.004 100 One N.D. N.D. N.D. 200 2.98 1.04 0.0062 6 20 One N.D. N.D. N.D. 200 1.48 0.52 0.0004 100 One N.D. N.D. N.D. 200 3.14 1.07 0.0012 7.5 20 One N.D. N.D. N.D. 200 1.48 0.037 0.0004 100 One N.D. N.D. N.D. 200 2.05 0.086 0.0006 8.5 20 One N.D. N.D. N.D. 200 1.54 0.042 0.0002 100 One N.D. N.D. N.D. 200 1.84 0.049 0.0001

As shown in Table 4, it was confirmed that over 98% of lead was removed after 24 hours regardless of the initial copper concentration in the pH range of 4 to 8.5.

Test Example  5. Power measurement according to electrolyte concentration

As in Example 2, the maximum power density according to the concentration of bicarbonate (NaHCO ₃ ) used as an electrolyte after the artificial wastewater having a pH of 5 was injected into the fuel cell is shown in FIG.

As shown in FIG. 8, it was confirmed that the maximum power density was increased in proportion to the concentration of bicarbonate, and in particular, when the concentration of bicarbonate was 0.56 M, the maximum power density was 4500 mW / m 2.

Therefore, it can be seen that high density power can be produced by increasing the concentration of the electrolyte when the wastewater is fed into the fuel cell according to the present invention.

Test Example  6. Power measurement according to ion exchange membrane type

As in Examples 6 to 7, artificial wastewater having a pH of 5 was charged into a fuel cell having a cation exchange membrane or anion exchange membrane, and the concentration of bicarbonate (NaHCO ₃ ) And the maximum power density obtained by calculating the voltage and current as an average value are shown in Fig. 9 (Example 6) and Fig. 10 (Example 7), respectively.

As shown in FIG. 9, when the anion exchange membrane was used, it was confirmed that the maximum power density was 6000 mW / m 2, and when the cation exchange membrane was used as shown in FIG. 10, the maximum power density was 5000 mW / m 2.

Therefore, it can be seen that high density of power can be produced by supplying wastewater into the fuel cell according to the present invention and performing the reaction.

Claims (18)

A wastewater inflow portion into which wastewater containing heavy metals flows;
An electrocoagulation reaction unit for receiving wastewater flowing in from the wastewater inflow section and reacting with the inflow wastewater to treat the inflow wastewater; And
And a treated water discharging portion through which the waste water having undergone the reaction in the electrocoagulation reaction portion is discharged,
The electrocoagulation reaction unit may include:
A fuel cell including a negative electrode, a positive electrode, a catalyst layer provided between the negative electrode and the positive electrode so as to be in contact with the negative electrode, and a cation exchange membrane, an anion exchange membrane and a separator provided between the catalyst layer and the positive electrode and,
One kind selected from the group consisting of the cation exchange membrane, the anion exchange membrane and the separation membrane,
Wherein the catalyst layer is provided so as to abut against the catalyst layer so as to prevent the catalyst layer from being contaminated by the inflow wastewater and to prevent the negative electrode abutting the catalyst layer from being contaminated by the inflow wastewater. A wastewater treatment system for removing heavy metals while producing power from wastewater. The wastewater treatment system according to claim 1, wherein the negative electrode is exposed to the atmosphere, wherein the negative electrode is exposed to the atmosphere. The wastewater treatment system according to claim 1, wherein the negative electrode is a carbon cloth. The system according to claim 1, wherein the negative electrode is carbon cloth. The method according to claim 1, wherein the positive electrode is made of iron, stainless steel, aluminum, aluminum alloy, zinc, zinc alloy, magnesium, magnesium alloy or a mixture thereof. A wastewater treatment system for removal. delete 2. The waste water treatment system according to claim 1, wherein when the selected one species is the separation membrane, the separation membrane has a pore size of 10 nm to 10 mu m. . delete delete A wastewater inflow portion into which wastewater containing heavy metals flows;
An electrocoagulation reaction unit for receiving wastewater flowing in from the wastewater inflow section and reacting with the inflow wastewater to treat the inflow wastewater; And
And a treated water discharging portion through which the waste water having undergone the reaction in the electrocoagulation reaction portion is discharged,
The electrocoagulation reaction unit may include:
A fuel cell including a negative electrode, a positive electrode, a catalyst layer provided between the negative electrode and the positive electrode so as to be in contact with the negative electrode, and a cation exchange membrane, an anion exchange membrane and a separator provided between the catalyst layer and the positive electrode and,
And a metal ball disposed between the positive electrode and the one selected from the group consisting of the cation exchange membrane, the anion exchange membrane, and the separation membrane, and increasing the reaction surface area between the introduced wastewater and the positive electrode to improve the reaction efficiency Wherein the wastewater treatment system is adapted to remove heavy metals while producing power from the wastewater. The method according to claim 1, wherein the heavy metal is at least one selected from the group consisting of lead, zinc, arsenic, copper, manganese, cadmium, selenium, hexavalent chromium, nickel and antimony. A wastewater treatment system to remove heavy metals while producing. The wastewater treatment system according to claim 1, wherein the pH of the wastewater is adjusted to 2 to 10 to produce electric power. The wastewater treatment system for producing heavy electric power from heavy wastewater containing heavy metals. A wastewater inflow portion into which wastewater containing heavy metals flows;
An electrocoagulation reaction unit for receiving wastewater flowing in from the wastewater inflow section and reacting with the inflow wastewater to treat the inflow wastewater; And
And a treated water discharging portion through which the waste water having undergone the reaction in the electrocoagulation reaction portion is discharged,
The electrocoagulation reaction unit may include:
A fuel cell including a negative electrode exposed to the atmosphere, a positive electrode, and a catalyst layer provided between the negative electrode and the positive electrode so as to be in contact with the negative electrode,
The positive electrode
Iron, stainless steel, or a mixture thereof, and the amount of OH ^- required to produce Fe (OH) ₃ required to produce the magnetic iron compound And the pH of the influent wastewater is increased. The wastewater treatment system according to claim 1, 13. The method of claim 12,
The inflowing wastewater is supplied to the water-
a pH of 5 to 9,
The pH,
Wherein the water is raised by the reaction of the positive electrode. 13. The wastewater treatment system according to claim 12, wherein the external resistance is 10 to 200 [Omega] when the magnetic iron compound is produced in the fuel cell. 13. The wastewater treatment system according to claim 12, wherein the magnetic iron compound is magnetite (Fe ₃ O ₄ ), for producing electric power from heavy wastewater containing heavy metals and for removing heavy metals. delete delete delete

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