KR101667479B1 - Method for removing perchlorate ion using electrodeposited Hg or Bi thin-layer electrode - Google Patents
Method for removing perchlorate ion using electrodeposited Hg or Bi thin-layer electrode Download PDFInfo
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- KR101667479B1 KR101667479B1 KR1020150041167A KR20150041167A KR101667479B1 KR 101667479 B1 KR101667479 B1 KR 101667479B1 KR 1020150041167 A KR1020150041167 A KR 1020150041167A KR 20150041167 A KR20150041167 A KR 20150041167A KR 101667479 B1 KR101667479 B1 KR 101667479B1
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Abstract
The present invention relates to an apparatus, system and method for removing perchloric acid ions using a mercury or a bismuth thin film electrode. More specifically, the present invention relates to an apparatus, system and method for removing perchloric acid ions by using a mercury or a bismuth thin film electrode, According to the method of decomposing perchloric acid of the present invention, the mercury thin film electrode is capable of decomposing the perchloric acid decomposition potential to -1.7 without disturbing the generation of hydrogen. V can be effectively applied, and an electrochemical decomposition method can be used to effectively decompose perchloric acid within a relatively short time.
Description
The present invention relates to a method for removing perchloric acid ions using a mercury or bismuth electrodeposited thin film electrode. More specifically, the present invention relates to a method for removing perchloric acid ions by electrochemically depositing a metal thin film such as mercury or bismuth on a glass or porous carbon electrode And a method for electrochemically decomposing and decomposing perchloric acid ions in an aqueous solution using the same.
Perchlorate ion has a condition that it is easily thermodynamically reduced, but it has a very stable tetrahedral form in aqueous solution and has a very high activation energy from the kinetic point of view. It is also an environmentally important contaminant that can interfere with thyroid function and cause various cancers when consumed. Therefore, various technologies for treating perchloric acid have been developed and applied.
The method is largely divided into a method of separation and recovery and a method of reducing and decomposing into relatively harmless chlorine ions. Examples of the former method include a method using an anion exchange resin, a filtration method using a membrane, and an electrodialysis method. The latter methods include a reduction method using a chemical method such as zero valence iron, a method using a photocatalyst, a method using a microorganism, And a method of reducing and decomposing perchloric acid electrochemically including a method.
Perchloric acid is known to undergo electrochemical reduction as shown in the following equation.
ClO 4 - + 8H + + 8e - - > Cl - + 4H 2 O E o = 1.29 V
(Almeida, et. Al., 1997), a method of electrochemically reducing and decomposing perchloric acid ions using a tin (Sn) electrode at a potential value of -0.85 to -1.1 V, The same experiment (Rusanova, et al., 2006) was performed using a platinum assisted electrode and a potential of -0.9 V, A direct electrochemical decomposition method using a rhodium (Rd) electrode has been attempted. However, in this case, the decomposition efficiency of perchlorate ions is very low and there is a problem in applying to actual samples such as electrode erosion.
In addition, a study (Lang, et. Al., 2008) of a study of the decomposition mechanism of perchloric acid using rhodium (Rd) electrodes under acidic conditions was published. In this paper, we confirmed that the rate-determining step of the reaction is the first reduction step, and reported that it is possible to effectively remove the disturbance caused by the adsorption of the electrode surface on the rotating electrode by using the rotating disk electrode. However, most of the direct electrochemical methods have a problem in that the decomposition reaction of perchloric acid occurs competitively with the decomposition reaction of water, and the hydrogen generation causes interference. Further, when a low potential is applied to avoid hydrogen generation, there is a problem that the decomposition efficiency of perchlorate ion is very low and takes a long time.
(Wang et al., 2009; Lee, et. Al., 2011) was proposed to decompose perchloric acid and nitrate ions using indirect electrochemical decomposition using a titanium (Ti) electrode. In other words, Ti (III) and Ti (II) are generated by giving oxidation potential to the titanium electrode, and these materials can effectively decompose perchlorate ion as a strong reducing agent. In this case, problems such as hydrogen generation and low efficiency reported in the above-mentioned electrode can be solved to some extent, but also the decomposition efficiency is low for a high concentration of perchlorate ions and there is a problem of electrode erosion.
In the present invention, a metal electrodeposited thin film electrode which is not disturbed by the generation of hydrogen is applied while applying a sufficient potential to directly reduce the decomposition of perchloric acid, and the conditions for analyzing the perchlorate ion are optimized using the electrode. The theoretical standard reduction potential at which hydrogen is generated in the electrode is 0 V. However, actually, hydrogen is generated at a potential lower than the voltage, which is called overvoltage. Recently, there has been a paper (Wang and Xu, et al., 2012) in which experimental results are reported to prevent the generation of hydrogen in a stripping cyclic volatametry experiment using high overvoltage of Bi (Bi) . Indeed, mercury (Hg) has a very large overvoltage on the reduction of hydrogen ions at the surface, so even reactions taking place at a lower potential than the reduction of hydrogen ions can cause the reduction of perchlorate ions without competing with hydrogen ions.
Therefore, in the present invention, the electrodeposited thin film electrode is manufactured by using mercury having the lowest melting point of all metals and having the highest overvoltage and high-hydrogen overvoltage, and by optimizing the conditions for decomposing the perchlorate ion, Thereby completing the invention.
When decomposing perchloric acid ions using conventional electrochemical methods, there are problems such as erosion of electrodes, generation of byproducts and generation of hydrogen gas, and when a relatively high potential is used to avoid this, a low decomposition rate of perchlorate ions There is a problem that the time required for decomposition is large.
Therefore, in the present invention, an electrodeposited thin film electrode is manufactured by using mercury or bismuth with high overvoltage for hydrogen generation, thereby increasing the decomposition rate of perchloric acid ions and reducing the decomposition time.
Another object of the present invention is to provide a possibility of applying perchlorate ion as an environmental pollutant to practical samples by using a mercury electrodeposited thin film electrode or a Bi smear electrodeposited thin film electrode.
In the present invention, the above problem is solved by preparing an electrodeposited thin film electrode using mercury and beeswax having the lowest melting point of all metals and having a high hydrogen overvoltage and optimizing conditions for decomposing perchlorate ion using the electrode.
In the perchloric acid ion decomposition system according to the present invention, the thin film electrode is manufactured by electrodepositioning mercury or bismuth into a glass or porous carbon electrode by an electrochemical method in a solution.
The inventors of the present invention have found that the overvoltage on the metal surface due to hydrogen generation varies depending on the kind of the electrode, the polarity of the electrode surface, the current density, and the temperature. It is possible to efficiently decompose perchloric acid ions.
In addition, when the mercury is dissolved in the solution in the mercury electrode, it is completely removed by the precipitation reaction with chlorine ion generated by the decomposition of perchloric acid, and the mercury ion was not found in the solution after the reaction. .
According to the perchloric acid decomposition system of the present invention, the mercury thin-film electrode can effectively apply the decomposition potential of perchloric acid to -1.7 V without interfering with the generation of hydrogen, and when the bisimuss is used, the decomposition potential of perchlorate ion is effectively applied to -1.5 V And it is possible to decompose very quickly as compared with the conventional method. When mercury electrodeposition electrodes were used within a relatively short time of 5 hours using the electrochemical decomposition method, 35% of perchloric acid at 350 mg / L was reduced to 14% by using a bismuth electrodeposition electrode, Decomposition rate of perchloric acid of 10 mg / L was improved by more than 89% in 5 hours and by 92% in 24 hours. According to the perchloric acid decomposition system of the present invention, mercury or bismuth is not eluted at all (mercury or non-mercury redox potentials are not present in addition to the perchloric acid potential during CV progression to 14 times) .
FIG. 1 is a schematic diagram of a three-electrode system. The system used in the present invention is a three-electrode system in which a working electrode and an auxiliary electrode are used in addition to a reference electrode. A current flows between the auxiliary electrode and the working electrode, thereby preventing a voltage drop And is used to decompose a sample by electrodepositing a mercury thin film on a carbon electrode used as a working electrode using a potentiostat using a three-electrode system.
2 shows a cyclic voltammogram of a 1 mM Hg (NO 3 ) 2 in 0.1 M HNO 3 solution in a glassy carbon electrode (Scan rate: 100 mV / s, 5 mL, Potential: 1.0 to -1.0 V), thereby confirming the oxidation and reduction potential of the mercury ion.
3 shows a cyclic voltammogram of a 1 mM Bi (NO 3 ) 3 in 1 M HNO 3 solution in a glassy carbon electrode (Scan rate: 100 mV / s, 5 mL, Potential: 0.5 to -0.5 V), so that the oxidation and reduction potential of the non-smectic ion can be confirmed.
Figure 4 compares the LSV of the mercury electrodes according to the deposition time in the two solutions (black: 100 ppm ClO 4 - in 0.1 M Na 2 SO 4 , 5 mL, red: 0.1 M Na 2 SO 4 , 5 mL , Solid: 10 minutes, Dash: 20 minutes, Short dot: 30 minutes).
Figure 5 compares the LSV of the non-smudged electrode with the deposition time in both solutions. (100 ppm ClO 4 - in 0.1 M Na 2 SO 4 , 5 mL Blue: 10 min, red: 20 min, green: 30 minute).
FIG. 6 shows a cyclic voltammogram (short dot: 1000, short dash: 3000, solid: 5000 ppm ClO 4 ) of 1000, 3000, and 5000 ppm ClO 4 - solutions at 14 cycles of CV using a mercury- - ).
FIG. 7 shows a cyclic voltammogram (red: 1000, green: 3000, blue: 5000 ppm ClO 4 - ) of 1000, 3000, and 5000 ppm ClO 4 - solutions at 14 cycles in the CV of the non- Lt; / RTI >
(A) fixing a glass or porous carbon electrode together with a reference electrode and an auxiliary electrode in a cell containing a mercury ion solution or a bismuth ion solution; And (b) a mercury thin film electrode is prepared by injecting a constant potential of -0.4 to -0.6 V at room temperature, or a constant potential of -0.1 to -0.15 V is injected at room temperature to prepare a non-smith thin film electrode, Or a working electrode on which a mercury or a bismuth thin film is deposited on a porous carbon electrode. The present invention also provides a method of manufacturing a three-electrode device comprising a reference electrode, an auxiliary electrode, and a working electrode.
In one aspect of the present invention, a mercury thin film electrode is prepared by injecting a constant potential of -0.4 to -0.6 V, specifically about -0.5 V, in preparing the mercury thin film in step (b). More specifically, the mercury thin film electrode can be manufactured by scanning with a constant potential of about -0.5 V for 10 minutes or more.
In one embodiment of the present invention, a non-smear thin film electrode is prepared by injecting a constant potential of -0.1 to -0.15 V, specifically about -0.1 V, in the production of the non-smear thin film in step (b). More specifically, at a constant potential of about -0.1 V for at least 10 minutes to produce a non-smith thin film electrode.
In one embodiment of the present invention, the thickness of the electrodeposited metal may be controlled and electrodeposited according to the amount of mercury or bismuth added to the glass or porous carbon electrode.
In one embodiment of the present invention, the rate of decomposition of perchloric acid increases accordingly when the size of the electrode is increased.
In one aspect of the present invention, the three-electrode device is characterized by being for decomposing perchloric acid ions. The three-electrode device according to the present invention has auxiliary electrodes in addition to the working electrode and the reference electrode, and is used to prevent a voltage drop occurring on the working electrode due to the current flowing between the auxiliary electrode and the working electrode. A mercury thin film or a non-sulfide thin film is electrodeposited on a carbon electrode used as a working electrode using a potentiostat using a three-electrode device, and then the potential is used to decompose the sample.
In one aspect of the present invention, a platinum assist electrode may be used as the auxiliary electrode, and the form thereof may be a wire, a coil, a net, a plate, or the like.
In one embodiment of the present invention, an Ag / AgCl (saturated NaCl) reference electrode or a commercial reference electrode may be used as the reference electrode.
In one embodiment of the present invention, the specific surface area of the working electrode to which the mercury or the bismuth thin film is deposited is proportional to the surface area of the glass-like or porous carbon electrode to be used, and the electrodeposited mercury or the bismuth thin film also has porosity.
The present invention relates to a reference electrode; Electrode, and a working electrode on which a mercury or a bismuth thin film is deposited on a glass or porous carbon electrode.
In one aspect of the invention, the three electrode device is for decomposing perchloric acid ions.
In one aspect of the present invention, a platinum assist electrode may be used as the auxiliary electrode, and the form thereof may be a wire, a coil, a net, a plate, or the like.
In one embodiment of the present invention, an Ag / AgCl (saturated NaCl) reference electrode or a commercial reference electrode may be used as the reference electrode.
In one embodiment of the present invention, the specific surface area of the working electrode to which the mercury or the bismuth thin film is deposited is proportional to the surface area of the glass-like or porous carbon electrode to be used, and the electrodeposited mercury or the bismuth thin film also has porosity.
In one aspect of the present invention, a reference electrode; There is provided a three-electrode system comprising an auxiliary electrode and a working electrode on which a mercury or a bismuth thin film is deposited on a glass or porous carbon electrode.
In one aspect of the invention, the three electrode device is for decomposing perchloric acid ions.
In one aspect of the present invention, a platinum assist electrode may be used as the auxiliary electrode, and the form thereof may be a wire, a coil, a net, a plate, or the like.
In one embodiment of the present invention, an Ag / AgCl (saturated NaCl) reference electrode or a commercial reference electrode may be used as the reference electrode.
In one aspect of the present invention, a method of removing perchlorate ions using a three electrode device is provided.
In one embodiment of the present invention, decomposition of the perchlorate ion can be carried out at a temperature condition of 30 to 70 캜. Perchlorate ion may explode in a temperature range exceeding the above temperature range.
In one embodiment of the present invention, decomposition of perchlorate ions can be performed using a mercury electrodeposition electrode at a pH of 2 to 4, and decomposition of perchlorate ions is performed at a pH of 4 to 7 using a non-sulfided electrodeposition electrode . When the pH is out of the above range, decomposition efficiency of perchlorate ion is low. When the pH is increased by 7 or more, a salt is formed in the reference electrode, so that a constant current does not flow.
In the present invention, the perchloric acid decomposition potential is characterized by being -1.7 V or higher when a working electrode on which a thin film of mercury or a thin film of non-sulfide is electrodeposited is used. At -1.7 V, it shows the highest perchloric acid decomposition rate, and when it is lowered, the decomposition rate changes from stagnation to decline due to the generation of hydrogen.
More specifically, in one aspect of the present invention, a mercury or non-mercury thin film electrode can be manufactured by the following method:
The porous carbon electrode was washed with a solution of hydrogen peroxide and sulfuric acid in a ratio of 3: 1. The glass carbon working electrode was polished with ALS solution, washed with distilled water, and immersed in 1 mM Fix to the cell containing the Hg (NO 3 ) 2 solution. The mercury thin-film electrode can be prepared by using the time-of-day current method and injecting it at a constant potential of -0.5 V, which is the mercury reduction potential at room temperature, for 10 minutes or more. The BiSM thin film electrode can also be prepared by using the time zone current method and injecting at a constant potential of -0.1 V which is the reduction potential of the BiSuS at room temperature for at least 10 minutes.
In the present invention, the performance of the mercury electrode and the non-smudge electrode manufactured over time can be evaluated by the LSV method. For example, to prevent mercury or bismuth from oxidizing in solution, add -0.5 V and -0.1 V for 1 minute, respectively, and for mercury -0.5 to -2.5 V to 20 mV / In this case, inject from -0.7 to -2.0 V at 10 mV / s. The stability of electrodeposited mercury or non-mercury electrodes is evaluated while varying the scanning time and the amount of current.
Hereinafter, the present invention will be described in more detail with reference to Examples and Experimental Examples. It should be understood, however, that the following Examples and Experiments are for the purpose of promoting understanding of the present invention and are not intended to limit the scope of the present invention.
<Materials>
In the present invention, a glass carbon working electrode, a Ag / AgCl (reference NaCl) reference electrode, a platinum auxiliary electrode, and a porous carbon electrode were used. The solution used for electrodepositing mercury was prepared by dissolving 1 mM of Hg (NO 3 ) 2 in 0.1 M nitric acid solution. The solution used for electrophoresis of Bi smears was prepared by dissolving 1 mM Bi (NO 3 ) 3 in 1 M nitric acid solution. A solution of 100, 1000, 3000, 5000 ppm NaClO 4 in 0.1 M Na 2 SO 4 solution was used to evaluate the stability of the prepared mercury thin film electrode. The decomposition solution of the sample was dissolved by the 10, 350 ppm NH 3 ClO 4 and NaClO 4 to 0.01 M of Na 2 SO 4 pH was adjusted using a HClO 4.
Potentiostat / Galvanostat was used for electrodeposition and electrochemical decomposition, and ion chromatography (Ion Chromatography) was used for the determination of ClO 4 - ion in solution. For stability assessment, ICP-AES was used to identify mercury remaining in the solution after completion of the decomposition.
Example One. Glass phase Or mercury is electrodeposited on a porous carbon electrode to produce a thin film electrode
The mercury thin film electrode was prepared as follows. The porous carbon (RVC: 250 X 100 X 50 mm) electrode was washed with a solution of hydrogen peroxide and sulfuric acid in a ratio of 3: 1 for 20 minutes. The glass working carbon electrode was polished with a polishing patch using ALS solution, cleaned with distilled water, and plated with a platinum auxiliary electrode and a reference electrode (Ag / AgCl in Sat'd NaCl) at 0.1 M And fixed in a cell containing 1 mM Hg (NO 3 ) 2 solution dissolved in nitric acid. The mercury thin film electrode was fabricated by using the time zone current method and injecting at a constant potential of mercury reduction potential of -0.5 V for 10 minutes or more at room temperature.
Experimental Example 1. Stability and Electrode Optimization of Prepared Electrodes
The performance of mercury electrodes fabricated by time was evaluated by LSV method. To prevent mercury from oxidizing in solution, -0.5 V was applied for 1 min and -0.5 to -2.5 V at 20 mV / s. The stability of the electrodeposited mercury electrode was evaluated while varying the scanning time and the amount of current.
The mercury was electrodeposited on perchloric acid solution for 10 minutes. To prevent mercury from oxidizing in solution, -0.5 V was applied for 1 min and repeatedly injected at a scan rate of 100 mV / s from -0.5 to -2.0 V.
Example 2. Glass phase Or a porous carbon electrode Bismuth Manufacture of thin film electrode by electrodeposition
The Bismuth electrodeposited thin film electrode was prepared as follows. The porous carbon (RVC: 250 X 100 X 50 mm) electrode was washed with a solution of hydrogen peroxide and sulfuric acid in a ratio of 3: 1 for 20 minutes. The glass working carbon electrode was polished with a polishing patch using ALS solution, cleaned with distilled water, and cleaned with a platinum auxiliary electrode and a reference electrode (Ag / AgCl in Sat'd NaCl) 1 mM Bi dissolved in nitric acid (NO 3) 3 solution was set in a cell contained. The BMS thin film electrode was fabricated by using the time - of - current method and injecting it at a constant potential of -0.1 V, which is the reduction potential of the bismuth at room temperature, for at least 10 minutes.
Experimental Example 2. Manufactured Bismuth Electrode Stability and Electrode Optimization Investigation
The performance of mercury electrodes fabricated by time was evaluated by LSV method. To prevent mercury from oxidizing in solution, -0.1 V was applied for 1 min and injected from -0.7 to -2.0 V at 10 mV / s. The stability of the electrodeposited non - smudged electrode was evaluated while varying the scanning time and the amount of current.
CV was performed using a glassy carbon electrode electrodeposited with beeswax for 20 minutes. To prevent the oxidation of the beeswax in solution, -0.1 V was applied for 1 min and repeatedly injected at -0.6 to -1.9 V at a scan rate of 100 mV / s.
Experimental Example 3. Decomposition of perchloric acid electrochemically using the prepared thin-film electrode
15 mL of digestion solution was used, and all solutions were purged with nitrogen gas for 20 minutes to remove dissolved oxygen. The prepared electrode was washed with tertiary distilled water and placed in a 350 ppm perchloric acid ion solution dissolved in a 0.01 M electrolyte solution, and a constant potential was applied for 5 to 24 hours. The temperature was maintained at 50 ° C for all experiments, the pH was 3 at the mercury electrodeposition electrode and 5.7 at the bismuth electrodeposition electrode. The concentrations before and after decomposition were measured by ion chromatography.
<Results and Discussion>
The mercury or bismuth electrodeposited thin film electrode was prepared by electrodepositing a metal using a porous carbon electrode having a wide surface area as a working electrode using a three electrode system (Fig. 1) to maximize the contact area with the solution.
The electrodeposition conditions were confirmed by the following method. In order to confirm the redox potential of mercury ions, 1 mM Hg (NO 3 ) 2 solution dissolved in 0.1 M nitric acid was circulated by a voltage-current method at a scan rate of 100 mV / V < / RTI > (see Figure 2 for cyclic voltammogram). In the graph, the oxidation potential of mercury (Hg 2 + ) appears at 0.55 V, and the reduction potential is in a wide range from 0.3 to -1.0 V. In order to find the redox potential of the BiSMe ions, 1 mM Bi (NO 3 ) 3 solution dissolved in 1 M nitric acid was circulated by the cyclic voltammetric method at a scan rate of 10 mV / V < / RTI > (see FIG. 3 for a cyclic voltammogram). The oxidation potential is 0.05 V, the reduction potential of the non-seumeuseu (Bi + 3) in the graph shown at -0.1 V.
The mercury electrodeposited thin film electrodes were fabricated by time - of - current method. At room temperature, the mercury reduction potential of -0.5 V was constantly maintained at 600, 1200, and 1800 seconds. As a result, mercury was thinly electrodeposited on the working electrode. After electrodeposition, the surface of the electrode changed to a silver color that can be distinguished by mercury. We investigated the relationship between the amount of charge Q and the thickness of mercury film over time of mercury electrodeposition. When the amount of charge was kept constant over time during mercury electrodeposition, the film thickness increased at a certain rate depending on the electrodeposition time. In addition, a thin gray film was electrodeposited by constantly applying 600, 1200, and 1800 seconds of the -0.1 V reduction potential of Bismuth. Thickness of the thin film of Bismuth was confirmed by the same method as that of mercury, and the results are shown in Table 1 and Table 2, respectively.
(μm)
(μm)
An LSV graph of 100 mg / L perchloric acid ion solution (0.10 M Na 2 SO 4 ) and 0.10 M Na 2 SO 4 base solution without perchloric acid is shown in FIG. The LSV graph obtained from the solution containing perchloric acid over time showed the largest value at 30 minutes after electrodeposition, but not great difference. However, it was confirmed that the current value of the electrode was larger than that of the case where only the electrolyte was included. Therefore, the presence of perchloric acid appears to be due to the magnitude of the current. As a result of this experiment, there was no difference in the current size according to the electrodeposition time. Therefore, in the subsequent experiment of the present invention, an electrode electrodeposited for 10 minutes was used.
In all solution conditions, the perchloric acid solution was repeatedly injected from -0.5 to -2.0 V at a scan rate of 100 mV / s. As a result, the magnitude of the current decreased as the number of repetitions increased. The magnitude of the current at different voltages was similar in all solution conditions, but no appreciable perchloric acid reduction current was found in 1000 mg / L perchloric acid solution. However, in the 3000 and 5000 mg / L perchloric acid solutions, reduction currents were found at -1.6 to -1.8 V and -.4 to -1.75 V, respectively. The oxidation current was not measured by the irreversible reaction of perchlorate ions (see FIG. 6). In other words, it was confirmed that the amount of reduction current increased in proportion to the concentration of perchloric acid, and the pH was decreased with increasing concentration of perchloric acid, and the reduction potential was shifted to the (+) position. During the CV up to 14 cycles, the source of mercury oxidation source potential was not found besides the perchloric acid potential, and the mercury electrode was confirmed to be stable under the experimental conditions.
The decomposition rate of perchloric acid was verified at various potentials using the time - zone current method.
(
mg
/ L)
(° C)
(V)
(%)
(
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/ L)
(° C)
(V)
(%)
The solution was subjected to perchloric acid decomposition while converting only the potential value from -0.9 to -1.7 V under the above test conditions. As can be seen in Table 1, at the decomposition time of 5 hours, the highest decomposition rate of perchloric acid was observed at -1.7 V, where the dislocation value decreased in the (-) direction. However, when the potential value is lowered, the decomposition rate is changed from stagnation to decline due to the generation of hydrogen.
Since the concentration of perchloric acid in the actual environment sample is very low, it is less than 10 mg / L, and the decomposition rate of perchloric acid was confirmed over time at this concentration.
(
mg
/ L)
(° C)
(V)
(%)
The potential was set to -1.5 V and the experiment was performed using the time-of-day current method. The degradation rate of 88.9% perchloric acid was already decomposed in 5 hours of decomposition reaction using mercury electrodeposition electrode and increased to 92% when the time was increased to 24 hours. The decomposition rate of perchloric acid was also found to increase with increasing the size of the electrode.
Although mercury was extracted from the mercury electrodes in various solutions, mercury was not detected in any case.
Claims (19)
(b) preparing a mercury thin film electrode by scanning a constant potential of -0.4 to -0.6 V at room temperature, or preparing a viscous thin film electrode by scanning a constant potential of -0.1 to -0.15 V at room temperature, Comprising the steps of: preparing a working electrode to which a mercury or a bismuth thin film is deposited on a porous carbon electrode;
A method of manufacturing a three-electrode device comprising a reference electrode, an auxiliary electrode, and a working electrode.
Wherein the three-electrode device is for decomposing perchloric acid ions.
Wherein the auxiliary electrode is a platinum assisted electrode.
Wherein the reference electrode is an Ag / AgCl (saturated NaCl) reference electrode.
Wherein the specific surface area of the working electrode on which the mercury or the non-sulfided thin film is deposited is proportional to the surface area of the glass or porous carbon electrode to be used and the electrodeposited mercury or the non-sulfided thin film has porosity.
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