KR20220159541A - Electrochemical heavy metal removal method using asymmetric electrodes - Google Patents

Abstract

The present invention provides a method for removing heavy metals in feed, which comprises the steps of: (a) providing feed; (b) applying power to an electrode to generate a flocculant in the feed, wherein an anode and a cathode of the electrode are different in a form; (c) binding the flocculant to heavy metals to form floccules; (d) introducing a polymer-based coagulant into the feed including floccules to form aggregates; (e) settling down the aggregates to remove the same; and (f) recovering the feed whose aggregates have been removed.

Description

Electrochemical heavy metal removal method using asymmetric electrodes {Electrochemical heavy metal removal method using asymmetric electrodes}

The present invention is a method for removing heavy metals from feed, more specifically, by forming a coagulant through hydration of an anode having a different form from a cathode, condensing heavy metals present in wastewater such as reverse osmosis concentrated water, and then precipitating them. It's about how to remove it.

Heavy metals such as antimony, arsenic, and vanadium are toxic to specific target organs such as the intestine and respiratory tract when exposed to humans, can cause cancer, and are toxic to aquatic organisms, so they must be separated from the water system.

As a method for separating heavy metals from the water system, a method of precipitating and removing heavy metals by adding an aluminum-based coagulant such as poly aluminum chloride (PAC) to the water system to coagulate the heavy metals may be considered.

However, as described above, in the case of the chemical coagulation method in which a coagulant is added to coagulate heavy metals, the pH of the water system tends to decrease during the coagulation reaction. There is a problem that requires additional processing for.

Registered Patent Publication No. 10-2185989

Accordingly, the present disclosure provides a method of condensing and precipitating heavy metals in an aqueous system to remove them by coagulating and precipitating them by an electrochemical method using electrodes having different shapes of anode and cathode without separately introducing a coagulant. aims to do

According to one aspect of the present disclosure, a method for removing heavy metals in a feed is provided, the method comprising: (a) providing a feed containing heavy metals; (b) applying power to an electrode to generate a coagulant in the feed, wherein the shape of the anode and cathode of the electrode is different from each other; (c) combining the coagulant with the heavy metal to form an agglomerate; (d) injecting a polymer-based flocculant into a feed containing the agglomerates to form agglomerates; (e) precipitating and removing the agglomerates; and (f) recovering the feed from which the aggregates are removed.

According to one embodiment of the present disclosure, the heavy metal may be any one of antimony (Sb), vanadium (V), arsenic (As), and a combination thereof.

According to one embodiment of the present disclosure, the heavy metal in the feed of step (a) may be present at a concentration of 0.1 to 7 ppm.

According to one embodiment of the present disclosure, the feed may be any one of boiler concentrated water, reverse osmosis (RO) concentrated water, leachate, capacitive deionizer (CDI) concentrated water, and ion exchange resin recycled wastewater.

According to one embodiment of the present disclosure, the method may further include supplying an electrolyte to the feed before step (b).

According to one embodiment of the present disclosure, the electrolyte may include any one of NaCl, Na ₂ SO ₄ , and a combination thereof.

According to one embodiment of the present disclosure, the pH of the feed before applying power in step (b) may be 4 to 9.

According to one embodiment of the present disclosure, each of the positive electrode and the negative electrode of the electrode may include any one of aluminum (Al), iron (Fe), and titanium (Ti).

According to one embodiment of the present disclosure, the polymer-based coagulant may be an acrylamide-based polymer.

According to one embodiment of the present disclosure, the amount of the polymer-based coagulant may be 1 to 15 ppm.

According to one embodiment of the present disclosure, the size of the aggregate may be 0.1 to 200 mm.

According to one embodiment of the present disclosure, step (d) may further include controlling the input amount of the polymer-based coagulant in real time according to the particle size of the agglomerate.

According to one embodiment of the present disclosure, step (d) may further include stirring the feed at a stirring speed of 30 to 80 rpm after the coagulant is added.

According to one embodiment of the present disclosure, step (e) may include allowing the feed to stand for 30 minutes to 100 minutes.

According to one embodiment of the present disclosure, the feed recovered in step (f) may contain less than 0.05 ppm of total heavy metals.

According to the method for removing heavy metals according to the present disclosure, since the change in pH of the feed during the condensation reaction of heavy metals is small, an additional treatment process for pH control can be omitted when recovering and reusing the feed from which heavy metals have been removed. In addition, according to the electrochemical heavy metal removal method using different types of positive and negative electrodes according to the present disclosure, higher heavy metal condensation efficiency is guaranteed compared to the method of electrochemical heavy metal removal using the same positive and negative electrodes.

1 is a schematic diagram of an apparatus for removing heavy metals through electrochemical coagulation and precipitation of the present disclosure.
2 shows an exemplary form of an anode having a shape different from the planar cathode of the present disclosure.
3 is a schematic diagram illustrating a monopolar arrangement and a bipolar arrangement of electrodes.
4 is a schematic diagram illustrating parallel and series connection of electrodes.
5 is a plot of the concentration of antimony and the reduction rate of antimony for each electrochemical treatment time when the positive and negative electrode types are the same and different according to an embodiment of the present disclosure.
6 is a plot of antimony removal rate according to pH in the case of using an electrochemical condensation method and a chemical condensation method.

Throughout this specification, descriptions of unnecessary parts that may obscure the core of the technical idea of the present disclosure may be omitted.

According to one aspect of the present disclosure, a method for removing heavy metals in a feed is provided, and the method may include providing a feed. Here, the feed is not limited as long as it is wastewater containing heavy metals. For example, among boiler concentrated water, reverse osmosis (RO) concentrated water, leachate, capacitive deionizer (CDI) concentrated water, and ion exchange resin recycled wastewater. It may be any one, and they are suitable for electrochemical treatment as a feed with a high ion concentration.

The heavy metal refers to a metal having a specific gravity of 4 or more, and more specifically refers to arsenic (As), antimony (Sb), lead (Pb), mercury (Hg), cadmium (Cd), and vanadium (V). . Among them, heavy metals preferred for treatment in the present disclosure may be any one of antimony, arsenic, vanadium, and combinations thereof, which are toxic to specific target organs such as the intestine and respiratory tract when exposed to the human body and can cause cancer. In addition, in the method of the present disclosure, in addition to the heavy metals, metals such as copper (Cu), zinc (Zn), cobalt (Co), barium (Ba), nickel (Ni), and chromium (Cr) can also be removed by condensation. .

In one embodiment, heavy metals in the feed may be present at a concentration of 0.1 to 7 ppm. More specifically, the heavy metal concentration in the feed is 0.1 to 7 ppm, 0.1 to 6 ppm, 0.1 to 5 ppm, 0.1 to 4 ppm, 0.1 to 3 ppm, 0.1 to 2 ppm, 0.1 to 1 ppm, 0.3 to 7 ppm, 0.3 to 6 ppm, 0.3 to 5 ppm, 0.3 to 4 ppm, 0.3 to 3 ppm, 0.3 to 2 ppm, 0.3 to 1 ppm, 0.5 to 7 ppm, 0.5 to 6 ppm, 0.5 to 5 ppm, 0.5 to 4 ppm, It may be 0.5 to 3 ppm, 0.5 to 2 ppm, 0.5 to 1 ppm, preferably 0.7 to 3 ppm, more preferably 0.7 to 1 ppm. In general, it is difficult to remove such heavy metals from the feed containing trace amounts, but the present invention enables the removal of trace amounts of heavy metals through appropriate control of electrochemical condensation process conditions.

In one embodiment, the method may further include supplying an electrolyte to the feed. Most of the wastewater, including the boiler concentrated water and reverse osmosis concentrated water listed above, already contains ionic materials and does not require additional input of ionic materials. Electrolyte must be supplied to the feed, which is the reaction medium of the electrochemical reaction to do this. The electrical conductivity of a feed suitable as a reaction medium for the electrochemical reaction of the present disclosure is between 0.01 μS/cm and 50 mS/cm, preferably between 200 μS/cm and 35 mS/cm, and most preferably between 400 μS/cm and 7 mS/cm. to be.

The electrolyte supplied to the feed is not particularly limited, but may exemplarily include any one of NaCl, Na ₂ SO ₄ and combinations thereof. In addition to Na ⁺ , Ca ²⁺ , Cl ^- and SO ₄ ^2- formed by dissolving the electrolyte in the feed, Mg ²⁺ , K ⁺ , Br ^- , I ^- , F ^- , ClO ₄ present in trace amounts in the water in the feed ^- Ions such as CO ₃ ^2- and HCO ₃ ^- maintain the electrical conductivity of the feed.

In addition, NaOH, HCl and/or H ₂ SO ₄ may be added to the feed to maintain the pH of the feed suitable for the electrochemical condensation reaction of the present disclosure.

The method may include applying power to an electrode to create a condensate within the feed. The electrode is placed in the reactor, and the entire anode and cathode are immersed in the feed.

Here, the current density of the applied power may be 0.5 mA/cm ² to 200 mA/cm ² , preferably 10 mA/cm ² to 150 mA/cm ² , more preferably 50 mA/cm ² to 100 mA/cm ² . When the current density exceeds 200 mA/cm ² , economic feasibility may decrease.

When power is applied to the electrode and current flows, the electrode material is ionized from the anode and dissolved in water to generate a hydrate of the metal material constituting the anode, which acts as a coagulant for coagulating heavy metals present in the feed. As described above, as the coagulant is generated by hydration of the metal constituting the anode, the anode is consumed and the size of the anode is gradually reduced, and when the size is reduced to 80% or less of the initial electrode area, which is the effective area of the electrode , the anode can be replaced.

In one embodiment, each of the positive electrode and the negative electrode of the electrode may include any one of aluminum (Al), iron (Fe), and titanium (Ti), wherein the standard reduction potential of the negative electrode is greater than or equal to the standard reduction potential of the positive electrode. . For hydration of Al, Fe, and Ti ions, which are metals constituting the electrode, the pH of the feed may be 4 to 9, preferably 5 to 8, and most preferably 6 to 7. The size and number of electrodes containing any one of Al, Fe, and Ti are not limited, but as the size and number increase, the performance as a coagulant for their hydrates increases, while the current is increased to maintain the same current density. should give

The chemical condensation reaction of heavy metals using conventional coagulants such as Al (PAC, Alum) and Fe (ferric sulfate or ferric sulfate) is a reaction in which the surface of the coagulant metal is modified with OH to generate H ⁺ . While the pH is lowered, the electrochemical condensation of the present disclosure does not lower the pH because H ⁺ is reduced to H ₂ gas at the cathode and escapes from the aqueous system. However, depending on the reaction conditions, the pH of the feed may increase slightly when the hydrogen reduction reaction is strong. However, as described above, in the electrochemical condensation method, the pH of the feed is in the range of 4 to 9 (in a suitable pH range wider than chemical condensation) This slight increase in pH is not a problem, as it is not significantly affected by coagulant formation. In the case of chemical condensation, the change in heavy metal removal rate according to the change in pH is large, and the range of appropriate pH is very narrow. have.

When the anode of the electrode includes Al, a chemical formula of a reaction in which a coagulant is generated is as follows.

Metal Al ions dissolved from the anode are hydrated by water contained in the feed to form an Al complex, which forms sludge-type agglomerates by combining with heavy metals contained in the feed. Metal ions included in the anode have higher heavy metal condensation performance as the hydration proceeds more. For example, when the anode is Al, the chemical formula when hydration proceeds is as follows.

The arrangement of the electrodes may be a monopolar arrangement having the same polarity on both sides of the electrodes or a bipolar arrangement having different polarities on both sides of the electrodes, and one or more of each arrangement may be mixed.

As shown in FIG. 3, the unipolar arrangement is advantageous in terms of energy efficiency as coagulant is generated only at the positively charged electrode, and the bipolar arrangement generates condensate at all electrodes, so the electrodes are consumed evenly and the wire is at both ends. Since it is connected only to the electrode of the electrode, it is advantageous in terms of easy replacement of the electrode.

The connection method of the electrodes may be a parallel connection in which the flow direction of the feed on both sides of the electrode is the same, or a series connection in which the flow direction of the feed on both sides of the electrode is different, or one or more of the respective connection methods may be mixed.

As shown in FIG. 4, the parallel connection is advantageous in that the feed flux per unit area is large, and the serial connection is advantageous in that the contact time between the feed and the electrode is long.

The above-mentioned electrode arrangement and connection method can coexist without limitation, and can be selected in an optimal direction according to the configuration of the process and the shape of the reactor.

In one embodiment, the shape of the positive electrode and the negative electrode of the electrode may be different from each other. More specifically, the positive electrode and the negative electrode may have unevenness of the electrodes, or may have different shapes or sizes, or may have a mesh structure. For example, if it is assumed that the shape of the cathode is flat, examples of possible examples of the shape of the anode different from this are as shown in FIG. 2 . When the shape of the anode and the cathode is the same, the net electric field acting on the particle located at any point between the anode and the cathode is 0, and when the particle is not charged, it is not affected by the electric field. On the other hand, when the shape of the anode and the shape of the cathode are different from each other, the strength of the electric field from the anode and the electric field from the cathode acting on the particle located at an arbitrary point between the anode and the cathode are not the same, and the particle is Or, it is more affected by the electric field of either one of the cathodes, and even when the particle is not charged, it is subjected to a force by the electric field, and this force is referred to as a dielectrophoresis force. Heavy metal particles between the positive and negative electrodes of different shapes are located at the point where the forces in the electric field are balanced by the electrophoretic polarization force, and the same particles move to the same position, and each heavy metal such as As, Sb and V Silver can be easily condensed by being intensively distributed at a specific point between the anode and the cathode.

In addition, when the shape of the anode and the cathode are different, due to the electrophoretic polarization power as described above, the heavy metal in the feed is intensively distributed at a specific point away from the electrode by a certain distance, resulting in passivation and fouling of the electrode Fouling can be prevented.

In one embodiment, the method may include introducing a polymer-based flocculant into a feed comprising the agglomerates to form agglomerates. Agglomerates in which heavy metals such as As, Sb, and V are physicochemically combined with hydrates of Al, Ti, or Fe electrodes have a higher specific gravity than water, so they can be precipitated over time and separated from the feed. However, since it takes a lot of time to completely separate the agglomerates through precipitation by simply leaving the agglomerates, a polymer-based coagulant that promotes aggregation between the agglomerates to form agglomerates can be introduced in order to shorten the time required for precipitation. have. The aggregate refers to a lump formed by aggregation of the aggregate formed in the coagulation step by a crosslinking action due to the affinity between ions with the polymer-based coagulant. The agglomerates need to be of a large size to allow rapid settling within the feed. Specifically, the size of the aggregate is comparable to the naked eye, 0.1 to 200 mm, 1 to 190 mm, 1 to 180 mm, 1 to 170 mm, 1 to 160 mm, 1 to 150 mm, 1 to 140 mm, may be 1 to 130 mm, preferably 1 to 120 mm, more preferably 1 to 110 mm, and most preferably 1 to 100 mm.

Conventionally, precipitation of a material is achieved by a difference in density between the material and the solvent, but in the present invention, the agglomerates containing heavy metals and Al, Ti or Fe and the polymer-based coagulant are aggregated as compared to the water component in the feed. Since the density is high, the degree of sedimentation of the agglomerates can be grasped by visually comparing the size of the agglomerates.

The polymer-based coagulant is not limited as long as it has an affinity between phosphate aggregates and ions and can form phosphate aggregates by crosslinking, and is preferably an acrylamide-based polymer, and the material included in the acrylamide-based polymer is Examples include polyacrylamide or acrylamide copolymers (acrylamide-methacryloyloxyethyltrimethylammonium chloride copolymer, etc.).

The amount of the polymer-based flocculant may be 1 to 15 ppm, 1 to 14 ppm, 1 to 13 ppm, 1 to 12 ppm, 1 to 10 ppm, 1 to 9 ppm, and 1 to 8 ppm, preferably 2 to 10 ppm. It may be 12 ppm, 2 to 11 ppm, 2 to 10 ppm, 2 to 9 ppm, or 2 to 8 ppm, more preferably 3 to 10 ppm, 3 to 9 ppm, or 3 to 8 ppm. When the input amount of the polymer-based coagulant is less than 1 ppm, the amount of the precipitated aggregate is reduced because the coagulation of the coagulum is not sufficient, and a low heavy metal removal rate of less than 10% can be exhibited, and the input amount of the polymer-based coagulant is 15 ppm If it exceeds, the viscosity of the water in the feed may increase and the sedimentation efficiency may rather decrease, and due to the high viscosity of the polymer-based coagulant, channeling of the resin flow due to the excessive coagulant or blockage of the pipe due to solidification etc., and may also be disadvantageous in terms of economic efficiency due to the high price of the polymer-based coagulant.

The step of adding the coagulant may further include controlling the amount of the polymer-based coagulant in real time according to the particle size of the coagulum. The step may include measuring the size and distribution of the agglomerates present in the water system by an intelligent particle dispersion analyzer (iPDA). The average particle size of the agglomerate is calculated in real time from the measured size and distribution of the agglomerate, and the input amount of the polymeric coagulant can be controlled in real time from the calculated average particle size of the heavy metal agglomerate.

The step of adding the coagulant may further include a step of stirring the coagulant after adding the polymer-based coagulant. Here, the stirring speed may be 30 to 80 rpm, preferably 30 to 60 rpm, and most preferably 30 to 50 rpm, which is slower than the stirring speed in the heavy metal agglomerate forming step. The stirring step allows the polymer-based coagulant to better contact the agglomerate to form the agglomerate, and when the stirring speed exceeds 80 rpm, the bond between the polymer-based coagulant and the agglomerate may be destroyed. The stirring step may be performed for 300 seconds to 500 seconds, preferably 300 seconds to 450 seconds, more preferably 300 seconds to 400 seconds, and most preferably 300 seconds to 400 seconds.

The method may include settling and removing agglomerates in the feed. A method of condensing and/or coagulating heavy metals in the feed and then filtering them through a filter to remove them can also be considered. have. In addition, a method of treating the coagulant to increase the particle size can be considered, but as described above, the coagulant is a high-viscosity material and has the problem of causing filter clogging. Therefore, in removing heavy metal aggregates, the removal method by precipitation is more preferable The step may further include leaving the feed stationary. The standing time may be 30 minutes to 100 minutes, preferably 30 minutes to 90 minutes, and more preferably 40 minutes to 90 minutes. If the standing time is less than 30 minutes, this is not enough time for the previously formed agglomerates to precipitate, which can lead to a low heavy metal removal rate of less than 20%, and if the standing time is more than 100 minutes, large-scale equipment is required, This can be unfavorable from an economic point of view.

A structure of a lamella structure may be installed in the stationary facility to increase the stationary efficiency by increasing the sedimentation area.

The method may include precipitating and removing the heavy metal aggregates and then recovering the feed from which the aggregates are removed. As described above, the feed recovered in the above step can be used as industrial water, effluent water, or reused water, and has a heavy metal content suitable for each purpose. In the case of heavy metals, more specifically, the feed recovered in the step may contain less than 0.05 ppm of heavy metals, preferably less than 0.03 ppm of heavy metals, more preferably less than 0.01 ppm of heavy metals. may contain

Hereinafter, preferred embodiments are presented to aid understanding of the present disclosure, but the following examples are provided to more easily understand the present disclosure, and the present disclosure is not limited thereto.

Example - Measurement of electrochemical antimony removal rate using electrodes of the same type and electrodes of different types

Experimental example

An antimony removal experiment was conducted by an electrochemical coagulation method for reverse osmosis concentrated water having an antimony concentration of about 4.5 ppm. The concentrated reverse osmosis water had an electrical conductivity of 7,539 μS/cm, a pH of 7.3, and room temperature. Among the electrodes used, the anode was an Al electrode, and four Al rods with a length of 2 mm were bonded at 1 cm intervals to the surface of the electrode facing the cathode. A flat electrode with no structure on the surface was used as the negative electrode, Fe electrode. As a result, the form of the electric field generated at the anode and cathode was different, so that a uniform electric field was not created, and the generation of electrophoretic polarization force was induced. After the gap was set at 0.6 cm, an alternating current of 0.4 A and 60 Hz was passed at a constant voltage. Samples were collected at 4-minute intervals while current was applied for 15 minutes, and the collected samples were allowed to stand for 60 minutes to analyze the antimony concentration of the supernatant. The antimony removal rate was calculated through the analyzed concentration.

Comparative Experimental Example

In order to compare the effect of the electrophoretic polarization power, samples were taken using the same flat-plate electrode as the cathode and the other conditions were the same as the experimental example, and the antimony removal rate was calculated therefrom.

As shown in FIG. 5, the antimony removal rate was about 73% when treated for 4 minutes, the antimony removal rate was 93% when treated for 8 minutes, and the antimony removal rate was 98% when treated for 15 minutes. In Example 1 in which the electrophoretic polarization force was induced, the antimony removal rate was improved by 2 to 5% compared to Comparative Example 1 without the electrophoretic polarization force by using the same type of electrode.

From the above experimental results, it can be seen that in the electrochemical coagulation treatment for heavy metal removal in the feed, a higher heavy metal removal rate appears due to the electrophoretic polarization force caused when electrodes having different types of anode and cathode are used.

Example - Determination of Antimony Removal Rate Depending on pH of Electrochemical Coagulation and Chemical Coagulation

Experimental example

An antimony removal experiment was conducted by an electrochemical coagulation method for reverse osmosis concentrated water having an antimony concentration of about 4.5 ppm. The concentrated reverse osmosis water had an electrical conductivity of 7,539 μS/cm, a pH of 7.3, and room temperature. Caustic soda and sulfuric acid were added to reverse osmosis concentrated water to prepare samples having a pH of 3 to 10 at intervals of 1, respectively. As the electrode, a plate-type flat electrode of the same shape was used with Al as the anode and Fe as the cathode. After the gap between the electrodes was set to 0.6 cm, a constant voltage of 0.18 A was applied and treated for 15 minutes. The treated water was allowed to stand for 60 minutes and the antimony concentration of the supernatant was analyzed. The antimony removal rate was calculated through the analyzed concentration.

Comparative Experimental Example

In order to compare chemical aggregation with electrochemical aggregation, samples having different pHs were prepared using the same reverse osmosis concentrated water as in Experimental Example in the same manner. Since chemical coagulation is usually treated at pH 8, ferric sulfate was added as a coagulant so that a removal rate similar to the maximum removal rate in the electrochemical coagulation treatment was obtained at pH 8, at which time the concentration of ferric sulfate was 550 ppm. After treatment for 15 minutes, the solution was allowed to stand for 60 minutes, and the antimony removal rate was calculated by analyzing the antimony concentration of the supernatant.

As shown in FIG. 6 , electrochemical aggregation (circled points in FIG. 6 ) exhibits a uniform antimony removal rate of about 70% to 90% in the range of pH 4 to pH 9, whereas chemical aggregation (points circled in FIG. 6 ) Marked points) showed a high antimony removal rate of about 70% or more only at pH 7.5 or higher, and particularly a very low antimony removal rate of less than 30% at pH 4 to 6. The pH of this embodiment is the reaction result for 15 minutes based on the initial concentration of the sample, but when the reaction time is long, the chemical aggregation significantly reduces the pH and the antimony removal rate is further lowered.

From the above experimental results, it can be seen that electrochemical coagulation is less constrained by pH than chemical coagulation, and relatively excellent heavy metal removal rates are exhibited in a wide pH range.

Claims (15)

A method for removing heavy metals in a feed, the method comprising:
(a) providing a feed comprising heavy metals;
(b) applying power to an electrode to generate a coagulant in the feed, wherein the shape of the anode and cathode of the electrode is different from each other;
(c) combining the coagulant with the heavy metal in the feed to form an agglomerate;
(d) injecting a polymer-based flocculant into a feed containing the agglomerates to form agglomerates;
(e) precipitating and removing the agglomerates; and
(f) a method for removing heavy metals in a feed comprising the step of recovering the feed from which the agglomerates have been removed. The method of claim 1,
The heavy metal is any one of antimony (Sb), vanadium (V), arsenic (As), and combinations thereof, a method for removing heavy metals in the feed. The method of claim 1,
The method for removing heavy metals in the feed, wherein the heavy metals in the feed of step (a) are present at a concentration of 0.1 to 7 ppm. The method of claim 1,
The feed is any one of boiler concentrated water, reverse osmosis (RO) concentrated water, leachate, CDI (capacitive deionizer) concentrated water and ion exchange resin recycled wastewater, a method for removing heavy metals in the feed. The method of claim 1,
wherein the method further comprises supplying an electrolyte to the feed prior to step (b). The method of claim 5,
The electrolyte is a method for removing heavy metals in the feed, including any one of NaCl, Na ₂ SO ₄ and combinations thereof. The method of claim 1,
The method for removing heavy metals in the feed, wherein the pH of the feed before applying power in step (b) is 4 to 9. The method of claim 1,
Each of the anode and cathode of the electrode includes any one of aluminum (Al), iron (Fe) and titanium (Ti), a method for removing heavy metals in the feed. The method of claim 1,
The method for removing heavy metals in the feed, wherein the polymer-based coagulant is an acrylamide-based polymer. The method of claim 1,
The method for removing heavy metals in the feed, wherein the amount of the polymer-based coagulant is 1 to 15 ppm. The method of claim 1,
The method for removing heavy metals in the feed, wherein the size of the agglomerates is 0.1 to 200 mm. The method of claim 1,
Step (d) further comprises the step of controlling the input amount of the polymer-based coagulant in real time according to the particle size of the coagulum. The method of claim 1,
Step (d) is a method for removing heavy metals in the feed, further comprising the step of stirring the feed at a stirring speed of 30 to 80 rpm after the coagulant is added. The method of claim 1,
Step (e) comprises allowing the feed to stand for 30 to 100 minutes. The method of claim 1,
The method of claim 1 , wherein the feed recovered in step (f) contains less than 0.05 ppm of heavy metals in total.

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