JP6679231B2 - Heavy metal removing device and method - Google Patents

Description

  The present invention relates to a heavy metal removing device that removes heavy metals from a solution, and more particularly to a simple and high recovery efficiency heavy metal removing device that does not require external chemical addition.

  In Japan, drinking-grade tap water is supplied to each household, but household water purifiers are also widespread, and users are highly interested in further purification of tap water. In household water purifiers, contaminants are removed by using various filtration membranes such as ion exchange resin membranes and reverse osmosis membranes (RO membranes), but since these membranes are consumables, they are used for a certain period. Although it is necessary to replace the water purifier after its use, this replacement increases the running cost of the water purifier and many users find it annoying.

  Therefore, if it is possible to further remove pollutants such as heavy metals in the preceding stage of such a filter, the frequency of exchanging such a filter can be suppressed, and a certain level of drinking water can be obtained even without a filter, for the user. It is expected that the cost will be reduced, the usability will be improved, and the further spread of the water purifier will be promoted.

  On the other hand, in some industrialized countries, the contamination of drinking water due to the deterioration of water supply pipes and the mixing of rust, etc., and the heavy metal contamination of drinking water has become a serious problem due to the industrial pollution of rivers. . For example, in China, where polluted rivers and groundwater are used as the source of tap water, the removal of harmful heavy metals is an issue. Thus, the removal of heavy metals contained in drinking water has become an important issue common to all countries. Under such circumstances, various heavy metal removing devices for removing heavy metals in an aqueous solution have been proposed.

  Conventionally, in an aqueous solution such as wastewater, by injecting an alkaline agent and / or an additive such as a pH adjuster or a coagulant as necessary, after the heavy metal ions are flocculated to form aggregates, Various heavy metal removing devices have been disclosed which remove heavy metals by filtering with a filter.

  As such a conventional heavy metal removing apparatus, for example, there is one that adds sodium hydroxide to carry out alkali coagulation treatment at a pH of 8.5 to 10 (see Patent Document 1). In addition, there is also one that attempts to enhance the cohesive action by the addition of an alkaline agent by further adding a magnesium compound to waste water (see Patent Documents 2 and 3).

  Further, from the viewpoint of filtration efficiency, there is one that attempts to improve the filtration efficiency by disposing a filter configured by assembling crystalline fibers composed of basic magnesium sulfate and magnesium hydroxide (Patent Document 4). In addition, there is also one that uses a cross-flow type filtration device and circulates waste water before filtration in the preceding stage of the cross-flow type filtration device to reuse the agglomerates for filtration to improve the efficiency of filtration. (See Patent Document 5).

  In addition to this, as a conventional heavy metal removing device, for example, a device intended to remove heavy metals contained in the bottom mud deposited on the bottom of rivers, lakes, seas, ponds, etc. Focusing on the fact that existing heavy metals exist as metal sulfides, it consists of an alkaline tank and an acidic tank for containing contaminated water or contaminated bottom mud for the purpose of dissociating sulfur bound to heavy metals by oxidation. There is a device for collecting heavy metal by putting contaminated water or diluted contaminated bottom mud in an acid tank and passing an electric current (see Patent Document 6).

JP, 2008-264626, A JP-A-2-157090 JP 61-192386A JP, 2003-285079, A JP, 2006-320862, A JP, 11-57788, A

  However, there are some conventional heavy metal removing devices that inject additives such as an alkaline agent, a pH adjusting agent, and a coagulant from the outside, but since such an additive is a consumable item, it is regularly replaced. However, there is a problem that the cost and labor are additionally required for the additive. Especially when used as a water purifier for drinking water for consumers, it is difficult to disseminate the product due to running cost and labor.

  Further, from the viewpoint of improving filtration efficiency, for example, a filter configured by collecting crystalline fibers is used, or a technical feature of a filter that circulates waste water before filtration in the preceding stage of a cross-flow type filtration device. However, since the filter is a consumable item, it needs to be replaced regularly, and there is a problem that the cost and labor of the filter are high. Especially when used as a water purifier for drinking water for consumers, it is difficult to disseminate the product due to running cost and labor.

  In addition to this, there is one that puts contaminated water or contaminated bottom mud in an acid tank, focusing on the fact that heavy metals present in bottom mud exist as metal sulfides, but when applied to domestic drinking water, , Domestic drinking water cannot be used as it is because it is different from the metal contained in the bottom mud, which is the premise, and acid treatment is performed in the initial stage when alkali coagulation treatment is performed. Therefore, there is a problem that a step of significantly increasing the pH value is required, and extra cost and labor are required.

  The present invention has been made to solve the above problems, and an object of the present invention is to provide a heavy metal removing apparatus that does not require an external additive from the outside, is simple, and is suitable for household use, has a low cost, and has reduced labor. And

  The heavy metal removing apparatus disclosed in the present application, raw water containing heavy metals is supplied to a tank, electrolysis means for electrolyzing the raw water to produce an alkaline solution and an acidic solution, and the alkaline solution produced by the electrolysis means. PH is adjusted, and a pH adjusting means for producing a heavy metal hydroxide from the heavy metal contained in the alkaline solution, and the heavy metal hydroxide produced by the pH adjusting means are separated from the alkaline solution to obtain a filtrate. And a filtering means for generating the same.

  Thus, without adding an additive from the outside to the raw water, further, the alkaline state is formed immediately without going through the acidic state of the raw water, since the alkaline state is maintained, the heavy metal water The production of oxides is efficiently promoted, and heavy metals can be efficiently removed from raw water at low cost.

  In the heavy metal removing device disclosed in the present application, the filtering means centrifuges the heavy metal hydroxide as necessary. As described above, since the filtering means centrifuges the heavy metal hydroxide, it is possible to prevent the heavy metal hydroxide produced from sticking and remaining in the apparatus. The accuracy of separating heavy metal hydroxides is improved, and the pollution in the device is suppressed, so that it is possible to efficiently remove heavy metals from raw water and suppress the running cost.

  The heavy metal removing apparatus disclosed in the present application neutralizes the pH value of the filtrate by mixing the acidic solution produced by the electrolysis means with the filtrate produced by the filtration means, if necessary. It is equipped with means. Thus, since the acidic solution produced by the electrolysis means is cyclically mixed with the filtrate to neutralize the pH value of the filtrate, a highly alkaline state can be obtained without using an external additive. Since the liquid properties of the above-mentioned filtrate can be relaxed, the above-mentioned filtrate satisfying the usage level such as drinking can be obtained at low cost and efficiently.

  The heavy metal removing apparatus disclosed in the present application is provided with a pH control unit that periodically fluctuates the pH value of the alkaline solution generated by the electrolysis unit, as necessary. As described above, in the alkaline solution, the heavy metal hydroxide is rapidly produced at a high pH value in the initial stage, and subsequently, the pH value of the alkaline solution is lowered, so that the heavy metal hydroxide produced. Since the re-dissolution of OH is suppressed and the crystalline state is maintained, the production efficiency of heavy metal hydroxide is increased, and efficient removal of heavy metal from raw water can be realized.

  In the heavy metal removing device disclosed in the present application, the pH control unit intermittently mixes the acidic solution generated by the electrolyzing unit with the alkaline solution, as necessary. Thus, when the pH is adjusted in the pH control means, the acidic solution produced by the electrolysis means is circulated to close the inside of the apparatus without using an external additive such as a pH adjuster. Since the pH value is periodically fluctuated up and down in the system, no extra cost such as an additive is needed for pH adjustment performed by the pH control means, which is low cost and efficient, and efficient from raw water. It is possible to realize the removal of heavy metals.

  In the heavy metal removing device disclosed in the present application, the pH adjusting means adjusts the pH of the filtrate produced by the filtering means, if necessary. In this way, the pH adjusting means adjusts the pH of the filtrate produced by the filtering means, so that the filtrate produced by the filtering means has a pH more suitable for drinking, which is low cost and efficient. It is possible to easily obtain drinking water from which heavy metals have been removed from raw water.

  Further, the heavy metal removal method disclosed in the present application, raw water containing heavy metals is supplied to a tank, an electrolysis step of electrolyzing the raw water to produce an alkaline solution and an acidic solution, and the electrolysis step produced by the electrolysis step. The pH of the alkaline solution is adjusted, a pH adjusting step of producing a heavy metal hydroxide from the heavy metal contained in the alkaline solution, and the heavy metal hydroxide produced by the pH adjusting step is separated from the alkaline solution. And a filtration step for producing a filtrate.

  Thus, without adding an additive from the outside to the raw water, further, since the raw water is immediately formed and maintained in the alkaline state without passing through the acidic state, the formation of the heavy metal hydroxide Is efficiently promoted, and heavy metals can be removed from raw water efficiently at low cost.

  In the heavy metal removing method disclosed in the present application, the filtration step centrifuges the heavy metal hydroxide, if necessary. In this way, the filtration step, by centrifuging the heavy metal hydroxide, the heavy metal hydroxide produced is prevented from sticking and remaining in the device, and thus the filtration step in the filtration step is performed. The accuracy of separating heavy metal hydroxides is improved, and the pollution in the device is suppressed, so that it is possible to efficiently remove heavy metals from raw water and suppress the running cost.

  The heavy metal removing method disclosed in the present application, if necessary, neutralizes the pH value of the filtrate by mixing the acidic solution produced by the electrolysis step with the filtrate produced by the filtration step. It includes a process. Thus, since the acidic solution produced by the electrolysis step is cyclically mixed with the filtrate to neutralize the pH value of the filtrate, a highly alkaline state can be obtained without using an external additive. Since the liquid properties of the above-mentioned filtrate can be relaxed, the above-mentioned filtrate satisfying the usage level such as drinking can be obtained at low cost and efficiently.

  The heavy metal removal method disclosed in the present application includes a pH control step of periodically changing the pH value of the alkaline solution generated by the electrolysis step up and down, if necessary. As described above, in the alkaline solution, the heavy metal hydroxide is rapidly produced at a high pH value in the initial stage, and subsequently, the pH value of the alkaline solution is lowered, so that the heavy metal hydroxide produced. Since the crystalline state is maintained without being redissolved, the production efficiency of heavy metal hydroxide is increased, and efficient removal of heavy metal from raw water can be realized.

  In the heavy metal removal method disclosed in the present application, the pH control step intermittently mixes the acidic solution produced by the electrolysis step with the alkaline solution, if necessary. Thus, when performing pH adjustment in the pH control step, the acidic solution produced in the electrolysis step was circulated to close the inside of the apparatus without using an external additive such as a pH adjuster. Since the pH value is periodically fluctuated up and down in the system, no extra cost such as an additive is required for pH adjustment performed in the pH control step, which is low cost and efficient, and efficient from raw water. It is possible to realize the removal of heavy metals.

  In the heavy metal removal method disclosed in the present application, the pH adjustment step adjusts the pH of the filtrate produced in the filtration step, if necessary. In this way, the pH adjustment step adjusts the pH of the filtrate produced by the filtration step, so that the filtrate produced by the filtration step has a pH more suitable for drinking, which is low cost and efficient. It is possible to easily obtain drinking water from which heavy metals have been removed from raw water.

The block diagram of the heavy metal removal apparatus which concerns on the 1st Embodiment of this invention is shown. The block diagram about the modification of the heavy metal removal apparatus which concerns on the 1st Embodiment of this invention is shown. The block diagram about the modification of the heavy metal removal apparatus which concerns on the 1st Embodiment of this invention is shown. The block diagram about the modification of the heavy metal removal apparatus which concerns on the 1st Embodiment of this invention is shown. The perspective view of the heavy metal removal apparatus which concerns on the 1st Embodiment of this invention is shown. The block diagram (a) of the filtration means of the heavy metal removal apparatus which concerns on the 2nd Embodiment of this invention, and its operation example (b) and (c) are shown. The block diagram of the filtration means of the heavy metal removal apparatus which concerns on the 2nd Embodiment of this invention is shown. The block diagram of the heavy metal removal apparatus which concerns on the 3rd Embodiment of this invention is shown. The block diagram about the modification of the heavy metal removal apparatus which concerns on the 3rd Embodiment of this invention is shown. The block diagram of the heavy metal removal apparatus which concerns on the 4th Embodiment of this invention is shown. The pH adjustment example of the heavy metal removal apparatus which concerns on the 4th Embodiment of this invention is shown. The block diagram of the heavy metal removal apparatus which concerns on the 5th Embodiment of this invention is shown. The block diagram about the modification of the heavy metal removal apparatus which concerns on the 5th Embodiment of this invention is shown. The block diagram of the heavy metal removal apparatus which concerns on other embodiment of this invention is shown.

(First embodiment)
Hereinafter, the heavy metal removing apparatus according to the first embodiment will be described with reference to FIGS.

  In the heavy metal removing apparatus according to the first embodiment, as shown in FIG. 1, raw water A containing heavy metals is supplied to a tank 100, and the raw water A is electrolyzed to generate an alkaline solution and an acidic solution. The electrolyzing means 1, the pH adjusting means 2 for adjusting the pH of the alkaline solution produced by the electrolyzing means 1 by the pH sensor 21, and producing the heavy metal hydroxide from the heavy metal contained in the alkaline solution, and the pH adjusting means. The heavy metal hydroxide produced by the means 2 is separated from the alkaline solution to produce the filtrate B, and the filtration means 3 is provided.

  The electrolysis means 1 is composed of a DC power supply 10, an anode 11 on the anode side connected to the DC power supply 10, and a cathode 12 on the cathode side connected to the DC power supply 10.

  The pH adjusting means 2 includes a pH sensor 21 that detects the pH value of the alkaline solution generated by the electrolyzing means 1. Further, the pH adjusting means 2 performs switching for switching whether or not to supply a potential between the electrodes composed of the anode 11 and the cathode 12 based on the pH value detected by the pH sensor 21, and also the anode. The pH is adjusted by determining the magnitude of the potential applied between the electrodes consisting of 11 and the cathode 12.

  The filtering means 3 includes a filtration container 3a containing an alkaline solution containing the heavy metal hydroxide produced by the pH adjusting means 2 and a filter 31 for separating the heavy metal hydroxide from the alkaline solution to produce a filtrate B. Equipped with. The shape of the filtration container 3a is not particularly limited, and examples thereof include a cylindrical shape, a conical shape, an inverted conical shape, a truncated cone shape (for example, a truncated cone shape, a truncated pyramid shape), and an inverted truncated cone shape (for example, The shape may be an inverted truncated cone shape, an inverted truncated pyramid shape, or the like. A hollow fiber membrane or a filter cloth (nonwoven fabric) can be used for the filter 31. For example, the filter cloth (nonwoven fabric) is first used to remove coarse dust such as heavy metal hydroxide and red rust, and then the hollow fiber membrane is used. It is preferable to carry out a two-step filtration in which final filtration is performed to remove microbes of a micrometer order and the like. With such a simple configuration, the heavy metal hydroxide can be efficiently filtered.

  The tank 100 includes a separator 101 using a salt bridge between the anode 11 and the cathode 12. The alkaline solution and the acidic solution are partitioned from each other and physically separated by the separator 101. The tank 100 may be a storage tank (storage tank) that stores the raw water A or a continuous tank that continuously supplies the raw water A. Further, the tank 100 may be a tank (tank) separate from the pH adjusting means 2 or the same body (electrolytic tank), and can be selected according to the installation place and the throughput. is there.

Examples of heavy metals contained in the raw water A include cadmium (Cd), mercury (Hg), lead (Pb), zinc (Zn), iron (Fe), copper (Cu), arsenic (As), selenium ( Se), hexavalent chromium (Cr ⁶⁺ ), and compounds thereof.

  A method for removing heavy metals from raw water by using the heavy metal removing device having the above configuration will be described below.

  First, the raw water A containing heavy metals is supplied to the tank 100, the raw water A is electrolyzed, and separated into an alkaline solution generated on the cathode 12 side and an acidic solution generated on the anode 11 side. (Electrolysis step). The heavy metal to be removed contained in the raw water A is not particularly limited, but examples thereof include Cd, Hg, Se, Pb, hexavalent Cr, Zn, Al, Fe, Cu, Mn, As, and Ni.

  The pH of the generated alkaline solution on the cathode 12 side is adjusted using the pH sensor 21, and heavy metal hydroxide is generated from the heavy metal contained in the alkaline solution (pH adjusting step). In this pH adjustment, it is set based on the pH value detected by the pH sensor 21 so as to supply a potential between the electrodes composed of the anode 11 and the cathode 12 (in FIG. 1, it is set using a switch). In addition, the magnitude of the potential applied between the electrodes composed of the anode 11 and the cathode 12 is determined.

  The pH value set by this pH adjustment is preferably carried out at a pH of 10 to 14, more preferably at a pH of 12 to 14, from the viewpoint of producing more heavy metal hydroxide. For example, it can be performed at pH 13. This heavy metal hydroxide is produced by a chemical reaction between a cation heavy metal and an anion hydroxide ion, and an example of this chemical reaction is shown below.

(Chemical formula 1)
^{Cd 2+ + 2OH - → Cd (} OH) 2 ↓
^{2Ag + + OH - → 2AgOH →} AgO ↓ + H 2 O
^{Pb 2+ + 2OH - → Pb (} OH) 2 ↓
^{Zn 2+ + 2OH - → Zn (} OH) 2 ↓
^{Cu 2+ + 2OH - → Cu (} OH) 2 ↓
^{Fe 2+ + 2OH - → Fe (} OH) 2 ↓
^{Fe 3+ + 3OH - → Fe (} OH) 3 ↓

  Next, this heavy metal hydroxide is separated from this alkaline solution using the filter 31 to produce the filtrate B (filtering step). In order to more reliably remove contaminants such as heavy metal hydroxides, a membrane such as an ion exchange resin membrane or a reverse osmosis membrane (RO membrane) is arranged at the filter 31 itself or at the subsequent stage of the filter 31. It is more preferable to provide it. Incidentally, unlike the conventional heavy metal removing device, because the water quality situation in which contaminants including heavy metal hydroxides are significantly removed by the time it reaches the membrane such as the ion exchange resin membrane, The frequency of exchange of the membrane such as the ion exchange resin membrane can be suppressed more than ever, and the running cost can be suppressed.

  That is, when the degree of contamination of raw water is high, using only the ion-exchange resin membrane or the like causes immediate overtreatment and frequent replacement is required. By the decomposition, since the heavy metals are sufficiently removed from the raw water by the time it reaches the membrane such as the ion exchange resin membrane, the exchange frequency related to the membrane exchange such as the ion exchange resin membrane will be suppressed as compared with the conventional one. The running cost can be suppressed.

  Further, when the degree of contamination of raw water is low, even if the user neglects to exchange the ion exchange resin membrane or the reverse osmosis membrane (RO membrane), the contaminants are significantly removed. It becomes possible to obtain the filtrate B that satisfies the water quality standard, and it is possible to enhance the safety for the user when using it as drinking water. It should be noted that installation of this ion exchange resin membrane or reverse osmosis membrane (RO membrane) is not essential, and when the degree of contamination of raw water is low or when heavy metals can be sufficiently removed from raw water, the ion exchange resin membrane or It is of course possible to adopt a configuration in which the reverse osmosis membrane (RO membrane) is not provided.

  Further, the pH adjustment by the pH adjusting means 2 can also be performed on the filtrate B that has passed through the filter 31. That is, it is also possible to adopt a configuration in which the pH adjusting means 2 adjusts the pH of the produced filtrate B (for example, adjusting to transit to a weak alkaline region of pH 8.5 to 9.5). In this case, since the pH adjustment is performed after the filtration is once performed, the heavy metal hydroxide is in a solution state having a higher pH value than the case where the pH value is adjusted and then filtered in the weak alkaline region for beverages. As a result, a larger amount of heavy metal hydroxide is formed, and a larger amount of heavy metal is removed from the solution, so a solution with sufficient removal of heavy metal is obtained at a pH suitable for drinking. It is possible to easily obtain drinking water from which heavy metals have been removed from raw water at low cost and efficiently. That is, a large amount of heavy metals can be removed more efficiently than when filtered after adjusting the pH to a weak alkaline region to suit the drinking level, and the pH adjusted to a weak alkaline region close to neutral. Water can be simply obtained by adjusting the pH of the pH adjusting means 2.

  Thus, without adding an additive from the outside to the raw water A, further, the alkaline state is quickly formed without going through the acidic state of the raw water A, and since this alkaline state is maintained, The production of this heavy metal hydroxide is efficiently promoted, and the heavy metal can be removed from the raw water A efficiently at low cost.

  Further, as shown in FIG. 2, the acidic solution C can be circulated through the filtering means 3. Thus, the pH value can be neutralized with respect to the filtrate that passes through the filtering means 3 that is biased toward alkaline, water purification treatment with less loss can be performed, and the filter life can be extended. Further, as shown in FIG. 3, it is possible to provide a heavy metal discharge port 31a for discharging the heavy metal accumulated in the filter 31 on the upper stage of the filter 31, and to prevent the filter 31 from being clogged by the heavy metal. In addition, the filter life can be extended. 2 and 3, the flow path for circulating the acidic solution C through the filtering means 3 is provided, but, for example, as shown in FIG. 1, the outlets of the filtrate B and the acidic solution C are not joined. After the filtrate B is obtained separately, reverse electrolysis by the electrolysis means 1 is performed, and the reversely charged acidic solution produced by this reverse electrolysis is passed through the filtration means 3 and then by the filter 31 of the filtration means 3. The heavy metal hydroxide to be removed can be removed (dissolved), which can contribute to extending the life of the filter 31. At this time, the heavy metal hydroxide to be removed (dissolved) may be discharged from the outlet of the filtrate B, but as shown in FIG. 3, a heavy metal discharge port 31a is provided so that the heavy metal discharge port 31a can be discharged. It is preferable to discharge it.

  Further, as shown in FIG. 4, in order to further remove the heavy metal accumulated in the filter 31 of the filtering means 3, a pair of opposing solutions are provided to the solution discharged via the heavy metal discharge port 31a. It is also possible to provide a reverse electrolytic cleaning means 31b for cleaning using reverse electrolysis by electrodes. By this reverse electrolytic cleaning means 31b, it is possible to discharge the solution in which excess heavy metal is further suppressed.

  In addition, the heavy metal removing apparatus according to the present embodiment has a simple configuration in which heavy metals are removed by using electrolysis on the alkaline solution side, and thus there is an advantage that the conventional alkaline ionized water device can be used as it is. . For example, as shown in FIG. 5 above, using the alkaline ionized water device 200 having the above-described configuration of FIG. 1, the raw water A is injected from the water supply hose 201, and the purified water discharge port 203 is passed through the discharge water passage 202. The filtrate B is discharged from the outlet and the acidic solution C is discharged from the outlet 204. Further, the operation can be performed by a touch operation using the operation panel 205 on the surface.

  The heavy metal removing apparatus according to the present embodiment has an excellent effect that heavy metals can be efficiently removed from a large amount of raw water A by continuously flowing the raw water A as in the above-described configuration. On the other hand, the present invention is not limited to this form, and in addition to this, it is also possible to efficiently remove heavy metals from the raw water A by a batch method.

(Second embodiment)
Hereinafter, the heavy metal removing apparatus according to the second embodiment will be described with reference to FIG.

  The heavy metal removing apparatus according to the second embodiment includes the electrolyzing unit 1, the pH adjusting unit 2, and the filtering unit 3, as in the first embodiment, and further, the filtering unit 3 includes: The heavy metal hydroxide is centrifuged.

  As shown in FIG. 6A, the filtering means 3 according to the present embodiment includes a centrifugal separator 32 that rotates the filter 31, and an opening / closing window 33 that opens and closes according to the rotation of the centrifugal separator 32. The storage container 34 is provided outside the filtration container 3a and in the vicinity of the opening / closing window 33, and has a storage plate 34 for storing the heavy metal hydroxide. The centrifuge 32 is composed of a motor 32a that rotates and a rotating shaft 32b that receives the drive of the motor 32a and rotates.

  The centrifuge 32 is driven by the motor 32a so that the rotary shaft 32b rotates. The filter 31 also rotates in accordance with this rotation operation. The opening / closing window 33 is opened and closed intermittently, and is in a closed state when the filter 31 is stationary without rotating and is in an open state when the filter 31 is rotating.

  As shown in FIG. 6B, when the centrifuge 32 does not rotate, the open / close window 33 is closed and the formation of heavy metal hydroxide is promoted in the filtration container 3a.

  As shown in FIG. 6 (c), as the centrifugal separator 32 rotates, the heavy metal hydroxide formed on the filter 31 is pushed out to the vicinity of the inner wall of the filtration container 3 a and the filtration is performed. The heavy metal hydroxide fixed near the inner wall of the container 3a is scraped out. That is, it is possible to prevent the produced heavy metal hydroxide from sticking and remaining in the apparatus. That is, when the centrifuge 32 rotates, the heavy metal hydroxide is pushed out to the vicinity of the inner wall of the filtration container 3a and discharged to the storage tray 34, and the heavy metal hydroxide is produced. And the discharge can be performed efficiently.

  As described above, since the filtering means 3 centrifuges the heavy metal hydroxide, it is possible to prevent the heavy metal hydroxide from sticking and remaining in the apparatus. Therefore, the heavy metal in the filtering means 3 is suppressed. The separation accuracy of the hydroxide is improved, and the contamination in the device is suppressed, so that it is possible to realize both efficient removal of heavy metals from raw water and suppression of running cost.

  Further, in the above, the configuration is such that the filter 31 is passed through after being centrifuged, but the configuration is not limited to this. As a modification, it is possible to perform centrifugation without using the filter 31 (filterless).

  In the case where the filter 31 is not used, for example, as shown in FIG. 7A, the centrifuge 32 is provided, and the heavy metal discharge port 31a is disposed below the filtration container 3a. The discharge port for the filtrate B is arranged above the filtration container 3a. At the outlet of the filtrate B, for example, a pump for sucking the filtrate B can be arranged. With such a configuration, the formed heavy metal hydroxide is centrifugally separated, and due to its own weight, it is settled down and discharged from the heavy metal discharge port 31a. As a result, the filtrate B from which the heavy metal hydroxide has been removed is obtained, and the heavy metal can be removed from the raw water at low cost and efficiently.

  Although the configuration using the centrifugal separator 32 is given as an example in FIG. 7A, the configuration is not limited to this configuration. For example, as shown in FIG. 7 (b), the centrifugal separator 32 is not used, and the raw water A is introduced along the outer circumference (outer wall) of the filtration container 3a. A configuration in which a cyclone flow is formed from the upper part to the lower part inside is also possible. With such a configuration, the formed heavy metal hydroxide is centrifugally separated, and due to its own weight, it is settled down, and the heavy metal hydroxide is discharged from the heavy metal discharge port 31a. The shape of the filtration container 3a in this case is not particularly limited, but from the viewpoint of facilitating the generation of the rotational flow of the cyclone flow described above, a cylindrical shape, a conical shape, or a truncated conical shape having a circular cross section ( In particular, an inverted cone shape or an inverted truncated cone shape is preferable, and an inverted cone shape or an inverted truncated cone shape is preferable from the viewpoint of easily discharging the heavy metal toward the heavy metal discharge port 31a. With this configuration, the filtrate B from which the heavy metal hydroxide is removed can be obtained, and the heavy metal can be removed from the raw water A efficiently at low cost.

  Further, as a modified example of the configuration that does not use the filter 31, as shown in FIG. 7C, a configuration in which the entire filtration container 3a performs a rotating operation is possible. With such a configuration, the formed heavy metal hydroxide is centrifugally separated, and due to its own weight, it is settled down, and the heavy metal hydroxide is discharged from the heavy metal discharge port 31a. Thus, the filtrate B from which the heavy metal hydroxide is removed is obtained, and the heavy metal can be removed from the raw water A at low cost and efficiently.

(Third Embodiment)
Hereinafter, the heavy metal removing apparatus according to the third embodiment will be described with reference to FIGS. 8 and 9.

  The heavy metal removing apparatus according to the third embodiment includes the electrolyzing unit 1, the pH adjusting unit 2, and the filtering unit 3 as in the first embodiment, and further, as shown in FIG. In addition, the neutralization means 4 for mixing the acidic solution C produced by the electrolysis means 1 with the filtrate B produced by the filtration means 3 to neutralize the pH value of the filtrate B is provided. .

  The neutralizing means 4 mixes the acidic solution C produced by the electrolyzing means 1 with the filtrate B in a circulating manner to neutralize the pH value of the filtrate B exhibiting a strong alkalinity so that the liquidity is neutralized. Transition to a propensity (neutralization step). From this, it is possible to relax the liquidity of the filtrate B in a highly alkaline state without using an additive from the outside, and to obtain the filtrate B that meets the usage level for drinking etc. at low cost and efficiently. it can. The neutralizing means 4 is not limited to the above-described configuration in which the acidic solution C is circulated. For example, an electrolytic bath is separately provided, and the acidic solution produced by the electrolytic bath is used as the filtrate B. Of course, it is also possible to adopt a configuration in which they are mixed.

As shown in FIG. 9, an acidic-side heavy metal removing means 41 that removes heavy metals contained in the acidic solution C can be provided for the acidic solution C. As the acidic side heavy metal removing means 41, for example, a strongly acidic cation exchange resin containing a sulfonic acid group (-SO ₃ H) as an exchange group or a weak acidic cation exchange resin containing a carboxylic acid group (-COOH) as an exchange group. A gel or porous ion exchange resin such as a cation exchange resin can be used. In the case of the weakly acidic cation exchange resin, a methacrylic acid cation exchange resin or an acrylic acid cation exchange resin can be selected and used. For example, when the acidity of the solution is stronger, the acrylic acid-based cation exchange resin can be used, and when the acidity of the solution is weaker, the methacrylic acid-based cation exchange resin can be selected. This is possible and the processing can be optimized. By the acid-side heavy metal removing means 41, the heavy metal is efficiently removed from the acidic solution C, and the heavy metal can be removed with higher accuracy.

  In the present embodiment, the filtering means 3 may be configured to centrifuge the heavy metal hydroxide as in the second embodiment described above. In this case, the filtration means 3 further centrifuges the heavy metal hydroxide to prevent the heavy metal hydroxide from sticking and remaining in the apparatus. The separation accuracy of the heavy metal hydroxide in 3 is improved, and the pollution in the device is suppressed, and it is possible to obtain the effects of efficiently removing the heavy metal from the raw water and suppressing the running cost.

(Fourth Embodiment)
Hereinafter, the heavy metal removing apparatus according to the fourth embodiment will be described with reference to FIGS. 10 and 11.

  The heavy metal removing apparatus according to the fourth embodiment includes the electrolyzing unit 1, the pH adjusting unit 2, the filtering unit 3, and the neutralizing unit 4, as in the third embodiment, and As shown in FIG. 10, the pH control means 5 is provided to periodically fluctuate the pH value of the alkaline solution generated by the electrolysis means 1.

  The pH control means 5 periodically fluctuates the pH value setting in the pH adjusting means 2 up and down based on the pH value of the pH sensor 21 (pH control step). From the viewpoint of producing more heavy metal hydroxide, this pH value is preferably varied up and down within the range of pH 10 to 14, and more preferably as shown in the pH adjustment example of FIG. First, it is to fluctuate up and down with time within the range of pH 12-14.

  As described above, in the alkaline solution, the heavy metal hydroxide is rapidly produced at a high pH value in the initial stage, and subsequently, the pH value of the alkaline solution is lowered, whereby the heavy metal hydroxide produced. Since the re-dissolution of slag is suppressed and its crystalline state is maintained, the production efficiency (maintenance efficiency) of heavy metal hydroxides is increased, and efficient removal of heavy metals from raw water A is realized. You can

  In this embodiment, the neutralizing means 4 may not be provided, that is, the pH control means 5 may be provided in the heavy metal removing apparatus according to the first and second embodiments. It can also be configured to be provided. This structure is significant under the condition that the neutralizing means 4 is not used, and the heavy metal can be efficiently removed from the raw water A by a simpler device structure.

(Fifth Embodiment)
The heavy metal removing apparatus according to the fifth embodiment will be described below with reference to FIGS. 12 and 13.

  The heavy metal removing apparatus according to the fifth embodiment includes the electrolyzing unit 1, the pH adjusting unit 2, and the filtering unit 3 as in the first embodiment, and further, as shown in FIG. In addition, the control means 51 including the function of the pH control means 5 for intermittently mixing the acidic solution generated by the electrolysis means 1 with the alkaline solution is provided. As shown in FIG. 12, a valve 102 disposed in each flow path on the alkaline solution side and the acidic solution side discharged from the tank 100 and a flow for intermittently mixing the acidic solution C with the alkaline solution. And a pump 103 disposed on the road, and the control means 51 controls the valve 102 and the pump 103. That is, the control unit 51 controls the valve 102 and the pump 103 to control the amount of the acidic solution C to be circulated to control the pH value, and the pH value is controlled based on the control of the control unit 51. The adjusting means 2 sets the optimum pH value of the alkaline solution.

  Thus, when the control means 51 performs pH adjustment, the acidic solution C generated by the electrolysis means 1 is simply circulated without requiring an external additive such as a pH adjusting agent. Since the pH value is periodically changed up and down in a closed system inside the apparatus with such a configuration, an extra cost such as an additive is unnecessary for the pH adjustment performed by the control means 51, resulting in low cost and efficiency. Therefore, efficient removal of heavy metals from the raw water A can be realized.

  As a modified example of the heavy metal removing apparatus according to the fifth embodiment described above, as shown in FIG. 13, the control unit 51 converts the filtrate B that has passed through the filtration unit 3 into raw water A again. It is also possible to circulate and intermittently mix with the raw water A. As a result of this circulation, the filtrate B is controlled by the control means 51 after repeating filtration a predetermined number of times by the filtration means 3 or when a predetermined pH value is reached, as shown in FIG. It can be configured to be discharged to the outside from the discharge valve 104.

  From a similar point of view, as a modified example, the pH adjusting means 2 performs pH adjustment (for example, adjustment for transition to a weak alkaline region of pH 8.5 to 9.5) on the produced filtrate B. It can also be configured. In this case, since the pH is adjusted after the filtration is once performed, the heavy metal hydroxide is produced in a solution state having a higher pH value than the case where the filtration is performed after the pH adjustment. Heavy metal hydroxide is formed and a larger amount of heavy metal is removed from the solution, so that the solution free of heavy metal can be obtained at a pH suitable for drinking, which is low cost and efficient from raw water. Drinking water from which heavy metals have been removed can be easily obtained.

  In this way, when the pH is adjusted in the control means 51, not only the acidic solution C produced by the electrolysis means 1 but also the filtrate B is used without using an external additive such as a pH adjuster. Since the pH value is periodically circulated and vertically fluctuated in a closed system inside the apparatus, the fluctuation range of the vertical fluctuation of the pH adjustment performed by the control unit 51 can be significantly increased, and the cost can be reduced. Efficient removal of heavy metals from the raw water A can be realized efficiently. Further, since the filtrate B is discharged to the outside after repeating the filtration by the filtering means 3 a predetermined number of times, the removal efficiency of heavy metals is increased by the plurality of times of filtration, and more efficient removal of heavy metals is achieved. Can be realized.

  In the present embodiment, the filtering means 3 may be configured to centrifuge the heavy metal hydroxide as in the second embodiment described above. In this case, the filtration means 3 further centrifuges the heavy metal hydroxide to prevent the heavy metal hydroxide from sticking and remaining in the apparatus. The separation accuracy of the heavy metal hydroxide in 3 is improved, and the pollution in the device is suppressed, so that it is possible to obtain the effects of efficiently removing the heavy metal from the raw water and suppressing the running cost.

  Further, in the present embodiment, similarly to the above-described third embodiment, the acidic solution C produced by the electrolysis means 1 is cyclically mixed with the filtrate B to obtain a filtrate B having strong alkalinity. It is also possible to provide the neutralizing means 4 that neutralizes the pH value and shifts the liquidity toward the neutrality. With this configuration, the liquid properties of the filtrate B in a highly alkaline state can be relaxed without using an additive from the outside, and the effect of obtaining the filtrate B that meets the usage level for drinking etc. at low cost and efficiently You can also get

(Other embodiments)
In each of the above-described embodiments, the pair of anode 11 and cathode 12 is arranged inside the tank 100. However, the present invention is not limited to this structure. For example, another embodiment is shown in FIG. As described above, the plurality of anodes 11 and the plurality of cathodes 12 can be arranged so as to be alternately circulated inside the cylindrical tank 100. With such a configuration, the electrolysis efficiency in the tank 100 is enhanced, and more efficient heavy metal removal by electrolysis can be realized.

DESCRIPTION OF SYMBOLS 1 Electrolysis means 11 Anode 12 Cathode 2 pH adjustment means 21 pH sensor 3 Filtration means 3a Filtration container 31 Filter 31a Heavy metal discharge port 31b Reverse electrolysis cleaning means 32 Centrifugal separator 32a Motor 32b Rotating shaft 33 Opening window 34 Storage tray 4 Neutralization means 41 Acidic-side heavy metal removing means 5 pH control means 51 Control means 100 Tank 101 Separator 102 Valve 103 Pump 104 Discharge valve 200 Alkaline ion water conditioner 201 Water supply hose 202 Discharge water channel 203 Clean water discharge outlet 204 Discharge outlet 205 Operation panel A Raw water B Filtrate C acidic solution

Claims (12)

Having a separator between the anode and the cathode and the anode and the cathode , cadmium, mercury, lead, zinc, iron, copper, arsenic, selenium, hexavalent chromium, aluminum, manganese, nickel, silver, and compounds thereof. Electrolyzing raw water containing a heavy metal such as to generate an alkaline solution containing a heavy metal on the cathode side, and an electrolytic means to generate an acidic solution on the anode side,
The alkaline solution produced by the electrolyzing means is adjusted in the pH range of 10 to 14, and the heavy metal contained in the alkaline solution is converted into a heavy metal by the chemical reaction between the heavy metal ion of the cation and the hydroxide ion of the anion. PH adjusting means for producing hydroxide,
The heavy metal hydroxide produced by the pH adjusting means is provided with a filtering means for separating the heavy metal hydroxide from the alkaline solution to produce a filtrate,
The pH adjusting unit includes a pH sensor that detects the pH value of the alkaline solution, and whether or not to supply a potential between the electrodes composed of the anode and the cathode based on the pH value detected by the pH sensor. The heavy metal removing apparatus is characterized in that the pH is adjusted by performing switching for switching between the electrodes and determining the magnitude of the potential applied between the electrodes composed of the anode and the cathode. The heavy metal removing apparatus according to claim 1,
The heavy metal removing device, wherein the filtering means centrifuges the heavy metal hydroxide. The heavy metal removing device according to claim 1 or 2,
A heavy metal removing apparatus comprising a neutralizing means for mixing the acidic solution produced by the electrolyzing means with the filtrate produced by the filtering means to neutralize the pH value of the filtrate. The heavy metal removing apparatus according to any one of claims 1 to 3,
A heavy metal removing apparatus comprising: a pH control unit that periodically fluctuates the pH value of the alkaline solution generated by the electrolyzing unit. The heavy metal removing apparatus according to claim 4,
The heavy metal removing apparatus, wherein the pH control unit intermittently mixes the acidic solution generated by the electrolyzing unit with the alkaline solution. The heavy metal removing device according to any one of claims 1 to 5,
The heavy metal removing apparatus, wherein the pH adjusting means adjusts the pH of the filtrate produced by the filtering means. With a separator between the anode and the cathode, applied between the electrodes consisting of the anode and the cathode , cadmium, mercury, lead, zinc, iron, copper, arsenic, selenium, hexavalent chromium, aluminum, manganese, nickel, An electrolysis step of electrolyzing raw water containing heavy metals such as silver and these compounds to produce an alkaline solution containing heavy metals on the cathode side and an acidic solution on the anode side,
A pH adjustment step of adjusting the pH of the alkaline solution produced by the electrolysis step in the range of pH 10 to 14, and producing a heavy metal hydroxide from the heavy metal contained in the alkaline solution;
The heavy metal hydroxide produced by the pH adjusting step, a filtration step of separating the alkaline solution from the alkaline solution to produce a filtrate,
The pH adjusting step includes a pH sensor that detects the pH value of the alkaline solution, and whether or not to supply a potential between the electrodes composed of the anode and the cathode based on the pH value detected by the pH sensor. The method for removing heavy metals is characterized in that the pH is adjusted by performing switching for switching between the electrodes and determining the magnitude of the potential applied between the electrodes composed of the anode and the cathode. The heavy metal removing method according to claim 6,
The method of removing heavy metals, wherein the filtering step centrifuges the heavy metal hydroxide. The heavy metal removing method according to claim 6 or 7,
A method for removing heavy metals, comprising a neutralization step of mixing the acidic solution produced by the electrolysis step with the filtrate produced by the filtration step to neutralize the pH value of the filtrate. The heavy metal removing method according to any one of claims 6 to 8,
A method for removing heavy metals, comprising a pH control step of periodically fluctuating the pH value of the alkaline solution generated by the electrolysis step. The heavy metal removing method according to claim 9,
The heavy metal removing method, wherein the pH controlling step intermittently mixes the acidic solution generated by the electrolyzing step with the alkaline solution. The heavy metal removing method according to any one of claims 7 to 11,
The method for removing heavy metals, wherein the pH adjusting step adjusts the pH of the filtrate produced in the filtering step.

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