JP4135801B2 - Liquid passing method and apparatus for liquid passing capacitor - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention obtains a desalting solution from which the ionic components of the liquid to be treated are removed by applying a DC voltage to the pair of electrodes held therein, and then regenerates the pair of electrodes by short-circuiting or reversely connecting them. In addition, the removal ionic component is collected together with the liquid to be treated, and the ionic component of the liquid to be treated is removed and collected according to the purpose. The present invention relates to a method for passing a type capacitor.
[0002]
[Prior art]
The liquid-passing capacitor uses an electrostatic force to remove and recover (regenerate) ionic components in the liquid to be treated, and its principle is as follows. In other words, a liquid-flowing capacitor is removed by applying a DC voltage to the pair of electrodes it holds and adsorbing ionic components, charged particles, or organic substances in the liquid to be treated to the pair of electrodes. To obtain a desalted solution from which the ionic components have been removed, and then short-circuit the pair of electrodes or reversely connect a DC power source to release the ionic components adsorbed on the pair of electrodes and regenerate the pair of electrodes. However, the removal ion component is repeatedly collected as a concentrated liquid together with the liquid to be treated in the liquid.
[0003]
Such a liquid passing type capacitor is disclosed in Japanese Patent Laid-Open No. 5-258992. In this example of the known example, an inlet for introducing a liquid to be processed into a column and a liquid from which ion components have been removed are discharged. An outlet is provided, and the pair of electrodes is accommodated in the column. In both of these pairs of electrodes, a high surface area conductive surface layer is supported on a conductive support layer, and a nonconductive porous spacer is further included. Therefore, a pair of electrodes is a non-conductive porous spacer of one electrode, a conductive support layer, a high surface area conductive surface layer, a non-conductive porous spacer of the other electrode, a conductive support layer, a high surface area conductive. The surface layer has a six-layer structure. The pair of electrodes are wound around a hollow porous central tube with a high surface area conductive surface layer inside to form a cartridge. Lead wires extend from the conductive support layer of one electrode and the conductive support layer of the other electrode to the outside of the column and are connected to a DC power source. A liquid supply source to be processed is connected to the inlet of the column, and a switching valve for separating the desalted liquid from which the ionic component has been removed and the concentrated liquid from which the ionic component has been recovered is connected to the outlet.
[0004]
The liquid passing method of the above liquid passing type capacitor will be described with reference to FIG. In FIG. 8, 50 is a liquid passing type capacitor. First, the switching valve 51 is opened, the switching valve 52 is closed, the switch 53 is turned on, a DC voltage is applied to the pair of electrodes 54 and 55, and the liquid to be processed is supplied from the liquid source 56 to be processed. When supplied to the capacitor 50, an ion component is adsorbed on the pair of electrodes 54 and 55, and a desalted solution from which the ion component is removed on the downstream side of the switching valve 51 is obtained. If this state continues, the water quality monitoring device 57 measures that the ion component is gradually adsorbed to the pair of electrodes 54 and 55 and becomes saturated and the ion component removal performance gradually decreases. 51 is closed, the switching valve 52 is opened, the switch 53 is turned off, and the application of the DC voltage is stopped. In order to regenerate the ion component removal performance, when the switch 58 is turned on and the pair of electrodes 54 and 55 are short-circuited or the DC power source 59 is reversely connected, the ion component adsorbed on the pair of electrodes 54 and 55 is recovered. Is released, and a concentrated liquid is obtained in which the ionic component is recovered downstream of the switching valve 52 while the pair of electrodes 54 and 55 is regenerated, and one cycle of removal and recovery (regeneration) of the ionic component in the liquid to be treated is obtained. Ends. And the to-be-processed liquid is always supplied to the flow-through type capacitor | condenser 50 from the to-be-processed liquid supply source 56, The said cycle is repeated and the desalted liquid from which the ionic component was removed, and the concentrated liquid which collect | recovered the ionic component alternately Can get to.
[0005]
[Problems to be solved by the invention]
However, the conventional method for passing a liquid-type capacitor has a problem that the ability to remove ionic components from the liquid to be treated decreases as the liquid-pass capacitor is cycled. In order to recover the removal ability of such an electrode, there is also a method of once stopping the supply of the liquid to be treated and providing a cleaning process for supplying a chemical solution such as acid, alkali or bactericidal agent. There are various problems such as installation of supply equipment and waste liquid treatment of chemicals.
[0006]
Accordingly, the object of the present invention is to eliminate the need for chemical cleaning for recovering the electrode removal ability, to keep the separation ability of the ionic component of the liquid-flowing capacitor constant even during operation over a long period of time, and to extend the life of the electrode material. An object of the present invention is to provide a liquid passing method and apparatus for a liquid passing type capacitor which can be made into a liquid.
[0007]
[Means for Solving the Problems]
In such a situation, as a result of earnest studies, the present inventors applied a DC voltage to at least a pair of electrodes to remove the ionic component of the liquid to be treated and then short-circuited or reversely connected, In the flow method of the flow-through type condenser for recovering the removed ionic component to the water to be treated, the liquid to be treated is set to a specific temperature range or a specific pH value, or a deaeration treatment or a reduction treatment. If the liquid is passed through, etc., the effective surface area of the electrode can be maintained even during long-term operation without reducing the ionic component separation ability of the liquid-type capacitor, and the electrode material has a long service life. As a result, the present invention has been completed.
[0008]
That is, the present invention applies a DC voltage to a pair of electrodes to remove the ionic component of the liquid to be treated in the liquid flow to obtain a desalting solution, and then short-circuits the pair of electrodes or reversely connects a DC power source. The removed ionic component is passed through the liquid to be collected as a concentrated liquid together with the liquid to be processed, and the liquid to be processed is passed at pH 5 or lower or pH 9 or higher. It is an object of the present invention to provide a liquid passing method for a liquid passing type capacitor.
[0010]
The present invention also provides a desalting solution by applying a DC voltage to the pair of electrodes to remove the ionic components of the liquid to be treated while passing the solution, and then short-circuiting the pair of electrodes or reversely connecting a DC power source. The removed ion component is recovered as a concentrated liquid together with the liquid to be processed and the liquid is passed through the condenser. The liquid to be processed is degassed. The present invention provides a liquid passing method for a liquid passing type capacitor.
[0012]
Further, the present invention removes ionic components of the liquid to be treated by applying a DC voltage to the pair of electrodes, and removing the ionic components by short-circuiting the pair of electrodes or reversely connecting a DC power source. A liquid-flowing type comprising: a liquid-flowing condenser that collects the liquid to be treated together with the liquid to be treated; and a deaeration means that is located upstream of the liquid-flowing condenser and degasses the liquid to be treated. A liquid passing device for a capacitor is provided.
[0014]
DETAILED DESCRIPTION OF THE INVENTION
Next, a liquid passing method of the liquid passing type capacitor according to the embodiment of the present invention will be described with reference to FIG. FIG. 1 is a flowchart showing a liquid passing method of a liquid passing type capacitor according to an embodiment of the present invention. In the figure, reference numeral 1 denotes a liquid-flow type capacitor. The upstream side of the liquid-flow type capacitor 1 is connected to a pretreatment device 4 by a supply pipe 2 and further connected to a liquid supply source 5 to be processed by a connection pipe 3. On the other hand, the downstream side is connected to a water quality monitoring device 8 by a connection pipe 6, and the outflow pipe 7 of the water quality monitoring device 8 is a desalted liquid outflow pipe 9 having a switching valve 11 and a concentrated liquid outflow pipe having a switching valve 12. There are 10 branches. The processing liquid supply source 5 includes a processing liquid tank and a liquid feed pump for quantitatively supplying the processing liquid from now on (not shown).
[0015]
The liquid-flowing capacitor 1 includes at least a pair of electrodes 30 and 31, and the electrode 30 is connected to the cathode of the DC power supply 34 via the switch 32, and the electrode 31 is connected to the anode of the DC power supply 34. Further, the pair of electrodes 30 and 31 of the liquid-flowing capacitor 1 are connected to each other via a switch 35. The operation control of the devices shown in FIG. 1 is performed by a known control device such as a sequencer or a microcomputer. As the detailed operation control, for example, a liquid passing method of a liquid passing capacitor described later is used. Can be mentioned.
[0016]
The structure of the liquid-flowing capacitor 1 is not particularly limited, but here, electrodes 30 and 31 formed by contacting a high surface area activated carbon with a collecting electrode such as metal or graphite are accommodated in a column. A non-conductive spacer is interposed. And this liquid flow type capacitor 1 connects the direct-current power supply 34 to a pair of electrodes 30 and 31, and lets the to-be-processed liquid containing an ion pass in a column in the state which applied DC voltage, for example, 1-2V. Then, the pair of electrodes 30, 31 adsorb ions, and the ionic components are removed to obtain a desalted solution. After that, when the pair of electrodes 30, 31 are short-circuited, they are electrically neutralized and adsorbed. The concentrated ions are released from the pair of electrodes 30 and 31 to regenerate the pair of electrodes 30 and 31 and to obtain a concentrated liquid in which a concentrated ion component is recovered. The voltage applied between the pair of electrodes 30 and 31 can be set arbitrarily.
[0017]
As another example of the structure of the liquid-permeable capacitor 1, a pair of electrodes, which are activated carbon layers mainly composed of activated carbon with a high specific surface area, are arranged with a spacer made of a non-conductive porous liquid-permeable sheet interposed therebetween, A pair of collector electrodes is arranged outside the electrode, and a flat plate shape is formed with a holding plate arranged outside the collector electrode. A DC power source is connected to the collector electrode, and a short circuit between the collector electrodes or reverse connection of the DC power source is performed. You may do it. Further, the electrode and the collector electrode may be integrated.
[0018]
The pretreatment device 4 is for adjusting the liquid to be treated to be supplied to the liquid-flow condenser 1 to a specific property, and a heat exchanger for adjusting the temperature of the liquid to be treated to 30 ° C. or lower or 50 ° C. or higher, Examples include pH adjusting means for adjusting the pH of the liquid to be treated to pH 5 or lower or pH 9 or higher, a degassing apparatus for degassing the liquid to be processed, and a reducing apparatus (reducing means) for reducing the liquid to be processed. These pretreatment devices may be installed alone or in combination of two or more. Here, the liquid to be treated is not particularly limited. For example, city water, industrial water, river water, permeated water obtained by treating these with a reverse osmosis membrane, or an electronic component member such as a semiconductor wafer or a liquid crystal display is treated with ultrapure water. Cleaning wastewater discharged at the time of cleaning in the above, condensate of the circulation system of the steam turbine of the power plant, and the like. If these are included in the temperature range, for example, the pretreatment device 4 can be omitted. . The liquid to be treated of the present invention may be subjected to a raw water pretreatment such as a coagulation sedimentation treatment or a filtration treatment performed in the case of so-called pure water production or the like, which is different from the pretreatment.
[0019]
Examples of the heat exchanger for adjusting the temperature of the liquid to be treated to 30 ° C. or less, preferably 0 to 20 ° C. include a cooler and a heater, and the temperature of the liquid to be treated is 50 ° C. or higher, preferably 60 ° C. to boiling point or lower. A heat exchanger is mentioned as a heat exchanger which adjusts to. In addition, when the liquid to be treated is heated, bubbles are likely to be generated, which is not preferable in that gas accumulates on the surface of the activated carbon electrode or in the fine pores, reducing the effective electrode surface. It is preferable to perform such deaeration treatment before or after the heat treatment. By setting the liquid to be treated within the above temperature range, microorganisms are prevented from being generated in the flow-through capacitor, and the reduction of the effective electrode surface area due to the microorganisms or microorganism metabolites covering the carbon electrode surface is suppressed. it can. Conventionally, in a liquid processing apparatus, there is a method of continuously or intermittently injecting an oxidant as a method for preventing the generation of microorganisms. However, the use of an oxidant oxidizes an activated carbon electrode to reduce ionic component removal performance. .
[0020]
As pH adjusting means for adjusting the pH of the liquid to be treated to pH 5 or less, preferably pH 1 to pH 3, an acidic liquid storage tank and an acidic liquid supply pump are provided, and a pH meter is disposed between the acidic liquid supply point and the liquid-flowing type condenser. Can be used (not shown). Examples of the acidic liquid include a sulfuric acid solution and a hydrochloric acid solution. As pH adjusting means for adjusting the pH of the liquid to be treated to pH 9 or more, preferably pH 10 to pH 13, an alkaline liquid storage tank and an alkaline liquid supply pump are provided, and a pH meter is disposed between the alkaline liquid supply point and the liquid-flowing type condenser. Can be used (not shown). Examples of the alkaline liquid include caustic soda and trimethylammonium hydroxide. By setting the liquid to be treated within the above pH range, microorganisms are prevented from being generated in the flow-through capacitor, and the effective surface area of the electrode is prevented from being reduced by covering the carbon electrode surface with microorganisms or microbial metabolites. it can.
[0021]
In addition, the lower the TOC concentration of the liquid to be treated, the more preferable in terms of reducing the influence of microorganisms. The liquid to be treated has a TOC concentration of 1000 ppb or less, preferably 100 ppb or less. In order to reduce the TOC concentration of the liquid to be treated, a commonly used known method may be applied.
[0022]
As a degassing device for degassing the liquid to be treated, any device that removes in advance gas components such as nitrogen, oxygen, ammonia, methane and volatile organic hydrocarbons dissolved in the liquid to be treated can be used. Examples thereof include a vacuum deaerator, a membrane deaerator, and a heated deaerator. By these deaeration devices, the liquid to be treated is adjusted to, for example, a dissolved oxygen gas concentration of 1.0 mg / L or less, preferably 0.1 mg / L or less. Moreover, the deaeration apparatus can also use a method of supplying liquid into the decompressed tank. Moreover, the method of accelerating | stimulating generation | occurrence | production of a bubble by giving an ultrasonic vibration to a to-be-processed liquid, and removing the produced | generated bubble just before a liquid-type capacitor | condenser can also be used. By degassing the liquid to be treated, for example, gas can be prevented from accumulating on the surface of the activated carbon electrode or in the fine pores, and an effective electrode surface area reduction accompanying the gas accumulation can be suppressed.
[0023]
Examples of the reducing device (reducing means) for reducing the liquid to be treated include a reducing agent injection means, a hydrogen gas dissolving means, a filtration device using activated carbon or activated carbon fibers, and these are used alone or in combination of two or more. Examples of the reducing agent include sodium sulfite and sodium bisulfite. The injection amount of the reducing agent may be an amount sufficient to reduce and neutralize the oxidizing agent in the liquid to be treated. When the liquid to be treated is city water, examples of the oxidizing agent in the city water include sodium hypochlorite and chloramine, and examples of the oxidizing agent contained in the washing waste water of electronic parts include ozone and peroxidation. Hydrogen etc. are mentioned. Further, the dissolution of the hydrogen gas by the hydrogen gas dissolving means may cause the generation of bubbles in the liquid-flowing capacitor, and is preferably controlled to be equal to or lower than the saturation solubility of the hydrogen gas. In this case, the amount of dissolution may be controlled by a method in which a separate liquid to be processed is provided, hydrogen gas is added to a part of the liquid to be processed, and the hydrogen gas is mixed with the liquid to be processed that is not dissolved. By reducing the liquid to be treated with a reducing device (reducing means), the oxidizing agent in the liquid to be treated is reduced and neutralized, so that the oxidation of the surface of the activated carbon electrode of the flow-through capacitor is suppressed, and an effective electrode Reduction in surface area can be suppressed.
[0024]
The water quality monitoring device 8 is not particularly limited as long as it is a measuring device that measures liquid quality and can accurately grasp the degree of ion removal, and includes a conductivity meter and a specific resistance meter. In form it is a conductivity meter. Note that the water quality monitoring device may measure by bypassing a part of the treated water.
[0025]
Next, a method for passing the liquid-passing capacitor of the present invention will be described. First, the switch 32 is turned on to apply a DC voltage to the pair of electrodes 30 and 31, the switching valve 11 is opened, the switching valve 12 is closed, and the water quality monitoring device 8 is in a monitorable state. The pump of the supply source 5 and the pretreatment device 4 are operated, and the pretreated liquid is quantitatively supplied to the liquid condenser 1. At this stage, the flow-through capacitor 1 enters an ionic component removal step, and the liquid to be treated is adsorbed to the pair of electrodes 30 and 31 of the flow-through capacitor 1 to become a desalted solution from which the ionic component has been removed, It flows out through the desalted liquid outflow pipe 9.
[0026]
If this state is continued, the ion adsorption ability of the pair of electrodes eventually approaches a saturated state, the ion removal ability decreases, and the conductivity of the desalting solution gradually increases. When the electrical conductivity measured by the water quality monitoring device 8 becomes an unacceptable value for desalted liquid, the switching valve 11 is closed, the switching valve 12 is opened, and the switch 32 is immediately turned off to stop the application of the DC voltage. Further, the switch 35 is turned on, the pair of electrodes 30 and 31 are short-circuited, the adsorbed ion component is separated from the pair of electrodes 30 and 31, moved to the liquid side, and the pair of electrodes 30 and 31 is regenerated. Enter the process.
[0027]
The removal step and the recovery step are defined as one cycle, and by repeating this cycle, a desalted solution from which the ionic component has been removed from the liquid to be treated and a concentrated solution having a high ion concentration from which the removed ionic component has been recovered. In addition, the saturation and regeneration of the pair of electrodes 30 and 31 of the liquid-flowing capacitor 1 are repeated.
[0028]
In the present invention, the pretreatment is basically preferably a continuous treatment, but even if it is an intermittent treatment, it is possible to remarkably recover the ion removal ability of the flow-through capacitor whose performance has been reduced by removing bubbles on the surface. it can.
[0029]
In the present invention, examples of the desalting solution include softened water, desalted water, pure water, and solution desalting solution. These desalting solutions are used for boiler water, drinking water, washing water, and the like. The concentrated liquid can be used for recovering valuable materials.
[0030]
In the present invention, there may be a plurality of liquid-flow type capacitors, for example, two units are arranged in parallel, and one liquid-flow type capacitor is used as an ionic component removal step, and the other liquid-flow type capacitor is used as an ionic component recovery step. It can also be applied to a liquid passing method in which this is alternately repeated.
[0031]
【Example】
EXAMPLES Next, the present invention will be described more specifically with reference to examples. However, this is merely an example and does not limit the present invention.
Reference example 1
The liquid to be treated used was industrial water having an electrical conductivity of 330 μS / cm, pH 5.9, temperature 23 ° C., TOC 0.8 ppm, and a liquid-flow condenser manufactured by Kansai Thermochemical Co., Ltd. was used, as shown in FIG. One unit was placed and connected. The pre-treatment device uses a membrane deaerator (equipped with a Liqui-cel 2.5 inch type (manufactured by Celgard) as a deaerator) and performs a vacuum deaeration treatment with an absolute pressure of 100 torr, resulting in a dissolved oxygen concentration of 0.1 mg / L. The industrial water was passed through a liquid condenser. The applied voltage to the liquid passing type capacitor was set to 1.2V DC. The water to be treated was continuously supplied to the flow-through condenser at 250 ml / min, and the above-described removal process and recovery process were repeated, and this was performed 50 times (cycle). At that time, the quality of the effluent of the liquid-flow condenser was monitored with a conductivity meter. The result is shown in FIG.
[0032]
Here, if the flow rate of the water to be treated is constant, the ion removal ability of the liquid-flow condenser is determined by the amount of deionized water from which ion components have been removed to a predetermined concentration in the removal step. Therefore, a time for maintaining the 10% concentration of the water to be treated (hereinafter referred to as “time to reach the 10% concentration value”) was used as an index of the ion removing ability of the liquid condenser. This will be described with reference to FIG. FIG. 2 shows a typical example of the relationship between the conductivity of the effluent water over time. In the figure, at the beginning of the removal step, the conductivity 330 μS / cm of the water to be treated decreases to 20 μS / cm, and the ionic components are removed to obtain demineralized water. Thereafter, when the ion component is accumulated in the electrode and approaches a saturated state, the quality of the effluent water decreases, and after 26 minutes, it exceeds 33 μS / cm, which is 1/10 of the conductivity of the water to be treated. Thereafter, the electrodes are short-circuited to perform an electrode regeneration step, that is, a recovery step, whereby a concentrated liquid of ionic components accumulated in the liquid-flowing capacitor is obtained, and the conductivity of the liquid to be processed increases. In FIG. 2, the time to reach the 10% concentration value is 26 minutes. Therefore, if the time to reach the 10% concentration value is shorter than the time to reach the 10% concentration value in the initial operation, it can be understood that the ion component removing ability of the liquid-flowing capacitor is lowered.
[0033]
As is clear from FIG. 3 in Reference Example 1 , since the membrane deaeration treatment was performed as a pretreatment of the water to be treated, the ion component removal ability at the beginning of operation was maintained even after 50 cycles. .
[0034]
Comparative Example 1
The same procedure as in Reference Example 1 was performed except that the operation of the pretreatment device was stopped. The results are shown in FIG. From FIG. 3, the ionic component removal ability of the flow-through type capacitor decreased from about 20 cycle operation, and the removal ability decreased to about 40% of the initial value in 50 cycle operation.
[0035]
Reference example 2
After the 50-cycle operation of Comparative Example 1, the operation of the pretreatment device was started and the operation was continued in the same manner as in Reference Example 1 . The results are shown in FIG. From FIG. 3, the removal ability of the liquid-flowing type condenser whose ion component removal ability was reduced gradually recovered by supplying deaerated water. This is probably because the gas accumulated in the fine pores of the electrode was dissolved and removed in deaerated water, and the effective surface area of the electrode was recovered.
[0036]
Reference Examples 3-8, Comparative Examples 2 and 3
The pretreatment device is a membrane deaerator and a heat exchanger, and the temperature of the water to be treated is 23 ° C. ( Reference Example 3), 20 ° C. ( Reference Example 4), 30 ° C. ( Reference Example 5), 35 ° C. (Comparison) example 2), 40 ° C. (Comparative example 3), 50 ° C. (example 6), except that 60 ° C. (as reference example 7) or 70 ° C. (example 8) were 50 cycle operation and 100 cycle operation, reference The same method as in Example 1 was used. The results are shown in FIG. At any of the above temperatures, the initial removal ability was maintained in the initial stage such as 10-cycle operation. From FIG. 4, it can be seen that in the operation over a long period of time, the removal ability decreases when the temperature of the water to be treated exceeds 30 ° C. and is less than 50 ° C.
[0037]
Examples 1-7 , Comparative Examples 4-6
The pretreatment device is arranged in this order from the upstream side as a heat exchanger (heater), a membrane deaeration device, and a pH controller, the temperature of the water to be treated is 23 ° C., and the pH of the water to be treated is 5.9. (Example 1 ), pH 3 (Example 2 ), pH 4 (Example 3 ), pH 5 (Example 4 ), pH 6 (Comparative Example 4), pH 7 (Comparative Example 5), pH 8 (Comparative Example 6), pH 9 ( example 5), pH 10 (and example 6) or pH 11 (example 7), except that the 50 cycle operation and 100 cycle operation was conducted in the same manner as in reference example 1. The results are shown in FIG.
[0038]
Examples 8-14 , Comparative Examples 7-9
It was performed by the same method as Examples 1 to 7 and Comparative Examples 4 to 6 except that the temperature of the water to be treated was changed to 35 ° C. The results are shown in FIG.
[0039]
Examples 15-21 , Comparative Examples 10-12
It carried out by the method similar to Examples 1-7 and Comparative Examples 4-6 except that the temperature of to-be-processed water was 40 degreeC . The result was similar to FIG.
[0040]
From FIG. 5 and FIG. 6, if the pH value of the water to be treated is maintained at 4 or lower or 9 or higher even in a liquid passing temperature range of 30 ° C. to 40 ° C. in which a decrease in the ionic component removing ability is recognized, It can be seen that the decrease in the thickness can be prevented.
[0041]
Reference Example 9 and Comparative Example 13
In the same manner as in Reference Example 1, except that industrial water is used as the liquid to be treated instead of city water having a conductivity of 330 μS / cm, pH 6.0, temperature 20 ° C., and 50 cycle operation is changed to 1500 cycle operation. A first water flow treatment was performed. Subsequently, the activated carbon treatment (pretreatment) is performed by filtering the city water using a commercially available activated carbon treatment device (PCF-500A type, manufactured by Organo Corporation), and the second water flow treatment is performed for 500 cycles. went. Subsequently, instead of the activated carbon treatment, a reduction treatment (pretreatment) in which 3 ppm of sodium bisulfite was injected was carried out, and a third water flow treatment was performed in which this was performed for 500 cycles. Subsequently, a fourth water treatment was performed by returning to city water and operating in the same manner as the first water treatment. The results are shown in FIG.
[0042]
From FIG. 7, the first water treatment and the fourth water treatment showed a slight decrease in the removal ability, although it was very slight. This is because an oxidizing substance such as sodium hypochlorite in the city water attacked the electrode and reduced the electrode surface area. Moreover, the fall tendency of the electrode removal ability stopped in the 2nd water flow treatment and the 3rd water flow treatment, and the 4th water flow treatment after that showed the downward trend again. In the second water treatment and the third water treatment, the reduction tendency of the electrode removal ability stopped because the oxidizing agent in the city water was neutralized by the reduction treatment with activated carbon or sodium bisulfite, and the electrode was oxidized. This is because it was suppressed.
[0043]
【The invention's effect】
According to the present invention, since the liquid passing temperature of the liquid to be treated is 30 ° C. or lower or 50 ° C. or higher, or the pH value of the liquid to be processed is pH 5 or lower or pH 9 or higher, microorganisms are generated in the electrode. It is possible to prevent the reduction of effective electrode surface area due to the surface of the carbon electrode covered with microorganisms or microbial metabolites. In addition, since the liquid to be treated is supplied after being deaerated, it is possible to prevent gas from accumulating on the surface of the activated carbon electrode or in the fine pores, and to suppress a reduction in effective electrode surface area associated with the accumulation of the gas. In addition, since the liquid to be treated is supplied after being reduced, oxidation of the surface of the activated carbon electrode is suppressed, and an effective reduction in electrode surface area due to the oxide film can be suppressed. For this reason, the problem that the removal capability of the ionic component from a to-be-processed liquid falls as a processing cycle is repeated. Further, if the pretreatment is performed by combining a plurality of the above pretreatment means for the liquid to be treated, the above effect becomes more remarkable.
[Brief description of the drawings]
FIG. 1 is a flowchart showing a liquid passing method of a liquid passing type capacitor according to an embodiment of the present invention.
FIG. 2 is a characteristic diagram showing the relationship between the electrical conductivity of the effluent and time in the liquid passing method of the liquid passing type capacitor according to the embodiment of the present invention.
FIG. 3 is a diagram showing the influence of the liquid passing cycle of the liquid passing type capacitors of Examples 1 and 2 and Comparative Example 1;
FIG. 4 is a diagram showing the influence of the liquid passing temperature of the liquid passing type capacitors of Examples 3 to 8 and Comparative Examples 2 and 3;
FIG. 5 is a diagram showing the influence of liquid passing pH of liquid passing type capacitors of Examples 9 to 15 and Comparative Examples 4 to 6.
6 is a graph showing the influence of liquid passing pH of liquid passing type capacitors of Examples 16 to 22 and Comparative Examples 7 to 9. FIG.
7 is a graph showing the influence of the liquid passing cycle of the liquid passing type capacitors of Example 30 and Comparative Example 13. FIG.
FIG. 8 is a flowchart showing a conventional liquid passing method for a liquid passing type capacitor.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1,50 Flow-through type capacitor | condenser 2,3 Supply piping 4 Pretreatment apparatus 6,7,9,10 Connection piping 5,56 Processed liquid supply source 8,57 Water quality monitoring apparatus 30,31,54,55 Electrode 32,35 , 53, 58 Switch 34, 59 DC power supply 11, 12, 51, 52 selector valve

Claims (3)

  A desalted solution was obtained by applying a DC voltage to the pair of electrodes to remove the ionic component of the liquid to be treated while passing through the solution, and then the paired electrodes were short-circuited or reversely connected to a DC power source to remove the solution. A method for passing a ionic component through a liquid condenser that collects an ionic component together with a liquid to be treated as a concentrated liquid, wherein the liquid to be treated is passed at pH 5 or lower or pH 9 or higher. Liquid type capacitor flow method.   A desalted solution was obtained by applying a DC voltage to the pair of electrodes to remove the ionic component of the liquid to be treated while passing through the solution, and then the paired electrodes were short-circuited or reversely connected to a DC power source to remove the solution. A flow-through method of a flow-through type condenser for collecting an ionic component as a concentrated liquid together with a liquid to be treated, wherein the liquid to be treated is degassed. How to pass the capacitor.   A DC voltage is applied to the pair of electrodes to remove the ionic component of the liquid to be treated, and the paired electrodes are short-circuited or a DC power supply is reversely connected to pass the removed ionic component in the liquid. A liquid-passing device for a liquid-flowing capacitor, comprising: a liquid-flowing condenser that collects together with the processing liquid; and a deaeration unit that is located upstream of the liquid-passing capacitor and degasses the liquid to be treated.

Images