JPS6038998B2 - Method for regenerating porous conductive materials - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for regenerating porous electrically conductive materials, and more specifically, the present invention relates to a method for regenerating porous electrically conductive materials, and more specifically, the present invention relates to a porous electrically conductive material that has adsorbed metal ions, inorganic ions, and organic matter in wastewater by electrolytic treatment of porous electrically conductive materials. The present invention relates to a method for regenerating a porous conductive material that effectively regenerates the material.

Porous conductive materials used as adsorbents for wastewater treatment include:
Porous and electrically conductive adsorbents such as activated carbon and porous and electrically conductive selective ion exchange agents such as zeolite are used, and their shapes and sizes are not particularly limited and are usually about the same size. It is applied as spherical granules.

In particular, activated carbon, particularly granular activated carbon, has many excellent properties as an adsorbent and is therefore widely used in wastewater purification processes, but used activated carbon must be recycled for use due to cost considerations.

Activated carbon regeneration methods can be broadly divided into heating regeneration methods and chemical regeneration methods. The former method uses high-temperature gas or water vapor to decompose and remove adsorbed substances, but it requires multiple handling operations, and the activated carbon is consumed during regeneration.
Furthermore, there remain problems such as accumulation of non-volatile components in the adsorbed substance. In addition, the latter is a method in which the adsorbed substance is eluted by reaction by soaking it in chemicals such as acids, alkalis, and oxidizing agents, but there are problems such as limitations in regeneration efficiency and difficulties in processing the eluted chemicals. There is. by the way,
Recently, a method of filling porous conductive materials such as activated carbon between supporting electrodes and treating wastewater while applying electricity has been in the spotlight. In this wastewater treatment method, each particle of the porous conductive material is polarized negatively and positively, and has the properties (adsorption ability if activated carbon is used, selective ion exchange ability if it is made of zeolite).
In addition, active chlorine and oxygen are generated by the electrolytic reaction that occurs around each particle of the porous conductive material, that is, at the interface, decomposing and removing organic components such as COD and cation components, and inorganic ions. Both negative and positive particles are occluded in the pores of particles by Coulomb force, and the metal may be ionized.
becomes carbonate and is exposed on the particle surface. By this method, nitrogen-containing ions such as N03- and NH+ can be effectively removed as inorganic ions. To explain this adsorption phenomenon in detail, metal ions such as calcium ions contained in wastewater are absorbed by exposure, inorganic anions such as nitrate ions and nitrite ions, and inorganic cations such as ammonium ions are absorbed by occlusion, and organic substances are absorbed by occlusion. It is collected into particles of porous conductive material by adsorption.

In the present invention, for convenience, the above-mentioned inorganic anions and inorganic cations are collectively referred to as inorganic ions, and the above-mentioned electrodeposition, occlusion, and adsorption are collectively referred to as adsorption. The porous conductive material used in the electrolytic treatment of wastewater in this manner cannot be completely regenerated by the above-described regeneration methods using heating or chemicals.

This is because, unlike the above two methods in which it is sufficient to simply remove the adsorbed substance in the narrow sense, it is necessary to also remove the lightning-induced substance and the occlusion substance. From this point of view, a regeneration method using electrolytic regeneration has been proposed.

Some examples are shown below. {a} JP-A-53-3815
The method described in Publication No. 3 is a filling electrolysis method using activated carbon by applying AC current, in which nonionic components are ionized by redox, and the ionized components, metal salts, and metal ion components are electrostatically applied to activated carbon. It is removed by suction and adhesion.

To regenerate activated carbon, we stop the supply of wastewater and apply electricity in still water to release deposits even within the micropores, followed by backwashing with clean water. {b- The methods and devices described in Japanese Patent Publication No. 48-14553, Hakama Publication No. 49-2072, and Japanese Patent Publication No. 48-41836 all involve soaking adsorbed activated carbon in an electrolyte solution and discharging it between electrodes. The method is to energize the

Salt, sulfuric acid, sodium sulfate, sodium acetate, etc. are used as electrolytes, and cationically charged substances and nonions are treated at the anode, anionically charged substances are treated at the cathode, and organic substances such as COD components are treated at the cathode. It receives electrical energy and is electrophoretically desorbed, and is further stabilized by reacting with substances such as c12 and NaOH generated at the electrode and interface. In particular, cationic substances are anodic oxidized and decomposed at the same time as they are removed, forming flocs and becoming stable substances. Lightning deposits such as calcium ions can be desorbed to some extent by a method of applying electricity using electrolytes such as sulfuric acid and common salt.

Although acids are more advantageous than salts in treating metal ions, they have the following disadvantages. If calcium is used as a metal and sulfuric acid is used as an acid, the crystallization is mainly performed in the form of calcium carbonate, and calcium carbonate reacts well with sulfuric acid or an aqueous sulfate solution to form calcium sulfate. Therefore, when electricity is applied using an acid as an electrolyte, the acid is re-electrodeposited on the surface of the porous conductive material in the form of calcium or calcium sulfate. In this regard, the results of comparing acid treatment and acid energization treatment will be shown in an experimental example to be described later. The state of adsorption of adsorbed substances onto a porous conductive material is such that inorganic ions are occluded in the pores on the anode and cathode sides, and organic substances such as COD components and salt-type metal deposits are present around them. Furthermore, single metal and salt type lightning precipitates are adsorbed around it, especially on the cathode side.

Therefore, if desorption of the metal electrolyte is incomplete during regeneration, desorption of inorganic ions occluded in the string holes will also be incomplete. For the above reasons, there is a problem in that the conventional single-step electrolytic regeneration treatment cannot exhibit sufficient effects.

The present invention was made in view of the current situation, and
The purpose is to provide a method for regenerating a porous conductive material that effectively regenerates a porous conductive material that has adsorbed metal ions, inorganic ions, and organic matter in wastewater through electrolytic treatment of the porous conductive material. It is.

To summarize the present invention, the method for regenerating a porous conductive material of the present invention involves flowing wastewater through an electrolytic cell filled with a porous conductive material, and electrolytically treating the wastewater to eliminate metal ions, inorganic ions, and In regenerating the porous conductive material that has adsorbed organic matter, the method is characterized by including the steps of cleaning the porous conductive material with an acid, cleaning it with a solution containing chloride ions, and applying electricity. .

The present inventors have developed a method in which wastewater is treated by filling a porous conductive material (hereinafter referred to as porous material) between supporting electrodes and applying electricity (hereinafter referred to as filling electrolytic treatment method) to adsorb substances to be adsorbed. When desorbing adsorbed substances from porous materials, water, acid, and chloride ion-containing solutions were used as regenerating liquids to compare their effects in order to confirm the type of desorbent to be applied and the effect of energization. Furthermore, the present invention was completed as a result of investigating the effects of energization.

These basic experiments and the confirmation items obtained are shown below as experimental examples. Experimental Example 1 Figure 1 is a cross-sectional schematic diagram of the apparatus used in this experiment, and a
b shows a side view, and b shows a front view.

Further, reference numeral 1 indicates a flotation separation band, 2 an electrolytic band, 3 activated carbon, 4 a support electrode, 5 a waste water supply joint, and 6 a regeneration liquid supply joint and treated water discharge port. The overall dimensions of the treatment tank are 750 x 150 x 4 on the height 400 side of the floating separation zone 1,
The height of electrolytic band castle 2 was set to 200 ribs. The anode material of the supporting electrode 4 was ferrite, the cathode material was SUS, and the electrode plate dimensions were 200 x 150 x 5 in side units. Further, the waste water supply port 5 was installed 235 times above the top surface of the electrolytic zone 2, and granular activated carbon having an average particle size of 8 times was used as the activated carbon 3. A simulated wastewater containing calcium as a metal component is supplied from the wastewater supply port 5, passed through the flotation separation zone 1 and the electrolytic band 2, and is energized to the supporting electrode 4 to perform charging electrolytic treatment, so that it is deposited on the surface of the activated carbon 3. Contains calcium (including salt form).

Next, the calcium adsorbed on the activated carbon 3 was eluted and desorbed using water, sulfuric acid, and a saline solution, with or without applying electricity, to perform regeneration.

Each playback time is 1 hour, and when energized, DC 2A
A current was applied. Further, the regenerating liquid was used in circulation, and the regenerating liquid was passed through the activated carbon 3 from below to above at a rate of 500 m/min.
Note that the regenerating solution was used in circulation for a predetermined period of time for each solution. The results obtained are shown in FIG.

Figure 2 is a graph showing the relationship between the lacquer release time and the calcium ion elution rate in this example, where A is 1% by weight.
If you simply leave the port using sulfuric acid with a concentration of
When using sulfuric acid with a concentration of 1% by weight and applying electricity at the same time as elution, C uses a saline solution with a concentration of 1% by weight, and when electricity is applied simultaneously with elution, D uses a saline solution with a concentration of 1% by weight. E shows the case where elution was simply performed using tap water. As is clear from the graph of FIG. 2, the maximum calcium ion removal effect is obtained when sulfuric acid is used for simple elution, that is, the processing speed is fast. Experimental Example 2 Using the same equipment as in Experimental Example 1, nitrate ions were adsorbed onto activated carbon 3 in the same manner as in Experimental Example 1 using simulated wastewater containing nitrate ions (N03) as inorganic ions, and then the regenerated liquid Activated carbon 3 was regenerated using saline solution with or without electricity.

Each playback time is 3 hours, and when electricity is applied, DC 2A
A current was applied. Further, the regenerating liquid was used for circulation, and the regenerating liquid was passed through the activated carbon 3 from below to above at a rate of 500 per minute. Note that the regenerating solution was used in circulation for a predetermined period of time for each solution. The results obtained are shown in FIG.

Figure 3 is a graph showing the relationship between elution time and nitrate ion elution rate in this experimental example, where F is when elution was simply performed using 5% saline, and G is salt at a concentration of 5% by weight. This shows the case where water is used and electricity is applied at the same time as melting. As is clear from the graph of FIG. 3, nitrate ions can be eluted in a shorter time and more efficiently by simply eluating (or more accurately, replacing) with saline. Experimental Example 3 A square container with overall dimensions of 100 x 50 x 100 in units of ribs was used as the treatment tank.
The regeneration effect of saline solution was investigated in the same manner as in Experimental Example 2 using granular activated carbon having a particle size of 5 to 1 dia as the activated carbon 3.

In addition, the adsorbed substances are nitrate ions and calcium ions,
Simultaneous energization was not performed. Calcium nitrate was electrolyzed in the treatment tank, and 0.5 nitrate ions and 0.65 calcium ions were adsorbed onto the activated carbon 3.

Next, activated carbon was regenerated by circulating 300 ml of saline solution having a concentration of 5% by weight through the treatment tank.

The results obtained are shown in FIG. Figure 4a is a graph showing the relationship between elution time and calcium ion elution rate in this experimental example, and Figure 4b is a graph showing the relationship between total elution time and nitrate ion elution rate in this experimental example. This is a graph. As is clear from FIG. 4, the elution rate of both ions increases with the passage of time, with approximately 90% of the calcium ion being eluted in about 2 hours and the nitrate ion being eluted in about 4 hours. Experimental Example 4 Using a solution containing phenol as an organic substance and sewage, 100 pieces of granular activated carbon (same as in Experimental Example 3) were electrolytically adsorbed.

The adsorption amount is 5.2 days for phenol and 1.2 hours for sewage.
5 o'clock [measured by TOD (total oxygen demand)]. For regeneration, a saline solution 300 with a concentration of 5% by weight was passed through the treatment tank in the same manner as in Example 3, and a current of 1. The insects were used to energize and generate chlorine gas to oxidize and decompose organic matter.

The regeneration rate of the activated carbon 3 over time in each case was determined from the adsorption amount of the methylene full drop.

That is, after drying powdered activated carbon 3 at 1000° for 2 hours, methylene flue solution (150 ppm) 100
Fifty caps of the activated carbon 3 were added to the pot, and the amount of adsorption after three cycles was measured from the absorbance. The results obtained are shown in FIGS. 5 and 6. Figure 5 shows the 6th column in the case of phenol liquid.
The figure is a graph showing the regeneration rate over time in the case of sewage. As is clear from these graphs, in both cases the regeneration rate increases depending on the energization (electrolysis) time, that is, the amount of chlorine generated, but in the case of the phenol solution, the regeneration rate increases over a relatively short period of time, for example 1. Approximately 90% of wastewater is regenerated immediately, whereas in the case of sewage, the regeneration rate is approximately 65%. From the above experiments, the present inventors have found that calcium ions and nitrate ions can be particularly effectively removed when regeneration with acid and saline solution is performed without energization, and when regeneration with saline solution is performed with energization. It was confirmed that organic substances in particular can be effectively removed, and based on this, the present invention was completed.

In the present invention, the porous material that has adsorbed the adsorbed substance is washed with acid, thereby eluting substances that are easily soluble in acid, that is, metal ions, particularly calcium ions, and hazy precipitates such as carbonates thereof.

Since this cleaning is performed by backwashing, even if precipitates such as calcium sulfate occur, they can be sequentially entrained in the backwashing acid and removed from the treatment tank before the crystals grow. In this case, it is preferable not to apply electricity, since metals or metal salts such as calcium or calcium sulfate will be electrodeposited again on the surface of the porous material, reducing the elution effect. Examples of acids in the present invention include inorganic acids such as sulfuric acid, nitric acid, and hydrochloric acid, but sulfuric acid is suitable for use in view of the corrosivity of the equipment.

Moreover, the concentration of acid is 0.5 to 1. A sufficient effect can be obtained in a short period of time with approximately 1% by weight. The acid used for regeneration is recycled and reused, but is disposed of as appropriate depending on the degree of contamination and reduction in regeneration ability.

Next, in the present invention, the porous material that has adsorbed the adsorbed substance is washed with a solution containing chlorine ions, thereby desorbing (replacing) inorganic ions such as nitrate ions, nitrite ions, nitrite ions, and ammonium ions. ).

Since this cleaning is carried out by backwashing as in the case of the acid, deposits such as flocs, reaction products, lacquer deposits, precipitates, etc. are sequentially entrained in the chlorine ion-containing solution and discharged and removed. Applying electricity in this step is undesirable because it reduces the effect of elution of inorganic ions. A saline solution is suitable as the chlorine ion-containing solution in the present invention, and a sufficient effect can be obtained at a concentration of about 0.5 to 5% by weight.

It has been found that there is a tendency to improve the desorption and elution of inorganic ions by increasing the specific conductivity of the aqueous solution by increasing the concentration of the saline solution. The chlorine ion-containing solution used for regeneration is recycled and reused in the same way as acid, but it is disposed of as appropriate depending on the degree of contamination and the deterioration of the regeneration facility.

In the present invention, the order of the acid washing step and the chlorine ion-containing solution washing step is not particularly limited, but it is more effective to perform the acid washing step first.

In addition, as a pre-process for cleaning with an acid and chlorine ion-containing solution, backwashing with water, especially water with air bubbles, is performed to remove deposits such as flocs and make the next regeneration process more efficient. be able to.

After cleaning with an acid and a chlorine ion-containing solution, direct current is applied with the chlorine ion-containing solution flowing or with the solution stopped.

For example, when the porous material is activated carbon, the electric current is applied at a rate of 7.5 kg per 1 lb of activated carbon. The direct current is about the same level as Mikimisaki, and as a result,
In particular, when a chlorine ion-containing solution is present, the chlorine ions in the solution are oxidized by the electrolytic effect and become chlorine (regardless of free or bound) that exhibits effective activity in oxidizing Cl2 and NaC1o, etc. These actions decompose organic substances such as COD components. Further, at this time, since chlorine gas is generated in the pores inside the polarized porous conductive material, the adsorbed organic matter can be effectively decomposed. Furthermore,
By applying electricity while backwashing with a chlorine ion-containing solution, the charging castle or polarization region (negative,
positive/positive position) changes as the position of each particle changes,
This produces the effect that the adsorbed inorganic ions are removed by repulsive force. By carrying out the above steps, it is possible to effectively remove adsorbed materials adsorbed onto porous materials, but the present invention has the advantage that it can be easily carried out in the same treatment tank as that used in wastewater treatment. have.

Next, specific examples of the present invention will be described with reference to the drawings.

FIG. 7 is a schematic cross-sectional view showing a specific example of the apparatus used in the present invention, in which 101 and 118 are pumps, 102 is a wastewater storage tank, 103 is a pressurized flotation separation tank, 104 is a foam separation tank, and 105 106 is an electrolytic cell, 106 is a flotation separation zone, 107 is a porous material, 108 is a porous plate, 109 is a supporting electrode, 110
is an electrolysis zone, 111 is a treated water storage tank, 112 is a coagulant storage tank, 1 13 is a pressurized water generator, 1 14 is a compressor, 1 1
5 is a water tank, 116, 117, 122, 126, 127,
130, 132, 133 and 134 are valves, 1 19
120 is a regeneration liquid supply path, 120 is a regeneration liquid supply connection port, 121 is a regeneration liquid discharge port, 123 is an air supply path, 124 is a bubbling device, 125 is a regeneration liquid discharge path, 128 is an acid storage tank, 131
indicates a chlorine ion-containing solution storage tank, A is wastewater, B is treated water, C is a flocculant, D is pressurized water, B is water, F is acid, G
indicates a solution containing chloride ions. The wastewater A is pumped up to a wastewater storage tank 102 by a pump 101.

The pumped wastewater A is sequentially supplied from the wastewater storage tank 102 to the pressurized flotation separation tank 103, the foam separation tank 104, and the flotation separation band 106 of the electrolytic cell 105 equipped with the regeneration function of the present invention using natural head. Next, the porous material 107 flows through an electrolytic band 110 filled with porous material 107 between supporting electrodes 109 on an impermeable porous plate 108, and becomes treated water B to reach a treated water storage tank 111. . In the process from the wastewater storage tank 102 to the pressurized flotation separation tank 103, the flocculant storage tank 1
Flocculant C from 12 and pressurized water D from pressurized water generator 113 are added. Air is blown from the compressor 114 into the liquid pool at the bottom of the pressurized water generator 113 and into the bottom of the foam separation tank 104, and further into the electrolytic tank 10 in the practice of the present invention.
It is blown into the bottom of 5. In the above-mentioned wastewater treatment process, metal ions, inorganic ions, and organic substances (such as COD components) in the wastewater are adsorbed and removed, especially by passing through the electrolytic belt 110.

Removal of these substances at the string pores and interfaces of the porous material 107 is largely due to oxidation and reductive decomposition as well as adsorption and concentration. However, over a long period of time, the adsorbed substances may be adsorbed onto the porous material 107, and flocs may be deposited over almost the entire upper surface of the electrolytic zone 110. In the re-discharging process, first, the water E in the water tank 115 is supplied to the bottom of the electrolytic cell 105 from the regeneration liquid supply port 120 via the regeneration liquid supply path 119 by the pump 118 with the valves 116 and 117 opened.

The water E supplied into the electrolytic cell 105 passes through the porous plate 108 and rises through the gaps between the porous substances 107, peels off the flocs that are deposits by backwashing, and drains the recycled liquid outlet 1.
21 to the outside of the electrolytic cell 105. In this backwashing process, water E is supplied from the compressor 104 to the valve 12 at the same time.
2 is opened and the bubbling device 12 passes through the air supply path 123.
4, air is blown downward from the porous plate 108 in the electrolytic cell 105 to perform bubbling. The water E that has contributed to the regeneration is returned to the water tank 115 from the regeneration liquid discharge row 21 via the regeneration liquid discharge path 125 by opening the valve 126. In this way, the water E is recycled and used, but is discarded by opening the valve 127 as appropriate depending on the degree of contamination. After backwashing with water E' using bubbling, the acid F in the acid storage tank 128 is removed from the valve 1.
29 is opened, and the regenerating liquid supply row 20 is supplied to the bottom of the electrolytic cell 105 through the same route and in the same manner as water E.

The acid F supplied into the electrolytic cell 105 passes through the porous plate 108 and rises through the gap between the porous materials 107, and becomes acid F'.
Easily dissolved substances, particularly calcium ions and electrodeposited substances such as carbonates thereof, are discharged from the regenerating liquid discharge row 21 to the outside of the electrolytic cell 105. In this backwashing process using acid F, even if precipitates such as calcium sulfate are formed, they are entrained by acid F and sent to the reclaimed liquid discharge row 2 before they grow.
It is discharged and removed from 1. The acid F that contributed to the regeneration is passed from the regenerating liquid outlet 121 to the regenerating liquid outlet 125 to the valve 13.
0 and returned to the acid storage tank 128. In this way, the acid F is recycled and used, but is discarded by opening the valve 127 as appropriate depending on the degree of contamination and the decline in regeneration ability. The distribution of acid F is
Since the effect appears in a short time, time should be taken into consideration to prevent damage to the equipment and the porous material. After backwashing with acid F, the chlorine ion-containing solution G in the chlorine ion-containing solution storage tank 131 is supplied to the bottom of the electrolytic cell 105 through the same route and in the same manner as water E and acid F by opening the valve 132.

The chlorine ion-containing solution G passes through the porous plate 108 and rises through the gaps between the porous substances 107, and the porous substances 107
In the Tsumugi hole, when using salt water as the solution G containing a substance that easily replaces the ions constituting the solution, especially chlorine ions, BH40, N03-, N02-, etc. are replaced and the regenerated liquid outlet 121 is used. is discharged from the electrolytic cell 105.
Next, direct current is applied between the supporting electrodes 109 while the chlorine ion-containing solution G is flowing.

As a result, the chlorine ions in the chlorine ion-containing solution G are oxidized by the electrolytic effect to become c12, Naclo, etc., and organic substances, ie, COD components, etc. are decomposed by these actions. Through this backwashing and electrolytic process, eluates, decomposition products, flocs, etc. are discharged and removed from the regeneration liquid discharge row 21 along with the chlorine ion-containing solution G. The chlorine ion-containing solution G contributed to the regeneration is returned to the chlorine ion-containing beach liquid storage tank 131 by opening the valve 133 via the regenerating liquid discharge path 125 from the regenerating liquid discharge row 21. In this way, the chlorine ion-containing solution G is recycled and used, but the valve 127 is opened depending on the degree of contamination and the reduction in regeneration ability, and the solution is disposed of as appropriate.
Note that chlorine gas generated during electrolysis is harmful, but
As shown in the figure, since the pent is combined with other grains, it is diluted and then released into the atmosphere.

As described above, as a specific example of the present invention, wastewater adsorbed to a porous material by electrolytic treatment filled with a porous material is obtained by pickling, washing with a chlorine ion-containing solution, and further electrolyzing. Metal ions, inorganic ions, and organic substances inside can be easily and effectively removed and regenerated.

Next, the present invention will be explained by examples, but the present invention is not limited to these in any way. Example 1 Using the same apparatus shown in FIG. 1 as in Example 1, sewage was subjected to electrolytic treatment under the conditions of a current of 2 A, a flow rate of 200'/min, and a feed time of 1 time, to remove contaminated water in the sewage. The adsorbate was removed by adsorption on granular activated carbon.

As a result, calcium 1.2 pm, TNI. 4th evening, COD
I. 8 particles and 0.84 particles of suspended matter were removed and adsorbed. The regeneration method of the present invention was applied to this granular activated carbon.

The elution (regeneration) conditions are shown below. Acid cleaning: 1% by weight
Sulfuric acid with a concentration of 500 / min, cyclic use, 3 minutes saline washing: saline solution with a concentration of 5% by weight, 500 / min, cyclic use, 1 hour saline electrolysis: saline washing Table 1 shows the results of subsequent saline treatment (with a concentration of 5% by weight) under direct current for 1 hour.

The results were expressed as port departure and port exit percentage in the treated water. Note that since COD is oxidatively decomposed, the amount eluted in the saline electrolysis was unknown. Table 1 As is clear from Table 1, according to the present invention, about 90% of the adsorbed substances adsorbed on granular activated carbon from sewage are eluted,
It can be attached and detached.

The total regeneration rate of the granular activated carbon including the elution effect and the decomposition effect (measured by the same method as in Experimental Example 4) was about 90% or more. Example 2 Using the same equipment as in Example 1, a solution containing calcium nitrate [Ca(N03)2] and bepton was discharged as a test solution, at a flow rate of 200 I/min, for 8 hours. The granular activated carbon was electrolytically treated under the following conditions: calcium 0.9 hours, nitrate ions 4.3 hours, and CODI. 1 night was adsorbed and removed.

The regeneration method of the present invention was applied to this granular activated carbon.

In addition, in this example, the case where saline washing was performed after ta} acid washing and the case where acid washing was performed after saline water washing are also described {b}. The elution (regeneration) conditions were as follows. Acid washing: sulfuric acid with a concentration of 1% by weight, 50%
0/min, circulation use, time 30 minutes Saline washing total: 5 wt% concentration saline, 500 secretion/min, circulation use, time 1 hour Saline electrolysis: Saline solution after saline washing (5 wt. % concentration) Direct current, 1 hour treatment results are shown in Table 2, {a} and {b.

The results were expressed as the elution amount and elution percentage in the treated water. In addition,
Since COD is oxidatively decomposed, the amount eluted in saline electrolysis was unknown. Table 2 (a) As is clear from Table 2 and Table 2, there is an effect of a dissolution rate of 70% or more in any case, but the case where acid washing is performed first is particularly excellent. % or higher elution rate can be obtained.

It has been found through regeneration tests that only a small amount of the COD component associated with beptone is adsorbed on activated carbon, and most of it is oxidized and decomposed. As explained above, according to the present invention, it is possible to easily and effectively regenerate the porous conductive material that has adsorbed metal ions, inorganic ions, and organic matter in wastewater by electrolytic treatment of the porous conductive material. can.

[Brief explanation of drawings]

Fig. 1 is a schematic cross-sectional view of the apparatus used in the experimental examples and examples of the present invention, where a shows a side view and b shows a front view, and Fig. 2 shows the elution time and calcium ion elution in Experimental Example 1 of the present invention. Figure 3 is a graph showing the relationship between elution time and nitrate ion elution rate in Experimental Example 2 of the present invention, and a and b in Figure 4 are graphs showing the relationship between elution time and nitrate ion elution rate in Experimental Example 3 of the present invention. Graphs showing the relationship between elution time, calcium ion elution rate, and nitrate ion elution rate. Figures 5 and 6 are graphs showing the regeneration rate of activated carbon over time in Experimental Example 4 of the present invention. Figure 5 is a graph showing the regeneration rate of activated carbon over time in Experimental Example 4 of the present invention. In the case of liquid, FIG. 6 shows the case of sewage, and FIG. 7 is a schematic cross-sectional view showing one specific example of the apparatus used in the present invention. 1...flotation separation zone, 2...electrolysis zone, 3
...Activated carbon, 4... Support electrode, 5...
... Drainage supply port, 6 ... Regeneration liquid supply port and treated water discharge port, 101, 118 ... Pump, 10
2...Drainage storage tank, 103...Pressure flotation separation tank, 104...Foam separation tank, 105...
...Electrolytic cell, 106...Flotation separation belt castle, 10
7...Porous substance, 108...Porous plate, 1
09... Support electrode, 110... Electrolysis zone, 111... Treated water storage tank, 112... Coagulant storage tank, 113... Pressurized water generator , 114・
...Compressor, 115...Water tank, 116, 11
7, 122, 126, 127, 130, 132, 133
and 134... Valve, 119... Regeneration liquid supply port, 120... Regeneration liquid supply port, 121... Regeneration liquid discharge port, 123... Air supply path, 124・・・
... Bubbling device, 125 ... Regeneration liquid discharge path, 128 ... Acid storage tank, 131 ...
Chlorine ion-containing solution storage tank, A...Drainage, B...
... Treated water, C ... Coagulant, D ... Pressurized water, E ... Water, F ... Acid, G ...
...Solution containing chlorine ions. O figure Sai 2 figure spear 3 figure spear 4 figure spear 5 figure 6 figure spear 7 figure

Claims (1)

[Scope of Claims] 1. In regenerating the porous conductive material that has adsorbed metal ions, inorganic ions, and organic matter in the waste water through electrolytic treatment by passing wastewater through an electrolytic cell filled with a porous conductive material. A method for regenerating a porous conductive material, comprising the steps of: washing the porous conductive material with an acid; washing the porous conductive material with a solution containing chlorine ions; and applying electricity. 2. A method for regenerating a porous conductive material according to claim 1, wherein the porous conductive material is washed with an acid and then washed with a solution containing chlorine ions. 3. A method for regenerating a porous conductive material according to claim 1, wherein the porous conductive material is washed with a chlorine ion-containing solution and then washed with an acid. 4. Regeneration of a porous conductive material according to claim 1 or 2, in which, after cleaning the porous conductive material with a chlorine ion-containing solution, electricity is supplied while the flow of the chlorine ion-containing solution is stopped. Method. 5. A method for regenerating a porous conductive material according to claim 1 or 2, wherein the porous conductive material is washed with a chlorine ion-containing solution and at the same time, electricity is applied while the chlorine ion-containing solution is flowing. 6. A method for regenerating a porous conductive material according to any one of claims 1 to 5, wherein the porous conductive material is backwashed with water before being washed with an acid. 7. The method for regenerating a porous conductive material according to claim 6, wherein backwashing is performed with water accompanied by air bubbles.