JP3764009B2 - Adsorbent and water treatment method - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an adsorbent, a water treatment agent, and a water treatment method.
[0002]
[Background Art and Problems to be Solved by the Invention]
Various methods for treating contaminated water for purifying contaminated water contaminated with various pollutants such as organic substances such as industrial wastewater have been proposed.
[0003]
For example, in Japanese Patent Application Laid-Open No. 55-39281, ferric hydroxide is added to biologically treated water of organic waste water to adsorb organic substances, and then an iron salt catalyst is added to the obtained treated water. Then, an organic wastewater treatment method has been proposed in which an organic substance is oxidized and decomposed, and an alkali is further added to precipitate and separate an iron salt catalyst as ferric hydroxide sludge.
[0004]
However, the adsorbent used for adsorbing contaminants in such a conventionally proposed processing method has a problem of poor handling and storage stability.
[0005]
On the other hand, wastewater often contains phosphorus, arsenic, humic acid, and the like. Since phosphorus causes eutrophication in lakes, seas, etc., it is desirable to exclude phosphorus. In addition, phosphorus, arsenic, etc. excluded from the wastewater can be recycled and reused. Humic acid is a chromaticity component in water, and heavy metals adsorbed on humic acid can also be recycled.
[0006]
Therefore, an object of the present invention is to provide an adsorbent that is easy to handle and excellent in storage stability.
Another object of the present invention is to provide a water treatment agent and a water treatment method capable of easily and satisfactorily removing contaminants from contaminated water contaminated with various contaminants.
[0007]
[Means for Solving the Problems]
In one aspect of the present invention, an adsorbent containing iron hydroxysulfate as an active ingredient is provided.
[0008]
In the present invention, a precipitate obtained by adding a peroxide to an aqueous solution containing divalent iron ions and sulfate ions, the main component of which is amorphous iron hydroxysulfate is used as an active ingredient. It is preferable.
[0009]
In another aspect of the present invention, a water treatment agent containing the adsorbent as a main component is provided.
In another aspect of the present invention, an adsorption step of bringing the adsorbent and / or the water treatment agent into contact with water; an aggregation step of adding a flocculant to the water containing the adsorbent;
A water treatment method is provided.
[0010]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, a preferred embodiment of the present invention will be described.
The adsorbent of the present invention is characterized by using iron hydroxysulfate as an active ingredient.
Hydroxysulfate includes trivalent iron hydroxysulfate. The hydroxycarbonate iron sulfate, for _{example, 2Fe 2 O 3 · 5SO 3} , Fe 2 O 3 · 2SO 3, Fe 2 O 3 · 2SO 3, 3Fe 2 O 3 · 4SO 3, Fe 2 O 3 · SO 3, 2Fe 2 O ₃ and SO ₃ are included. These are described below. For iron hydroxysulfate, 7Fe ₂ O ₃ · 18SO ₃ · nH ₂ O, 7Fe ₂ O ₃ · 15SO ₃ , 3Fe ₂ O · SO ₃ , 7Fe ₂ O ₃ · SO ₃ · 10.5H ₂ O, 10Fe ₂ O ₃ · SO ₃ · H ₂ O have also been reported.
[0011]
2Fe ₂ O ₃ · 5SO ₃ is described. Seventeen hydrates exist in the Fe ₂ O ₃ —SO ₃ —H ₂ O system at about 90 ° or less. Eighteen hydrates are present at 25 ° in the Fe ₂ O ₃ —SO ₃ —H ₂ O system. Alternatively, it is obtained by boiling a concentrated iron (III) sulfate solution having a ratio of SO ₃ : Fe ₂ O ₃ larger than 2.5.
[0012]
The following describes Fe ₂ O ₃ · 2SO ₃ . The anhydride is obtained by heating iron (II) sulfate to about 300 ° in a dry air stream. Fifteen hydrates precipitate when an industrial iron mordant is left for a long time. Anhydride is a brownish powder and has deliquescence. The monohydrate is stable at about 80 ° C. or higher in the Fe ₂ O ₃ —SO ₃ —H ₂ O system. The heptahydrate is naturally produced as amaranthite. Octahydrate is naturally produced as castanite. Nine to eleven hydrates are naturally produced as fibroferrite. Fifteen hydrates are defusible and dissolve in crystal water when heated.
[0013]
2Fe ₂ O ₃ · 3SO ₃ is described. The anhydride is obtained by igniting iron (III) sulfate. The heptahydrate is naturally produced as raimondite. The octahydrate is obtained by oxidizing an iron (II) sulfate solution in air. In addition, when mercury (II) oxide is allowed to act on an iron (II) sulfate solution for a long time, a hydrate having an unknown water content is obtained.
3Fe ₂ O ₃ · 4SO ₃ is described. Nine hydrates are naturally produced as waratite and borgstromit. About 20% iron (III) sulfate solution is obtained by heating to 150 ° in a sealed tube.
[0014]
The following describes Fe ₂ O ₃ · SO ₃ . 4/3 ~ Dihydrate is naturally produced as Uterite. The trihydrate is obtained by adding potassium carbonate to an iron (III) sulfate solution. Fifteen hydrates are naturally produced as planoferrite.
[0015]
2Fe ₂ O ₃ · SO ₃ is described. Hexahydrate is naturally produced as a blocker light. It is obtained by oxidizing an iron (II) sulfate solution in air. The heptahydrate is obtained by treating Fe ₂ O ₃ .2SO ₃ .15H ₂ O with cold water. Octahydrate is naturally produced as hydroglockerite. It is obtained by adding hydrogen peroxide to an iron (II) sulfate solution.
In addition, when an iron (III) sulfate solution is heated, diluted, or sodium carbonate is added, a hydrate having an unknown water content is obtained.
[0016]
The adsorbent of the present invention preferably contains 50% by weight or more of iron iron hydroxysulfate, more preferably 70% by weight or more of iron iron hydroxysulfate, and 80% by weight or more of iron hydroxysulfate. It is still more preferable that iron is contained, and it is particularly preferable that 90% by weight or more of iron hydroxysulfate is contained.
[0017]
For example, the iron oxide iron sulfate is obtained by adding a peroxide such as hydrogen peroxide to an aqueous solution containing an iron compound containing divalent iron ions and a sulfuric acid compound containing sulfate ions, for example, an aqueous solution containing iron (II) sulfate. To obtain a precipitate. This amorphous iron hydroxysulfate is particularly preferable because of its high adsorption capacity and good handling properties such as sedimentation separation.
[0018]
In this synthesis method, the blending ratio (molar ratio) of iron and sulfate ions is preferably iron: sulfate ions = 2: 1 to 1: 2.
The iron content in the aqueous solution is preferably 10 to 50 mol / liter.
[0019]
Further, in the hydrogen peroxide solution, the content of hydrogen peroxide is preferably 1 to 5% by weight, and the amount used is 0.5 to 2 mol with respect to 1 mol of divalent iron ions. Is preferred.
[0020]
The reaction conditions are preferably 15 to 60 ° C. and 2 to 5 hours.
Further, the adsorbent of the present invention is not particularly limited as long as it contains the iron iron sulfate as an active ingredient, and those usually used for this type of adsorbent may be added without particular limitation. Alternatively, in the present invention, the iron iron hydroxysulfate may be used alone as an adsorbent.
[0021]
The adsorbent of the present invention can be used for purification of industrial wastewater contaminated with various pollutants. In particular, it is suitable for the treatment of industrial wastewater containing phosphorus, arsenic and the like, and can also be used for the treatment of domestic wastewater containing phosphorus in detergents.
[0022]
Further, the adsorbent of the present invention can be used in any usage form 1) in the form of a slurry, 2) granular material such as a powder, or 3) adsorbed on a carrier. For example, when preparing iron iron sulfate, a carrier such as sponge or granular activated alumina may be present to adsorb iron iron sulfate.
[0023]
The adsorbent of the present invention uses the iron hydroxysulfate prepared in advance as an active ingredient, and therefore has a high effect of removing contaminants, is easy to handle, and has high storage stability.
[0024]
Next, the water treatment agent of the present invention will be described.
The water treatment agent of the present invention is characterized by containing the adsorbent of the present invention as a main component.
[0025]
In the present invention, the water treatment agent may be composed only of the adsorbent. Alternatively, the water treatment agent may further contain other adsorbents such as activated carbon and activated alumina as components other than the adsorbent. These additive components and iron hydroxysulfate do not inhibit the interaction.
[0026]
The adsorbent may be used in any of the usage forms described above.
And the water treatment agent or adsorbent of the present invention can remove components such as phosphorus, arsenic, and heavy metal ions. After the reaction water and the water treatment agent of the present invention were added to the reaction tank and reacted, the reaction solution was added to the coagulation tank together with the coagulant to cause aggregation, and then the aggregate was precipitated in the precipitation tank, You may isolate | separate into a deposit and treated water. Or you may throw into the adsorption tower in which the to-be-processed object and the water treatment agent of this invention were enclosed, and you may throw into the filtration tank and filter the to-be-processed object after passing an adsorption tower.
[0027]
In the case of arsenic, it is preferable to oxidize arsenic as a pretreatment and then use the treatment agent of the present invention. In the case of heavy metal ions, it is preferable to perform a pretreatment by adding a chelating agent or the like that causes a coordinate bond with heavy metal ions such as ethylenediaminetetraacetic acid (EDTA) and humic acid, and then use the treatment agent of the present invention.
[0028]
FIG. 1 shows a processing apparatus comprising a reaction tank, a coagulation tank, and a precipitation tank. In addition, each tank can use a well-known thing without a restriction | limiting in particular, respectively, Preferably, each tank is each connected via the well-known connection pipe | tube.
[0029]
First, an object to be treated is introduced into a reaction tank in which the water treatment agent of the present invention has been introduced to adsorb phosphorus or the like. Although the usage-amount of a water treatment agent is arbitrary by the contamination condition of a to-be-processed object, it is preferable normally to set it as 20 to 200 times with respect to a to-be-processed component.
[0030]
Moreover, it is preferable that reaction conditions are performed in the normal temperature range of aqueous solution. The room temperature region is 10 to 35 ° C, preferably 15 to 25 ° C, unless otherwise specified.
Next, after completion of the reaction, the reaction solution is put together with a flocculant into a coagulation tank to be aggregated.
[0031]
Examples of the flocculant that can be used at this time include polyaluminum chloride (PAC), iron (III) sulfate bend chloride, anionic polymer flocculants, cationic polymer flocculants, and amphoteric polymer flocculants. The polymer may be a natural polymer or a synthetic polymer. Next, the aggregate is precipitated in a sedimentation tank by a known method, and separated into sludge as a precipitate and treated water.
[0032]
In addition, when processing by this system, the said adsorbent becomes a nucleus, and the aggregation floc with very good sedimentation is obtained. When the adsorbent is used in an ordinary coagulating sedimentation apparatus, the sedimentation rate is several times higher, and the size of the equipment can be reduced or the amount of treated water can be increased in existing equipment. Alternatively, when a granulation settling apparatus is used as a method for settling and separating the aggregated floc, the settling separation rate (about 300 mm / min. To 400 mm / min.) Faster than the normal settling separation rate (200 mm / min.). Design with is possible. In addition, a granulation precipitation apparatus means the apparatus which stirs, adding a flocculant, and forms a pellet form or a aggregated aggregate sludge.
[0033]
FIG. 2 shows a processing apparatus comprising an adsorption tower and a filtration tank. In addition, as an adsorption tower and a filtration tank, respectively, a well-known thing can be especially used without a restriction | limiting, Preferably, each tank is connected through the well-known connection pipe, respectively.
[0034]
First, an object to be treated is put into an adsorption tower filled with the water treatment agent of the present invention to adsorb phosphorus in the object to be treated.
The adsorbent used in the packed tower is preferably a granular material. The granular material may be a sphere, an ellipse, a polygon, a ring shape, a Raschig ring, or the like.
[0035]
Further, the conditions for introducing the object to be processed into the adsorption tower vary depending on the object to be processed, but are preferably as follows. As temperature, it is preferable to carry out at the normal temperature range of aqueous solution, for example, 10-35 degreeC, and it is still more preferable to carry out at 15-25 degreeC.
[0036]
Next, the processed material after passing through the adsorption tower is filtered through membrane filtration such as microporous membrane (MF membrane), ultrafine membrane (UF membrane), etc. And put into a filtration tank and filter to obtain treated water.
[0037]
FIG. 3 shows a processing apparatus comprising a reaction tank and a filtration tank. In addition, each tank can use a well-known thing without a restriction | limiting in particular, respectively, Preferably, each tank is connected through the well-known connection pipe, respectively.
[0038]
First, an object to be treated is introduced into a reaction tank in which the water treatment agent of the present invention has been introduced to adsorb phosphorus or the like. The amount of the water treatment agent used is arbitrary depending on the state of contamination of the object to be treated, but it is usually preferably 20 to 200 times the amount to be treated.
[0039]
The reaction is preferably carried out in the normal temperature range of the aqueous solution, and the reaction time is preferably 0.5 to 2 hours.
Next, after completion of the reaction, the reaction solution is filtered in a filtration tank by a known method, and separated into sludge mainly composed of a water treatment agent and filtrate (treated water). As the filtration tank, the filtration tank described in FIG. 2 can be used.
[0040]
FIG. 4 shows a dissolution tank, a first reaction tank, a first precipitation tank, a second reaction tank, a second precipitation tank, a first dryer for drying the precipitate obtained in the first precipitation tank, and a second precipitation tank. The reproduction | regeneration apparatus which has a 2nd dryer which dries the precipitate obtained by this. Sludge or used adsorbent is charged into a dissolution tank together with a strong acid such as hydrochloric acid and dissolved. Next, the dissolved solution is charged into the first reaction vessel and reacted under acidic conditions such as pH 3-5. The obtained reaction solution is transferred to a precipitation tank to be precipitated and separated into a first precipitate mainly composed of FeOOH and the like and treated water. Furthermore, treated water is thrown into a 2nd reaction tank with strong bases, such as calcium hydroxide, and it is made to react on basic conditions, such as pH 8-9. Next, the reaction solution is transferred to a precipitation tank and precipitated to separate into a second precipitate mainly composed of hydroxyapatite and the like and treated water. The first precipitate and the second precipitate thus obtained are transferred to the first dryer and the second dryer, dried, and used for reuse.
[0041]
As the strong acid, inorganic acids such as hydrochloric acid, sulfuric acid and phosphoric acid, and organic acids such as trifluoroacetic acid are used. In view of post-treatment and the like, inorganic acids are preferable.
As the strong base, inorganic bases such as calcium hydroxide, barium hydroxide, sodium hydroxide and potassium hydroxide are preferably used.
[0042]
The amount of strong base such as calcium hydroxide used in the second reaction tank is preferably 20 to 500% by weight, preferably 50 to 200% by weight, with respect to 1% by weight of phosphorus contained in the solution. It is preferably 80 to 150% by weight.
[0043]
FIG. 5 shows an apparatus for treating water containing arsenic. That is, the treatment apparatus includes an arsenic oxidation tank, a reaction tank, a coagulation tank, and a precipitation tank. In addition, each tank can use a well-known thing without a restriction | limiting in particular, respectively, Preferably, each tank is each connected via the well-known connection pipe | tube.
[0044]
First, the object to be treated is put into an arsenic oxidation tank together with an oxidizing agent to oxidize arsenic. As the oxidizing agent, chlorine or the like is used.
The amount of the oxidizing agent used at this time is arbitrary depending on the contamination status of the object to be processed, but is preferably 200 to 500 parts by weight with respect to 100 parts by weight of the component to be processed.
[0045]
Next, the object to be treated in which arsenic has been oxidized is introduced into a reaction vessel in which the water treatment agent of the present invention has been introduced for reaction. Usually, the adsorbent is preferably 10 to 200 times the component to be treated, more preferably 20 to 100 times. Moreover, it is preferable that reaction conditions shall be 0.5 to 2 hours in the normal temperature range of aqueous solution.
[0046]
Next, the reaction solution after completion of the reaction is put together with a flocculant into a coagulation tank to be aggregated. Examples of the flocculant that can be used in this case include the flocculants described above.
Next, the aggregate is precipitated in a sedimentation tank by a known method, and separated into sludge as a precipitate and treated water.
[0047]
FIG. 6 shows a processing apparatus including an arsenic oxidation tank, an adsorption tower, and a filtration tank. In addition, as an arsenic oxidation tank, an adsorption tower, and a filtration tank, a well-known thing can be used respectively without a restriction | limiting, Preferably, each tank is respectively connected via the well-known connection pipe | tube.
[0048]
First, arsenic is oxidized in the same manner as in the treatment method of FIG. 5, and then the object to be treated is put into an adsorption tower in which the water treatment agent of the present invention is sealed to adsorb arsenic in the object to be treated.
The conditions at the time of putting the workpiece into the adsorption tower, the adsorbent, and the adsorption tower are as described above. Next, filtration is performed in the same manner as the processing method of FIG.
[0049]
FIG. 7 shows a processing apparatus comprising a heavy metal coordination compound production tank, a reaction tank, a coagulation tank, and a precipitation tank. In addition, each tank can use a well-known thing without a restriction | limiting in particular, respectively, Preferably, each tank is each connected via the well-known connection pipe | tube.
[0050]
First, the heavy metal treatment agent is added to the object to be treated, and the reaction is performed so that heavy metal ions are coordinated.
Examples of the heavy metal treating agent include chelating agents such as ethylenediaminetetraacetic acid (EDTA), humic acid, and the like.
[0051]
The amount of heavy metal treating agent used at this time is arbitrary depending on the contamination status of the object to be treated, but is preferably 1000 to 5000 parts by weight with respect to 100 parts by weight of the object to be treated. The reaction conditions are preferably 0.5 to 2 hours in the normal temperature range of the aqueous solution.
[0052]
Subsequently, the to-be-processed object containing a heavy metal coordination compound is thrown into the reaction tank in which the water treatment agent of this invention is thrown, and is made to react. The adsorbent and the flocculant are as described above.
[0053]
Next, the aggregate is precipitated in a sedimentation tank by a known method, and separated into sludge as a precipitate and treated water.
FIG. 8 shows a treatment apparatus comprising a heavy metal coordination compound production tank, an adsorption tower, and a filtration tank. In addition, as a heavy metal coordination compound production | generation tank, an adsorption tower, and a filtration tank, a well-known thing can respectively be used without a restriction | limiting, Preferably, each tank is each connected via the well-known connection pipe | tube. .
[0054]
First, a heavy metal coordination compound is produced in the same manner as in the treatment method of FIG. Next, the object to be treated is put into an adsorption tower in which the water treatment agent of the present invention is enclosed, and the heavy metal coordination compound in the object to be treated is adsorbed.
[0055]
The conditions at the time of putting the workpiece into the adsorption tower, the adsorbent, and the adsorption tower are as described above.
Next, the processed material after passing through the adsorption tower is put into a filtration tank and filtered to obtain treated water. The conditions for filtration are as described above.
[0056]
【The invention's effect】
The adsorbent of the present invention is easy to handle and has excellent storage stability.
Moreover, according to the water treatment agent and the water treatment method of the present invention, contaminants can be easily and satisfactorily removed from contaminated water contaminated with various contaminants.
[0057]
In particular, when processing an object to be processed containing phosphorus, a recovered solution having a high phosphorus-containing concentration can be easily obtained from the adsorbent after use. Further, iron can be easily separated and recovered from the adsorbent after the treatment, and the adsorbent can be adjusted by reusing the recovered iron.
[Brief description of the drawings]
FIG. 1 is a schematic diagram showing an outline of a processing apparatus and processing method for an object to be processed containing phosphorus.
FIG. 2 is a schematic view showing an outline of a processing apparatus and processing method for an object to be processed containing phosphorus.
FIG. 3 is a schematic view showing an outline of a phosphorus adsorption step.
FIG. 4 is a schematic view showing an outline of an adsorbent regeneration treatment apparatus and a regeneration treatment method in a water treatment agent after treating phosphorus.
FIG. 5 is a schematic diagram showing an outline of a processing apparatus and processing method for an object to be processed containing arsenic.
FIG. 6 is a schematic diagram showing an outline of a processing apparatus and processing method for an object to be processed containing arsenic.
FIG. 7 is a schematic diagram showing an outline of a processing apparatus and processing method for an object to be processed containing heavy metal ions.
FIG. 8 is a schematic view showing an outline of a processing apparatus and processing method for an object to be processed containing heavy metal ions.

Claims (4)

Phosphorus adsorbent for water treatment containing amorphous iron hydroxysulfate as an active ingredient. The water treatment agent which has the phosphorus adsorption agent for water treatment of Claim 1 as a main component . An adsorption step of bringing the water treatment phosphorus adsorbent according to claim 1 and / or the water treatment agent according to claim 2 into contact with the phosphorus-containing waste water;
A coagulation step of adding a coagulant to the phosphorus-containing wastewater containing the water treatment phosphorus adsorbent;
A method for treating water containing phosphorus-containing wastewater . Furthermore, the phosphorus adsorbent for water treatment after use is dissolved together with a strong acid,
The dissolved solution pH React under 3-5 acidic conditions,
The precipitate is precipitated from the obtained reaction solution,
The method for water treatment of phosphorus-containing wastewater according to claim 3, comprising a step of reusing the precipitate as a raw material for the water treatment phosphorus adsorbent according to claim 1 and / or the water treatment agent according to claim 2. .

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