JP2010082497A - Water treating agent and method for treating water - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a water treating agent which can remove a toxic substance easily and efficiently from toxic substance-containing water and can be separated easily from the water where the concentration of the toxic substance is decreased satisfactorily and to provide a method for treating water, in which the toxic substance can be removed efficiently by using a simple apparatus, by a simple operation of the simple apparatus and by a small amount of chemicals and the water treating agent can be separated easily from the water where the concentration of the toxic substance is decreased satisfactorily. <P>SOLUTION: The water treating agent contains (A) at least one of calcium aluminate and a material obtained by heating a hydrate of calcium aluminate and (B) sulfate. The water treating agent is used in the method for treating water. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a water treatment agent and a water treatment method. More specifically, harmful substances can be easily and efficiently removed from water containing harmful substances (for example, industrial wastewater), and water and water treatment agents with sufficiently reduced concentrations of harmful substances can be easily separated. Water treatment agent that can be removed, and simple equipment and operations can remove harmful substances efficiently with a small amount of chemicals, and water and water treatment agents with sufficiently reduced concentrations of harmful substances can be easily obtained. The present invention relates to a water treatment method that can be separated.

  Industrial wastewater generated from various product manufacturing processes, combustion gas smoke cleaning processes, contaminated soil purification processes, selenium, copper, chromium, molybdenum, antimony, lead, arsenic, zinc, cadmium, nickel, manganese, It may contain heavy metals such as iron, tin and cobalt, and various harmful substances such as boron. Since these harmful substances may adversely affect animals and plants, it is required by law that the wastewater is discharged into public waters such as rivers, lakes and marshes after removing these harmful substances.

  Among these, boron compounds represented by boric acid and sodium borate are used in various industrial applications such as glass industry, pharmaceuticals, cosmetics, raw materials such as dyes, soap industry, components of alloys and semiconductor materials, and electroplating. The waste water generated from these production processes and the like contains a boron compound. In addition, boron compounds are often contained in wastewater generated from power plants, smoke washing wastewater in garbage incineration plants, landfill disposal site leachate wastewater, and the like. Boron compounds may also be contained in the wastewater of the inn business that runs hot springs. Thus, the boron compound is contained in various wastewaters. On the other hand, boron compounds are essential trace elements for animals and plants. However, excessive intake may cause plant growth inhibition, animal reproductive inhibition toxicity, and nerve / digestive system disorders. Therefore, a part of the Enforcement Order for Water Pollution Control Law was revised in 2001, and the drainage standard for boron and its compounds in public water areas such as rivers and lakes was set to 10 mg / L or less.

  In general, as a method for removing boron from water containing boron (hazardous substance), an aggregation precipitation method, an ion adsorption method, a solvent extraction method, an evaporation concentration method, a reverse osmosis membrane method, and the like are known. However, the coagulation-precipitation method has a problem that it is necessary to use a large amount of chemicals in order to sufficiently remove boron, resulting in an increase in the amount of chemicals used and an increase in the amount of sludge generated. There is also a problem that the removal rate decreases when chloride ions coexist in the waste water. The ion adsorption method is inefficient because it imposes a load on the resin used to treat wastewater containing a relatively high concentration of boron, and there is a problem that not only the cost of the resin itself but also the cost of regeneration treatment is high. is there. In the solvent extraction method, since the organic solvent as an extractant is dissolved in the treated water from which boron has been removed, it is necessary to remove the organic solvent, and there is a problem in that the cost is increased due to the loss of chemicals. The evaporation and concentration method requires a heat source for evaporation, enormous energy is required to crystallize the boron compound, and the reverse osmosis membrane method has a low boron removal rate and has a problem of membrane clogging.

  In order to solve these problems, a method of treating boron-containing water by combining an aggregation precipitation method using an aluminum compound and a calcium compound and an ion adsorption method using an anion exchange resin has been proposed (Patent Document 1). 2). However, even in this method, it is necessary to add a large amount of chemicals, the amount of generated sludge is large, and the treatment is difficult. Also, a method of treating boron-containing water by combining the evaporation concentration method and the coagulation precipitation method (Patent Document 3), or a method of treating the boron-containing water by combining the evaporation concentration method, the aggregation precipitation method and the ion adsorption method (Patent Document 3). 4) has also been proposed. However, even with these methods, there is a problem that a large amount of heat is required for evaporation, the apparatus becomes large-scale, the processing steps become complicated, and the cost increases. In addition, a harmful substance immobilization material that removes fluorine in waste liquid and phosphate ions in sludge has been proposed (Patent Document 5). unknown. Also, boron-containing water is treated by adding a wastewater treatment method (Patent Document 6) that adjusts pH by adding aluminum salt, sparingly soluble calcium salt, and slaked lime to boron-containing wastewater, and a combination of alkaline earth metal and aluminum salt. However, there is a problem that a sufficient boron removing power cannot be obtained by a combination of calcium aluminate hydrate produced in water and a hardly soluble calcium salt (Patent Document 7).

  Therefore, an excellent water treatment agent that can easily and efficiently remove harmful substances from harmful substance-containing water and that can easily separate water and water treatment agents having sufficiently reduced boron concentration. Development is still desired.

JP-A-57-81881 JP-A-57-180493 JP 7-323292 A Japanese Patent Laid-Open No. 10-314798 JP 2000-93927 A JP 2004-283731 A JP 2005-262186 A

  An object of the present invention is to solve the conventional problems and achieve the following objects. That is, the present invention provides a water treatment that can easily and efficiently remove harmful substances from water containing harmful substances and that can easily separate water and a water treatment agent having a sufficiently reduced concentration of harmful substances. Water that can efficiently remove harmful substances with a small amount of chemicals and can sufficiently separate the water treatment agent from water whose concentration of harmful substances has been sufficiently reduced by a simple agent and operation. An object is to provide a processing method.

  As a result of intensive studies to achieve the above object, the present inventors have (A) calcium aluminate and at least one of substances obtained by heat-treating calcium aluminate hydrate, B) A water treatment agent containing sulfate was found to have excellent harmful substance removal power and excellent cohesiveness (sedimentability) after removal of harmful substances, thereby completing the present invention. The present invention also provides a water treatment method using the above water treatment agent.

The present invention is based on the above findings by the present inventors, and means for solving the above problems are as follows. That is,
<1> A water treatment agent characterized by containing (A) calcium aluminate and at least one of substances obtained by heat-treating calcium aluminate hydrate and (B) sulfate. is there.
<2> (B) The water treatment agent according to <1>, wherein the sulfate is calcium sulfate.
<3> The water treatment agent according to any one of <1> to <2>, further comprising (C) a carbonate.
<4> A water treatment method using the water treatment agent according to any one of <1> to <3>.
<5> The method for treating toxic substance-containing water according to <4>, wherein the water treatment agent according to any one of <1> to <3> is dispersed in water and then used for treating toxic substance-containing water. It is.
<6> After treating harmful substance-containing water using the water treatment agent according to any one of <1> to <3>, (D) a polymer flocculant is added to the liquid after the treatment, The water treatment method according to any one of <4> to <5>, wherein the treated liquid is solid-liquid separated into the water treatment agent and water from which harmful substances have been removed.

  According to the present invention, the conventional problems can be solved, the object can be achieved, harmful substances can be easily and efficiently removed from harmful substance-containing water, and the concentration of harmful substances is sufficient. The water treatment agent that can easily separate the water and the water treatment agent, and simple equipment and operation, can remove harmful substances efficiently with a small amount of chemicals, and the concentration of harmful substances It is possible to provide a water treatment method capable of easily separating sufficiently lowered water and a water treatment agent.

(Water treatment agent)
The water treatment agent of the present invention comprises (A) calcium aluminate and at least one of substances obtained by heat-treating calcium aluminate hydrate, and (B) sulfate. (C) further contains a carbonate, and further contains other components as required.
In addition, “(A) Calcium aluminate and at least one of substances obtained by heat-treating calcium aluminate hydrate”, “(B) sulfate”, “(C) carbonate” "May be referred to simply as" (A) component "," (B) component ", and" (C) component ", respectively, in this specification.

<(A) component>
The component (A) is a material obtained by heat-treating calcium aluminate and calcium aluminate hydrate (in this specification, simply referred to as “heat-treated product of calcium aluminate hydrate”). Or at least one of them).

-Calcium aluminate-
The calcium aluminate is a general term for compounds mainly composed of CaO and Al ₂ O ₃ , and is not particularly limited and can be appropriately selected depending on the purpose. For example, CaAl ₂ O ₄ , CaAl ₄ O ₇ , CaAl ₁₂ O ₁₉ , Ca ₃ Al ₂ O ₆ , Ca ₁₂ Al ₁₄ O ₃₃ , Ca ₅ Al ₆ O ₁₄ , Ca ₉ Al ₁₀ O ₂₄ , Ca ₂ Al ₂ O _5, and mixtures thereof. Among these, as the calcium aluminate, Ca ₁₂ Al ₁₄ O ₃₃ , Ca ₃ Al ₂ O _6, and mixtures thereof are preferable in that the ability to remove harmful substances can be improved. The said calcium aluminate can be used individually by 1 type or in combination of 2 or more types as appropriate.
The calcium aluminate may contain impurities, but the type and content thereof are not particularly limited as long as they do not impair the effects of the present invention. Specific examples include, for example, calcium aluminum sulphonate _{hydrate, Fe 2 O 3, SiO 2} , MgO, TiO 2, P 2 O 5, Cl , and the like. The calcium aluminate may be a crystalline compound, a non-crystalline compound, a synthetic product, or a product naturally produced. Also good. The particle diameter is not particularly limited, and is preferably 0.1 μm or more from the viewpoint of handling.

Here, as hydrates of calcium aluminate, for example, Ca ₂ Al ₂ O ₅ .6H ₂ O, Ca ₃ Al ₂ O ₆ .6H ₂ O, Ca ₄ Al ₂ O ₇ .13H ₂ O, and the like are known. However, even if these hydrates are used as the calcium aluminate, sufficient harmful substance removing power cannot be obtained in the present invention. For example, even if water treatment is performed using sodium aluminate and calcium hydroxide or calcium hydroxide or aluminum hydroxide to produce calcium aluminate hydrate in water, sufficient removal of harmful substances can be obtained. I can't. Therefore, in the present invention, it is necessary to use calcium aluminate that is not in a hydrated state.

--Synthesis of calcium aluminate--
The calcium aluminate can be obtained, for example, by synthesis, and the synthesis is not particularly limited and can be performed by a known method. For example, a calcium aluminate hydrate is synthesized by mixing a calcium compound and an aluminum compound in water and then synthesized by firing at a high temperature (preferably a temperature of 60 ° C. or higher, more preferably a temperature of 100 ° C. or higher). It can also be synthesized by mixing an aluminum compound and a calcium compound and baking at a high temperature of 1,000 ° C. or higher, preferably 1,300 ° C. or higher (solid phase method). Although there is no restriction | limiting in particular in the upper limit of the heating time of a solid-phase synthesis method, 24 hours or less are preferable. Since hard crystals are produced when fired for a long time, the firing time is more preferably within 10 hours, and particularly preferably within 5 hours.
There is no restriction | limiting in particular also as an apparatus used for the said baking process, For example, it can carry out using a well-known hot air dryer, an electric furnace, a thermostat, a fluidized bed dryer, a vacuum dryer, a spray dryer, a rotary kiln etc. The calcium compound at this time is not particularly limited as long as it contains calcium, and examples thereof include calcium hydroxide, calcium nitrate, calcium oxide, calcium carbonate, calcium chloride, and hydrates thereof. Can be used singly or in appropriate combination of two or more. The aluminum compound is not particularly limited as long as it contains aluminum. For example, aluminum nitrate, aluminum hydroxide, aluminum oxide, aluminum chloride, polyaluminum chloride (PAC), aluminum carbonate, sodium aluminate, potassium aluminate, etc. And hydrates of these, and the like can be used singly or in appropriate combination of two or more. Further, these raw materials can be used not only as pure products but also as containing impurities such as aluminum sludge.

  In the reaction for synthesizing calcium aluminate hydrate in water as described above, the pH is preferably 9 or more. When pH adjustment is necessary, a general pH adjuster can be used. The pH adjuster is not particularly limited, and examples thereof include acids such as carbon dioxide, hydrochloric acid and nitric acid, sodium hydroxide, potassium hydroxide, calcium hydroxide, aluminum hydroxide, sodium carbonate, potassium carbonate, sodium bicarbonate, Alkaline agents such as potassium carbonate and ammonia can be used singly or in appropriate combination of two or more. In the synthesis reaction of the calcium aluminate hydrate, stirring may or may not be performed after pH adjustment. Stirring may be performed at room temperature or while heating. Moreover, after stirring, it may or may not be aged.

-Heat treatment of calcium aluminate hydrate-
The heat-treated product of the calcium aluminate hydrate can be obtained by further heat-treating the calcium aluminate hydrate. The heat treatment of calcium aluminate hydrate is preferably performed at a temperature of 60 ° C. or higher, more preferably 100 ° C. or higher for 10 minutes or more, and more preferably 30 minutes or more. Although there is no restriction | limiting in particular as an upper limit of the said heating temperature, 1,600 degrees C or less is preferable. The upper limit of the heating time is not particularly limited, but is preferably within 24 hours.
The heat treatment may be performed under an atmospheric pressure environment or may be performed while reducing the pressure. Moreover, after drying the synthesized calcium aluminate hydrate, the heat treatment may be performed, or the heat treatment may be performed without drying. There is no restriction | limiting in particular as an apparatus used for the said heat processing, For example, it can carry out using a well-known hot air dryer, an electric furnace, a thermostat, a fluidized bed dryer, a vacuum dryer, a spray dryer, a rotary kiln etc.

There is no restriction | limiting in particular as the usage-amount of at least any one of the said calcium aluminate and the heat processing thing of a calcium aluminate hydrate, Although it can select suitably according to the objective, For example, it is a process target. It is preferably used in an amount of 0.01 to 10% by mass, more preferably 0.05 to 3% by mass relative to the amount of harmful substance-containing water. When the amount used is within the preferable range, it is advantageous in that the ability to remove harmful substances can be further improved.
In addition, the calcium aluminate and the heat-treated product of the calcium aluminate hydrate may be used alone as the component (A), or both may be used in combination as the component (A). May be used as There is no restriction | limiting in particular as usage-amount ratio of the said calcium aluminate and the heat-processing thing of the said calcium aluminate hydrate when using both together, According to the objective, it can select suitably.

<(B) component>
The component (B) is a sulfate.
There is no restriction | limiting in particular as said sulfate, According to the objective, it can select suitably, For example, sodium sulfate, potassium sulfate, lithium sulfate, silver sulfate, calcium sulfate, ferrous sulfate, ferric sulfate, sulfuric acid Examples include nickel, cobalt sulfate, magnesium sulfate, barium sulfate, copper sulfate, manganese sulfate, aluminum sulfate, sodium aluminum sulfate, and potassium aluminum sulfate. Further, the sulfate may be a hydrate thereof.
Among these, as the sulfate, calcium sulfate, sodium sulfate, and aluminum sulfate are preferable, and among them, calcium sulfate is particularly preferable in that the ability to remove harmful substances can be further improved. The said sulfate can be used individually by 1 type or in combination of 2 or more types.

  The sulfate may be used as it is, or may be used in a state dissolved or dispersed in water. In addition, the sulfate can be produced, for example, by mixing sulfuric acid and a corresponding hydroxide in water (for example, calcium sulfate can be produced with sulfuric acid and calcium hydroxide, and sulfuric acid and water can be produced. Sodium oxide can produce sodium sulfate), but it may also be used in the form of an aqueous solution containing this produced sulfate.

  There is no restriction | limiting in particular as the usage-amount of the said sulfate, Although it can select suitably according to the objective, For example, it may be 0.01-10 mass% with respect to the harmful | toxic substance containing water amount which is a process target. It is preferably used in an amount such that it is 0.05 to 3% by mass. When the amount used is within the preferable range, it is advantageous in that the ability to remove harmful substances can be further improved.

<(A) component / (B) component>
There is no restriction | limiting in particular as usage-amount ratio of the said (A) component in the said water treatment agent, and the said (B) component, Although it can select suitably according to the objective, For example, by mass ratio, (A ) Component: (B) component = 20: 80 to 90:10 are preferably used, more preferably 25:75 to 75:25, and more preferably 30:70 to 70. : It is more preferable to use it so that it may become 30. It is advantageous in that the removal ratio of harmful substances can be further improved when the use amount ratio is within the preferable range.

<(C) component>
The component (C) is a carbonate.
There is no restriction | limiting in particular as said carbonate, According to the objective, it can select suitably, For example, calcium carbonate, potassium carbonate, sodium carbonate, sodium hydrogencarbonate, potassium hydrogencarbonate, sodium potassium carbonate, ammonium carbonate, hydrogencarbonate Examples include ammonium, magnesium carbonate, and hydrates thereof. Among these, as the carbonate, calcium carbonate, potassium carbonate, and sodium carbonate are preferable in that the ability to remove harmful substances can be further improved, and among these, calcium carbonate is particularly preferable. The said carbonate can be used individually by 1 type or in combination of 2 or more types as appropriate.

  There is no restriction | limiting in particular as usage-amount of the said carbonate, Although it can select suitably according to the objective, For example, it will be 0.01-10 mass% with respect to the harmful | toxic substance containing water amount which is a process target. It is preferably used in an amount such that it is 0.05 to 3% by mass. When the amount used is within the preferable range, it is advantageous in that the ability to remove harmful substances can be further improved.

<Other ingredients>
Moreover, the water treatment agent of the present invention may comprise only the component (A) and the component (B) (preferably further composed of the component (C), and further contains other components as appropriate. It may be made.
The other components are not particularly limited and may be appropriately selected depending on the purpose within a range not impairing the effects of the present invention. For example, calcium compounds used as raw materials, pH of acids, alkalis, and the like Examples thereof include regulators. In addition, there is no restriction | limiting in particular as usage-amount of the said other component, According to the objective, it can select suitably.

<Manufacturing, dosage form>
The water treatment agent of the present invention can be produced, for example, by mixing the component (A), the component (B), preferably the component (C), and other components as necessary. . Moreover, the said water treatment agent can be used in any states, such as lump shape, a granular form, and powder form. Granular and powdery water treatment agents can be produced, for example, by pulverization. The pulverization method is not particularly limited and can be performed using a known apparatus. Each of the component (A), the component (B), preferably the component (C), and other components as necessary. May be pulverized before mixing, or may be pulverized after mixing the component (A), the component (B), preferably the component (C), and other components as necessary. Also good.

  In addition, as the water treatment agent, the component (A), the component (B), and preferably a mixture in which the component (C) is further mixed in advance are added to the harmful substance-containing water at one time. For example, the component (A), the component (B), preferably the component (C), and other components as necessary are separately added to the harmful substance-containing water. It may be in the form used.

<Application>
The water treatment agent of the present invention can remove harmful substances from harmful substance-containing water easily and efficiently, and also has excellent cohesiveness (sedimentation) after removal of harmful substances. It is possible to easily separate the water and the water treatment agent that have been reduced to a low level. Therefore, the water treatment agent of the present invention can be suitably used for, for example, the water treatment method of the present invention described later.

(Water treatment method)
The water treatment method of the present invention is performed using the above-described water treatment agent of the present invention.

<Target water>
The water to be treated in the water treatment method of the present invention (treatment target water) is not particularly limited as long as it contains water that contains some harmful substance. For example, the manufacturing process of various products and the washing of combustion gas The industrial wastewater etc. which arise from a smoke process, the purification process of contaminated soil, etc. are mentioned. There are no particular restrictions on the hazardous substances to be treated. For example, heavy metals such as selenium, copper, chromium, molybdenum, antimony, lead, arsenic, zinc, cadmium, nickel, manganese, iron, tin, cobalt, and boron Etc. In particular, the water treatment method of the present invention is suitable for boron-containing water.
The boron-containing water usually contains boron in the form of orthoboric acid (H ₃ BO ₄ ), but may contain borate or other forms of boron. Examples of such boron-containing water include wastewater discharged from various processes and factories. In addition, the water treatment agent of the present invention can be used in the range of pH 2 to 14 of harmful substance-containing water, and is preferably used in the range of pH 2 to 13 and used in the range of pH 3 to 12. More preferably. In addition, the said water treatment agent can be used even if other ions, such as a chloride ion, coexist in harmful substance containing water. Moreover, since the heat-treated product of calcium aluminate or calcium aluminate hydrate contained in the water treatment agent is alkaline, the boron-containing water during the treatment is usually weakly alkaline. When the harmful substance-containing water is a strongly acidic solution, sodium hydroxide or calcium hydroxide can be added to make it weakly alkaline as necessary.

<Water treatment method with water treatment agent>
The water treatment method of the present invention is not particularly limited as long as the water treatment agent can come into contact with harmful substance-containing water. For example, after adding a predetermined amount of the water treatment agent to harmful substance-containing water to remove the harmful substance, the water treatment agent is separated by solid-liquid separation (addition method) or the water treatment agent is filled. Examples thereof include a method (packing method) for removing harmful substances by passing water containing harmful substances through the packed tower. In either method, it is possible to efficiently remove harmful substances.

-Treatment conditions for the addition method-
There is no restriction | limiting in particular in the addition amount of the water treatment agent in an addition method, According to the hazardous | toxic substance density | concentration of hazardous | toxic substance containing water, it determines suitably. Moreover, there is no restriction | limiting in particular also in the addition method of the water treatment agent in an addition method, For example, the method of adding to flow paths, such as piping of a wastewater treatment facility, and a water tank. Moreover, there is no restriction | limiting in particular also in the processing time in an addition method, For example, it is 10 minutes or more, Preferably it can be 30 minutes or more. Further, it may or may not be stirred during the treatment. When stirring, the apparatus and operation are not particularly limited, and conventionally known apparatus and operation can be used.

--Pre-treatment process--
In the addition method, it is preferable that the water treatment agent is dispersed in water in advance (pretreatment step) and then used for treatment of harmful substance-containing water. By using the water treatment agent in a state of being dispersed in water in advance, it is possible to efficiently remove harmful substances even when the water containing harmful substances is treated under low stirring force conditions. It is advantageous. There is no restriction | limiting in particular as a method to disperse | distribute the said water treatment agent in water, According to the objective, it can select suitably, For example, it can carry out using a conventionally well-known stirring apparatus. Moreover, there is no restriction | limiting in particular as the usage-amount of the water at the time of disperse | distributing the said water treatment agent, For example, it is preferable to use the quantity of water from which a water treatment agent will be 0.1 to 20%.

--- Post treatment process-
In addition, since the water treatment agent of the present invention is excellent in cohesiveness (sedimentation property), it can be easily solid-liquid separated into water from which the water treatment agent and harmful substances have been removed without adding a coagulant. If it is necessary to immediately move to the next step after the treatment of harmful substance-containing water, for example, as described above, the water treatment agent is dispersed in water in advance and then used for treatment of harmful substance-containing water. In such a case (when the pretreatment step is performed), the coagulability (sedimentability) of the water treatment agent is slightly lowered. Therefore, in such a case, after the harmful substance removal treatment, a polymer flocculant (sometimes referred to as “component (D)” in this specification) is added to the treated liquid (afterwards). Treatment step), the water treatment agent and the water from which harmful substances have been removed are preferably subjected to solid-liquid separation. The polymer flocculant is not particularly limited and can be appropriately selected depending on the purpose. For example, an anionic polymer flocculant, a nonionic polymer flocculant, a cationic polymer flocculant, an amphoteric polymer flocculant Examples thereof include a molecular flocculant. Among these, as the polymer flocculant, anionic polymer flocculants, nonionic polymer flocculants, and amphoteric polymer flocculants are preferable. There is no restriction | limiting in particular as the usage-amount of the said polymer flocculent, Although it can select suitably according to the objective, For example, 0.0001-1 mass% with respect to the harmful | toxic substance containing water amount made into the process target Is preferably used in such an amount that it is 0.005 to 0.5% by mass. It is advantageous in that the use amount is within the preferable range in that the coagulability of the water treatment agent can be further increased.

  Further, the solid-liquid separation can be carried out by using a normal apparatus by means such as decantation, filtration, and centrifugation. By performing the solid-liquid separation, it is possible to easily recover the water treatment agent after the harmful substance-containing water removal treatment, and the recovered water treatment agent is, for example, a harmful substance again after performing an appropriate treatment. It can be used as a water treatment agent for contained water. Specifically, the heat treatment product obtained by subjecting the water-insoluble substance (water treatment agent) recovered after the removal process of the harmful substance-containing water to the water is treated again with the water treatment agent containing the harmful substance-containing water. Can be used. This heat-treated product can be suitably reused as a water treatment agent for water containing harmful substances until the saturated harmful substance adsorption amount is reached.

-Processing conditions for filling method-
The amount of the water treatment agent packed into the packed tower in the packing method is not particularly limited, and is appropriately determined according to the size of the packed tower, the water flow rate of harmful substance-containing water, and the like.
The packed tower in the packing method is not particularly limited, and known ones can be used, and the number thereof is also not particularly limited. For example, only one packed tower can be used, or a plurality of packed towers can be used. Can be connected in series.
The inflow of the water treatment agent into the packed bed in the filling method may be an upward flow or a downward flow, and the space velocity (SV) is not particularly limited, but is, for example, ^{1 to} 120 hr ⁻¹ , preferably 5 to 50 hr ^−1. It can be.

<Application>
According to the water treatment method of the present invention, with a simple apparatus and operation, harmful substances can be efficiently removed with a small amount of chemical (amount of water treatment agent), and the concentration of harmful substances is sufficiently reduced. The water treatment agent can be easily separated. Therefore, the water treatment method of the present invention can be suitably used for removing harmful substances (particularly, boron removal) in various industrial wastewaters, for example.

EXAMPLES Hereinafter, although an Example and a comparative example are given and this invention is demonstrated in detail, this invention is not limited to these Examples at all. In the following Examples and Comparative Examples, “A-1” to “A-5”, “B-1” to “B-6”, “C-1”, “C-2”, “D-” 1 ”to“ D-5 ”,“ E-1 ”,“ E-2 ”,“ F-1 ”,“ F-2 ”((E) component and (F) component are compared with component (A)) The details of each component of (component), “G-1”, “G-4” are as shown in Table 1.
The components “G-1” to “G-4” are “A-1”, “A-2”, “A-3”, “A-5”, “E-1”, “E”. -2 "for synthesis of each component.

  In Table 1, each component of “A-1”, “A-2”, “A-3”, “A-5”, “E-1”, “E-2” shown as a synthetic product. Was synthesized by the following synthesis method.

<Synthesis Method of A-1 and E-2>
In 1 L of water, 41.2 g of aluminum hydroxide (G-1) and 58.8 g of calcium hydroxide (G-2) were mixed, stirred at 100 ° C. for 12 hours, and aged for 24 hours to be reacted. After completion of the reaction, the precipitate was filtered and dried at room temperature to obtain 81.7 g of an insoluble solid (E-2). This solid E-2 was calcined at 500 ° C. for 3 hours to obtain 59.5 g of a solid (A-1). Each product was analyzed by wide-angle X-ray diffractometry, solid A-1 is _Ca 12 _Al 14 _{O 33,} solid E-2 was identified as _{Ca 3 Al 2 O 6 · 6H} 2 O.

<Synthesis Method of A-2>
4.1 g of aluminum hydroxide (G-1) and 5.9 g of calcium hydroxide (G-2) are mixed, put in a crucible, and 1, using a baking furnace (manufactured by Motoyama Co., Ltd., SUPER BURN). Heating at 400 ° C. for 7 hours gave 7.0 g of a hard crystalline solid. This solid was pulverized in a mortar to obtain 7.0 g of solid (A-2). This solid A-2 was measured by wide-angle X-ray diffraction measurement and confirmed to be Ca ₃ Al ₂ O ₆ .

<Synthesis Method of A-3>
4.1 g of aluminum hydroxide (G-1) and 5.9 g of calcium hydroxide (G-2) are mixed, put in a crucible, and 1, using a baking furnace (manufactured by Motoyama Co., Ltd., SUPER BURN). Heating at 400 ° C. for 2 hours gave a soft solid. This solid was pulverized in a mortar to obtain 7.0 g of a solid (A-3). This solid A-3 was measured by wide-angle X-ray diffraction measurement and confirmed to be Ca ₃ Al ₂ O ₆ .

<Method for synthesizing A-5 and E-1>
Mix 14.1 g of aluminum nitrate nonahydrate (G-3) and 26.6 g of calcium nitrate tetrahydrate (G-4) in 1 L of water, and adjust the pH to 12 with sodium hydroxide. Then, the mixture was stirred at room temperature for 1 hour to be reacted. After completion of the reaction, the precipitate was filtered and dried at room temperature to obtain 10.9 g of an insoluble solid (E-1). This solid was measured by wide-angle X-ray diffraction measurement, and confirmed to be Ca ₂ Al ₂ O _5. 6H ₂ O. Moreover, this solid E-1 was baked at 500 degreeC for 3 hours, and solid (A-5) was obtained.

  In the following Examples and Comparative Examples, (1) Evaluation method of boron removal power, (2) Evaluation method of cohesiveness (precipitation), (3) Evaluation of harmful substance removal power, (4) Addition of polymer Evaluation methods for cohesiveness (precipitation) by (5) and (5) solid-liquid separation are as follows.

(1) Evaluation method of boron removing power (Examples 1 to 35, Comparative Examples 1 to 15)
About the obtained water treatment agent of Examples 1-35 and Comparative Examples 1-15, boron removal power is calculated by calculating the boron removal rate when the boron-containing water is treated under the conditions shown in Tables 2 to 5 below. evaluated. Specifically, 50.0 g of boron-containing water and a predetermined amount of water treatment agent (boron removal agent) were added to a 75 mL commercial mayonnaise bottle, and the mixture was stirred vigorously for 5 hours or more and then allowed to stand for 10 minutes. The treatment liquid was filtered and diluted with pure water as necessary, and then the boron concentration was measured using an ICP emission analyzer (manufactured by PerkinElmer Japan, optima 5300 DV). The boron removal rate was calculated by the following formula (1). The boron removal rate closer to 100% indicates higher boron removal power. In the present invention, 60% or more was regarded as a pass level for the boron removal rate. The results are shown in Tables 2-5.
[formula]
Boron removal rate (%) = (1−C ₁ / C ₀ ) × 100 (1)
C ₁ : Boron concentration after treatment (mg / L)
C ₀ : Initial boron concentration before treatment (mg / L)

(2) Evaluation of cohesiveness (precipitation) of water treatment agent (Examples 1 to 35, Comparative Examples 1 to 15)
Moreover, about the water treatment agent of Examples 1-35 and Comparative Examples 1-15, the cohesiveness (precipitation property) after boron removal was evaluated as follows. To a 75 mL commercial mayonnaise bottle, 50.0 g of boron-containing water and a predetermined amount of water treatment agent were added and stirred vigorously for 5 hours or more, and then allowed to stand. After 10 minutes, the height of the gas-liquid interface and the height of the solid-liquid interface were measured, and the aggregation rate (sedimentation rate) was calculated by the following formula (2) (see FIG. 1). In addition, although the aggregation rate is closer to 100%, the aggregation property is better. However, when the aggregation rate is 100%, the water treatment agent is dissolved in boron-containing water, and the aggregation property is excellent. This is not an indicator of this (Comparative Examples 7, 8, and 10). In the present invention, 50% or more (and less than 100%) is regarded as the acceptable level of the aggregation rate. The results are shown in Tables 2-5.
[formula]
Aggregation rate (%) = (1−b / a) × 100 (2)
a: Height of gas-liquid interface (mm)
b: Height of solid-liquid interface (mm)

In the table, “addition concentration” indicates the concentration (mass%) of each component with respect to the boron-containing water to be treated.

In the table, “addition concentration” indicates the concentration (mass%) of each component with respect to the boron-containing water to be treated.

In the table, “addition concentration” indicates the concentration (mass%) of each component with respect to the boron-containing water to be treated.

In the table, “addition concentration” indicates the concentration (mass%) of each component with respect to the boron-containing water to be treated.

(3) Evaluation of removal ability of harmful substances (nickel, zinc, iron, copper, lead, manganese) (Examples 24-35)
About the water treatment agent of obtained Examples 24-35, on the conditions shown in the following Table 6, water containing harmful substances (nickel, zinc, iron, copper, lead, manganese) other than boron and boron (treatment target water) Boron and harmful substance removal ability was evaluated by calculating boron removal rate and harmful substance removal rate when treated. Specifically, boron and harmful substance-containing water (treatment target water) 50.0 g and a predetermined amount of water treatment agent were added to a 75 mL commercially available mayonnaise bottle, and after vigorous stirring for a predetermined time, I put it. After the treatment liquid is filtered and diluted with pure water as necessary, an ICP emission analyzer (manufactured by PerkinElmer Japan, optima5300DV) or an ion electrode (manufactured by Thermoelectron, Orion 370) is used. Boron and toxic substance concentrations were measured. The harmful substance concentration was measured using the ICP emission spectrometer. The boron removal rate was calculated by the above formula (1), and the harmful substance removal rate was calculated by the following formula (3). The harmful substance removal rate closer to 100% indicates higher harmful substance removal power. In the present invention, 50% or more is regarded as an acceptable level of the harmful substance removal rate. The results are shown in Table 6.
[formula]
Hazardous substance removal rate (%) = (1−C ′ ₁ / C ′ ₀ ) × 100 (3)
C ′ ₁ : Concentration of harmful substances after treatment (mg / L)
C ′ ₀ : Initial harmful substance concentration before treatment (mg / L)

In the table, “addition concentration” indicates the concentration (% by mass) of each component with respect to boron to be treated and water containing harmful substances other than boron (nickel, zinc, iron, copper, lead, manganese).

(4) Evaluation of cohesiveness (precipitation) by addition of polymer (Examples 36 to 47)
The beaker containing the treatment liquid after the boron treatment was set in a jar tester (Miyamoto Seisakusho, MJS-2). While stirring at 120 rpm, a polymer flocculant (component (D))-containing aqueous solution was added as necessary, stirred at 120 rpm for 5 minutes, and then stirred at 30 rpm for 2 minutes. After standing for 3 minutes, the supernatant solution was sampled, and turbidity was measured using a water analyzer 2000N from Nippon Denshoku Industries Co., Ltd. In addition, it shows that the cohesiveness (settability) of a water treatment agent is so high that the value of turbidity is small, and it is preferable that the value of turbidity is 30 or less.

(5) Evaluation method of solid-liquid separation (Examples 36 to 47)
A filter paper having a diameter of 240 mm (Toyo Roshi Kaisha, No. 5B) is set in a funnel, and a treatment liquid after boron treatment (or a treatment liquid after boron treatment and polymer flocculant treatment) is poured and filtered. went. The filtrate weight after 10 minutes was measured. In addition, it shows that solid-liquid separation was performed favorably, so that the value of filtrate weight is large, and it is preferable that filtrate weight is 150 g or more.

[Examples 36 to 38: Examples when processing was performed without a pretreatment step]
(Example 36)
In a 500 mL beaker, 350 g of boron solution water with a boron concentration of 30 mg / L (pH ₆ ), 0.70 g of A-3 (Ca ₃ Al ₂ O ₆ ) and 0.70 g of B-1 (calcium sulfate dihydrate) Add a stirring blade (60 mm x 19 x 4 t, stirring rod (diameter 8 mm)) to 1.5 cm from the bottom of the beaker, and stir at 400 rpm for 5 hours using a three-one motor (Fine, FBL1200). Boron treatment was performed. As a result of evaluating the boron removing power of the treatment liquid after the boron treatment, the boron removal rate was 97.1%, and it was found that boron can be removed efficiently.
A 500 mL beaker containing a treatment solution after boron treatment was set in a jar tester, 7.0 g of 0.1% polymer (D-1) aqueous solution was added while stirring at 120 rpm, stirred at 120 rpm for 5 minutes, and then 30 rpm. For 2 minutes. After standing for 3 minutes, the supernatant solution was sampled and the turbidity was measured, and the rest was used for the filtrate weight measurement. As a result of evaluating the solid-liquid separability, the turbidity was 5 dos, the filtrate weight was 305 g, and the solid-liquid separability was good.

(Example 37)
The same as Example 36 except that the amount of B-1 (calcium sulfate dihydrate) added was changed from 0.70 g to 0.55 g and 0.15 g of C-1 (calcium carbonate) was added. Then, boron treatment was performed. As a result of evaluating the boron removing power of the treatment liquid after the boron treatment, the boron removal rate was 99.5%, and it was found that boron can be efficiently removed.
Moreover, as a result of evaluating the solid-liquid separability of the treatment liquid after the boron treatment by the same method as in Example 36, the turbidity was 5 dos, the filtrate weight was 300 g, and the solid-liquid separability was good. .

(Example 38)
The initial boron concentration was set to 100 mg / L (pH 6), and A-1 (Ca ₁₂ Al ₁₄ O ₃₃ ) 1.75 g was used instead of A-3 (Ca ₃ Al ₂ O ₆ ) 0.70 g. The boron treatment was performed in the same manner as in Example 36 except that the amount of B-1 (calcium sulfate dihydrate) added was changed from 0.70 g to 1.75 g. As a result of evaluating the boron removing power of the treatment liquid after the boron treatment, the boron removal rate was 92.1%, and it was found that boron can be efficiently removed.
In addition, the evaluation of the solid-liquid separability of the treatment solution after the boron treatment was the same as in Example 36 except that the addition amount of the 0.1% polymer (D-1) aqueous solution was changed to 17.5 g. As a result of evaluation by the method, the turbidity was 8 dos, the filtrate weight was 295 g, and the solid-liquid separation was good.

[Example 39: Example in which treatment was performed at a low stirring speed without a pretreatment step]
(Example 39)
Except that the stirring speed was changed to 400 rpm and 150 rpm, the boron treatment was performed in the same manner as in Example 38. As a result, the boron removal rate was 72.2%, and it was found that boron could be removed efficiently.
In addition, as a result of evaluating the solid-liquid separability of the treatment liquid after the boron treatment by the same method as in Example 38, the turbidity was 7 dos, the filtrate weight was 302 g, and the solid-liquid separability was also good. .

[Example 40: Example in which a pretreatment step is performed and treatment is performed at a low stirring speed]
(Example 40)
To a 500 mL beaker, add 175 g of water, 1.75 g of A-1 (Ca ₁₂ Al ₁₄ O ₃₃ ) and 1.75 g of B-1 (calcium sulfate dihydrate), and add 1.5 cm from the bottom of the beaker. Using a three-one motor with the stirring blade set, stirring was performed at 400 rpm for 20 hours to prepare a dispersion of a water treatment agent (pretreatment step).
The stirring speed of the three-one motor of the dispersion was set to 150 rpm, and 175 g of a 200 mg / L aqueous boron solution (pH 6) was added thereto (initial boron concentration: 100 mg / L), and the mixture was stirred at 150 rpm for 5 hours to perform boron treatment. went.
As a result of evaluating the boron removal power of the treatment liquid after the boron treatment, the boron removal rate is 91.9%, and by performing the pretreatment process, boron can be efficiently removed even under a low stirring force. I understood.
Moreover, as a result of evaluating the solid-liquid separability of the treatment liquid after the boron treatment by the same method as in Example 38, the turbidity was 9 dos and the filtrate weight was 295 g, and the solid-liquid separability was good. .

[Example 41: Example in which the pretreatment step was performed and the treatment was performed without stirring]
A pretreatment step was performed in the same manner as in Example 40 to prepare a dispersion of a water treatment agent.
Next, the stirring speed was changed to 150 rpm, and 175 g of a 200 mg / L aqueous boron solution (pH 6) was added thereto (initial boron concentration: 100 mg / L), stirred for 1 minute, and then allowed to stand for 5 hours for boron treatment. It was.
As a result of evaluating the boron removal power of the treatment liquid after the boron treatment, the boron removal rate is 80.5%. By performing the pretreatment process, boron can be efficiently removed even under conditions where stirring power cannot be applied. I knew it was possible.
Moreover, as a result of evaluating the solid-liquid separability of the treatment liquid after the boron treatment by the same method as in Example 38, the turbidity was 8 dos, the filtrate weight was 288 g, and the solid-liquid separability was good. .

[Examples 42 to 47: Examples in which pre-processing and post-processing steps are performed]
Instead of 1.75 g of A-1 (Ca ₁₂ Al ₁₄ O ₃₃ ), 0.44 g of A-3 (Ca ₃ Al ₂ O ₆ ) was used, and B-1 (calcium sulfate dihydrate) A pretreatment step was carried out in the same manner as in Example 40 except that the amount of addition of 1.75 g was changed to 0.44 g to prepare a dispersion of a water treatment agent.
Boron treatment was performed by adding 175 g of 40 mg / L boron aqueous solution (pH 9) (initial boron concentration 20 mg / L) and stirring at 400 rpm for 3 hours.
A 500 mL beaker containing a treatment solution after boron treatment was set in a jar tester (Miyamoto Seisakusho, MJS-2). While stirring at 120 rpm, the component (D) (polymer flocculant) shown in Table 7 was added (excluding Example 42), stirred at 120 rpm for 5 minutes, and then stirred at 30 rpm for 2 minutes to treat the polymer flocculant. (Post-processing step).
As described above, (1) boron removal power, (2) cohesiveness (sedimentation), and (3) solid-liquid separation were each evaluated. Table 7 shows the results.

In the table, “addition concentration” indicates the concentration (mass%) of each component with respect to the boron-containing water to be treated.

  As a result of Table 7, boron treatment is performed by performing not only a pretreatment step (step of dispersing a water treatment agent in water in advance) but also a post treatment step (step of adding a polymer flocculant after boron treatment). It has been shown that the coagulability of the subsequent water treatment agent can be increased, and the solid-liquid separation between the water treatment agent and the treated water can be efficiently performed. Among them, (D) as the polymer flocculant, D-1 and D-2 which are anionic polymer flocculants, D-3 which is a nonionic polymer flocculant, and D-4 which is an amphoteric polymer flocculant In particular, it was shown that the coagulability of the water treatment agent after the boron treatment can be enhanced, and the solid-liquid separation between the water treatment agent and the water after the treatment can be performed efficiently.

[Comparative Example 15 (when calcium sulfate is added in a system in which calcium aluminate hydrate is produced in water)]
In a 75 mL commercial mayonnaise bottle, 50.0 g of boron-containing water (boron concentration 105 mg / L, pH 9), 0.5 mass% of sodium aluminate (F-1) and 0.5 mass of calcium hydroxide (G-2) %, Calcium sulfate dihydrate (B-1) 0.5 mass% was added and stirred for 5 hours to carry out boron treatment. The boron removal rate was 20.1%, and the boron concentration was slightly reduced, but the effect was low.
In this system, it is considered that calcium aluminate hydrate was produced in water. However, the calcium aluminate hydrate and the added calcium sulfate have low boron removal power, and the calcium aluminate in the present invention, and The boron removal rate is inferior to those of Examples 1 to 23 using at least one of substances obtained by heat treating calcium aluminate hydrate.
Further, the aggregation rate at this time was 72%.

  The water treatment agent and water treatment method of the present invention are very useful for removing harmful substances in various industrial wastewaters, for example, for the purpose of satisfying wastewater standards for harmful substances (for example, boron).

FIG. 1 is a view showing a method for evaluating the cohesiveness (sedimentability) of a water treatment agent (a: height of gas-liquid interface (mm), b: height of solid-liquid interface (mm)). .

Claims (6)

  A water treatment agent comprising (A) at least one of calcium aluminate and a substance obtained by heat-treating calcium aluminate hydrate, and (B) a sulfate.   (B) The water treatment agent according to claim 1, wherein the sulfate is calcium sulfate.   Furthermore, the water treatment agent in any one of Claim 1 to 2 containing (C) carbonate.   A water treatment method using the water treatment agent according to claim 1.   The water treatment method according to claim 4, wherein the water treatment agent according to any one of claims 1 to 3 is dispersed in water and then used for treating harmful substance-containing water.   After treating the harmful substance-containing water using the water treatment agent according to any one of claims 1 to 3, (D) a polymer flocculant is added to the treated liquid, and the treated liquid is added to the treated liquid. The water treatment method according to any one of claims 4 to 5, wherein solid-liquid separation is performed between the water treatment agent and water from which harmful substances have been removed.