JP2013173117A - Magnetic particle for water treatment, and water treatment method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a magnetic particle for water treatment, capable of adsorbing, separating and repeatedly recycling a removal target substance in water.SOLUTION: A particle adsorbs a water-insoluble material and deposit in a treated water, is filtered from the water-insoluble material and deposit in the filtered object, and is recovered and used repeatedly, wherein the particle has a magnetic carrier comprising a magnetic single particle with a specific gravity of ≥1 or the aggregate thereof, and an adsorption part supported to the magnetic carrier and having a functional group for receiving a proton (H) in the treated water.

Description

  Embodiment described here is related with the water treatment method using the magnetic substance particle for water treatment used for purification | cleaning, such as a factory waste water and domestic waste water.

  Recently, the effective use of water resources has been required due to industrial development and population growth. In order to effectively use water resources, it is important to purify and reuse various wastewaters such as industrial wastewater and domestic wastewater. In order to purify the waste water, it is necessary to separate and remove water insoluble matters and impurities contained in the water. Examples of methods for purifying wastewater include membrane separation methods, centrifugal separation methods, activated carbon adsorption methods, ozone treatment methods, and suspended matter precipitation removal methods by adding flocculants. By using these water treatment methods, chemical substances having a great influence on the environment such as phosphorus and nitrogen contained in the wastewater can be removed, and oils and clays dispersed in water can be removed.

  Among these water treatment methods, the pressure flotation method and the coagulation sedimentation method are widely used to remove water-insoluble substances in the waste water. For example, Patent Document 1 describes an example of a pressure levitation method.

JP 2006-218381 A

  In the pressure flotation method described in Patent Document 1, agglomerated polymer is added to the waste water, the water insoluble substance (solid content) in the waste water is coarsened by the agglomerated polymer, and the water insoluble substance (solids) is injected by blowing compressed air. Min) is floated on the surface of the water as a floc, and the floated floc is separated and removed from the water.

  In the coagulation sedimentation method, the water-insoluble substance (solid content) in the wastewater is also coarsened by the coagulation polymer, and the sedimentation rate of the water-insoluble substance (solid content) is increased, and the water-insoluble substance (solid content) is precipitated. As a technique for separating and removing from water.

  However, in both the pressure flotation method and the coagulation sedimentation method, it is necessary to add a large amount of the coagulation polymer to the waste water, so that there is a problem that the cost of using the drug increases the running cost. Further, in these conventional techniques, there is a problem that the amount of waste is increased because the agglomerated polymer is recovered as sludge.

  The present invention has been made in view of the above problems, and employs magnetic particles for water treatment that can adsorb substances to be removed in water, separate adsorbates, collect them, and reuse them repeatedly. A water treatment method is provided.

The magnetic particles for water treatment according to the embodiments described herein adsorb water-insoluble substances and precipitates in water to be treated, and are filtered together with the water-insoluble substances and precipitates. Particles separated from precipitates, collected and repeatedly used, having a specific gravity greater than 1 magnetic single particles or aggregates thereof, supported on the magnetic support, and protons (H ^And an adsorption part having a functional group for receiving ( ⁺ ).

(A)-(c) is a schematic diagram which shows the reaction mechanism between a silane coupling agent and an inorganic surface. (A)-(c) is a schematic diagram which respectively shows the salt obtained by neutralizing the ferrite particle modified with each class amine with hydrochloric acid. The block diagram which shows the apparatus used for the water treatment method of 1st Embodiment. Process drawing which shows the water treatment method of 1st Embodiment using the apparatus of FIG. (A) is a cross-sectional schematic diagram which shows the aggregate which the magnetic particle aggregated, (b) is a cross-sectional schematic diagram which shows the magnetic particle coat | covered with the coating | covering material. The block diagram which shows the apparatus used for the water treatment method of 2nd Embodiment. Process drawing which shows the water treatment method of 2nd Embodiment using the apparatus of FIG.

  Various embodiments will be described below.

(1) The magnetic particle for water treatment according to the embodiment described herein adsorbs a water-insoluble substance in water to be treated, settles together with the water-insoluble substance, and is separated from the water-insoluble substance in the precipitate. A magnetic particle for water treatment which is recovered and repeatedly used, and comprises a magnetic core part composed of magnetic single particles having a specific gravity greater than 1 or an aggregate thereof, and is carried on the magnetic core part, and protons in the water to be treated And a surface layer portion including a functional group that receives (H ⁺ ).

As a method of supporting the functional group (proton donor) that releases protons (H ⁺ ) in water on the surface of the magnetic core (inorganic particles), the functional group is directly modified on the particle surface using a silane coupling agent. And a method of coating particles with resin.

There are three methods for coating the resin. That is, a first method of coating particles with a resin having a functional group that accepts protons (H ⁺ ) in water, and a resin having a functional group in a side chain that is converted into a functional group that accepts protons (H ⁺ ) when decomposed There are a second method for coating particles on the particle and a third method for coating a resin that can be attached by reacting a functional group that accepts protons (H ⁺ ) on the side chain.

  In the first method, particles such as polyvinylamine, polyallylamine and polyethylene copolymer are coated on the particles. A solution is prepared by dissolving the copolymer in a solvent, and the particles are immersed in the solution, or the solution is sprayed onto the particle surface, or the slurry mixed with the particles is spray-dried. In this first method, if the content of polyvinylamine or polyallylamine is too large, it becomes a water-soluble resin, so the content of polyethylene needs to be increased.

  In the second method, the amide can be converted to an amino group by coating a polyvinyl amide / polyethylene copolymer or the like and performing a deacetylation reaction. Alternatively, a polymer having an amide such as chitin can be coated and deacetylated to obtain chitosan.

  In the third method, for example, after coating a polymer having a hydroxyl group, an amino group can be supported by loading a diisocyanate compound and then decomposing an excess isocyanate group.

In the method of direct modification using a silane coupling agent, a compound containing an alkoxy group and a functional group that accepts protons (H ⁺ ) in water is reacted with the particle surface and supported on the particle. Here, “modification” means attaching a functional group to the surface of the inorganic material. “Attaching a functional group” refers to a state in which the functional group and the inorganic material are at least chemically bonded, and also includes a state in which a physical bond such as adsorption is combined with a chemical bond. Note that the state in which the inorganic material and the functional group are merely physically bonded (adsorbed) without chemically bonding to the inorganic material does not correspond to the modification in principle. However, only when the entire inorganic particles are covered with a polymer material having a specific functional group, the case where they are physically bonded is also included.

  Modification methods include a dry method in which particles are sprayed with a silane coupling agent solution having a functional group while stirring at high speed, and a wet method in which particles are reacted in a solvent containing a silane coupling agent. In both the dry method and the wet method, the reaction is allowed to proceed completely by volatilizing the solvent after the treatment and post-curing.

  In the said embodiment, since the magnetic substance particle for water treatment isolate | separated and collect | recovered can be reused repeatedly, an operating cost can be reduced significantly rather than a conventional product. Moreover, since the specific gravity of the magnetic core part exceeds 1, the magnetic particles for water treatment settle in the stationary water, and can be easily recovered as a precipitate. Further, a magnetic application means such as a permanent magnet or an electromagnet is provided. It is possible to easily separate magnetic particles only by selecting them magnetically from water.

  (2) In said (1), it is preferable that the functional group of a surface layer part is an amino group.

As a functional group (proton acceptor) that receives protons (H ⁺ ) in water, an amino group that easily attaches to the surface of the magnetic core (inorganic particles) (is easily modified) and easily reacts with an acid to form a salt is preferable. . The amino group may be any of an amino group (—NH ₂ ) of a primary amine, an amino group (—NHR) of a secondary amine, and an amino group (—NR ₂ ) of a tertiary amine.

  Silane coupling agents are used to attach amino groups to the surface of the particles. Examples of silane coupling agents include N-2- (aminoethyl) -3-aminopropylmethyldimethoxysilane, N-2- (aminoethyl) -3-aminopropyltrimethoxysilane, 3-aminopropyltrimethoxysilane, 3 -Aminopropyltriethoxysilane, N-phenyl-3-aminopropyltrimethoxysilane, dimethyl [3- (triethoxysilyl) propyl] amine and the like can be used.

  (3) In the above (1), the magnetic core part is preferably a ferrite compound.

Various ferrite compounds can be suitably used as the magnetic core portion. Ferrite compounds such as iron, iron-based alloys, magnetite (magnetite), titanite (ilmenite), pyrrhotite (pilotite), magnesia ferrite, manganese magnesium ferrite, manganese zinc ferrite, cobalt ferrite, nickel ferrite, nickel zinc ferrite, barium Ferrite, copper zinc ferrite, etc. can be used. Of these, it is most preferable to use a ferrite-based compound such as magnetite, magnesia ferrite, or manganese magnesium ferrite having excellent stability in water. In particular, magnetite (Fe ₃ O ₄ ) is not only inexpensive, but also exhibits stable properties as a magnetic substance in water and is composed of only safe and non-toxic elements, making it suitable for use in water treatment. ing.

  Further, the size of the magnetic powder is not particularly limited, but those having an average particle diameter of 0.1 to 100 μm are preferably used. Here, the average particle diameter is measured by a laser diffraction method. Specifically, it can be measured by a SALD-DS21 type measuring device (trade name) manufactured by Shimadzu Corporation. This size is a particle size in which magnetic particles are mixed with water moderately in water and settled relatively quickly when allowed to stand. That is, if the average particle size of the magnetic particles is larger than 100 μm, the sedimentation speed is too fast and may require a large amount of power when dispersed in water. Too late and impractical.

  When the magnetic particles of the embodiment described here are used for water treatment, the magnetic particles are excellent in all of the adsorption performance, separation performance and durability performance. Body particles can be used over and over again. For this reason, there exists an advantage that both an operating cost and a maintenance cost can be suppressed low.

  (4) In said (1), it is preferable that a surface layer part has the salt produced | generated by an inorganic acid and the said functional group reacting.

  After supporting the functional group on the particle surface, if necessary, particles having a functional group can be neutralized with an inorganic acid, and the inorganic acid can be reacted with the functional group to form a salt. By performing this neutralization treatment, a positive charge can be given by retaining protons in the functional group. This positive charge neutralizes the charge around the suspended matter (SS) that exists in a colloidal form in water, and the action of aggregating the magnetic substance and the suspended matter (SS) is obtained. As a method for producing a salt, for example, particles are dispersed in water and an inorganic acid is added little by little, and when the solution reaches a specific pH value, magnetic particles are removed from the water by a method such as membrane filtration or magnetic separation. Separate and collect.

When the functional group is an amino group (—NH ₂ ) of a primary amine, the particle is modified with, for example, 3-aminopropyltriethoxysilane as a silane coupling agent, and neutralized with hydrochloric acid to give 1 as a salt. A hydrochloride of a primary amine is produced (FIG. 2 (a)).

  When the functional group is an amino group (—NHR) of a secondary amine, the particle is modified using, for example, N-2- (aminoethyl) -3-aminopropyltrimethoxysilane as a silane coupling agent, When neutralized with hydrochloric acid, a hydrochloride of a secondary amine is produced as a salt ((b) of FIG. 2).

When the functional group is an amino group (—NR ₂ ) of a tertiary amine, the particles are modified using, for example, dimethyl [3- (triethoxysilyl) propyl] amine as a silane coupling agent, and this is added with hydrochloric acid. When added, a hydrochloride of a tertiary amine is produced as a salt ((c) of FIG. 2).

  (5) In the above (4), the inorganic acid is preferably any one of hydrochloric acid and sulfuric acid, or a mixture thereof.

By carrying out the neutralization treatment, it is possible to retain protons (H ⁺ ) in the amino group and give a positive charge to the particles. This positive charge neutralizes the charge around the suspended matter (SS) that exists in a colloidal form in water, and the action of aggregating the magnetic particles and the suspended matter (SS) is obtained. As a method of generating a salt, for example, particles are dispersed in water and hydrochloric acid is added little by little. When a specific pH is reached, the addition of hydrochloric acid is stopped, and particles are removed from water by a method such as membrane filtration or magnetic separation. Separate and collect.

(6) In the water treatment method according to the embodiment described herein, a water-insoluble substance in water to be treated is adsorbed by water treatment particles, and the water-treated particles are settled and separated together with the adsorbed water-insoluble substance. In the water treatment method in which the water treatment particles are separated, the separated water treatment particles are collected, and the collected water treatment particles are repeatedly used. (A) As the water treatment particles, the specific gravity is greater than 1. Preparing magnetic particles having a magnetic core portion made of a magnetic material and a surface layer portion containing a functional group that receives protons (H ⁺ ) in the water to be treated carried on the magnetic core portion; and (b) the magnetic particle Is dispersed in the water to be treated, and the magnetic particles are allowed to adsorb and trap water-insoluble substances in the water to be treated, and (c) the magnetic particles that have adsorbed and trapped the water-insoluble substances are precipitated in the water to be treated. By the water insoluble substance The adsorbed / trapped magnetic particles are separated into treated water, and (d) the magnetic particles adsorbed / trapped with the water-insoluble substance are dispersed in water to produce particle-dispersed water. Stirring, thereby desorbing the water-insoluble substance adsorbed and trapped from the magnetic particles, and (e) selectively attracting the magnetic particles in water by applying a magnetic field to the particle-dispersed water. Thus, the magnetic particles are magnetically separated from the water-insoluble substance in water. (F) The magnetically separated magnetic particles are adsorbed and trapped in the water to be treated in the step (b). To reuse.

The water treatment method of the said embodiment is a method corresponding to the sedimentation separation method using a precipitator. Magnetic particles having the specific functional group (functional group that receives protons (H ⁺ ) in water) are mixed in the water to be treated to adsorb water-insoluble substances in the water. This suspension is introduced into a sedimentation tank, and the magnetic particles are settled together with a water-insoluble substance and separated. Next, the magnetic particles and the water-insoluble substance are extracted from the lower part of the settling tank and mixed in water to separate the magnetic particles and the water-insoluble substance from the rest. Subsequently, this is sent from the washing tank to the magnetic separation tank, and stirred in the magnetic separation tank until each of the particles becomes a particle state, whereby the magnetic particles and the water-insoluble substance are uniformly dispersed in water. Next, the magnetic particles dispersed in water are adsorbed by a magnetic adsorption means such as a magnet, and the treated water containing the water-insoluble substance is discharged from the magnetic separation tank while the magnetic particles are adsorbed by the magnetic adsorption means. Next, the magnetic adsorption of the magnetic particles is released, the magnetic particles are dropped from the magnetic adsorption means, and treated water or tap water is sprayed on the magnetic adsorption means to wash the magnetic particles adhering to the magnetic adsorption means. ,to recover. The collected magnetic particles are sent from the magnetic separation tank to the water treatment particle supply device and reused.

  In the water treatment method of the above embodiment, since the magnetic particles are excellent in separability and durability, the magnetic particles can be repeatedly used in a cycle of dispersion → adsorption → separation → recovery → dispersion. For this reason, there exists an advantage that an operating cost and a maintenance cost can be restrained low.

(7) In the water treatment method according to the embodiment described herein, the water-insoluble substance in the water to be treated is adsorbed by the water-treatment particles, and the water-treated particles are centrifuged together with the adsorbed water-insoluble substance. In the water treatment method of separating the water treatment particles from the product, collecting the separated water treatment particles, and repeatedly using the collected water treatment particles, (A) the specific gravity of the water treatment particles is 1 Preparing magnetic particles having a magnetic core portion made of a large magnetic material and a surface layer portion containing a functional group for receiving protons (H ⁺ ) in the water to be treated carried on the magnetic core portion; (B) the magnetic material Disperse the particles in the water to be treated, adsorb and trap the water-insoluble substances in the water to be treated on the magnetic particles, and (C) apply a centrifugal force to the water to be treated to adsorb and trap the water-insoluble substances. Soaked magnetic particles in treated water Centrifugation, thereby separating the magnetic particles adsorbed and trapped by the water-insoluble substance and the treated water, and (D) dispersing the magnetic particles adsorbed and trapped by the water-insoluble substance in water to disperse the particles. And stirring the produced particle-dispersed water, thereby desorbing the water-insoluble substance adsorbed and trapped from the magnetic particles, and (E) applying a magnetic field to the particle-dispersed water, Selectively attracting the magnetic particles in water, thereby magnetically separating the magnetic particles from the water-insoluble substance in water; and (F) magnetically separating the magnetic particles in the step (B) Reuse to absorb and capture water-insoluble substances in treated water.

The water treatment method of the said embodiment is a method corresponding to the centrifugation method using a centrifuge. A cyclone can be used as the centrifuge. Magnetic particles having the above specific functional group (functional group that receives protons (H ⁺ ) in water) are dispersed in the water to be treated, and water-insoluble water-insoluble substances are adsorbed on the magnetic particles. The water to be treated which is in the state of adsorbing the water-insoluble substance is passed through a centrifuge, that is, a cyclone, and the magnetic particle / water-insoluble substance mixture is separated at the lower part of the centrifuge. Next, the magnetic particles and the water-insoluble substance are extracted from the lower part of the centrifugal separation layer and mixed in water to separate the magnetic substance particles / water-insoluble substance and the others. Subsequently, this is sent from the washing tank to the magnetic separation tank, and stirred in the magnetic separation tank until each of the particles becomes a particle state, whereby the magnetic particles and the water-insoluble substance are uniformly dispersed in water. Next, the magnetic particles dispersed in water are adsorbed by a magnetic adsorption means such as a magnet, and the treated water containing the water-insoluble substance is discharged from the magnetic separation tank while the magnetic particles are adsorbed by the magnetic adsorption means. Next, the magnetic adsorption of the magnetic particles is released, the magnetic particles are dropped from the magnetic adsorption means, and treated water or tap water is sprayed on the magnetic adsorption means to wash the magnetic particles adhering to the magnetic adsorption means. ,to recover. The collected magnetic particles are sent from the magnetic separation tank to the water treatment particle supply device and reused.

  Also in the water treatment method of the above embodiment, since the magnetic particles are excellent in separability and durability, the water treatment particles can be repeatedly used in a cycle of dispersion → adsorption → separation → recovery → dispersion. For this reason, there exists an advantage that an operating cost and a maintenance cost can be restrained low.

  (8) In any of the above (6) or (7), after reacting the magnetic core part with a silane coupling agent having an alkoxy group and an epoxy group as functional groups, the functional group is reacted with an inorganic acid, It is preferable to generate salt in the surface layer portion covering the magnetic core portion.

  A silane coupling agent is a reactant that contributes to two reactions, a hydrolysis reaction and a condensation reaction. In the hydrolysis reaction, the hydroxyl group M-OH (M is a metal atom) on the ferrite particle surface and the alkoxy group (RO-Si) contained in the silane coupling agent undergo a dealcoholization reaction, or (a) in FIG. As shown in (b), the alkoxy group (RO-Si) contained in the silane coupling agent reacts with water to hydrolyze to produce a silanol group, and the hydroxyl group on the surface of the inorganic particles (core part) It moves to the surface of the inorganic particle through the hydrogen bond. The hydrolysis rate of the silane coupling agent molecule is affected by the surface state of the inorganic particles, that is, the pH of the inorganic particle surface and the amount of adsorbed water. On the other hand, in the condensation reaction, as shown in FIGS. 1A and 1C, the silane coupling agent undergoes a dehydration condensation reaction and generates a strong covalent bond with the inorganic surface. In parallel with this reaction, silanol groups are condensed to produce a siloxane oligomer. These reactions can be accelerated in the presence of heat or catalyst. Further, the reaction can be promoted by discharging water, alcohol and the like by-produced by heating and drying to the outside of the system. Since the organic functional groups of the silane coupling agent molecules are oriented outside the powder particles, it is necessary to select the optimum solvent and blending ratio in consideration of the balance between the hydrophilicity and hydrophobicity of the silane coupling agent solution. .

  (9) In the above (8), the silane coupling agent is N-2- (aminoethyl) -3-aminopropylmethyldimethoxysilane, N-2- (aminoethyl) -3-aminopropyltrimethoxysilane, 3 1 or 2 selected from the group consisting of 2-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, N-phenyl-3-aminopropyltrimethoxysilane and dimethyl [3- (triethoxysilyl) propyl] amine It preferably consists of a mixture of seeds or more.

The basic chemical structure of the silane coupling agent is represented by the general formula _{X 3-n Me n Si-} R-Y. However, Me is a methyl group, R is an ethylene group or a propylene group, X is a hydrolyzable group having affinity / reactivity with an inorganic material, and Y is an organic functional group chemically bonded to the organic material. Such a silane coupling agent includes a hydrolyzable group (X) having an affinity for an inorganic material such as glass or metal in the molecule and an organic functional group (Y) capable of chemically bonding to an organic material such as a synthetic resin. In addition to reacting with ferrite particles that are inorganic materials, it can also react with various functional groups and salts thereof that are organic materials. For this reason, magnetic particles excellent in separability and durability can be formed, and the magnetic particles can be repeatedly reused in a cycle of dispersion → adsorption → separation → recovery → dispersion.

  Hereinafter, various embodiments will be described with reference to the accompanying drawings.

  There are two types of water treatment methods using the water treatment particles of the present embodiment, namely, a sedimentation separation method and a centrifugal separation method, but the apparatus used for each method is different in configuration, so each will be described below.

(Apparatus of the first embodiment)
First, the water treatment apparatus used in the first embodiment will be described with reference to FIG.

  The water treatment apparatus 1 of this embodiment is an apparatus used for a sedimentation separation method using a precipitator as a solid-liquid separation apparatus. The water treatment apparatus 1 includes a mixing tank 2, a precipitation tank 3, a separation tank 4, a water treatment particle supply apparatus 5, a raw water supply source and a drainage storage tank (not shown), and these devices and apparatuses are provided with a plurality of pipes. The lines L1 to L6 are connected to each other. Various pumps P1 and P2, valves V1 and V2, and measuring instruments and sensors (not shown) are attached to the piping lines L1 to L6. Detection signals are input from these measuring instruments and sensors to an input section of a controller (not shown), and control signals are output from the output section of the controller to the pumps P1 and P2 and valves V1 and V2, respectively. It has become so. As described above, the entire water treatment apparatus 1 is comprehensively controlled by a controller (not shown).

  The mixing tank 2 has a stirring screw 21 that stirs the water to be treated, and wastewater that becomes the water to be treated is introduced from a raw water supply source (not shown) via the line L1 to temporarily store the water to be treated. In the meantime, it is mixed with the water treatment particles supplied from the line L8, and fine water-insoluble solid particles contained in the water to be treated are adsorbed on the water treatment particles.

  The sedimentation tank 3 is divided into two upper spaces having different areas by a partition plate 31. Of the upper space of the settling tank, a small area is connected to the mixing tank 2 via a water supply line L2 having a pressure pump P1. Moreover, the treated water discharge line L3 is connected to the area where the area of the upper space is large.

  On the other hand, the lower space of the sedimentation tank 3 is connected to a sediment drawing line having a valve V1. This sediment drawing line is connected to a separation layer 4 described later, and transports the sediment by gravity.

  The separation tank 4 has a stirring screw 41 for stirring the mixture of water treatment particles and solids received from the lower space of the precipitation tank 3 through the precipitation tank drawing line L4, and for solids and water treatment. The magnet 42 for separating into particles is incorporated. The magnet 42 is housed in a cylindrical cylinder, is controlled by a controller (not shown), and is driven up and down by an air cylinder (not shown).

  In addition to the settling tank drawing line L4, a release agent supply line L5 for supplying a release agent from a tank (not shown) is connected to the upper portion of the separation tank 4. On the other hand, a concentrated water discharge line L6 and a water treatment particle return line L7 are connected to the lower part of the magnetic separation tank 4, respectively. The concentrated water discharge line L6 is a pipe for discharging water-insoluble matter concentrated water from the separation tank 4 to a storage tank (not shown). The water treatment particle return line L7 is a pipe having a pump P2 for returning the water treatment particles separated and collected from the separation tank 4 to the water treatment particle supply device 5.

  The water treatment particle supply device 5 is replenished with water treatment particles from a water treatment particle supply source (not shown), and the water treatment particles separated in the separation tank 4 are returned to the above-mentioned water treatment particle return line. Returned through L7. In addition, the water treatment particle supply device 5 supplies an appropriate amount of water treatment particles to the mixing tank 2 via a water treatment particle supply line L8 having a valve V2.

(Method of the first embodiment)
Next, the water treatment method according to the first embodiment using the above apparatus will be described with reference to FIG.

  The sedimentation separation method of FIG. 4 is particularly effective when the flow rate of waste water containing a solid content of water-insoluble matter is large. The water-insoluble solid content in the present embodiment is not particularly limited to organic substances and inorganic substances, but negatively charged particles can be suitably removed. Even if it is difficult to dehydrate particles such as heavy metal hydroxides or contains other difficult to dehydrate components such as oil, it can be easily adsorbed and separated by the structure of the water treatment particles. it can. In this case, it is preferable to appropriately select the coating material for the water treatment particles according to the properties of the wastewater as the water to be treated.

In the sedimentation separation method, first, the water to be treated and the functional powder for water treatment are mixed in the mixing tank 2 to adsorb the solid content of water-insoluble matter in the water treatment particles (step S1). The water treatment particles have magnetic single particles or aggregates thereof in the core portion, and have a surface layer portion containing amino groups (functional groups that receive protons) supported on the core portion on the surface. The concentration of the water treatment particles in the for-treatment water is adjusted by the solid concentration in the for-treatment water. Next, this suspension is supplied to the sedimentation tank 3, and the water treatment particles adsorbing the solid content in the water are settled and separated. (Process S2)
Moreover, the partition plate 31 is attached in the precipitation tank 3 so that the space above the precipitation tank is divided into two regions. At this time, the treated water supply line L2 having the pressurizing pump P1 is connected to the smaller area side, and the treated water discharge line L3 is connected to the larger area side. With such a structure, first, the water treatment particles and solids supplied from the to-be-treated water supply line L <b> 2 move to the lower part of the settling tank 3. At this time, the water flows upward from the larger area toward the treated water discharge line L3. However, since the area becomes larger, the flow rate becomes slower and sedimentation of solids is promoted. Can be collected.

  Further, a sediment drawing line L4 having a valve V1 is connected to the lower part of the sedimentation tank, and water treatment particles and solids are sent from the lower part of the sedimentation tank to the separation tank 4 through the line L4. The water treatment particles and the solid are stirred with the stirring screw 41 to disperse the water treatment particles and the solid content (step S3). If the stirring is sufficiently performed, the water treatment particles and the solid content are more uniformly dispersed in the suspension, and the water treatment particles can be easily separated. At this time, a release agent may be added from the line L5 as necessary. Examples of the release agent include acidic solutions and alkaline solutions that change the surface potential of the water treatment particles, and surfactants that reduce the surface tension of the surface of the water treatment particles.

  Next, water-treatment particles are recovered from the separated suspension using a magnetic separation method (step S4). As a method of magnetic separation, there are a method of collecting a permanent magnet or an electromagnet in a container of the separation tank 4 and a method of collecting particles by collecting them with a metal net magnetized by a magnet and releasing a magnetic field. Can be mentioned. Specifically, the magnet 42 contained in a cylinder is put into a separation tank by an air cylinder (not shown), and after water treatment particles are adsorbed and fixed in the suspension by the magnet 42, the magnet 42 is separated. The waste liquid containing the solid content is discharged from the container of the tank 4 to the storage tank (not shown) via the line L6, and then the magnet 42 is taken out of the separation tank 4 using an air cylinder, and the cylindrical container in which the magnet 42 is contained. The magnetic material for water treatment is dropped from the water, tap water is supplied into the container via a tap water supply line (not shown), tap water is added to the dropped water treatment particles to form a slurry or suspension, and this slurry Or suspension-like water treatment particles are sent from the separation tank 4 to the water treatment particle supply device 5 via a line L7 having a pump P2.

  Thereafter, the recovered water treatment particles are supplied from the water treatment particle supply device 5 to the mixing tank 3 via the line L8, and the recovered water treatment particles are reused for adsorption of the solid content. In this way, the water treatment particles can be repeatedly used in a cycle of solids adsorption → sedimentation separation → water treatment particles and solids separation → magnetic separation → recovery → solids adsorption.

(Magnetic particles)
Next, the magnetic particles will be described in detail.

The particles used in the present embodiment may be any particles that settle in water. However, magnetic particles are preferable because magnetic separation can be used during recovery, thereby widening the range of processes. The magnetic particles are desirably a substance exhibiting ferromagnetism in the room temperature region. However, it is not limited to these, and ferromagnetic materials can be generally used. For example, iron and alloys containing iron, magnetite, titanite, pyrrhotite, magnesia ferrite, cobalt ferrite, nickel ferrite, And barium ferrite. Of these, ferrite compounds having excellent stability in water can achieve the present invention more effectively. For example, magnetite (Fe ₃ O ₄ ), which is a magnetite, is preferable because it is not only inexpensive, but also stable as a magnetic substance in water and safe as an element, so that it can be easily used for water treatment. The magnetic powder can take various shapes such as a spherical shape, a polyhedron, and an indeterminate shape, but is not particularly limited. What is necessary is just to select suitably the particle size and shape of a magnetic support | carrier desired in use in view of manufacturing cost.

  The magnetic particles for water treatment may be single particles containing a magnetic material, and the surface of the magnetic core portion 11 is covered with a surface layer portion 12 such as a polymer as shown in FIG. May be. Further, the magnetic particles may be an aggregate 13 in which the particles of the magnetic core portion 11 coated with the polymer are aggregated as shown in FIG.

  As the magnetic particles 10 for water treatment, those having a magnetic core portion 11 made of magnetic particles and having an average particle diameter D1 in the range of 0.1 to 100 μm are used. The magnetic particles 10 for water treatment preferably have an average particle diameter D1 in the range of 0.1 to 100 μm, and more preferably in the range of 10 to 50 μm. This is because if the average particle diameter D1 of the water treatment particles 10 is larger than 100 μm, the dispersibility in water is poor and the ability to adsorb solids in water may be reduced. On the other hand, if the average particle diameter D1 of the magnetic particles for water treatment 10 is less than 0.1 μm, the sedimentation speed is lowered, and there is a possibility that the sedimentation apparatus cannot be separated. The magnetic core part 11 may be a single particle (primary particle) or an aggregate (secondary particle) obtained by aggregating a plurality of primary particles. The core portion 11 may be subjected to a coating process such as Cu plating or Ni plating if necessary.

  Here, the average particle diameter is calculated based on the result measured by the laser diffraction method. Specifically, a SALD-DS21 type measuring device (trade name) manufactured by Shimadzu Corporation can be used as an apparatus using a laser diffraction method. When the average particle size is 0.1 to 100 μm, the magnetic particles mix well with water in water, and settle down relatively quickly when left standing. That is, if the average particle size of the magnetic powder exceeds 100 μm, the sedimentation rate of the particles becomes too fast, and thus a large power is required for the stirrer when dispersing the magnetic powder in water. In particular, when the average particle size is 50 μm or less, the dispersibility of the particles in water becomes very good, and the load on the stirrer is greatly reduced. On the other hand, if the average particle size of the magnetic powder is smaller than 0.1 μm, the sedimentation rate of the particles when allowed to stand is too slow to be practical. Furthermore, practically, when the average particle diameter is 10 μm or more, the particles quickly settle in water, so that a short time treatment is possible. However, when the magnetic powder is magnetically adsorbed using a magnetic adsorption means such as an electromagnet, the particle size restriction is moderate.

  As a method for producing water treatment particles comprising an aggregate, a method of applying an amorphous material containing a specific functional group after first forming the aggregate with a granulator or the like, and using this amorphous material as a primary binder There is a method of granulating particles. In the former, primary particles and organic binder or inorganic binder are kneaded with a spray dryer or Henschel mixer, etc., and after forming a granulated material, an amorphous material containing a specific functional group is applied to 100 ° C to 200 ° C. And a method of applying an amorphous material containing a specific functional group after producing a porous core part by sintering the magnetic material in a porous form by spray drying or the like. The latter is directly granulated with a Henschel mixer, a spray dryer or the like using an amorphous material containing a specific functional group in the binder.

  Incorporation of these irregular materials containing specific functional groups into water treatment particles increases the specific gravity of the water treatment particles, so that sedimentation by gravity and separation by centrifugal force using a cyclone can be performed magnetically. Therefore, the water treatment particles can be quickly separated from the water.

(Functional group and modification method)
In this embodiment, an amino group is carried on the surface of the magnetic core part (inorganic particles) as a functional group.

As a method of supporting amino groups on the surface of inorganic particles, there are a method of coating a resin or a method of directly modifying particles using a silane coupling agent. As a method of coating the resin, a first method of coating particles with a resin having a functional group that receives protons (H ⁺ ) in water, and a functional group that is converted into a functional group that receives protons (H ⁺ ) when decomposed are provided. There are a second method of coating particles with a resin having a side chain, and a third method of coating a resin that can be attached by reacting a functional group that receives protons (H ⁺ ) to the side chain. In the first method, particles such as polyvinylamine, polyallylamine and polyethylene copolymer are coated on the particles. A solution is prepared by dissolving the copolymer in a solvent, and the particles are immersed in the solution, or the solution is sprayed onto the particle surface, or the slurry mixed with the particles is spray-dried. In this first method, if the content of polyvinylamine or polyallylamine is too large, it becomes a water-soluble resin, so the content of polyethylene needs to be increased. In the second method, the amide can be converted to an amino group by coating a polyvinyl amide / polyethylene copolymer or the like and performing a deacetylation reaction. Alternatively, a polymer having an amide such as chitin can be coated and deacetylated to obtain chitosan. In the third method, for example, after coating a polymer having a hydroxyl group, an amino group can be supported by loading a diisocyanate compound and then decomposing an excess isocyanate group.

On the other hand, in the method of direct modification using a silane coupling agent, a compound containing an alkoxy group and a functional group that accepts protons (H ⁺ ) in water is reacted with the particle surface and supported on the particle. Modification methods include a dry method in which particles are sprayed with a silane coupling agent solution having a functional group while stirring at high speed, and a wet method in which particles are reacted in a solvent containing a silane coupling agent. In both the dry method and the wet method, the reaction is allowed to proceed completely by volatilizing the solvent after the treatment and post-curing. It is also possible to carry a functional group by reacting an alkoxy group and a compound having an epoxy group after reacting epoxy silane.

As the functional group that receives protons (H ⁺ ) in water, an amino group that easily attaches to the surface of the magnetic core (inorganic particles) (is easy to modify) and easily reacts with an acid to form a salt is preferable. The amino group may be any of an amino group (—NH ₂ ) of a primary amine, an amino group (—NHR) of a secondary amine, and an amino group (—NR ₂ ) of a tertiary amine ((( a), (b), (c)).

  Moreover, these particles are used in the form of a salt with an inorganic acid, if necessary. By performing this treatment, a positive charge can be given by retaining protons in the amino group. This positive charge neutralizes the charge around the suspended matter (SS) that exists in a colloidal form in water, and the action of aggregating the magnetic substance and the suspended matter (SS) is obtained. As a method of generating a salt with an inorganic acid, for example, particles are dispersed in water and an inorganic acid is added little by little, and when it reaches a specific pH value, it is removed from the water by a method such as membrane filtration or magnetic separation. Is obtained.

(Device of Second Embodiment)
Next, a water treatment device 1A used in the water treatment method of the second embodiment will be described with reference to FIG. In addition, description of the part which this embodiment overlaps with said embodiment is abbreviate | omitted.

  The water treatment apparatus 1A of the present embodiment is used for a centrifugal separation method and is particularly effective when the flow rate is small or the installation area of the apparatus is small. The difference between the apparatus 1A of the present embodiment and the apparatus 1 of the first embodiment is that a cyclone 6 is provided instead of the settling tank 3 in the apparatus 1A. In this cyclone, the fluid flows down in a conical cylinder with a wide upper part and a narrow lower part, so that the solid content is separated along the wall surface by centrifugal force and discharged to the pot 61 at the lower part of the cyclone. is there. The pot 61 is connected to the upper portion of the separation tank 4 by a line L4 having a valve V1, and the fluid is transferred by gravity. Moreover, the water from which the solid content has disappeared is discharged as treated water through a line L7 connected to the upper part of the cyclone.

(Method of Second Embodiment)
Next, a centrifugation method as a second water treatment method using the above apparatus will be described with reference to FIGS. Since the mixing tank 2, the separation tank 4, and the water treatment particle supply device 6 are the same as those in the first embodiment, description thereof is omitted.

  Separation process K2 of this embodiment is performed by cyclone 6 instead of a sedimentation tank. The water introduced into the cyclone 6 from the line L2 swirls at high speed along the circumference of the cyclone, and the solids and water treatment particles are separated from the water by the centrifugal force at this time, and the separated solids / particles are separated. Is accumulated in the pot 61 at the bottom of the cyclone. The water treatment particles and solids stored in the pot 61 at the lower part of the cyclone are sent to the separation tank 4 through the line L4 by opening the valve V1. The opening and closing of the valve V1 may be performed periodically or may be performed at any time according to the amount of slurry in the pot 61.

  In the separation tank 4, the water treatment particles and the solid are stirred by the stirring screw 41 to disperse the water treatment particles and the solid content (step K3). If the stirring is sufficiently performed, the water treatment particles and the solid content are more uniformly dispersed in the suspension, and the water treatment particles can be easily separated. At this time, a release agent may be added from the line L5 as necessary. Examples of the release agent include acidic solutions and alkaline solutions that change the surface potential of the water treatment particles, and surfactants that reduce the surface tension of the surface of the water treatment particles.

  Next, the water treatment particles are recovered from the separated suspension using a magnetic separation method (step K4). As a method of magnetic separation, there are a method of collecting a permanent magnet or an electromagnet in a container of the separation tank 4 and a method of collecting particles by collecting them with a metal net magnetized by a magnet and releasing a magnetic field. Can be mentioned. Specifically, the magnet 42 contained in a cylinder is put into a separation tank by an air cylinder (not shown), and after water treatment particles are adsorbed and fixed in the suspension by the magnet 42, the magnet 42 is separated. The waste liquid containing the solid content is discharged from the container of the tank 4 to the storage tank (not shown) via the line L6, and then the magnet 42 is taken out of the separation tank 4 using an air cylinder, and the cylindrical container in which the magnet 42 is contained. The magnetic material for water treatment is dropped from the water, tap water is supplied into the container via a tap water supply line (not shown), tap water is added to the dropped water treatment particles to form a slurry or suspension, and this slurry Or suspension-like water treatment particles are sent from the separation tank 4 to the water treatment particle supply device 5 via a line L7 having a pump P2.

  Thereafter, the recovered water treatment particles are supplied from the water treatment particle supply device 5 to the mixing tank 3 via the line L8, and the recovered water treatment particles are reused for adsorption of the solid content. In this way, the water treatment particles can be repeatedly used in a cycle of solids adsorption → sedimentation separation → water treatment particles and solids separation → magnetic separation → recovery → solids adsorption.

  According to said embodiment, collection | recovery and reuse of the particle for water treatment are easy, and it can remove fine solid substance in water efficiently, without throwing in a chemical | medical agent.

  According to the above embodiment, by introducing the magnetic particles into water, not only the object to be removed can be adsorbed and quickly separated by sedimentation and / or magnetism, but also separated from the adsorbed object to be removed. Since it can be reused again, magnetic particles capable of reducing the amount of waste can be provided.

  Various examples and comparative examples will be described below.

(Manufacture of magnetic particles)
Various sample particles shown in Table 1 were prepared as follows. These particles are used as filter aids for water treatment, and were evaluated through experiments under various conditions.

(Particle B-1)
Manganese magnesium ferrite particles were produced as follows and used for the magnetic core portion of the magnetic particles for water treatment.

Manganese oxide (MnO) powder, magnesium oxide (MgO) powder and iron oxide (Fe ₂ O ₃ ) powder are mixed in a molar ratio of 40:10:50, and the mixture is granulated by adding polyvinyl alcohol as a binder. did. The granulated product was temporarily fired at a temperature of 1000 ° C. In addition, temporary baking is an arbitrary process that can be omitted. The preliminarily fired granulated product was pulverized again, polyvinyl alcohol was added as a binder to the pulverized product, and re-granulated, and the re-granulated product was finally fired at a temperature of 1200 ° C. The calcined granulated product was pulverized and the pulverized product was classified to obtain desired manganese magnesium ferrite particles ((MnO · Fe ₂ O ₃ ), (MgO · Fe ₂ O ₃ )). The obtained manganese magnesium ferrite is a mixture of (MnO · Fe ₂ O ₃ ) and (MgO · Fe ₂ O ₃ ), and its composition is 80% by mass of MnO · Fe ₂ O ₃ , MgO · Fe. ₂ O ₃ was 20% by mass.

  While stirring manganese magnesium ferrite powder having an average particle size of 20 μm at high speed, a silane coupling agent (3-aminopropyltriethoxysilane) diluted with ethanol was added dropwise. After adjusting so that it might become a 1 mass% silane coupling agent with respect to a ferrite, it took out from the stirrer and dried at 120 degreeC for 2 hours, and obtained the magnetic body particle B-1.

(Particle B-2)
Particle B-1 was dispersed in pure water so as to be 20% by mass, and hydrochloric acid was added dropwise. When the pH reached 5, dropping was stopped and recovered with a filtration membrane to obtain magnetic particles B-2.

(Particle C-1)
A silane coupling agent diluted with ethanol (N-2- (aminoethyl) -3-aminopropyltrimethoxysilane) was added dropwise while stirring manganese magnesium ferrite powder having an average particle size of 20 μm at high speed. After adjusting so that it might become a 1 mass% silane coupling agent with respect to a ferrite, it took out from the stirrer and heat-dried on the conditions of 120 degreeC x 2 hours, and obtained the magnetic body particle C-1.

(Particle C-2)
Particle C-1 was dispersed in pure water so as to be 20% by mass, and hydrochloric acid was added dropwise. When pH 5 was reached, dropping was stopped and recovered with a filtration membrane to obtain magnetic particles C-2.

(Particle D-1)
Particle D-1 was produced in the same manner as Particle B-1 except that the modification was performed using a wet method.

(Particle E-1)
Unmodified manganese magnesium ferrite powder having an average particle diameter of 20 μm was used as sample particle E-1 of the comparative example.

[Evaluation of water treatment particles]
A water treatment evaluation test was performed using the above various sample particles, and the performance of the particles was evaluated. The evaluation results are shown in Table 2. In Table 2, the transparency of the treated water is measured with a turbidimeter using a formazine standard solution. The lower value (turbidity of 30 FTU or more and less than 100 FTU) was set as a triangle, and the lowest value (turbidity of 100 FTU or more) was set as X (failed). As One Portable Turbidimeter HI 93703C was used as a turbidimeter. Industrial wastewater containing surfactant, fine suspended solids (SS) and sand was used as the treated water.

Example 1
A test solution was prepared by dispersing 200 ppm bentonite slurry and 800 ppm lubricating oil in pure water. When 10000 ppm of particles B-1 were added to the simulated waste water and the mixture was stirred and mixed for 3 minutes and allowed to stand, the abrasive in the water was adsorbed and settled together to obtain treated water with high transparency.

(Examples 2 to 6)
A test was conducted in the same manner as in Example 1 except that the type of particles was changed. As a result, treated water having high transparency was obtained as in Example 1. The results are shown in Table 2.

(Example 7)
To factory wastewater containing surfactant, fine SS and sand, add 10000 ppm of particles A-1 and stir and mix for 3 minutes. However, treated water with slightly high transparency was obtained. The transparency of the treated water of Example 7 was inferior to that of Example 1 described above.

(Example 8)
A test was conducted in the same manner as in Example 7 except that the particle type was changed to A-2. As a result, treated water having a high transparency was obtained as in Example 1, but the transparency was higher than in Examples 1 and 7. Was inferior.

(Examples 9 to 12)
A test was conducted in the same manner as in Example 7 except that the type of particles was changed to A-2. As a result, treated water having high transparency was obtained as in Example 7. The results are shown in Table 1.

(Comparative Example 1)
A test was conducted in the same manner as in Example 7 except that the type of particles was changed to unmodified ferrite. As a result, turbid water was obtained without settling with suspended solids (SS).

From the results shown in Table 2, good suspended solids (SS) adsorption and sedimentation performance were shown for all of the six particles for the abrasive simulated waste water. For domestic wastewater, the salted particles B-2 and C-2 show very good results, and the unsalted particles B-1, C-1 and D-1 also have suspended solids. (SS) Adsorption and sedimentation performance could be confirmed.

1, 1A ... water treatment device, 2 ... mixing tank,
3 ... settling tank, 31 ... partition plate,
4 ... separation tank, 5 ... particle supply device for water treatment,
DESCRIPTION OF SYMBOLS 10 ... Magnetic substance particle (primary particle) for water treatment, 11 ... Magnetic core part (carrier | carrier), 12 ... Surface layer part,
13 ... secondary aggregate (aggregate of primary particles),
P1-P2 ... pump, V1-V2 ... valve,
L1 ... Raw water supply line, L2 ... Treatment water supply line, L3 ... Treatment water discharge line, L4 ... Solid matter discharge line, L5 ... Release agent supply line, L6 ... Drainage line, L7 ... Water treatment particle return line, L8 ... Particle supply line for water treatment.

Claims (9)

Water treatment magnetic particles for adsorbing a water-insoluble substance in water to be treated, sedimenting together with the water-insoluble substance, separated from the water-insoluble substance in the precipitate, recovered and used repeatedly,
A magnetic core part consisting of magnetic single particles having a specific gravity greater than 1 or an aggregate thereof;
A surface layer portion containing a functional group supported on the magnetic core portion and receiving protons (H ⁺ ) in the water to be treated;
A magnetic substance particle for water treatment, comprising:   2. The magnetic particle for water treatment according to claim 1, wherein the functional group of the surface layer portion is an amino group.   The magnetic particle for water treatment according to claim 1, wherein the magnetic core part is a ferrite compound.   2. The magnetic particle for water treatment according to claim 1, wherein the surface layer portion includes a salt generated by a reaction between an inorganic acid and the functional group.   The magnetic particle for water treatment according to claim 4, wherein the inorganic acid is either hydrochloric acid or sulfuric acid. Water-insoluble substances in the water to be treated are adsorbed by the water-treatment particles, and the water-treatment particles are settled and separated together with the adsorbed water-insoluble substances, and the water-treatment particles are separated from the precipitate. In the water treatment method of collecting and repeatedly using the collected water treatment particles,
(A) As the water treatment particles, a magnetic core portion made of a magnetic material having a specific gravity greater than 1, and a surface layer portion containing a functional group that receives protons (H ⁺ ) in the water to be treated carried on the magnetic core portion. Preparing magnetic particles having,
(B) The magnetic particles are dispersed in the water to be treated, and the magnetic particles are caused to adsorb and trap water-insoluble substances in the water to be treated.
(C) The magnetic particles that have adsorbed and trapped the water-insoluble substance are settled in treated water, thereby separating the magnetic particles that have adsorbed and trapped the water-insoluble substance into treated water,
(D) Dispersing the magnetic particles adsorbed and trapped in the water-insoluble substance in water to prepare particle-dispersed water, stirring the prepared particle-dispersed water, and the water-insoluble substance adsorbed and trapped thereby Is desorbed from the magnetic particles,
(E) applying a magnetic field to the particle-dispersed water to selectively attract the magnetic particles in water, thereby magnetically separating the magnetic particles from the water-insoluble substance in water;
(F) A water treatment method, wherein the magnetically separated magnetic particles are reused for adsorption / capture of water-insoluble substances in the water to be treated in the step (b). Water-insoluble substances in the water to be treated are adsorbed by the water-treatment particles, the water-treatment particles are centrifuged together with the adsorbed water-insoluble substances, the water-treatment particles are separated from the centrifuged product, and the water-treatment particles are separated. In the water treatment method in which the collected water treatment particles are repeatedly used,
(A) As the water treatment particles, a magnetic core portion made of a magnetic material having a specific gravity greater than 1, and a surface layer portion containing a functional group that receives protons (H ⁺ ) in the water to be treated carried on the magnetic core portion. Preparing magnetic particles having,
(B) The magnetic particles are dispersed in the water to be treated, and the magnetic particles are adsorbed and trapped with water-insoluble substances in the water to be treated.
(C) Magnetic particles in which a centrifugal force is applied to the water to be treated, and the magnetic particles that have adsorbed and trapped the water-insoluble substance are centrifuged in the water to be treated, thereby adsorbing and capturing the water-insoluble substance. And treated water,
(D) Dispersing the magnetic particles having adsorbed and trapped the water-insoluble substance in water to prepare particle-dispersed water, stirring the prepared particle-dispersed water, and thereby the water-insoluble substance being adsorbed and trapped Is desorbed from the magnetic particles,
(E) applying a magnetic field to the particle-dispersed water to selectively attract the magnetic particles in water, thereby magnetically separating the magnetic particles from the water-insoluble substance in water;
(F) A water treatment method, wherein the magnetically separated magnetic particles are reused for adsorption / capture of water-insoluble substances in the water to be treated in the step (B).   After reacting the magnetic core part with a silane coupling agent having an alkoxy group and an epoxy group as functional groups, the functional group is reacted with an inorganic acid, thereby generating a salt on the surface layer part covering the magnetic core part. The water treatment method according to any one of claims 7 and 8, wherein:   The silane coupling agent is N-2- (aminoethyl) -3-aminopropylmethyldimethoxysilane, N-2- (aminoethyl) -3-aminopropyltrimethoxysilane, 3-amino. One or more selected from the group consisting of propyltrimethoxysilane, 3-aminopropyltriethoxysilane, N-phenyl-3-aminopropyltrimethoxysilane and dimethyl [3- (triethoxysilyl) propyl] amine The water treatment method according to claim 8, wherein the water treatment method comprises:

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