JP2013158736A - Particle for water treatment, and water treatment method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide particles for water treatment that adsorb a substance to be removed in water, has the adsorbed substance separated, and are recovered to be repeatedly used, and a water treatment method utilizing the same.SOLUTION: There are provided particles for water treatment that adsorb a water-insoluble substance in water to be treated, and precipitate together with the water-insoluble substance, and separated from the water-insoluble substance in the precipitate and recovered to be repeatedly used, the particles for water treatment each having a core part consisting of an inorganic substance whose specific gravity is larger than 1 and a surface layer part including polyamine carried by the core part.

Description

  Embodiment described here is related with the particle | grains for water treatment used for purification | cleaning of factory waste water, domestic waste water, etc., and the water treatment method using the same.

  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 coagulation polymer to the waste water, so that the cost of using the drug increases the running cost, resulting in an increase in the total cost. There is a problem. Moreover, in these prior arts, there is a problem that the amount of waste increases because the agglomerated polymer is discharged as sludge as it is.

  The present invention has been made in view of the above problems, and water treatment particles capable of adsorbing substances to be removed in water, separating adsorbates, collecting them, and reusing them repeatedly and water treatment using the same. A method is provided.

  The water treatment particles of the embodiments described herein adsorb water-insoluble substances in the water to be treated, settle together with the water-insoluble substances, are separated from the water-insoluble substances in the precipitate, and are collected and used repeatedly. The water treatment particles have a core portion made of an inorganic material having a specific gravity greater than 1, and a surface layer portion containing polyamine supported on the core portion.

(A)-(c) is a schematic diagram which shows the reaction mechanism between a silane coupling agent and an inorganic surface. The schematic diagram which shows reaction of the inorganic substance surface modified with the silane coupling agent, and polyethylenepolyamine. 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 for solving the above problems will be described below.

  (1) The water treatment particles according to the embodiment described herein adsorb a water-insoluble substance in water to be treated, settle with the water-insoluble substance, and are separated from the water-insoluble substance in the precipitate and collected. Thus, the water treatment particles are repeatedly used, and have a core portion made of an inorganic substance having a specific gravity larger than 1, and a surface layer portion containing a polyamine supported on the core portion.

  As a method for supporting polyamine on the surface of inorganic particles, a resin having an alkoxy group and an epoxy group is coated on the inorganic particles, a compound having an alkoxy group and an epoxy group is reacted with the surface of the inorganic particles in advance, and the compound is then reacted with the inorganic particles. And then the polyamine can be reacted with the epoxy group. Examples of the compound having an alkoxy group and an epoxy group include 2- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, 3-glycidoxypropylmethyldimethoxysilane, 3-glycidoxypropyltrimethoxysilane, and 3-glycol. Sidoxypropylmethyldiethoxysilane, 3-glycidoxypropyltriethoxysilane, etc. are used.

  On the other hand, in the method of directly modifying the surface of the inorganic particles with a silane coupling agent, a compound having an alkoxy group and an epoxy group is reacted with the particle to carry a desired functional group on the surface of 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.

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

  In the said embodiment, since the particle | grains 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 core part exceeds 1, the water treatment particles settle in standing water and can be easily separated and recovered as a precipitate.

  (2) In the above (1), the core part is preferably made of a magnetic material. Since a magnetic material is used for the core portion, it is possible to quickly and reliably magnetically separate water treatment particles and solids (water insoluble substances such as SS) using a magnetic adsorption means such as an electromagnet. The shape of the water treatment particles can take various shapes such as a spherical shape, a polyhedron, and an irregular shape, but is not particularly limited. Desirable particle size and shape of the core portion may be appropriately selected in view of manufacturing cost, and it is particularly preferable that the core portion has a polyhedral structure having a spherical shape or rounded corners. By making the core part a magnetic material, the specific gravity of the water treatment particles is relatively increased, and gravity sedimentation separation in a sedimentation tank and centrifugal separation in a cyclone are facilitated. By using these mechanical separation methods in combination with the magnetic separation method, it becomes possible to quickly and efficiently separate water treatment particles from water. Further, since the core portion is made of a magnetic material, water treatment particles can be separated and collected using a magnetic adsorption means such as an electromagnet, and there is an advantage that the range of process selection is widened.

  Thus, according to the above embodiment, the magnetically separated water treatment particles can be recovered with high efficiency, and the collected water treatment particles can be repeatedly reused.

(3) In the above (2), the magnetic material is preferably a ferrite compound. Various ferrite compounds can be suitably used as the magnetic single particles of the water treatment particles. 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.

  (4) In the above (2), it is preferable that the polyamine of the surface layer portion is selected from the group consisting of polyethylene polyamine and polyallylamine.

  Examples of the polyamine include polyethylene polyamine and polyallylamine. Of these, polyethylene polyamines are preferred because both ends are primary amines and the inside of the molecule is secondary amines, so both ends, which are highly reactive primary amines, easily react with epoxy groups and the molecular length is easily adjusted.

  (5) In said (4), it is preferable that the polyamine of a surface layer part is a polyethylene polyamine whose number of amino groups is 6 or less.

  When the total number of amino groups is 6 or less, entanglement between molecules hardly occurs, the reactivity is good, and the surface modification rate is improved. Examples of such polyethylene polyamines include ethylenediamine, diethylenetriamine, triethylenetetramine, tetraethylenepentamine, and pentaethylenehexamine.

  (6) In the above (2), the surface layer portion has a salt produced by reacting a silane coupling agent having an alkoxy group and an epoxy group with a core portion made of a magnetic material and further reacting with an inorganic acid. It is preferable.

  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.

  In the condensation reaction, as shown in FIGS. 1A and 1C, the silane coupling agent undergoes a dehydration condensation reaction to form 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. .

  (7) In the above (6), it is preferable that the inorganic acid is one of hydrochloric acid and sulfuric acid, or a mixture thereof.

  By carrying out the neutralization treatment, it is possible to retain protons in the amino group and give a positive charge. 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 with an inorganic acid, for example, by dispersing particles in water and adding an inorganic acid little by little, when it reaches a specific pH, it is separated and removed from the water by a method such as filtration or magnetic separation. can get.

  (8) 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 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 particles having a magnetic core portion made of a magnetic material and a surface layer portion containing polyamine supported on the magnetic core portion; (b) mixing the water treatment particles and water to be treated; and the water treatment particles. (C) separating the treated water and the water treatment particles by solid-liquid separation by sedimentation of the adsorbed and captured water treatment particles; and (d) the separated water treatment particles. Mix the particles in water with water treatment particles (E) Magnetically separating the water treatment particles from the mixture; (f) Reusing the separated water treatment particles for adsorption and capture of solids in the step (b). .

  The water treatment method of the said embodiment is a method corresponding to the sedimentation separation method using a precipitator. Water treatment particles having the specific functional group (polyamine such as polyethyleneamine or polyallylamine) are mixed in the water to be treated to adsorb water-insoluble substances and precipitates in the water. This suspension is introduced into a sedimentation tank, and the water treatment particles are settled together with the solids and separated.

  Next, the water treatment particles and the solid content are extracted from the lower part of the settling tank, and mixed in water to separate the water treatment particles 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 them becomes a particle state, whereby the water treatment particles and the solid content are uniformly dispersed in the water.

  Next, the water treatment particles dispersed in water are adsorbed by a magnetic adsorption means such as a magnet, and the treated water containing solids is discharged from the magnetic separation tank while the water treatment particles are adsorbed by the magnetic adsorption means. . Subsequently, the magnetic adsorption of the water treatment particles is released, the water treatment particles are dropped from the magnetic adsorption means, and further treated water or tap water is sprayed on the magnetic adsorption means to adhere to the magnetic adsorption means. Wash and collect. The collected water treatment 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 water treatment 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.

  (9) 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 particles having a magnetic core portion made of a large magnetic material and a surface layer portion containing polyamine supported on the magnetic core portion; (B) mixing the water treatment particles and water to be treated; Solids are adsorbed and captured by the particles, (C) the water treatment particles adsorbed and captured are separated into solid and liquid by centrifugal force to separate the treated water and the water treatment particles, and (D) the separated water For treatment of water by mixing particles for treatment in water And (E) magnetically separating the water treatment particles from the mixture, and (F) reusing the separated water treatment particles to adsorb and capture the solid content in the step (B). Use.

  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. Water treatment particles having the specific functional group (polyamine such as polyethyleneamine or polyallylamine) are dispersed in the water to be treated, and water-insoluble solids are adsorbed to the water treatment particles. The water to be treated in an adsorbed state for a minute is passed through a centrifuge, that is, a cyclone, and a water treatment particle / solid content mixture is separated at the bottom of the centrifuge.

  Next, the water treatment particles and the water-insoluble substances and precipitates are extracted from the lower part of the centrifugal separation layer and mixed in water to separate the water treatment particles from 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 them becomes a particle state, whereby the water treatment particles and the solid content are uniformly dispersed in the water.

  Next, the water treatment particles dispersed in water are adsorbed by a magnetic adsorption means such as a magnet, and the treated water containing solids is discharged from the magnetic separation tank while the water treatment particles are adsorbed by the magnetic adsorption means. . Subsequently, the magnetic adsorption of the water treatment particles is released, the water treatment particles are dropped from the magnetic adsorption means, and further treated water or tap water is sprayed on the magnetic adsorption means to adhere to the magnetic adsorption means. Wash and collect. The collected water treatment 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 water treatment 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.

  (10) In any one of the above (8) or (9), the magnetic substance having a specific functional group is reacted with a silane coupling agent having an alkoxy group and an epoxy group in the magnetic core portion, It is produced by reacting and thereby supporting the polyamine on the magnetic core part.

  In the hydrolysis reaction between the silane coupling agent and the magnetic core, 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. Alternatively, as shown in FIGS. 1 (a) and 1 (b), an alkoxy group (RO-Si) contained in the silane coupling agent is hydrolyzed by reacting with water to produce a silanol group, and inorganic It moves to the surface of the inorganic particle through a hydrogen bond with a hydroxyl group on the surface of the particle (core part). 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. .

  (11) In the above (10), it is preferable to react the polyamine with the magnetic core part and then react with an inorganic acid, thereby generating a salt in the surface layer part covering the magnetic core part.

  First, a silane coupling agent is allowed to act on the surface of the core part to carry a functional group comprising an alkoxy group and an epoxy group on the surface of the inorganic material core part. Next, an inorganic acid (hydrochloric acid or sulfuric acid) is allowed to act on the functional group, and a salt having an alkoxy group and an epoxy group on the surface of the inorganic material core is generated by a reaction between the functional group and the acid. Since the salt produced in this way has a high ability to adsorb water-insoluble solids floating in water, the purification action by adsorption is greatly improved.

  Further, the polyamine is allowed to act on the inorganic surface modified with the silane coupling agent to generate a salt. For example, when polyethylenepolyamine is allowed to act on a modified inorganic surface, a salt is generated by a reaction in which the polyethylenepolyamine binds to a hydroxyl group on the inorganic surface (FIG. 2).

  Since the salt produced in this way has a high ability to adsorb water-insoluble solids floating in water, the purification action by adsorption is greatly improved. Further, by carrying out the neutralization treatment, it is possible to retain a proton in the amino group and give a positive charge. 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 with an inorganic acid, for example, by dispersing particles in water and adding an inorganic acid little by little, when it reaches a specific pH, it is separated and removed from the water by a method such as filtration or magnetic separation. can get.

  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 part, and have a surface layer part containing either an amide group or a ureido group supported on the core part 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.

(Water treatment particles)
Next, the water treatment 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 a room temperature region, and a ferromagnetic substance such as a ferrite compound can be generally used. 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. 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 preferable in use in view of manufacturing cost.

  The water treatment particles may be single particles containing a magnetic material, or the surface of the magnetic material particles 11 may be coated with a coating agent 12 such as a polymer as shown in FIG. Good. Further, the water treatment particles may be an aggregate 13 in which the polymer-coated magnetic particles 11 are aggregated as shown in FIG.

  The water treatment particles 10 include those having a core portion 11 made of magnetic particles and having an average particle diameter D1 in the range of 0.1 to 100 μm. The water treatment particles 10 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 water treatment particles 10 is less than 0.1 μm, the sedimentation speed decreases, and there is a possibility that the sedimentation apparatus cannot be separated. The 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, polyamine is supported on the surface of the inorganic particles (core part).

  As a method of supporting polyamine 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, there is a method of coating a resin having an alkoxy group and an epoxy group, or a method of coating a resin having a reactive functional group on the side chain and reacting a compound having an alkoxy group and an epoxy group. is there.

  As a method for supporting polyamine on the surface of inorganic particles, a resin having an alkoxy group and an epoxy group is coated on the inorganic particles, a compound having an alkoxy group and an epoxy group is reacted with the surface of the inorganic particles in advance, and the compound is then reacted with the inorganic particles. After that, the polyamine is reacted with the epoxy group. Examples of the compound having an alkoxy group and an epoxy group include 2- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, 3-glycidoxypropylmethyldimethoxysilane, 3-glycidoxypropyltrimethoxysilane, and 3-glycol. Sidoxypropylmethyldiethoxysilane, 3-glycidoxypropyltriethoxysilane, or the like can be used.

  On the other hand, in the method of directly modifying the surface of the inorganic particles with a silane coupling agent, a compound having an alkoxy group and an epoxy group is reacted with the particle to carry a desired functional group on the surface of the particle.

  Examples of the modification method include a dry method in which the silane coupling agent solution is sprayed while stirring the particles at a high speed, and a wet method in which the particles are reacted in a solvent containing the silane coupling agent. In both the dry method and the wet method, the reaction is allowed to proceed completely by post-curing after the treatment. 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 described above, an epoxy group is supported on the particle surface and then reacted with a polyamine in an organic solvent. A polyamine is defined as having two or more amino groups. Examples of the polyamine include polyethylene polyamine and polyallylamine. Of these, polyethylene polyamines are preferred because both ends are primary amines and the inside of the molecule is secondary amines, so both ends, which are highly reactive primary amines, easily react with epoxy groups and the molecular length is easily adjusted. In particular, when amino acids having a total number of 6 or less are used, entanglement between molecules hardly occurs, the reactivity is good, and the surface modification rate is improved. Examples of such polyethylene polyamines include ethylenediamine, diethylenetriamine, triethylenetetramine, tetraethylenepentamine, and pentaethylenehexamine.

  These particles are used in the form of a salt with an inorganic acid / organic acid as required. By performing this treatment, a positive charge can be given by retaining protons in the amino group. This positive charge neutralizes the charge around SS that exists in a colloidal form in water, and the action of aggregating the magnetic substance and SS can be obtained. As a method of making a salt with inorganic acid / organic acid, for example, particles are dispersed in water, inorganic acid / organic acid is added little by little, and when it reaches a specific pH, it is separated and removed from water by a method such as filtration or magnetic separation. Can be 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 the above embodiment, the water treatment particles can be easily reused, and fine solid matter in water can be removed without adding chemicals.

  Various examples and comparative examples will be described below.

[Manufacture of water treatment particles]
Various sample particles shown in Table 1 were prepared as follows. These particles are used as water treatment particles, and were evaluated by conducting experiments under various conditions.

(Particle A-1)
Commercially available spherical alumina particles (product number AX-116 manufactured by Micron Corporation) were prepared as the core part. While stirring spherical alumina having an average particle diameter of 20 μm at high speed, 3-glycidoxypropyltriethoxysilane diluted with ethanol was added dropwise. After adjusting so that it might become a 1 mass% silane coupling agent with respect to spherical alumina, it took out from the stirrer and heat-dried at 120 degreeC * 2 hours, and obtained the particle | grains by which the epoxy group was carry | supported. The particles were dispersed in acetone, mixed with diethylenetriamine (product of Wako Pure Chemical Industries, Ltd.) equivalent to 5 times the epoxy group, and reacted under the conditions of 40 ° C. × 6 hours. The particles were washed with acetone and water and then dried to obtain water treatment particles.

(Particle A-2)
Particle A-1 was dispersed in pure water so as to be 20% by mass, and hydrochloric acid was added dropwise thereto. When the pH reached 7, dropping of hydrochloric acid was stopped and recovered by membrane filtration to obtain water treatment particles.

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

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.

  A water treatment particle was obtained in the same manner as the particle A-1, except that manganese magnesium ferrite having an average particle diameter of 20 μm was used.

(Particle B-2)
Particle B-1 was dispersed in pure water so as to be 20% by mass, and hydrochloric acid was added dropwise thereto. When the pH reached 7, the dropping of hydrochloric acid was stopped and recovered by membrane filtration to obtain water treatment particles.

(Particle C-1)
Particle B-1 was obtained in the same manner as the particle B-1, except that diethylenetriamine was changed to ethylenediamine (product of Wako Pure Chemical Industries, Ltd.).

(Particle D-1)
Particle B-1 was obtained in the same manner except that diethylenetriamine was changed to triethylenetetramine (product of Wako Pure Chemical Industries, Ltd.).

(Particle E-1)
Particle B-1 was obtained in the same manner as the particle B-1, except that diethylenetriamine was changed to tetraethylenepentamine (product of Wako Pure Chemical Industries, Ltd.).

(Particle F-1)
Particles B-1 were obtained in the same manner as the particles B-1, except that diethylenetriamine was changed to an ethyleneamine mixture of pentaethylenehexamine (product of Wako Pure Chemical Industries, Ltd.).

[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 treated water is measured with a turbidimeter using a formazine standard solution, the highest transparency (turbidity less than 10 FTU) is double circle (◎), and the next highest value (turbidity of 10 FTU or more) The lower value (turbidity of 30 FTU or more and less than 100 FTU) was set as a triangle (Δ), and the lowest value (turbidity of 100 FTU or more) was set as a cross (×). As One Portable Turbidimeter HI 93703C was used as a turbidimeter. Industrial wastewater or domestic wastewater containing surfactant, fine suspended solids (SS) and sand was used as treated water.

Example 1
To the domestic wastewater containing surfactant, fine suspended solids (SS) and sand, add 10000 ppm of particles A-1 and stir and mix for 3 minutes, then adsorb the suspended solids (SS) in water. And settled together, and treated water with high transparency was obtained.

(Example 2)
A test was conducted in the same manner as in Example 1 except that the type of particles was changed to A-2. As a result, treated water having high transparency was obtained as in Example 1. Compared with Example 1, the treatment of Example 2 was obtained. The transparency of the water was high.

(Examples 3 to 8)
When each test was conducted in the same manner as in Example 1 except that the particle type was changed, treated water having high transparency was obtained in the same manner as in Example 1. The results are shown in Table 2.

(Comparative Example 1)
As Comparative Example 1, the same test as in Example 1 was performed except that the type of particles was changed to unmodified alumina particles. As a result, turbid treated water was obtained without sedimentation along with suspended matter SS. It was.

(Comparative Example 2)
As Comparative Example 2, a test was performed in the same manner as in Example 1 except that the type of particles was changed to unmodified ferrite. As a result, turbid treated water was obtained without sedimentation along with suspended matter SS. .

  From the results shown in Table 2, all of the four particles showed good SS adsorption and sedimentation performance. Since the unmodified particles did not settle, it is considered that the amide group aggregated by neutralizing the charge of SS and settled. It was also found that good results were obtained when the number of amino groups was in the range of 2-6.

Example 9
A simulated drainage containing 2000 ppm of bentonite was prepared. When 20000 ppm of particles A-1 were added and stirred, and stirred and mixed for 3 minutes, the mixture was allowed to stand, and the suspended matter SS in the water was adsorbed and settled together. As a result, treated water with slightly high transparency was obtained.

(Example 10)
A test was conducted in the same manner as in Example 9 except that the type of particles was changed to A-2. As a result, treated water having high transparency was obtained as in Example 1, but compared with Example 1, Example 10 was compared. The transparency of the treated water was low.

(Examples 11 to 16)
Each test was conducted in the same manner as in Example 10 except that the particle type was changed. As a result, treated water having high transparency was obtained in the same manner as in Example 1. The results are shown in Table 2.

1, 1A ... water treatment device, 2 ... mixing tank,
3 ... settling tank, 31 ... partition plate,
4 ... separation tank, 5 ... particle supply device for water treatment,
10 ... Water treatment particles (primary particles), 11 ... Core part (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 (11)

Water treatment particles that adsorb water-insoluble substances in water to be treated, settle together with the water-insoluble substances, are separated from the water-insoluble substances in the precipitate, and are collected and used repeatedly.
A water treatment particle comprising: a core portion made of an inorganic substance having a specific gravity greater than 1; and a surface layer portion containing a polyamine supported on the core portion.   The particle for water treatment according to claim 1, wherein the core portion is made of a magnetic material.   The water treatment particle according to claim 2, wherein the magnetic substance is a ferrite compound.   The water treatment particle according to claim 2, wherein the polyamine in the surface layer portion is selected from the group consisting of polyethylene polyamine and polyallylamine.   The water treatment particle according to claim 4, wherein the polyamine in the surface layer portion is a polyethylene polyamine having 6 or less amino groups.   3. The surface layer portion has a salt produced by reacting a silane coupling agent having an alkoxy group and an epoxy group with the core portion made of a magnetic substance and further reacting with an inorganic acid. The particle for water treatment as described.   7. The water treatment particle according to claim 6, wherein the inorganic acid is one of hydrochloric acid and sulfuric acid or a mixture thereof.   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) a magnetic core portion made of a magnetic material having a specific gravity greater than 1 and a polyamine supported on the magnetic core portion as the water treatment particles And (b) mixing the water treatment particles and the water to be treated, causing the water treatment particles to adsorb / capture solid components, and (c) adsorb / capture the particles. The water treatment particles are separated into solid and liquid by sedimentation to separate the treated water and the water treatment particles. (D) The separated water treatment particles are mixed in water to separate the water treatment particles from the solid content. (E) the water treatment granules from the mixture The magnetically separated, (f) water treatment method characterized by reusing the separated water treatment particles in adsorption and trapping of solids 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) the water treatment particles are supported on the magnetic core portion made of a magnetic material having a specific gravity greater than 1 and the magnetic core portion. Particles having a surface layer portion containing polyamine are prepared, (B) the water treatment particles and the water to be treated are mixed, and the water treatment particles are caused to adsorb and capture a solid component, and (C) the adsorption and trapping. The water treatment particles are separated into solid and liquid by centrifugal force to separate the treated water and the water treatment particles, and (D) the separated water treatment particles are mixed in water to obtain the water treatment particles and the solid content. And (E) the water treatment from the mixture. The use particles were magnetically separated, (F) water treatment method characterized by reusing the separated water treatment particles in adsorption and trapping of solids in step (B).   10. The method according to claim 8, wherein the magnetic core portion is reacted with a silane coupling agent having an alkoxy group and an epoxy group, and then reacted with a polyamine, thereby supporting the polyamine on the magnetic core portion. The water treatment method according to claim 1.   The water treatment method according to claim 10, wherein after the polyamine is reacted with the magnetic core part, an inorganic acid is reacted to thereby generate a salt on the surface layer part covering the magnetic core part.

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