JP2013154326A - Water treatment particle and water treatment method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a water treatment particle which can adsorb a removing target substance in the water and is repeatedly usable by desorbing absorbed matters and collecting the water treatment particle, and to provide a water treatment method using the same.SOLUTION: A water treatment particle adsorbs insoluble substances in the water to be treated and sediments with the insoluble substances, and is then separated and collected from the insoluble substances in the sediments to be repeatedly used. The water treatment particle includes: a core 11 with a higher specific weight than 1; and a surface layer 12 including one of an amide group and an ureido group carried on the core.

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 particle is characterized by having a core part having a specific gravity greater than 1 and a surface layer part containing either an amide group or a ureido group supported on the core part.

(A)-(c) is a schematic diagram which shows the reaction mechanism between a silane coupling agent and an inorganic surface. The block diagram which shows the water treatment apparatus which concerns on 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 water treatment apparatus which concerns on 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 part having a specific gravity greater than 1, and a surface layer part containing either an amide group or a ureido group supported on the core part.

Since the surface layer of the particle contains either an amide group (RCONH-) or a ureido group (H ₂ NCONH-), these functional groups have high efficiency in the solid content (various water-insoluble substances) contained in the waste water. Adsorb at.

  Further, since the separated and recovered water treatment particles can be reused repeatedly, the operating cost can be greatly reduced as compared with the 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 (1) above, 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.

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

  (4) In the above (1), the surface layer part reacts either an amide group or a ureido group with a silane coupling agent having an alkoxy group, and further reacts at least one of an inorganic acid and an organic acid, It is preferable to have a salt generated on the surface of the core part.

  First, a silane coupling agent is allowed to act on the surface of the core portion, and a desired functional group composed of either an amide group or a ureido group and an alkoxy group is supported on the surface of the core portion. Next, an inorganic acid and / or an organic acid is allowed to act on the desired functional group, and a salt having either an amide group or a ureido group and an alkoxy group on the surface of the core portion 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 solids in water, the purification action by adsorption can be remarkably improved.

  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. .

  (5) In the above (4), it is preferable that the silane coupling agent is either 3-ureidopropyltriethoxysilane or 3-glycidoxypropyltriethoxysilane.

  When 3-ureidopropyltriethoxysilane is reacted with an inorganic acid or an organic acid as a silane coupling agent, a surface layer portion (proton acceptor) containing a ureido group on the surface of the core portion is generated.

  When 3-glycidoxypropyltriethoxysilane is reacted with an inorganic acid or an organic acid as a silane coupling agent, a surface layer portion (proton acceptor) containing an amide group is formed on the surface of the core portion.

  (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 particles having a magnetic core portion made of a magnetic material and a surface layer portion containing either an amide group or a ureido group carried on the magnetic core portion; and (b) mixing the water treatment particles and the water to be treated. And (c) separating the treated water from the water treatment particles by solid-liquid separation of the adsorbed and captured water treatment particles by sedimentation, and (d) ) The separated water treatment particles in water In combination, the water treatment particles and the solid content are separated, (e) the water treatment particles are magnetically separated from the mixture, and (f) the separated water treatment particles are solidified in the step (b). Reuse for adsorption and capture of water.

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

  Next, the water treatment particles, the water-insoluble substance and the precipitate are extracted from the lower part of the settling tank 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.

  (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 particles having a magnetic core portion made of a large magnetic material and a surface layer portion containing either an amide group or a ureido group carried on the magnetic core portion; and (B) the water treatment particles and the water to be treated. Mixing, causing the water treatment particles to adsorb and capture solids, and (C) separating the water and water treatment particles by solid-liquid separation of the adsorbed and captured water treatment particles by centrifugal force, (D) The separated water treatment particles (E) magnetically separating the water treatment particles from the mixture, and (F) separating the water treatment particles from the step (B). Reused for adsorption and capture of solids.

  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 (either amide group or ureido group) 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 mixture of water treatment particles / solids 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.

  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 is connected to the upper part of the separation tank 4 from a tank (not shown). 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 shown in FIG. 2 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 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. The water treatment particles may be aggregates 13 in which 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, either an amide group or a ureido group is supported on the surface of the inorganic particles (core part).

  As a method for supporting amide 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, there are a method of coating a resin having an amide group, or a method of coating a resin having a reactive functional group on the side chain and reacting a compound having an amide group.

  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 alkoxysilyl group and an amide group or ureido 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 material is coated with a polymer material having a specific functional group, the case where the material is 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 a compound having an amide group or a ureido group after reacting with epoxysilane.

  As described above, after a functional group is supported on the particle surface, it is used in the form of a salt with an inorganic acid / organic acid, if necessary. For example, by reacting either an amide group or a ureido group with a silane coupling agent having an alkoxy group on the surface of the magnetic particles (core part), and then reacting at least one of an inorganic acid and an organic acid, It produces salt in the surface area of the part.

  By performing this treatment, a proton can be held in the functional group and a positive charge can be given. 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 making a salt with inorganic acid / organic acid, for example, dispersing particles in water and adding inorganic acid / organic acid little by little, and removing from water by filtration or magnetic separation when a specific pH is reached. Is obtained.

(Surface part)
Next, a method for adjusting the thickness of the polymer coating containing functional groups and a method for adjusting the aggregate diameter of the aggregate in which the polymer-coated magnetic particles are aggregated will be described.

  In order to determine the coating thickness of the polymer (surface layer portion) 12 at the time of production, the coating ratio is calculated from the mixing ratio of the polymer and magnetic particles (core portion) 11, the density of the resin, and the specific surface area of the magnetic particles. That is, when the volume of the resin to be added is obtained from the weight and density of the resin to be added and divided by the surface area of the magnetic particles obtained from the weight and specific surface area of the magnetic particles, the average coating thickness t of the polymer is obtained. Further, although the control of the particle diameter varies depending on the type of spray liquid and the spraying method, the droplet diameter of the droplets to be spray-dried may be reduced in order to reduce the aggregate. For example, when the spraying pressure of the spray nozzle is increased, the spraying speed is decreased, or the rotation of the spraying disk is increased, the particle size of the produced aggregate is decreased.

  Next, a method for measuring the thickness of the polymer coating in the already formed aggregate will be described.

  The calculation of the coating thickness of the polymer may be measured by observation with an optical microscope or SEM. However, the polymer coating thickness is preferably raised to a high temperature in an oxygen-free state and the resin composite is thermally decomposed to reduce the weight loss, that is, the polymer coating weight It can be accurately obtained by calculating and calculating the average thickness of the polymer layer from the specific surface area of the particles.

(Device of Second Embodiment)
Next, a water treatment apparatus 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 centrifugal separation 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.

  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.

  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 but less than 30 FTU) 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.

(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 particles having an average particle diameter of 20 μm at high speed, a silane coupling agent (3-ureidopropyltriethoxysilane) diluted with ethanol was added dropwise. After adjusting the spherical alumina particles to be 1% by mass of a silane coupling agent, the particles are taken out from the stirrer and dried by heating under the conditions of 120 ° C. × 2 hours to carry water treatment particles (water) carrying ureido groups. 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 to the dispersion solution. When pH 5 was reached, dropping of hydrochloric acid was stopped, and the dispersion was filtered through a filtration membrane 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% of MnO · Fe ₂ O ₃ and MgO · Fe _2. O ₃ was 20%.

  While stirring manganese magnesium ferrite particles having an average particle diameter of 20 μm at high speed, a silane coupling agent (3-ureidopropyltriethoxysilane) diluted with ethanol was added dropwise. It adjusted so that the ratio of a silane coupling agent might be 1 mass% with respect to a ferrite. The reaction mixture was taken out of the stirrer and dried by heating at 120 ° C. for 2 hours to obtain water treatment particles carrying ureido groups.

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

(Particle C-1)
While stirring manganese magnesium ferrite particles having an average particle diameter of 20 μm at high speed, a silane coupling agent (3-glycidoxypropyltriethoxysilane) diluted with ethanol was added dropwise. After adjusting so that a silane coupling agent might be 1 mass% with respect to a ferrite, it took out from the stirrer and dried on 120 degreeC * 2 hours heating conditions, and obtained the particle | grains for water treatment. Further, adipic acid and excess ethylenediamine were reacted in acetone at 60 ° C., washed and dried to synthesize an amide compound. The magnetic particles were dispersed in acetone and reacted with the synthesized amide compound at 40 ° C. for 6 hours. Thereafter, the reaction product was filtered, washed with acetone and water and then dried to obtain water treatment particles carrying amide groups.

Example 1
Surfactant, fine suspended solids (SS) and industrial wastewater containing sand were mixed with 10000ppm particle A-1 and mixed for 3 minutes. ) Was adsorbed and precipitated, and treated water with slightly high transparency was obtained.

(Example 2)
The test was conducted in the same manner as in Example 1 except that the water treatment particles used were changed from the particles A-1 to the particles A-2. In Example 2, treated water having high transparency was obtained as in Example 1, and the transparency was higher than that of treated water in Example 1.

(Example 3)
The test was conducted in the same manner as in Example 1 except that the water treatment particles used were changed from the particles A-1 to the particles B-1. In Example 3, treated water with high transparency was obtained as in Example 1.

Example 4
The test was performed under the same conditions as in Example 1 except that the water treatment particles used were changed from the particles A-1 to the particles B-2. In Example 4, treated water having high transparency was obtained as in Example 1.

(Example 5)
The test was performed under the same conditions as in Example 1 except that the water treatment particles used were changed from the particles A-1 to the particles C-1. Also in Example 5, similarly to Example 1, treated water having high transparency was obtained.

(Comparative Example 1)
Example 1 was tested in the same manner except that the type of particles was changed to unmodified alumina particles. In Comparative Example 1, the added particles did not settle together with the suspended solids (SS) and became turbid water.

(Comparative Example 2)
Example 1 was tested in the same manner except that the type of particles was changed to unmodified ferrite particles. In Comparative Example 2, the added particles did not settle together with the suspended solids (SS) and became turbid water.

(Example 6)
A simulated drainage containing 2000 ppm of bentonite was prepared. When 20000 ppm of particle A-1 was added and stirred, mixed for 3 minutes and allowed to stand, adsorbed and precipitated suspended matter (SS) in water, and treated water with slightly high transparency was obtained.

(Example 7)
The test was conducted in the same manner as in Example 6 except that the water treatment particles used were changed from the particles A-1 to the particles A-2. In Example 7, treated water having high transparency was obtained as in Example 1, but the transparency was lower than that in Example 1.

(Example 8)
The test was conducted in the same manner as in Example 6 except that the water treatment particles used were changed from the particles A-1 to the particles B-1. In Example 8, treated water having high transparency was obtained as in Example 1.

Example 9
The test was conducted in the same manner as in Example 6 except that the water treatment particles used were changed from the particles A-1 to the particles B-2. In Example 9, treated water having high transparency was obtained as in Example 1.

(Example 10)
The test was conducted in the same manner as in Example 6 except that the water treatment particles used were changed from the particles A-1 to the particles C-1. In Example 10, treated water having high transparency was obtained as in Example 1.

(Example 11)
The test was performed under the same conditions as in Example 1 except that manganese magnesium ferrite particles C-2 having an average particle diameter of 14 μm were used. In Example 11, treated water having high transparency was obtained as in Example 1.

(Example 12)
The test was performed under the same conditions as in Example 1 except that manganese magnesium ferrite particles C-3 having an average particle diameter of 37 μm were used. In Example 12, treated water having high transparency was obtained as in Example 1.

(Example 13)
The test was performed under the same conditions as in Example 1 except that manganese magnesium ferrite particles C-4 having an average particle diameter of 55 μm were used. In Example 13, treated water having high transparency was obtained in the same manner as in Example 1, but the transparency was low as compared with Example 1.

(Example 14)
The test was performed under the same conditions as in Example 1 except that manganese magnesium ferrite particles C-5 having an average particle diameter of 89 μm were used. In Example 14, the transparency was low as compared with Example 1 in which treated water having high transparency was obtained as in Example 1.

  The test results are shown in Table 2.

From the results of Table 2, all the particles of Examples 1 to 14 showed good suspended solid (SS) adsorption and sedimentation performance, respectively. On the other hand, since the unmodified particles of Comparative Examples 1 and 2 did not settle, it is considered that the amide group aggregated by neutralizing the charge of the suspended matter (SS) and settled.

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 (7)

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 having a specific gravity greater than 1; and a surface layer portion containing either an amide group or a ureido group 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 surface layer portion is generated in the surface region of the core portion by reacting either an amide group or a ureido group with a silane coupling agent having an alkoxy group, and further reacting at least one of an inorganic acid and an organic acid. The water treatment particles according to claim 2, wherein the water treatment particles have a salt.   The water treatment particle according to claim 4, wherein the silane coupling agent is either 3-ureidopropyltriethoxysilane or 3-glycidoxypropyltriethoxysilane. 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 particle having a magnetic core portion made of a magnetic material having a specific gravity greater than 1 and a surface layer portion containing either an amide group or a ureido group supported on the magnetic core portion is prepared as the water treatment particle. ,
(B) mixing the water treatment particles and the water to be treated, causing the water treatment particles to adsorb and capture a solid component,
(C) Separating treated water and water treatment particles by solid-liquid separation of the adsorbed and captured water treatment particles by sedimentation;
(D) mixing the separated water treatment particles in water to separate the water treatment particles and solids;
(E) magnetically separating the water treatment particles from the mixture;
(F) The separated water treatment particles are reused for adsorption and capture of the solid content in the step (b).
A water treatment method characterized by the above. 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) A particle having a magnetic core portion made of a magnetic material having a specific gravity greater than 1 and a surface layer portion containing either an amide group or a ureido group carried on the magnetic core portion is prepared as the water treatment particle. ,
(B) Mixing the water treatment particles and the water to be treated, causing the water treatment particles to adsorb and capture a solid component,
(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;
(D) mixing the separated water treatment particles in water to separate the water treatment particles and the solids;
(E) magnetically separating the water treatment particles from the mixture;
(F) The separated water treatment particles are reused for adsorption and capture of the solid content in the step (B).
A water treatment method characterized by the above.

Images