JP2013233487A - Phosphorus collecting material, method of manufacturing the same, and phosphorus collecting method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a novel high-performance phosphorus collecting material making the best use of phosphorus collecting capability by a cross-linked body independently of the characteristics of a carrier.SOLUTION: A phosphorus collecting material comprises a cross-linked structure obtained by heating a mixed solution comprising one or more of a water-soluble zirconium compound or a water-soluble titanium compound and a water-soluble polymer compound including at least one of an alcohol group, an amino group and a carboxyl group and performing cross-linking reaction so as to be insolubilized. The form of the cross-linked structure is a fibrous cross-linked structure.

Description

The present invention relates to a phosphorus collection material that collects phosphorus from various wastewaters such as domestic wastewater and industrial wastewater, and water such as rivers, lakes, and oceans, a manufacturing method thereof, and a phosphorus collection method.
Related.

  Phosphorus is an indispensable element for the life activity of living organisms, and human beings have been used and discharged in large quantities for many years as fertilizers and various industrial raw materials. As a result, it causes environmental problems such as mass generation of red tides due to eutrophication of rivers, lakes, and oceans, and destruction of aquatic ecosystems. Therefore, wastewater treatment technology that removes phosphorus in wastewater has been researched and developed for environmental considerations, and it can be said that phosphorus removal technology has been sufficiently effective from the viewpoint of environmental conservation. It has not reached.

  On the other hand, as a result of the rapid increase in the world population and increased production of food and industrial products accompanying rapid economic growth in developing countries such as China and India, mass consumption of phosphorus resources has progressed, and now phosphorus resources on a global scale Depletion has begun. The US and China, which are phosphorus resource countries, have started banning and restricting exports of phosphorus ore as a strategic resource. Japan, which does not have phosphorus ore in Japan and relies on imports for 100% of it, recovers phosphorus from various wastewaters such as domestic wastewater and industrial wastewater that contain a large amount of used phosphorus. However, it has been attracting attention as an urgent issue, research and development has been conducted in various fields, and in some cases, phosphorus recovery as a fertilizer raw material has been attempted, but it is far from reusing phosphorus resources.

  As these conventional phosphorus removal technologies, phosphorus compounds dissolved as phosphoric acid or organic phosphorus compounds in wastewater are concentrated and collected in sludge using microorganisms, or aggregated and precipitated using a flocculant. However, since all of them contain a large amount of components other than the phosphorus compound, it was impossible to separate and recover only the phosphorus compound. For this reason, the use of the collected phosphorus-containing material has been extremely limited.

  Therefore, the present inventors have previously developed a phosphorus scavenger that selectively collects only phosphorus and can in principle recover a phosphorus compound in a state that does not contain impurities (Patent Document 1). reference). This phosphorus scavenger is a water-soluble polymer compound such as polyvinyl alcohol (PVA) having any one of alcohol group (hydroxyl group), amino group and carboxylic acid group, and one kind of water-soluble Zr compound and Ti compound. It consists of a crosslinked structure that is insolubilized by heating a mixed aqueous solution of two types with Zr or Ti as a crosslinking point and crosslinking with an alcohol group, amino group, or carboxylic acid group without adding a special crosslinking agent. It is a phosphorus scavenger that can be reused repeatedly. As usage forms of this phosphorus scavenger, a ceramic particle type phosphorus scavenger (refer to Patent Document 2) in which a crosslinked body is supported on porous ceramic particles, or a corrugate that is supported on a nonwoven sheet and formed into a corrugated type. The type | mold phosphorus collection material (refer patent document 3) is proposed. In particular, as for the corrugated phosphorus collection material, as a result of producing a small pilot device and conducting a phosphorus recovery test from chicken manure incineration ash, phosphorus can be recovered in a high yield in the form of apatite containing no impurities, and It has been proved that this phosphorus trapping material can be reused repeatedly (see Non-Patent Document 1).

Japanese Patent No. 4839445 Japanese Patent No. 4908261 JP 2011-78870 A

Shoji Yamanaka et al., “Highly selective phosphorus resource recovery adsorbent using non-woven fabric”, Convertech, December 2010, p. 58-61

  The phosphorus scavenger used as the above-mentioned water-soluble polymer compound and Zr or Ti cross-linked structure (hereinafter simply referred to as cross-linked product) is to selectively collect only phosphorus and wash it with an alkali. Phosphorus is recovered as an alkaline aqueous solution such as an aqueous solution of sodium phosphate or a phosphorylated solid such as Ca phosphate (apatite), and the phosphorus scavenger returns to the original cross-linked structure and reacts with phosphorus. Since Zr and Ti that collects carbon remain separated as a constituent element of the cross-linked body without being separated and consumed from the cross-linked body structure, the original phosphorus-capturing function is restored and the scavenger can be used repeatedly. It has the great feature of becoming.

  However, in the case of the ceramic particle type phosphorus trapping material described in Patent Document 2 as its use form, if the particle size is 1 mm or less in order to increase the amount of crosslinked body supported per unit weight, treated water The flow path becomes narrower and the chance of contact with the phosphorus scavenger increases, so when applied to a relatively low concentration raw water with a phosphorus concentration of several tens of ppm or less, the phosphorus concentration in the treated water becomes 1 ppm or less. However, when applied to high-concentration raw water of several thousand ppm, it will saturate in a short time, so the switching cycle of phosphorus collection and separation / recovery will be short, resulting in high-concentration raw water. Not suitable for. In addition, since most of the weight of the phosphorus collection material is occupied by ceramics, the amount of phosphorus collected per unit weight of the collection material becomes extremely small, and the phosphorus collection reactor filled with the collection material has high strength. There is a problem that a high metal material is required, the equipment becomes large, and the equipment cost increases.

  On the other hand, in the case of the corrugated phosphorus collecting material described in Patent Document 3 and Non-Patent Document 1, a mixed aqueous solution in which PVA and a water-soluble Zr compound or Ti compound are dissolved is acid-resistant such as a vinylon nonwoven fabric. Applying to the surface of a lightweight sheet having alkali resistance and forming it in a corrugated shape, followed by drying and overheating to cause a crosslinking reaction, and applying a mixed aqueous solution to form a corrugated shape and then heating and drying. Some cause a cross-linking reaction. Since this collection material is lighter than the above-described ceramic particle type phosphorus collection material, the amount of crosslinked material supported per unit weight can be increased, and the flow path of treated water is easily secured. Applicable to raw water with high concentration of several thousand ppm. In addition, the reactor filled with the trapping material also has the advantage that it can be made of a lightweight plastic material. However, when applied to low-concentration raw water, the phosphorus component in the treated water is transferred to the corrugated surface in the corrugated flow path. Therefore, when the phosphorus concentration in the treated water is about several tens of ppm, the phosphorus collection rate is extremely lowered and the concentration is low. There is a problem that its application to raw water is inappropriate.

  The ceramic particle type phosphorus collecting material and the corrugated type phosphorus collecting material are each a system in which a cross-linked body serving as a phosphorus collecting agent is held on the surface of the carrier, and the phosphorus collecting performance is the specific surface area of the phosphorus collecting material. Because of this, a porous carrier having a high specific surface area such as a ceramic particle type phosphorus collector is used, or the collector itself such as a corrugated phosphorus collector is formed to have a large specific surface area. At the same time, how to uniformly support the crosslinked body on the surface of the carrier is the key to the manufacturing technique. Therefore, the viscosity of the mixed aqueous solution becomes an important factor, and when the viscosity is lowered so that it can be easily impregnated or applied uniformly, the amount of the crosslinked body and the amount of Zr and Ti having a phosphorus collecting function contained in the crosslinked body are decreased. If the viscosity is increased and the viscosity is increased, the amount of Zr and Ti can be increased. However, the pores of the carrier are blocked to reduce the specific surface area, and the coating thickness is unnecessarily increased to increase the phosphorus collection. There is a problem that performance decreases. Moreover, no matter how it is devised, the use of a carrier has the fundamental problem that the phosphorus collection performance depends on the carrier characteristics.

  Therefore, the first object of the present invention is to provide a novel high performance phosphorus scavenger that makes the most of the phosphorus scavenging ability of the cross-linked body regardless of the characteristics of the carrier. Second, to provide a simple method for producing the high-performance phosphorus collection material, and third, to provide a method for recovering phosphorus in waste water using the high-performance phosphorus collection material. In other words, the phosphorus concentration in the raw water can be applied to the whole range from low to high, and low concentrations such as rivers, lakes, and oceans from relatively high concentrations of phosphorus-containing wastewater in factory wastewater and domestic wastewater. A new phosphorus-collecting material that can efficiently collect and recover the phosphorus component dissolved in these waters in a reusable form, as well as phosphorus-containing water, and its production method and phosphorus It is to provide a collection method.

  In order to solve the above problems, the present invention provides a phosphorus collecting material for collecting a phosphorus compound in water, comprising at least one of a water-soluble zirconium compound and a water-soluble titanium compound, an alcohol group, and an amino group. A mixed aqueous solution comprising a water-soluble polymer compound having at least one of a group and a carboxyl group is heated, and at least one of zirconium in the water-soluble zirconium compound and titanium in the water-soluble titanium compound is used as a crosslinking point. A recyclable structure comprising a cross-linked structure formed by cross-linking reaction with any of alcohol group, amino group and carboxylic acid group of the water-soluble polymer compound and insolubilizing, and the form of the cross-linked structure is fibrous. By adopting it, as a phosphorus collector with a large specific surface area without using a carrier, it can be cross-linked without being influenced by the properties of the carrier Phosphorus trapping ability of which make it possible to maximize.

  The fiber diameter of the fibrous cross-linked structure is preferably 170 μm or less, and more preferably 100 μm or less. By reducing the fiber diameter of the cross-linked structure in this way, a specific surface area of several to several tens of times can be obtained even when a cross-linked body under the same conditions is used as compared with a conventional corrugated collector. Therefore, the phosphorus collecting ability can be improved dramatically from several times to several tens of times. Further, if the content of Zr or Ti responsible for the phosphorus collecting function is increased, the phosphorus collecting ability can be further improved several times.

  The fibrous phosphorus collection material may be formed in a woven fabric or a non-woven fabric.

  The present invention also relates to a method for producing a phosphorus collector for collecting a phosphorus compound in water, comprising at least one of a water-soluble zirconium compound and a water-soluble titanium compound, an alcohol group, an amino group, and A drying and solidification step in which a mixed aqueous solution composed of a water-soluble polymer compound having at least one of carboxyl groups is discharged from a spinning nozzle into a heated gas and dried by heating to form a fibrous dried body, and this is further heated. A crosslinked structure obtained by crosslinking reaction with any one of alcohol group, amino group and carboxylic acid group of the water-soluble polymer compound using at least one of zirconium of the water-soluble zirconium compound or titanium in the water-soluble titanium compound as a crosslinking point And a cross-linking reaction step.

  The method for producing the phosphorus collecting material is a method in which the drying and solidification step and the crosslinking reaction step are continuously performed, or the fibrous dry body obtained in the drying and solidification step is used as an intermediate product, which is separately provided. It can be set as the method of performing a crosslinking reaction process with the provided heating apparatus.

  The water-soluble zirconium compound may be selected from the group of zirconyl chloride, zirconyl sulfate, zirconyl nitrate, zirconyl acetate, zirconyl ammonium carbonate, chelate-type zirconium and aminocarboxylic acid-type zirconium, and the water-soluble titanium compound is It may be selected from the group consisting of titanium trichloride, titanium tetrachloride, titanium sulfate, titanium lactate, peroxotitanate and chelate titanate.

  The water-soluble polymer compound is selected from the group consisting of polyvinyl alcohol, ethylene vinyl alcohol, polyacrylic acid, polyacrylamide, polyallylamine and carboxymethyl cellulose, and copolymers and block polymers of these water-soluble polymer compounds. It is good to do.

  The water-soluble polymer compound is most preferably polyvinyl alcohol (PVA), and in the production of a crosslinked fiber using PVA, an aqueous solution of PVA and the water-soluble PVA compound are mixed at a temperature of 50 ° C. or less. It is preferable that the mixed liquid is discharged from a spinning nozzle into hot air to form a fiber, and this is subjected to a crosslinking reaction at 100 to 250 ° C. to form a crosslinked structure.

  The concentration of PVA in the mixed aqueous solution of PVA and water-soluble Zr compound is preferably 40% by weight or less, and the weight ratio of PVA and Zr is preferably selected within the range of 9: 1 to 9: 3.

  As a method for collecting phosphorus using the above-described phosphorus collection material, a method of collecting phosphorus by floating a fibrous phosphorus collection material in a phosphorus-containing wastewater is preferable as a simple method.

  The phosphorus scavenger according to the present invention is a mixture comprising at least one of a water-soluble zirconium compound and a water-soluble titanium compound and a water-soluble polymer compound having at least one of an alcohol group, an amino group and a carboxyl group. The aqueous solution is heated to cause a crosslinking reaction with any of the alcohol group, amino group, and carboxylic acid group of the water-soluble polymer compound using at least one of zirconium in the water-soluble zirconium compound and titanium in the water-soluble titanium compound as a crosslinking point. Since the cross-linked structure is made in the form of fibers and the form of the cross-linked structure is fibrous, the phosphorus scavenging ability of the cross-linked product can be maximized regardless of the characteristics of the carrier.

  In addition, since the cross-linked body is made into a fibrous form, it is possible to produce various types of processed fiber products such as yarn, string, woven fabric, and non-woven fabric. This brings about a fundamental change in the concept of phosphorus trapping material. It is expected to bring about a big change in the concept of collection and collection plant.

Schematic diagram showing the structural model of zirconium hydroxide polynuclear ions produced when zirconium oxychloride, one of the water-soluble Zr compounds, is dissolved in water Schematic diagram showing the structural model of the crosslinked structure produced when PVA is crosslinked with Zr as the crosslinking point The conceptual diagram which shows an example of the manufacturing apparatus of the phosphorus collection material which concerns on this invention The conceptual diagram which shows the other example of the manufacturing apparatus of the phosphorus collection material which concerns on this invention Photograph of a cross-linked product of phosphorus-collecting material produced in the example

  The present invention is described in detail below. First, the phosphorus scavenger used in the present invention will be described. Since this phosphorus scavenger is described in detail in Patent Document 1 and Patent Document 2, only the main points will be described here. Three functions are required as a raw material having the ability to produce a crosslinked product used in the present invention and collect phosphorus. The first is cross-linking reactivity with a water-soluble polymer compound, that is, insolubilization by formation of a cross-linked structure, the second is water-soluble, and the third is reproducibility. The first function is an indispensable requirement for making a phosphorus scavenging substance chemically bonded to a polymer compound by a crosslinking reaction so as to be insolubilized and stably held. In the process of being used, it will be released into water, leading to a decrease in the performance of the phosphorus absorbent. The second function is a function necessary for producing a uniform phosphorus scavenger by mixing and dispersing uniformly with the water-soluble polymer compound in the production of the phosphorus scavenger. The third function is a function necessary for collecting the collected phosphorus and reusing it as a phosphorus resource.

Substances that satisfy the first to third functions and are economically selected are the water-soluble Zr compound and water-soluble Ti compound used in the present invention. The phosphorus scavenger raw material used in the present invention selected from such a viewpoint includes water-soluble Zr compounds such as zirconyl chloride, zirconyl sulfate, zirconyl nitrate, zirconyl acetate, zirconyl ammonium carbonate, chelate-based zirconium, aminocarboxylic acid-based zirconium, etc. And water-soluble Ti compounds such as titanium trichloride, titanium tetrachloride, titanium sulfate, titanium lactate, peroxotitanate, and chelate titanate.

Next, the water-soluble polymer compound will be described. As the polymer compound used in the present invention,
Two functions are required. The first is water-solubility, and the second is that it is complexed with a Zr compound or Ti compound having a potential phosphorus scavenging function by a crosslinking reaction by heating. The first function is a function necessary for producing a uniform phosphorus trapping material by uniformly mixing with a water-soluble Zr compound or Ti compound as described above, and the second function is potentially a phosphorus trap. This is a function necessary for insolubilizing and stabilizing the Zr compound or Ti compound having a collecting function and exhibiting an excellent phosphorus collecting ability. From such a viewpoint, the water-soluble polymer compound used in the present invention is a water-soluble polymer compound having any one of an alcohol group, an amino group, and a carboxyl group. Specifically, polyvinyl alcohol (PVA), ethylene Examples include vinyl alcohol (EVOH), polyacrylic acid (PAA), polyacrylamide, polyallylamine, and carboxymethyl cellulose (CMC), and copolymers and block polymers of these water-soluble polymer compounds. Among them, PVA is the most preferable material in consideration of crosslinkability and economy.

  Next, the production | generation of this crosslinked body is demonstrated. Figure 1 shows the structure of zirconium hydroxide polynuclear ion ([Zr4 (OH) 8] 8 + .nH2O) produced when zirconium oxychloride (ZrOCl2 · 8H2O), one of the water-soluble Zr compounds, is dissolved in water. FIG. 2 shows a model of a crosslinked product formed when this and PVA are crosslinked. That is, when the aqueous solution of the water-soluble Zr compound and the aqueous solution of PVA in FIG. 1 are mixed at an appropriate ratio, a mixed solution in which zirconium hydroxide polynuclear ions and PVA are uniformly mixed is obtained. At this point, the crosslinking reaction has occurred. Absent. When this mixed solution is heated, a part of the water is first evaporated to form a dry solidified body in which PVA and Zr hydroxide polynuclear ions are uniformly mixed. In this state, almost no crosslinking reaction occurs. Although it can be stored in this dried and solidified state, when it is immersed again in water, it will return to a homogeneous mixed solution of PVA and hydroxylated Zr polynuclear ions, and cannot be used as a phosphorus collecting material intended by the present invention. . Accordingly, when heating is performed continuously or in another process, as shown in FIG. 2, the alcohol group [—OH] of PVA and the hydroxyl group [—OH] of Zr hydroxide polynuclear ion release H 2 O by a condensation reaction, The polymer chains of PVA generate a three-dimensional polymer insoluble in water starting from Zr, and an insolubilized crosslinked structure is generated. This cross-linked body becomes a phosphorus scavenger.

  A part of the functional group of Zr in the cross-linked body adsorbs phosphate ions in water to form a phosphate Zr bond to collect phosphorus. Next, when this is washed with alkali, phosphorus binds to alkali ions and is desorbed from the cross-linked product to recover phosphorus. At the same time, Zr returns to its original reusable state. Here, since Zr in the crosslinked body reacts only with phosphorus ions, the selectivity to phosphorus becomes extremely high, and Zr is retained in the crosslinked body by a chemical bond, so that the Zr component is eluted during use. It does not peel off and exhibits high durability. Therefore, the collected phosphorus compound becomes a high-purity phosphorus compound containing no impurities. 1 and 2, the example in which zirconium oxychloride is used as the water-soluble Zr compound is shown. However, this is the same for the other Zr compounds and water-soluble Ti compounds described above. Although an example using PVA as a water-soluble polymer compound is shown, it goes without saying that the same applies to other water-soluble polymer compounds described above.

  Next, a method for producing the fibrous crosslinked body according to the present invention will be described.

  First, as in the conventional method for producing a crosslinked product, one or more aqueous solutions of a water-soluble Zr compound and a water-soluble Ti compound are prepared, and an aqueous solution of a water-soluble polymer compound is mixed therewith to prepare a uniform mixed solution. To do. In the following description, a water-soluble Zr compound is used as a representative of a water-soluble Zr compound and a water-soluble Ti compound, and PVA is used as a representative of a water-soluble polymer compound.

  In the conventional sheet coating method and porous carrier impregnation method, it is necessary to keep the viscosity of the mixed aqueous solution low. Therefore, as the PVA to be used, a PVA solution of about 10% by mass is used. The raw material solution was adjusted so that the Zr content was about 10% by mass of the amount. However, in the raw material solution of this level, the content of PVA and Zr is small and the viscosity is low. It is impossible to make it. Therefore, in the present invention, since the raw material solution discharged from the spinning nozzle is heated to evaporate and solidify the moisture, it can be said that the smaller the moisture is, the easier it is to solidify and energy saving, but the viscosity is too high. Therefore, the PVA raw material concentration to be used is preferably 30 to 50% by mass. In order to obtain this PVA aqueous solution, an aqueous solution having an appropriate viscosity can be obtained by adding PVA while heating at a water temperature of about 85 to 95 ° C. to obtain an aqueous solution. In addition, although the aqueous solution of Zr compound is added and mixed with this PVA aqueous solution, since the quantity of the Zr compound aqueous solution to add is small compared with the amount of PVA, this PVA density | concentration does not have a large difference with the PVA density | concentration in a mixed solution.

  Next, an aqueous solution of a Zr compound is added to and mixed with the PVA solution. When an aqueous solution of the Zr compound is added to and mixed with the high-temperature PVA solution at 85 to 95 ° C., the crosslinking reaction starts to proceed at that point. The solution is cooled to 60 ° C. or less where the crosslinking reaction is difficult to proceed, and an aqueous solution of a Zr compound is added and mixed. When PVA and a Zr compound are mixed in a temperature range higher than this, the mixed solution is gelled by a crosslinking reaction, and fiberization through a spinning nozzle becomes difficult. Since the amount of Zr compound added to the aqueous solution is generally proportional to the amount of Zr, the higher the amount of Zr added, the better the amount of Zr added to the amount of PVA in the mixed solution. The ratio, that is, PVA / Zr needs to be 9: 1 or more. On the other hand, if the amount of Zr is too large, the viscosity becomes too high and it becomes difficult to discharge from the spinning nozzle, so it is necessary to suppress it to 9: 3 or less. Let it be the mixed solution (raw material solution) of PVA and Zr compound adjusted in the way which concerns. That is, since the viscosity of the raw material affects the success or failure of the fiberization, as described above, the mixing ratio of PVA and Zr compound is adjusted appropriately from 9: 1 to 9: 3, and the PVA concentration in the mixed solution is also 30 to A mixed solution adjusted to be about 50% by mass, preferably 40 ± 5% by mass is used as a raw material solution.

  The raw material solution is discharged from a spinning nozzle to be fiberized. Here, the temperature of the raw material solution is set to 60 ° C. or less, preferably 50 ° C. or less, which is a temperature level at which the cross-linking reaction does not easily proceed, and is continuously discharged from the spinning nozzle into a filament shape, which is dried and solidified in a heated atmosphere. A crosslinking reaction is performed to obtain a crosslinked fiber. There are roughly two types of methods for producing the crosslinked fiber. The first method is a method for producing a continuous cross-linked fiber, and the second method is a method for producing a non-woven fabric using the cross-linked fiber. In the former, the raw material solution is discharged into a heating cylinder through which heated gas is circulated from a number of spinning nozzles in a thread form, the Zr-PVA mixed solution discharged in a thread form is dried and solidified, and a crosslinking reaction is allowed to proceed as necessary. In the latter method, the raw material solution is discharged from the spinning nozzle into a yarn shape, and hot air is blown out from the periphery of the spinning nozzle to remove moisture in the discharged yarn-shaped raw material solution. A dry body of Zr-PVA mixture that has been dried and solidified with hot air while evaporating is generated, dropped onto a wire mesh conveyor disposed below, deposited in a non-woven form, transferred, and transferred as necessary This is a method for producing a non-woven fabric of cross-linked fibers by heating with hot air to advance the cross-linking reaction. Hereinafter, both will be described.

  The conceptual diagram of the said continuous bridge | crosslinking body fiber manufacturing apparatus is shown in FIG. This apparatus includes a heating cylinder 2 having a spinning nozzle 1 at the top, an inlet nozzle 3 for supplying heated gas into the heating cylinder from the top of the heating cylinder 2, and a heating gas discharge nozzle 4 below the heating cylinder 2. A roll 6 is disposed immediately below the lower end opening 5 of the heating cylinder 2. The spinning nozzle 1 is provided with a large number of discharge pores, and the raw material solution is pressurized from the pores and discharged as a thin filament 7 into the heated gas atmosphere in the heating cylinder 2. The discharged filamentary raw material solution is heated by a heated gas such as a combustion gas in the heating cylinder 2 to evaporate water and become a fibrous dry body of a Zr-PVA mixture. At this stage, a part of the cross-linking reaction of the mixture has occurred, so this cross-linked portion is a reinforcing material for the fibrous dry body, and is a fibrous dry body having higher strength than existing PVA fibers. The fiber in the heating cylinder 2 is stretched by winding it at a speed faster than the discharge speed from the spinning nozzle 1 with a winder (not shown) through a roll 6 and a take-up machine (not shown). Thus, further thinning can be achieved. The fibrous dried body is continuously heated in the heating cylinder 2 to cause a crosslinking reaction, and is taken out from the lower end opening 5 of the heating cylinder 2 in a state in which the crosslinking reaction is almost completed and is continuously crosslinked. It will be wound on a bobbin or the like.

  In addition, it takes out from the heating cylinder 2 in the state of the fibrous dry body in which the above-mentioned cross-linking reaction is not completed (cross-linking is incomplete) to form an intermediate product, and the cross-linking reaction is performed in a separately provided heating furnace for cross-linking reaction You can also. Thus, in the case where a separate crosslinking step is provided after producing a fibrous dry body that has not yet been crosslinked, only heating and drying are required in the heating cylinder 2, so that the heated gas has a temperature and flow rate at a level necessary for moisture evaporation. Since the residence time in the heating cylinder 2 can be shortened, the heating cylinder 2 can be reduced in size, and the fiberizing apparatus can be made compact. In addition, heat treatment is performed in a heating furnace for cross-linking reaction separately provided with a fibrous dry body, but the heating furnace for cross-linking reaction does not need to be heated while the fiber is running, Since a heating furnace that can heat-treat a large amount of the wound fibrous dried body at a time can be used, an energy saving effect that can reduce thermal energy for the crosslinking reaction can be expected.

The cross-linked fiber continuously wound around the bobbin can be processed into a twisted yarn or a woven fabric and further processed into an arbitrary shape structure. The material can be manufactured.

  The conceptual diagram of the said nonwoven fabric-like crosslinked body fiber manufacturing apparatus is shown in FIG. In this apparatus, a raw material solution flow path 10 and a heated gas flow path 11 are provided in a spinning nozzle 1 in which a large number of discharge ports 12 are arranged and swingable in a lateral direction. A heated gas jet 13 is formed so as to surround the discharge hole 12. Below the nozzle 1, a net-like conveyor belt 14 having air permeability is disposed, and a hood 15 is disposed in front of the moving direction so as to cover the conveyor belt 14. The raw material solution is pumped to the raw material solution flow path 10 in the spinning nozzle 1 by an appropriate means such as a feed pump (not shown), and a large number of filaments from a large number of the tip discharge holes 12 of the oscillating nozzle 1. It is discharged as a body. At the same time, the heated gas is sprayed from the heated gas outlet 13 provided around the discharge hole 12 through the heated gas flow path 11 in the nozzle 1 toward the filamentous raw material solution discharged from the discharge hole 12, The filamentary raw material solution is heated to dry, and becomes a fibrous dry body of a Zr-PVA mixture, which is a raw material mixture, falling onto the conveyor belt 14 below the nozzle 1 while undulating in the horizontal direction and deposited in a nonwoven fabric form However, it is transported forward. This fibrous non-woven fabric-like deposit 16 is partially a cross-linked reaction, but is basically a dry solid of an uncrosslinked raw material mixture. Further, as the spinning nozzle 1, one in which discharge ports 12 of about 0.1 to 0.5 mm are arranged at a pitch of about 0.3 to 1 mm is used. Depending on the diameter of the discharge port 12 and the degree of subsequent stretching, the width of the non-woven fabric deposit depends on the number of discharge holes and the swinging width of the nozzle 1 and is determined in consideration of the dimensional specifications of the collected product. Needless to say.

  The nonwoven fabric deposit 16 of the fibrous dry body is transferred to the lower side of the hood 15 disposed in front of the conveyor 14 in the transfer direction. This hood 15 can be used in two ways. The first is fiber cooling and the second is fiber heating and cooling. In the former case, cooling air is supplied into the hood 15 by an appropriate means, and the cooling air is blown onto the nonwoven fabric-like deposit 16 being transferred on the conveyor to cool the deposit, and uncrosslinked fibers. It winds up with the winder (not shown) of the nonwoven fabric arrange | positioned at the front-end | tip part of the conveyor 14 as a dried product, and stores in a roll state. In the latter case, a heated gas such as a combustion gas is supplied into the hood 15 by an appropriate means, and the heated gas is blown toward the fibrous dried body being transferred on the conveyor, so that the fibrous dried body is discharged. A crosslinking reaction is allowed to proceed to form a fibrous crosslinked body. Then, it cools in the cooling zone (not shown) continuously formed in the food | hood 15, and as above-mentioned, it winds up with a winder (not shown) and stores as a crosslinked nonwoven fabric product in a roll state To do.

  Here, the heated gas ejected from the spinning nozzle 1 only needs to supply the latent heat of vaporization of the water in the raw material solution, and even if a crosslinking reaction has partially occurred, it is not necessary to complete this. From the viewpoint, the temperature and flow rate of the heated gas are determined. Further, in the first case in which cooling air is supplied from the hood 15, only cooling of the unfinished fibrous dry body is performed, and therefore air may be supplied appropriately. In this case, the wound non-woven fabric is an uncrosslinked fibrous dry body and is an intermediate product, and therefore has little phosphorus collecting function. In order to commercialize this as a crosslinked fiber, it is necessary to complete the crosslinking reaction by heating it to a predetermined temperature in a separate heating furnace as in the case described above. On the other hand, in the second case in which the heated gas is supplied from the hood 15, the uncrosslinked fibrous dry body being transferred on the conveyor is heated to advance the crosslinking reaction, thereby obtaining a Zr-PVA crosslinked body as a product. Since it is necessary, a heating gas is supplied so as to promote the crosslinking reaction so that the temperature level necessary for the crosslinking reaction can be maintained.

  The nonwoven fabric-like crosslinked fiber can be laminated and immersed in running water as a filter to collect phosphorus, or suspended in running water to collect phosphorus.

  In any of the above production methods, in any case, the filamentous body of the mixed solution discharged from the spinning nozzle is first heated and dried to form a fibrous dried body, and then the fibrous dried body is heated to advance the crosslinking reaction. The temperature of the heated gas used in each step varies depending on the method for producing a crosslinked fiber. First, it is necessary to supply a large latent heat of vaporization in order to dry the filament passing through at a high speed in a short time in the heating method in the method for producing a continuous cross-linked fiber. For this purpose, the temperature exceeds the boiling point of water. The high temperature of 150 to 250 ° C. is preferred. Further, when the crosslinked fiber is produced by continuing the crosslinking reaction after drying, the temperature in the heating cylinder is controlled to be 150 to 250 ° C. at the temperature of the heating cylinder outlet portion of the fiber. . On the other hand, in the case of producing a nonwoven fabric-like cross-linked fiber, the fibrous dry body that drops and accumulates on the conveyor belt maintains at least the fiber state and does not flow out from the opening of the mesh-shaped conveyor belt. It is necessary to adjust the temperature and flow rate of the heated gas so that it is dried. As the temperature of the heated gas, it is necessary to dry the filament of the mixed solution discharged from the spinning nozzle in a short time. A heated gas spray at 0 ° C. is preferred. Subsequently, when the crosslinking reaction is allowed to proceed on the conveyor, a heated gas of 100 to 250 ° C. is sprayed.

Next, the fiber diameter of the crosslinked fiber will be described. This fiber diameter is determined by the nozzle diameter of the spinning nozzle and the degree of stretching at the time of winding in the case of the continuous crosslinked fiber manufacturing method, but in the case of dry spinning of PVA (similar to the method described in FIG. 3). A smooth surface is obtained at 1000 denier or less, but the surface tends to be rough at more than 1000 denier. In the crosslinked fiber of the present invention, since the crosslinking reaction proceeds from the fiber surface, there is a risk that the strength of the crosslinked fiber itself may be reduced if cracks occur in the crosslinked structure of the surface layer in the process of stretching during spinning, Since fine suspended matters (SS) in the treated water may be caught and cause a decrease in phosphorus collection performance, a fiber diameter of 1000 denier or more that tends to be rough on the surface should be avoided, so 1000 denier or less, The fiber diameter is 170 μm or less. The fiber diameter is inversely proportional to the surface area of the crosslinked fiber, that is, the smaller the fiber diameter, the greater the specific surface area per unit weight (surface area per unit weight) and the phosphorus capturing ability increases. It can be said that the thinner the fiber diameter, the better. Incidentally, in the conventional application method of Zr-PVA mixed solution, when a mixed solution in which Zr: PVA is mixed at a ratio of 1: 9 is applied to a vinylon sheet with a solution of 100 g in terms of Zr-PVA per 1 m ^2. 1 gq (mg equivalent = 31 mg phosphorus) has a phosphorus collection capacity per 1 g of Zr-PVA cross-linked product, but by simply fiberizing this, the amount of phosphorus collected in the case of the aforementioned fiber diameter of 170 μm is 1.8 times, 20 μm, about 15 times, 10 μm, 30 times, 5 μ, 60 times.

  If the amount of Zr added is adjusted in addition to the above fiber diameter design, a higher performance phosphorus scavenger can be obtained. That is, the phosphorus collection capacity of the crosslinked fiber is proportional to the Zr content. Therefore, when the conventional Zr addition amount is doubled (or tripled), the phosphorus collection capacity of the crosslinked fiber is 3.70 μm. It becomes 6 times (5.4 times), about 30 times (45 times) at 20 μm, 60 times (90 times) at 10 μm, and 120 times (180 times) at 5 μm. The performance improvement of general adsorbents could not be improved by several tens to several hundreds of times in this way, but in the phosphorus collection material of the present invention, it is amazing performance by fiberizing this An improvement can be achieved. By adjusting the amount of Zr added in addition to the design, a higher performance phosphorus scavenger can be obtained. That is, the phosphorus collection capacity of the crosslinked fiber is proportional to the Zr content. Therefore, when the conventional Zr addition amount is doubled (or tripled), the phosphorus collection capacity of the crosslinked fiber is 3.70 μm. It becomes 6 times (5.4 times), about 30 times (45 times) at 20 μm, 60 times (90 times) at 10 μm, and 120 times (180 times) at 5 μm. The performance improvement of general adsorbents could not be improved by several tens to several hundreds of times in this way, but in the phosphorus collection material of the present invention, it is amazing performance by fiberizing this An improvement can be achieved.

  Next, examples of the present invention will be described, but the present invention is not limited to these examples.

<Raw material solution: Preparation of Zr-PVA mixed aqueous solution>
Completely saponified PVA having an average degree of polymerization of 1200 is dissolved in ion exchange water at 90 ° C. while being cooled to 50 ° C., and the aqueous solution of zirconium acetate is adjusted so that the weight ratio of PVA / Zr = 9/1. The mixture was added and mixed while stirring with a drier to prepare a mixed solution (spinning stock solution) having a PVA concentration of 34 wt%.

<Manufacture of crosslinked fiber>
The above raw material solution is discharged into heated air at 150 ° C. using a spinning nozzle having a diameter of 0.1 mm and a number of holes of 25 by using the apparatus shown in FIG. 2 at 50 ° C. to dry the filamentous Zr-PVA mixture. After forming a body and stretching it 1.5 times, it was heat-treated with heated air at 220 ° C. to advance a crosslinking reaction to produce a Zr-PVA crosslinked body fiber. As a result, 12 g of a crosslinked fiber having a fiber diameter of 40 μm was obtained. A photograph of the crosslinked fiber is shown in FIG.

<Phosphorus collection test>
In order to investigate the phosphorus collection ability of the crosslinked fiber obtained by the above-mentioned production method, 0.2 g of the crosslinked fiber was prepared and immersed in 20 cc of 1000 ppm and 10 ppm of potassium dihydrogen phosphate aqueous solution for 3 days. The amount of phosphorus collected was measured. As a result, in the case of being immersed in a 10 ppm aqueous solution, almost all phosphorus was collected, and the phosphorus in the solution was 0.01 ppm or less. In the case of being immersed in a 1000 ppm solution, phosphorus in the solution was about 250 ppm, and about 750 ppm phosphorus was collected.

  As a result of this test, 0.2 g of the crosslinked fiber has 15 mg of phosphorus collecting ability, which indicates that 1 g of crosslinked fiber has 75 mg of phosphorus collecting ability. In other words, the phosphorus collection capacity of 1 g of the crosslinked fiber is about 2.5 meq, which is the same raw material blending ratio (PVA / Zr = 9/1) as compared with the case where the Zr-PVA mixed solution is applied to the conventional sheet. But the phosphorus collection capacity is about 2.5 times. Considering the above-mentioned wire diameter effect and Zr addition increasing effect, it was judged that it was easy to obtain a high-performance phosphorus collection material having a phosphorus collection ability several tens of times.

  In the above examples, zirconium acetate is used as the water-soluble Zr compound and PVA is used as the water-soluble organic compound. However, the present invention is not limited to this combination, and is described in the claims. Needless to say, combinations of various compounds can be used.

  In addition, heated gas is used to heat the uncrosslinked dry mixture to advance the crosslinking reaction, but this may be a method of immersing the dry mixture in an oil bath at 100 to 250 ° C. .

  Since the present invention has succeeded in fiberizing a reusable phosphorus trapping material comprising a crosslinked product of a polymer compound that uses a water-soluble Zr compound or a water-soluble Ti compound and a water-soluble polymer compound as raw materials, An ultra-high performance phosphorus collection material having a large specific surface area can be made inexpensively and easily, and since a carrier which is a conventional fixing concept of this kind is not used, the crosslinked fiber itself is 100% phosphorus collection. Since the device that is used as a material and is filled and used is also extremely compact and inexpensive, it is possible to efficiently and inexpensively recover the phosphorus resources demanded by the times. Therefore, it can be used to collect phosphorus in various wastewaters, recover phosphorus from rivers and lakes, and further recover phosphorus from the ocean, and not only remove conventional phosphorus for environmental problems and ecosystem conservation, but also 100% It becomes easy to establish a recycling system by collecting phosphorus resources that depend on imports. In this sense, the present invention is an extremely useful invention in terms of Japan's resource strategy, and thus has a great social significance and is expected to be used in various fields.

DESCRIPTION OF SYMBOLS 1 Spinning nozzle 2 Heating cylinder 3 Heated gas supply nozzle 4 Heated gas discharge nozzle 6 Roll 7 Discharged filament 10 Raw material solution flow path 11 Heated gas flow path 12 Raw material solution discharge hole 13 Heated gas ejection port 14 Conveyor belt 15 Heating ( Cooling) Hood 16 Fibrous deposit (nonwoven fabric)

Claims (16)

A phosphorus collecting material for collecting phosphorus compounds in water,
Heating a mixed aqueous solution comprising at least one of a water-soluble zirconium compound and a water-soluble titanium compound and a water-soluble polymer compound having at least one of an alcohol group, an amino group and a carboxyl group, to thereby form the water-soluble zirconium A crosslinked structure formed by insolubilizing at least one of zirconium in the compound or titanium in the water-soluble titanium compound by crosslinking reaction with any of alcohol group, amino group and carboxylic acid group of the water-soluble polymer compound A recyclable phosphorus collecting material comprising a body and having a crosslinked structure in a fibrous form.   The water-soluble zirconium compound is selected from the group consisting of zirconyl chloride, zirconyl sulfate, zirconyl nitrate, zirconyl acetate, zirconyl ammonium carbonate, chelate-based zirconium and aminocarboxylic acid-based zirconium. The phosphorus scavenger according to claim 1, which is selected from the group consisting of titanium chloride, titanium tetrachloride, titanium sulfate, titanium lactate, peroxotitanate and chelate titanate.   The water-soluble polymer compound is selected from the group of polyvinyl alcohol, ethylene vinyl alcohol, polyacrylic acid, polyacrylamide, polyallylamine and carboxymethyl cellulose, and copolymers and block polymers of these water-soluble polymer compounds The phosphorus trapping material according to claim 1 or 2.   The phosphorus scavenger according to claim 1, wherein the water-soluble polymer compound is polyvinyl alcohol and the water-soluble zirconium compound is zirconyl acetate.   The phosphorus trapping material according to any one of claims 1 to 4, wherein the fibrous crosslinked structure has a fiber diameter of 170 µm or less.   The phosphorus trapping material according to claim 5, wherein the crosslinked structure has a fiber diameter of 100 μm or less.   The phosphorus collection material according to claim 1, wherein the phosphorus collection material is formed on a woven fabric or a nonwoven fabric. A method for producing a phosphorus collector for collecting phosphorus compounds in water,
A mixed aqueous solution composed of one or more of a water-soluble zirconium compound and a water-soluble titanium compound and a water-soluble polymer compound having at least one of an alcohol group, an amino group, and a carboxyl group is discharged from a spinning nozzle into a heated gas. And drying and solidifying step to form a fibrous dried body, and further heating the water-soluble zirconium compound and at least one of titanium in the water-soluble titanium compound and titanium in the water-soluble titanium compound as the crosslinking point. The manufacturing method of the phosphorus collection material which has a crosslinking reaction process which carries out a crosslinking reaction with either the alcohol group of a high molecular compound, an amino group, and a carboxylic acid group, and makes it a crosslinked structure.   The method for producing a phosphorus-trapping material according to claim 8, wherein the drying and solidification step and the crosslinking reaction step are continuously performed.   The manufacturing method of the phosphorus collection material of Claim 8 which made the fibrous dry body obtained at the said drying solidification process an intermediate product, and performed the crosslinking reaction process with the heating apparatus which provided this separately.   The water-soluble zirconium compound is selected from the group consisting of zirconyl chloride, zirconyl sulfate, zirconyl nitrate, zirconyl acetate, zirconyl ammonium carbonate, chelate-based zirconium and aminocarboxylic acid-based zirconium. The method for producing a phosphorus scavenger according to any one of claims 8 to 10, which is selected from the group consisting of titanium chloride, titanium tetrachloride, titanium sulfate, titanium lactate, peroxotitanate and chelate titanate.   The water-soluble polymer compound is selected from the group of polyvinyl alcohol, ethylene vinyl alcohol, polyacrylic acid, polyacrylamide, polyallylamine and carboxymethyl cellulose, and copolymers and block polymers of these water-soluble polymer compounds The method for producing a phosphorus scavenger according to any one of claims 8 to 11.   The water-soluble polymer compound is polyvinyl alcohol, an aqueous solution of the polyvinyl alcohol and the water-soluble zirconium compound are mixed at a temperature of 50 ° C. or less, and this mixed liquid is discharged from a spinning nozzle into hot air to form a fiber. The manufacturing method of the phosphorus collection material in any one of Claims 8 thru | or 10 which made it crosslink-react at 100-250 degreeC to make a crosslinked structure.   The concentration of polyvinyl alcohol in the mixed aqueous solution of the polyvinyl alcohol and the water-soluble zirconium compound is 40% by mass or less, and the mass ratio of zirconium in the polyvinyl alcohol and the water-soluble zirconium compound is 9: 1 to 9: The method for producing a phosphorus scavenger according to claim 13, which is in the range of 3.   A phosphorus collection method for phosphorus-containing wastewater, wherein the phosphorus-collecting material according to claim 1 is suspended in the phosphorus-containing wastewater to collect phosphorus in the wastewater.   Phosphorus collection of phosphorus-containing wastewater in which the phosphorus-collecting material produced by the production method according to any one of claims 8 to 14 is suspended in the phosphorus-containing wastewater to collect phosphorus in the wastewater. Method.