JP2008238006A - Phosphorous scavenger, and method for removing phosphorous in water to be treated - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a scavenger capable of efficiently catching phosphorous. <P>SOLUTION: The phosphorous scavenger has a structure of specified general formula, and comprises a zinc complex compound having affinity to an organic solvent. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a phosphorus scavenger and a method for removing phosphorus in water to be treated using the same.

  One of the main components that brings about eutrophication in water areas such as rivers and lakes is phosphorus, and by removing this from the water area, large-scale occurrence of blue sea bream can be effectively prevented. Phosphorus compounds are more present in domestic household and domestic livestock wastewater than in factory wastewater. For this reason, a technique for efficiently removing phosphorus in wastewater including domestic wastewater is required.

  Patent Document 1 and Non-Patent Document 1 describe a compound that captures phosphorus for detecting phosphate ions contained in a solution. Since these compounds emit fluorescence or change color by ion exchange with phosphate ions, they can be used for detection of phosphate ions. However, even if it is applied to the removal of phosphorus in wastewater, it dissolves as a phosphate and exists in the wastewater. As a result, phosphorus (phosphate ions) cannot be removed from the wastewater.

  Patent Document 2 describes a zinc complex capable of capturing a substance having an anionic substituent such as a divalent phosphate monoester anion. In the column of utilization of the complex in paragraph [0058] of Patent Document 2, the capture target is a phosphate monoester anion, and the zinc complex is supported on a support such as a polymer membrane, a column support, or a plate hole. It is described that it is used as an agent. As a method of supporting a complex on a carrier, a method of covalently bonding a substituent (amino group, hydroxyl group, etc.) introduced into a pyridine skeleton, which is a ligand of the complex, to a carrier such as a polymer with a crosslinking agent, A method is described in which a binder is mixed with a complex and the mixture is foamed and granulated.

  However, since the zinc complex described in Patent Document 2 has high solubility in water, in the latter method in which the complex is simply supported on a carrier via a binder, a zinc complex that captures a phosphate monoester anion in wastewater is used. It becomes difficult to dissolve in the wastewater and separate from the wastewater. That is, it becomes difficult to remove the phosphate monoester anion in the wastewater.

The former method in which the complex is covalently supported on the polymer carrier allows the zinc complex to exist without being dissolved in the wastewater, and after the phosphate monoester anion in the wastewater is captured, the polymer is removed. By separating, the phosphate monoester anion in the wastewater can be removed. However, since the site of the zinc complex that is covalently bonded to the polymer is a Zn ligand that is directly involved in the capture of the phosphate monoester anion, the coordination structure of the zinc complex is supported when the zinc complex is supported on the polymer. May change, and the phosphorus capturing ability may be reduced.
JP2003-246788 WO2003 / 053932 Angew. Chem. Int. Ed. 2002, 41, No. 20, 3809-3811

  The present invention provides a scavenger capable of efficiently capturing phosphorus, and a method for removing phosphorus in treated water that can efficiently remove phosphorus as water purification of treated water such as wastewater. For the purpose.

According to the present invention, there is provided a phosphorus scavenger characterized by containing a compound represented by the following general formula (I) and having an affinity for an organic solvent.

R ₁ in the formula has 4 to 20 carbon atoms and is a hydrocarbon group selected from aliphatic hydrocarbons or aromatic hydrocarbons, and R ₂ , R ₃ , R ₄ and R ₅ are H or aliphatic. Represents a hydrocarbon group, which may be the same or different, and X represents N or O;

According to the present invention, the water to be treated containing phosphorus is stirred together with a phosphorus scavenger containing a compound represented by the following general formula (I) and a recovery solvent for the phosphorus scavenger, There is provided a method for removing phosphorus in water to be treated, characterized in that the recovered solvent that has been placed and has taken in the phosphorus scavenger is phase-separated from the water to be treated.

R ₁ in the formula has 4 to 20 carbon atoms and is a hydrocarbon group selected from aliphatic hydrocarbons or aromatic hydrocarbons, and R ₂ , R ₃ , R ₄ and R ₅ are H or aliphatic. Represents a hydrocarbon group, which may be the same or different, and X represents N or O;

  According to the present invention, there is provided a scavenger capable of efficiently capturing phosphorus, and a method for removing phosphorus in treated water that can efficiently remove phosphorus as water quality purification of treated water such as wastewater. Can be provided.

  Hereinafter, a phosphorus scavenger and a phosphorus removal method according to an embodiment of the present invention will be described in detail.

(First embodiment)
The phosphorus scavenger according to the embodiment is represented by the following general formula (I) and contains a compound having an affinity for an organic solvent. This compound is liquid and hardly soluble in water.

R ₁ in the formula has 4 to 20 carbon atoms and is a hydrocarbon group selected from aliphatic hydrocarbons or aromatic hydrocarbons, and R ₂ , R ₃ , R ₄ and R ₅ are H or aliphatic. Represents a hydrocarbon group, which may be the same or different, and X represents N or O;

As R ₁ in the general formula (I), an aliphatic hydrocarbon group having 4 to 20 carbon atoms or an aromatic hydrocarbon group is used. If the carbon number is less than 4, separation from the treated water may be difficult after capturing phosphorus in the treated water, and if the carbon number exceeds 20, the affinity for the organic solvent may be lost. More preferably, an aliphatic hydrocarbon group having 7 to 15 carbon atoms or an aromatic hydrocarbon group is used, and these aliphatic hydrocarbon groups may be saturated, unsaturated, linear or branched. For example, an alkyl group, cycloalkyl group, alkylcycloalkyl group, aryl group, arylalkyl group, alkaryl group, aryl group, aralkyl group, alkenyl group, alkynyl group, alicyclic and saturated or unsaturated heterocyclic group Specific aromatic hydrocarbon groups having the following structures (1) to (7) can be used.

  The aliphatic hydrocarbon group and the aromatic hydrocarbon group are preferably nonpolar groups in order to facilitate removal of phosphorus from the water to be treated. For example, a carboxyl group (—COOH) and a hydroxyl group (—OH) are preferred. May have various reactive groups.

<Synthesis method>
A compound represented by the general formula (I), for example, a compound in which R ₁ is a dodecyl group (n—C ₁₂ H ₂₅ —), R ₂ , R ₃ , R ₄ , R ₅ is H and X is O It can be synthesized by the following method.

First, p-dodecylphenol, 2,2′-dipicolylamine and paraformaldehyde are stirred under reflux in a solvent of pure water and ethanol. Subsequently, chloroform is added to this solution to extract (an organic solvent containing p-dodecylphenol, 2,2′-dicomylamine and paraformaldehyde), and then this extract is salted out with a saturated sodium chloride solution. The organic layer is dried over sodium sulfate, concentrated under reduced pressure, recrystallized with diethyl ether / hexane = 1/1, and is a compound that becomes a ligand of white crystals having a dodecyl group introduced as R ₁ , 2,6- Bis {[bis (2-pyridylmethyl) amino] methyl} 4-dodecylphenol is obtained. Next, this compound is dissolved in acetone, a zinc salt (for example, zinc perchlorate hexahydrate) is added, and acetone is concentrated under reduced pressure, whereby R _{1 in the} general formula (I) is converted to a dodecyl group (n-C ₁₂ H _25- ), a compound in which R ₂ , R ₃ , R ₄ and R ₅ are H and X is O is synthesized.

  The synthesized compound can be identified from, for example, NMR spectrum data.

  The phosphorus scavenger according to the embodiment can be used in a form in which the compound represented by the general formula (I) is supported on various carriers. As the carrier, metal oxides, chlorides, sulfides or silicate minerals, carbides, polymers, and the like can be used. For example, magnesium oxide, magnesium hydroxide, aluminum hydroxide, polyaluminum chloride, sodium aluminate, Aluminum sulfate, alumina hydrate with pseudoboehmite structure, Si-Al-Ca oxide, Si-Fe-Ca oxide, calcium silicate hydrate, calcium hydroxide, calcium sulfate, titanium oxide, titanium chloride , Iron hydroxide, electrolytic iron, iron chloride, pearlite, amorphous iron iron sulfate, iron powder, magnetic iron oxide (fine particles), copper hydroxide, zinc hydroxide, zirconium ferrite, zirconium silicate, rare earth hydroxide Activated alumina, aluminum sulfate impregnated alumina, mesoporous silica, poorly permeable soil, volcanic ash, high Mention may be made of slag, activated carbon, porous carbide, cement, silica gel, a.

  As described above, the phosphorus scavenger according to the embodiment includes the compound represented by the general formula (I), and the compound has a structure in which an aromatic ring is bonded to X (for example, O) coordinated with Zn. Therefore, it is possible to exhibit high trapping performance with respect to phosphorus (phosphate ion) in the Zn ligand. In addition, the compound represented by the general formula (I) is imparted with an affinity for an organic solvent by introducing a hydrophobic group, for example, an aliphatic hydrocarbon group having a specific carbon number, into the ligand.

<Method of removing phosphorus in treated water>
Next, the phosphorus removal method in to-be-processed water which concerns on embodiment is demonstrated in detail.

  For example, after mixing and stirring a phosphorus scavenger containing a compound represented by the general formula (I) and a phosphorus scavenger recovery solvent in treated water containing phosphorus, such as domestic household or domestic livestock wastewater Then, the recovered solvent that has been allowed to stand to take in the phosphorus scavenger is phase-separated from the water to be treated. At this time, phosphorus (phosphate ion) in the water to be treated is captured by the Zn ligand of the compound represented by the general formula (I), and the phosphorus scavenger containing the compound capturing the phosphorus is captured in the recovery solvent.

Specifically, the coexistence of the phosphorus scavenger and the recovery solvent in the water to be treated is (1) adding the phosphorus scavenger to the water to be treated and stirring to contact the water to be treated and the phosphorus scavenger. And then adding the recovered solvent further,
(2) A method in which the phosphorus scavenger and the recovery solvent are mixed in advance and added to the water to be treated.
Is adopted.

  Among the above methods, the method (2) is preferable because it can improve the phosphorus scavenging ability of the compound represented by the general formula (I) by the Zn ligand.

  The recovery solvent for the phosphorus scavenger is, for example, an organic solvent, and any solvent may be used as long as it is compatible or immiscible with water, and chloroform, ethyl acetate, toluene, xylene and the like can be used.

In particular, when the water to be treated is a weak alkali having a pH of 6 to 12, more preferably pH 9 to 11, a large amount in the water to be treated as divalent phosphate ions (HPO ₄ ²⁻ ) that easily capture phosphorus with respect to the phosphorus scavenger. It becomes possible to make it exist, and it becomes possible to improve the capture | acquisition property of phosphorus. In addition, when the pH value of to-be-processed water remove | deviates from 6-12, a pH adjuster is added. Examples of the pH adjuster used here include alkaline agents such as potassium hydroxide, sodium hydroxide, potassium carbonate and sodium carbonate, and acids such as hydrochloric acid and nitric acid.

  The scavenger is preferably added in an amount of 2 equivalents or more with respect to phosphate ions in the water to be treated.

  Next, the phosphorus in the water to be treated is removed by collecting the recovered solvent phase-separated from the water to be treated in a state in which the phosphorus scavenger is taken in and separating it from the water to be treated.

  The phosphorus scavenger incorporated in the separated recovery solvent can dissociate and recover phosphorus by adding an appropriate salt. For example, a calcium salt such as calcium chloride or calcium carbonate is added to the recovery solvent, an aqueous solution having a pH of 4 or less or a pH of 11 or more is added, and the phosphorus and the calcium trapped in the phosphorus scavenger are reacted by stirring to react with calcium phosphate The phosphorus is recovered by precipitation as Further, an aqueous solution containing a calcium salt such as calcium chloride or calcium carbonate is added to the recovery solvent, and the mixture is stirred and heated at a temperature below the boiling point of the recovery solvent used, for example, at a temperature of 40 to 60 ° C. Phosphorus is recovered by reacting phosphorus trapped in calcium with calcium to precipitate calcium phosphate.

  As described above, according to the present embodiment, the phosphorus scavenger containing the compound represented by the general formula (I) and the phosphorus scavenger recovery solvent coexist in the water to be treated containing phosphorus and stirred, and then left to stand for phosphorus. Phosphorus in the water to be treated can be efficiently removed by phase-separating the recovered solvent in which the scavenger is taken into the water to be treated and collecting the recovered solvent layer.

That is, in the compound of the general formula (I) constituting the phosphorus scavenger, a hydrophobic group such as an aliphatic hydrocarbon group is introduced into the ligand as R ₁ , and has an affinity for an organic solvent. Although it is sparingly soluble, it is liquid, so that it is difficult to separate and recover the scavenger from the water to be treated after capturing phosphorus in the water to be treated with the phosphorus scavenger.

  For this reason, utilizing the fact that the compound of the general formula (I) has an affinity for an organic solvent, allowing the phosphorus scavenger and the recovery solvent to coexist in the water to be treated, and then allowing to stand. Thus, the phosphorus scavenger can be taken into the recovered solvent and the recovered solvent can be phase-separated from the water to be treated. In other words, the phosphorus scavenger that has been difficult to separate from the water to be treated can be separated from the water to be treated by incorporating the phosphorus scavenger into the recovery solvent phase-separated from the water to be treated. As a result, by recovering the recovered solvent phase-separated from the water to be treated, the phosphorus scavenger trapped in the recovered solvent and trapping phosphorus is separated out of the water to be treated to remove phosphorus from the water to be treated. can do.

  In particular, before adding a water-insoluble phosphorus scavenger to the water to be treated, it is mixed in advance with an affinity organic solvent (recovered solvent), and phosphorus (phosphate ions) in the water to be treated is passed through the organic solvent. Thus, phosphate ions can be efficiently captured.

  Hereinafter, embodiments of the present invention will be described in detail.

(Synthesis Example 1)
A 100 mL flask was charged with 1.0 g of p-dodecylphenol, 2.89 g of 2,2′-dipicolylamine and 0.44 g of paraformaldehyde, and refluxed at 80 ° C. for 3 days in a solvent of 10 mL of pure water and 5 mL of ethanol. And stirred. This solution was extracted by adding 50 mL of chloroform, and salted out with a saturated sodium chloride solution. The organic layer was dried over sodium sulfate, concentrated under reduced pressure, and recrystallized with diethyl ether / hexane = 1/1 to obtain a white crystalline compound of the structural formula (A) shown below. Subsequently, 50 mg of the obtained compound was dissolved in acetone, 54 mg of zinc perchlorate hexahydrate was added, and acetone was further concentrated under reduced pressure to obtain a liquid compound.

The structural formula (A) ¹ H-NMR spectra at ¹ obtained following the spectroscopy H-NMR Acetone-d6 (room temperature), ¹³ C-NMR spectroscopy by obtained following ¹³ C-NMR Identified from spectrum in acetone-d6 (room temperature) and fast atom bombardment ionization mass spectrometry (FAB-MS method).

¹ H-NMR acetone-d6 (room temperature):
_{· 8.56-6.70ppm; 18H, NC 5 H} 4,
_{· 3.30-4.30ppm; 12H, CH 2 -N} , (s),
_{· 0.10-2.00ppm; 25H, C 12 H} 25, (m)
¹³ C-NMR acetone-d6 (room temperature):
· 170-105ppm; NC ₅ H _4,
· 65-50ppm; CH ₂ -N
Moreover, the molecular weight peak (m / e) obtained by FAB-MS method was 1013.

m / e indicates a number obtained by dividing the molecular weight of the compound by the valence.

(Synthesis Example 2)
A 100 mL flask was charged with 1.2 g of p-triphenylmethylphenol, 2.65 g of 2,2′-dipicolylamine and 0.41 g of paraformaldehyde, and the mixture was kept at 80 ° C. for 3 days in a solvent of 10 mL of pure water and 5 mL of ethanol. Stir under reflux. This solution was extracted by adding 50 mL of chloroform, and salted out with a saturated sodium chloride solution. The organic layer was dried over sodium sulfate, concentrated under reduced pressure, purified by silica gel column chromatography using chloroform / methanol = 29/1, and recrystallized with diethyl ether / hexane = 1/1. A white crystalline compound of structural formula (B) was obtained. Subsequently, 50 mg of the obtained compound was dissolved in acetone, 54 mg of zinc perchlorate hexahydrate was added, and acetone was further concentrated under reduced pressure to obtain a liquid compound.

The structural formula (B) is ¹ H-NMR spectra at ¹ obtained following the spectroscopy H-NMR Acetone-d6 (room temperature), ¹³ C-NMR spectroscopy by obtained following ¹³ C-NMR Identified from the spectrum at acetone-d6 (room temperature) and from the FAB-MS method.

¹ H-NMR acetone-d6 (room temperature):
_{· 8.55-6.8ppm; 33H, NC 5 H} 4 ( or _{C 6 H 5), (d} ),
_{· 4.3-3.2ppm; 12H, CH 2 -N} , (s),
¹³ C-NMR acetone-d6 (room temperature):
165-115 ppm; NC ₅ H ₄ (or C ₆ H ₅ ),
· 50-65ppm; CH ₂ -N
The molecular weight peak (m / e) obtained by the FAB-MS method was 1086.

Example 1
In the container, 50 mL of a pH 8.4 aqueous solution containing 20 ppm phosphate ions in the form of Na ₂ PO ₄ was accommodated. To this aqueous solution, 40 mg of the liquid compound obtained in Synthesis Example 1 which is a phosphorus scavenger (equivalent to phosphate ions) mixed with 10 mL of chloroform was added, and the aqueous solution and the compound were contacted while being stirred and dispersed. Thus, phosphorus (divalent phosphate ion: HPO ₄ ²⁻ ) in the aqueous solution was captured by the compound. After stirring for 5 minutes and suspending with chloroform, the mixture was allowed to stand, and chloroform was phase-separated and settled in the lower layer of the aqueous solution in the container. Thereafter, the aqueous solution and chloroform were separated. The residual phosphate ion concentration of the aqueous solution after separation was measured by molybdenum spectrophotometry. The results are shown in Table 1 below.

  Further, except that the liquid compound obtained in Synthesis Example 1 which is a phosphorus scavenger was added in 2 equivalents and 4 equivalents to the aqueous solution, respectively, phosphate ions were captured in the same manner, and the aqueous solution after separation of chloroform was separated. The residual phosphate ion concentration was measured by molybdenum spectrophotometry. The results are shown in Table 1 below.

(Example 2)
In the container, 50 mL of an aqueous solution of pH 8.3 containing 20 ppm phosphate ions in the form of Na ₂ PO ₄ was accommodated. To this aqueous solution, 40 mg of the liquid compound obtained in Synthesis Example 2 which is a phosphorus scavenger (equivalent to the phosphate ion) is added, and the aqueous solution and the compound are brought into contact with stirring to disperse the phosphorus (divalent) in the aqueous solution. Of phosphate ion: HPO ₄ ²⁻ ) was captured by the compound. Subsequently, 10 mL of chloroform was added to this mixed solution, and the mixture was stirred for 5 minutes to suspend the chloroform, and then allowed to stand. At this time, chloroform separated and floated on the aqueous solution in the container. Thereafter, the aqueous solution and chloroform were separated. The residual phosphate ion concentration of the aqueous solution after separation was measured by molybdenum spectrophotometry. The results are shown in Table 1 below.

Further, phosphate ions were captured and chloroform was separated in the same manner except that the liquid compound obtained in Synthesis Example 2 as a phosphorus scavenger was added in 2 equivalents and 4 equivalents to the aqueous solution. Thereafter, the residual phosphate ion concentration in the aqueous solution was measured by molybdenum spectrophotometry. The results are shown in Table 1 below.

  As is clear from Table 1 above, the compounds obtained in Synthesis Examples 1 and 2 which are phosphorus scavengers are mixed with chloroform in an aqueous solution containing phosphate ions and added to chloroform to separate chloroform. It can be seen that the method can sufficiently capture phosphorus with a phosphorus scavenger. Therefore, phosphorus can be removed from the aqueous solution by separating the capture agent that has captured phosphorus from the aqueous solution together with chloroform.

  In particular, the method of adding 4 equivalents of each of the compounds obtained in Synthesis Examples 1 and 2 that are phosphorus scavengers to an aqueous solution containing phosphate ions with respect to the phosphate ions has high phosphorus scavenging performance, It can be seen that phosphorus can be removed more efficiently.

In addition, the method of Example 2 in which 2 equivalents of the compound obtained in Synthesis Example 2 in which triphenylmethyl is introduced as R ₁ of the general formula (I) is added to an aqueous solution containing phosphate ions as a phosphorus scavenger is Compared to the method of Example 1 in which the same amount (2 equivalents) of the compound obtained in Synthesis Example 1 in which dodecyl is introduced as R ₁ of formula (I) is added as a phosphorus scavenger to an aqueous solution containing phosphate ions, It can be seen that the scavenging performance of is high and the removal rate of phosphorus in the aqueous solution can be remarkably improved.

(Example 3)
In the container, 50 mL of an aqueous solution having a pH of 8.3 containing 20 ppm phosphate ions in the form of Na ₂ PO ₄ and containing 20 ppm of NO ₃ ⁻ , SO ₄ ²⁻ , Cl ⁻ , and Br ⁻ as anions was accommodated. To this aqueous solution, 40 mg of the liquid compound obtained in Synthesis Example 1 which is a phosphorus scavenger (equivalent to phosphate ions) mixed with 10 mL of chloroform was added, and the aqueous solution and the compound were contacted while being stirred and dispersed. Then, phosphorus (divalent phosphate ion: HPO ₄ ²⁻ ) in the aqueous solution was selectively captured by the compound. After stirring for 5 minutes and suspending chloroform, the mixture was allowed to stand, and chloroform was phase-separated and settled on the upper and lower layers of the aqueous solution in the container. Thereafter, the aqueous solution and chloroform were separated. The residual phosphate ion concentration of the aqueous solution after separation was measured by molybdenum spectrophotometry. The results are shown in Table 2 below.

  The aqueous solution after selective capture of phosphate ions and separation of chloroform by the same method except that the liquid compound obtained in Synthesis Example 1 as a phosphorus scavenger was added to the aqueous solution in 2 equivalents and 4 equivalents, respectively. The residual phosphate ion concentration was measured by molybdenum spectrophotometry. The results are shown in Table 2 below.

Example 4
Example 3 except that 80 mg (2 equivalents of phosphate ion) of the liquid compound obtained in Synthesis Example 1 as a phosphorus scavenger was added to an aqueous solution containing phosphate ions and various anions, and ethyl acetate was used as the organic solvent. The residual phosphate ion concentration was measured by molybdenum absorptiometry by the same method as described above. The results are shown in Table 2 below.

(Example 5)
In the container, 50 mL of an aqueous solution having a pH of 8.3 containing 20 ppm phosphate ions in the form of Na ₂ PO ₄ and containing 20 ppm of NO ₃ ⁻ , SO ₄ ²⁻ , Cl ⁻ , and Br ⁻ as anions was accommodated. To this aqueous solution, 40 mg of the liquid compound obtained in Synthesis Example 2 which is a phosphorus scavenger (equivalent to the phosphate ion) is added, and the aqueous solution and the compound are brought into contact with stirring to disperse the phosphorus (divalent) in the aqueous solution. The phosphate ion: HPO ₄ ²⁻ ) was selectively captured by the compound. After stirring for 5 minutes and suspending chloroform, the mixture was allowed to stand, and chloroform was phase-separated and settled in the lower layer of the aqueous solution in the container. Thereafter, the aqueous solution and chloroform were separated. The residual phosphate ion concentration of the aqueous solution after separation was measured by molybdenum spectrophotometry. The results are shown in Table 2 below.

The aqueous solution after selective capture of phosphate ions and separation of chloroform by the same method except that the liquid compound obtained in Synthesis Example 2 as a phosphorus scavenger was added to the aqueous solution in 2 equivalents and 4 equivalents, respectively. The residual phosphate ion concentration was measured by molybdenum spectrophotometry. The results are shown in Table 2 below.

Further, the selective capture of phosphate ions and the ion concentrations of NO ₃ ⁻ , SO ₄ ²⁻ , Cl ⁻ and Br ⁻ in the aqueous solution after separation of chloroform were quantified by ion chromatography. As a result, chloroform was used as the organic solvent, and chlorine was contained in the zinc counter anion of the liquid compounds of Synthesis Examples 1 and 2, which exceeded the calibration curve. It was detected as the same amount of residual ions.

As is apparent from Table 2 and the quantitative results of ion chromatography, the general formula (I) is used in an aqueous solution in which NO ₃ ⁻ , SO ₄ ²⁻ , Cl ⁻ and Br ⁻ coexist with phosphate ions, that is, various anions coexist. The compound obtained in Synthesis Example 1 in which dodecyl was introduced as R ₁ was added as a phosphorus scavenger, and the method of Example 3 in which chloroform was added and chloroform was separated was the same as the compound obtained in Synthesis Example 1. It can be seen that it has the same phosphorus scavenging performance as Example 1 in Table 1 in which various anions do not coexist, that is, it has phosphorus selective scavenging performance. Therefore, phosphorus can be removed from the aqueous solution by separating the capture agent that selectively captures phosphorus from the aqueous solution together with chloroform.

Further, the compound obtained in Synthesis Example 1 in which dodecyl is introduced as R ₁ of the general formula (I) into an aqueous solution in which various anions coexist is added as a phosphorus scavenger, and ethyl acetate is added and ethyl acetate is separated. The method of Example 4 has higher phosphorus capture performance (that is, phosphorus selective capture performance) than the method of Example 3 using the compound obtained in Synthesis Example 1 and adding chloroform as an organic solvent. I understand that.

Furthermore, the compound obtained in Synthesis Example 2 in which triphenylmethyl was introduced as R ₁ of the general formula (I) into an aqueous solution in which various anions coexist with phosphate ions was added as a phosphorus scavenger, and chloroform was added. The method of Example 5 in which the separation is performed uses the compound obtained in Synthesis Example 2 and has lower phosphorus capture performance than Example 2 in Table 1 in which various anions do not coexist. This is because triphenylmethyl has higher electron donating properties than aliphatic hydrocarbon groups such as dodecyl, so it affects the electronic state of zinc, which is the adsorption field (capture field) of phosphorus, and affects the anion selectivity. It is thought that it is exerting. Therefore, when removing phosphorus from an aqueous solution in which various anions coexist with phosphate ions, a compound in which a hydrophobic group having no electron donating property such as an aliphatic hydrocarbon group is introduced as R _{1 in the} general formula (I) Is preferably used as a phosphorus scavenger.

(Example 6)
Each container contained 50 mL of an aqueous solution containing 20 ppm phosphate ions and having pH 4.6, pH 8.3, and pH 10.2. To these aqueous solutions, 80 mg of the liquid compound obtained in Synthesis Example 2 as a phosphorus scavenger (2 equivalents to phosphate ions) was added, and the aqueous solution and the compound were brought into contact with stirring to disperse the phosphorus ( A mixture of divalent phosphate ion: HPO ₄ ^2- ) mixed with 10 mL of chloroform was added, and the mixture was stirred for 5 minutes to suspend the chloroform, and then allowed to stand. After standing, chloroform was phase-separated and settled in the lower layer of the aqueous solution in the container. Thereafter, the aqueous solution and chloroform were separated. The residual phosphate ion concentration of each aqueous solution after separation was measured by molybdenum spectrophotometry. The results are shown in Table 3 below.

  As is clear from Table 3, the method of making the aqueous solution containing phosphate ions weakly alkaline (pH 10.2) and adding the compound obtained in Synthesis Example 2 to this aqueous solution as a phosphorus scavenger has phosphorus scavenging performance. It can be seen that phosphorus in the aqueous solution can be efficiently removed.

Claims (5)

A phosphorus scavenger comprising a compound represented by the following general formula (I) and having an affinity for an organic solvent.

R ₁ in the formula has 4 to 20 carbon atoms and is a hydrocarbon group selected from aliphatic hydrocarbons or aromatic hydrocarbons, and R ₂ , R ₃ , R ₄ and R ₅ are H or aliphatic. Represents a hydrocarbon group, which may be the same or different, and X represents N or O; The phosphorus scavenger according to claim 1, wherein R _{1 in the} general formula (I) is triphenylmethyl. The phosphorus scavenger containing the compound represented by the general formula (I) shown below and the phosphorus scavenger recovery solvent coexisted in the water to be treated containing phosphorus and stirred, and then left to stand to capture the phosphorus. A method for removing phosphorus in water to be treated, wherein the recovered solvent in which the agent is incorporated is phase-separated from the water to be treated.

R ₁ in the formula has 4 to 20 carbon atoms and is a hydrocarbon group selected from aliphatic hydrocarbons or aromatic hydrocarbons, and R ₂ , R ₃ , R ₄ and R ₅ are H or aliphatic. Represents a hydrocarbon group, which may be the same or different, and X represents N or O;   The method for removing phosphorus in water to be treated according to claim 3, wherein the water to be treated which is in contact with the scavenger is a weak alkali having a pH of 9 to 11.   4. The coexistence of the phosphorus scavenger and the recovery solvent in the water to be treated is performed by mixing the phosphorus scavenger and the recovery solvent and adding them to the water to be treated. The phosphorus removal method in the to-be-processed water of description.