JP5963230B2 - Mesoporous silica supporting strontium ion adsorbing compound, strontium ion collector, strontium ion concentration sensor, strontium removal filter and strontium recovery method using the same - Google Patents

Description

The present invention relates to a mesoporous silica having a regular arrangement carrying a strontium ion-adsorbing compound capable of selectively adsorbing strontium ions as a target element, and has recently become a problem. Strontium ions contained in a strontium ion dissolution solution using a strontium ion collector using mesoporous silica loaded with a strontium ion adsorbing compound capable of collecting and recovering radioactive strontium, and using a strontium ion adsorbing compound supported on mesoporous silica It is related with the method of collect | recovering efficiently. Furthermore, the present invention relates to a strontium ion collector and sensor using mesoporous silica for detecting strontium ion concentration.

Strontium (element symbol Sr) is a soft, silver-white alkaline earth metal with high chemical reactivity, rich malleability and ductility. Naturally, minerals such as celestite and strontian stone There is a trace amount in it. Because the flame reaction is red, strontium chloride is used for the red flames of fireworks and smoke cylinders. Sr is also used as a material for high-temperature superconductors. Strontium carbonate is added to the glass of a cathode ray tube such as a cathode ray tube or used as a raw material for magnetic materials such as ferrite. Furthermore, since simple strontium has high reactivity with oxygen, it is used as a getter for oxygen adsorption in a vacuum apparatus. Currently industrially, strontium carbonate is produced from celestite ore by the reduction roasting method (black ash method) or the soda method (wet method). The global production of strontium is about 500,000 tons (2006), and the top producers are Mexico, Spain and China. Japan does not produce, but it is the world's top consumer country.

As described above, strontium is a useful metal, but in nuclear power generation, ⁹⁰ Sr, which is a radioisotope, is generated from the fission reaction of uranium and plutonium. In the Chernobyl nuclear power plant accident and the recent Fukushima nuclear power plant accident, a large amount of radioactive element ⁹⁰ Sr was released into the environment. Since this radioactive element ⁹⁰ Sr has a long half-life of 28.8 years, once it is released into the environment, the organism will be exposed for a long time, and there is concern about the effect of radioactive strontium on the human body. In addition, leakage from the reactor during normal operation into the environment is becoming a problem.

Therefore, the removal of strontium is an urgent issue for waste disposal and environmental improvement. This element is found in the reactor coolant system of light water reactors at nuclear power plants and is also present in spent nuclear fuel. (Non-patent document 1) When the chemical reaction in the reactor is not carefully controlled, the chemical reaction proceeds rapidly, the pressure in the furnace rises, and the fuel rods corrode. When a fuel rod becomes old, there is a risk that the fuel rod will be broken by cracks or holes. The cracked fuel rods release radioactive strontium into the water that surrounds and cools the fuel rods. Radioactive strontium circulates in the system together with cooling water and eventually leaves the reactor to the environment, such as air, or becomes liquid and solid waste. From time to time, the reactor gas capture system may release a gas containing strontium to the environment. In this way, even if there is no accident of this Fukushima nuclear power plant, leakage of radioactive materials from waste and storage products as well as the existing system even under strict management can not be avoided, ⁹⁰ with a fairly long half-life Sr is a radionuclide that is found quite frequently in soil and groundwater. Strontium can bioaccumulate in bone and bone marrow, and easily replaces calcium, the same alkaline earth metal in the human body, causing bone tumors and blood cell cancer. (Non-Patent Document 2)

In order to remove radioactive strontium from the environment, separation techniques relating to the removal of strontium such as solvent extraction, fractional crystallization, ion exchange adsorption and iron oxide diffusion methods have been developed. (Non-Patent Documents 1, 3, and 4) Goethite, hematite, hemitate, kaolinite, pecan shell, zirconia-supported vermiculite (zirconia-modified)
Many adsorbents such as Vermiculite have been investigated. (Non-Patent Documents 5 to 9) As described above, adsorption by a selective adsorbent has been frequently used to remove radioactive elements, but a simple and inexpensive method has not yet been found. The detection limit is much higher than the human limit.

On the other hand, an optical method such as a visual collector (collecting agent) using color change or light absorption is important for accurately detecting a target element quickly and removing it from the environment. The visual detection and removal approach is a simple technique that does not require complex equipment or a well-controlled environment. However, for low concentration levels of radioactive strontium, no visual collector has yet been developed that is low in cost, good in selectivity, capable of rapid detection and removal of radioactive strontium.

Radioactive strontium is present at concentrations well below the extraction limits of most commonly used processing methods, and the acceptable level of radioactive strontium in the human body is very low, so strontium can be accurately detected at the ppb-ppm level. There is a worldwide demand to discover materials that have good selectivity and can be extracted quickly. Furthermore, there is a need for rapid, cost-effective, easy-to-use and reliable techniques for measuring and extracting trace strontium ion concentrations.

On the other hand, various methods for detecting metal ions using mesoporous silica have been studied. For example, in Patent Documents 1 and 2, a composite sensor is formed by holding dye molecules such as aminoporphyrin, dithizone, porphyrin sulfone, etc. on mesoporous silica, and Cd ions, mercury ions, Cr ions, etc. are adsorbed on the dye molecules, It is described that the ion concentration is detected using the spectral change. However, none of the previous patent documents and non-patent documents so far discloses a simple, rapid and accurate method for recovering strontium adsorbed on mesoporous silica.

JP2007-327886A JP2007-327887A

M. S. Denton, M. J. Manos, M. G. Kanatzidis, Highly selective removal of cesium and strontiumutilizing a new class of inorganic ion specific media-9267, WM2009 Conference, March 1-5, 2009, Phoenix, AZ. R. O. Abdel Rahman, H. A. Ibrahium, Y. T Hung, Liquid Radioactive Wastes Treatment: A Review, Water 2011, 3, 551-565. E. Bascetin, G. Atun, Adsorptive removal of strontium by binary mineral mixture of montmorillonite and zeolite, J. Chem. Eng. Data 2010, 55, 783-788. Lisa Ax, Paul R. Anderson, Sr Diffusion and Reaction within Fe Oxides: Evaluation of the Rate-Limiting Mechanism for Sorption, J. Colloid Interf. Sci. 1995, 175, 157-165. N. Sahai, SACaroll, S. Roberts, PA O'Day, X-ray adsorption spectroscopy of strontium (II) coordination. II. Sorption and precipitation at kaolinite, amorphous silica and goethitesurfaces, J. Colloid Interf. Sci., 2000 222, 198-212. O.N.Karasyova, L.I.Ivanova, L.Z.Lakshtanov and L. Lovgren, Strontium sorption on hematiteat elevated temperatures, J. Colloid Interf. Sci., 1999, 220, 419-428. C.H.Jeong, Mineralogical and hydrochemical effects on adsorption removal of Cs-137 and Sr-90 by kaolinite, J. Environ. Sci. Health A. Toxicol. Hazard. Subst. Environ. Eng., 2001, 36, 1089-1099. R.A.Shawabkeh, D.A.Rockstraw and R.K.Bhada, Copper and strontium adsorption by a novel carbonmaterial manufactured from pecan shells, Carbon, 2002, 40, 781-786. R. Qadeer, J. Hanif, M. Saleem and M. Afzal, Selective adsorption of strontium on activated charcoalfrom electrolytic aqueous solutions, Collection Czechoslovak Chem. Comm., 1992, 57, 2065-2072. SA El-Safty, T. Balaji, H. Matsunaga, T. Hanaoka, F. Mizukami, Optical sensors based on nanostructured cage materials for the detection of toxic metal ions, Angew. Chem. Int. Ed. 2006, 45, 7202-7208 .

As described above, strontium is used in various applications, but radioactive strontium such as ⁹⁰ Sr, which is a radioactive isotope, accumulates in the human body even in a trace amount on the order of ppb to ppm, and induces carcinogenicity. It is necessary to exclude not only water for daily use such as drinking water and washing water and air but also all environments such as waste water and soil.

Therefore, it is necessary to know how much strontium is contained in a solution such as domestic water or wastewater even in a small amount. However, there are few strontium collectors or concentration detection sensors that can quickly and accurately measure a very small amount of strontium concentration on the order of ppb to ppm, and there is a problem that even if there are few, it cannot be used repeatedly. In addition, since there are few collectors or sensors that selectively collect and detect strontium, a solution containing a plurality of elements and ions is affected by elements and ions other than strontium and cannot accurately measure the strontium concentration. Furthermore, when a small amount of radioactive strontium is present in a solution such as domestic water or wastewater, it is necessary to remove the radioactive strontium, but there are few methods for removing strontium to the ppb order level. In the case of an ion exchange resin or the like, although ppb order level ions can be removed, there is a problem that only strontium ions cannot be identified and removed. In other words, there is almost no material with good selectivity for selectively removing only strontium (ions).

In addition, after removing strontium with a recovery agent, there is a problem that it is difficult to effectively use the recovered strontium because the means for separating the strontium is difficult. Or there is also a problem that it is difficult to reuse the recovered agent. There is also a problem that the cost for collecting and recycling strontium in solutions such as domestic water and wastewater is high. With respect to the detection of strontium concentration in the environment, the removal of strontium from the environment, and the method of recovering and recycling useful strontium, there are simple, low-cost, selective, accurate, and high-speed methods that can be performed worldwide. Urgently required.

The present invention relates to a compound capable of selectively adsorbing strontium ions to mesoporous silica having a highly ordered structure (hereinafter referred to as strontium ion adsorbing compound (or meaning of collecting strontium (ions) (collecting agent)). An efficient method for recovering the adsorbed strontium by adsorbing the adsorbed strontium ion to the adsorbed strontium ion adsorbing compound, and the strontium ion used in the strontium ion A mesoporous silica carrying an adsorbing compound is provided, and the mesoporous silica carrying the strontium ion adsorbing compound is used to accurately detect the strontium ion concentration and measure a minute amount on the order of ppb to ppm. It provides a possible strontium ion collector and sensors.

After mixing the silica source and the surfactant, an acidic aqueous solution is added and calcined to produce mesoporous silica (HOM). This mesoporous silica carries a strontium ion-adsorbing compound (strontium ions have not yet been adsorbed). The strontium ion adsorbing compound is a compound that can selectively adsorb strontium ions. For example, a complex such as a chelate compound. (A compound that easily adsorbs a specific element ion is referred to as an element ion adsorbing compound in this application. Here, this means that a specific ion that the element ion adsorbing compound can selectively adsorb is recovered. The specific element is referred to as a target element.In the present invention, the target element is strontium.) Examples of compounds that selectively and preferentially adsorb strontium ions include chlorophosphonazo-III and 4- (2-diazenyl-1,3,4-thiadiazole) -6-dodecylresorcinol {4- (2-diazenyl-1,3,4-thiadiazole) -6-dodecylresorcinol (DTDR)}. These strontium ion adsorbing compounds are supported on mesoporous silica. (For example, these strontium ion-adsorptive compounds are collectively referred to as MC, and mesoporous silica supporting MC is referred to as HOM-MC.) These may be supported alone on HOMS, or a plurality of them may be mixed and supported on HOMS. You may do it. In addition, since chlorophosphonazo 3 (hereinafter abbreviated as CPP) is difficult to be supported by HOMS, as will be described later, using dimethylammonium dilauryl bromide (DDAB), After functionalizing the HOM pore surface, CPP is supported on DDAB. Therefore, in the case of CPP, HOM-DDAB (CPP) {in terms of structure, it is easier to describe as HOM-DDAB-CPP, but in this application, it is described as HOM-DDAB (CPP)}. In the case of DTDR, HOM-DTDR.

Contacting mesoporous silica carrying (or modifying) the strontium (ion) adsorbing compound in an ion-dissolved solution in which various ions including strontium (including not only element ions but also other cations and anions) are dissolved; Strontium ions (Sr ^2+, etc.) that are target element ions are adsorbed to the strontium ion-adsorbing compound supported on mesoporous silica. At this time, target element ions can be efficiently adsorbed by adjusting environmental factors such as pH value, solution concentration, and solution temperature of the ion-dissolved solution. (HOM-MC adsorbing strontium ions is referred to as HOM-MC-Sr.) For example, in the case of the above-mentioned HOM-DDAB (CPP), the pH value is 10.0 to 12.0, preferably 10.5. By contacting an ionic solution containing strontium ions adjusted to ˜11.5, HOM-DDAB (CPP) preferentially and selectively adsorbs strontium ions as target element ions. (HOM-DDAB (CPP) adsorbing strontium is referred to as HOM-DDAB (CPP) -Sr.) In the case of the aforementioned HOM-DTDR, the pH value is 7.0 to 11.0, preferably 8 By contacting an ionic solution containing strontium ions adjusted to 0.0-10.5, more preferably 9.0-10.0, HOM-DTDR preferentially and selectively selects the target element strontium. Adsorbs quickly and quickly. (HOM-DTDR adsorbing strontium is referred to as HOM-DTDR-Sr.)

Next, the mesoporous silica supporting the strontium ion adsorbing compound on which strontium ions are adsorbed is brought into contact with a solution capable of releasing strontium ions (strontium ion free solution), and the adsorbed strontium ions are dissolved in the strontium ion free solution. Let The solution is filtered to separate it into a solid and a liquid. Since the separated liquid dissolves only strontium ions, strontium, which is the target element, can be recovered. By controlling the concentration, pH, reaction temperature and the like of the solution, the recovery efficiency of strontium can be increased. The separated solid is mesoporous silica carrying a strontium ion adsorbing compound, and the strontium ion adsorbing compound carried on the mesoporous silica does not adsorb strontium. That is, the solid returns to mesoporous silica (HOM-MC) carrying a strontium ion adsorbing compound (not adsorbing strontium ions).

Moreover, since the main body (mesoporous silica supporting a strontium ion adsorbing compound) is not changed, it can be used again as an adsorbent (or collector (collecting agent) or extractant) for strontium ions that are target element ions. For example, by immersing HOM-MC-Sr in an acidic solution or an alkaline solution, Sr can be eluted to form HOM-MC. HOM-MC from which strontium has been separated can again be used as a strontium ion adsorbent (collector).

In the present invention, since the strontium ion adsorbing compound is supported (modified) on the surface of the mesoporous silica having a large surface area and a highly ordered structure and the inner wall of the pore (pore), the reactive group of the strontium ion adsorbing compound is Strontium ions are easily and quickly adsorbed. Therefore, not only the adsorption response speed is high, but also the strontium ion adsorption efficiency to the strontium ion adsorbing compound supported on the mesoporous silica is much larger than the strontium ion adsorption efficiency to the single strontium ion adsorbing compound. At the same time, the amount of strontium (ion) adsorption increases.

Further, since the strontium ions adsorbed on the strontium (ion) adsorbing compound are also arranged in order and closely adsorbed, the adsorbed strontium ions can be easily released (separated) quickly. Therefore, the liberation efficiency of strontium ions is very high. The strontium ion-adsorbing compound can selectively adsorb strontium ions in a large amount and rapidly by adjusting the pH value of the strontium ion solution. Therefore, only strontium (ion) can be efficiently recovered. Moreover, since a very small amount of strontium ions on the order of ppb to ppm can be adsorbed and removed, the concentration of strontium ions contained in a solution such as water for domestic use and waste water, soil and other ion solution can be reduced to a very small level. Since trace amounts of radioactive strontium in the environment, which has been a problem in recent years, can be removed efficiently and quickly, the HOM-MC of the present invention is a useful material for maintaining the health of the human body and purifying the environment.

Furthermore, the skeleton of mesoporous silica carrying a strontium ion-adsorbing compound has a strong skeleton, and the skeleton of mesoporous silica hardly changes even when the strontium ion-adsorbing compound is carried or adsorbed by strontium ions. Since the adsorbed strontium ions can be almost completely released, it returns to the original state (mesoporous silica supporting a strontium ion adsorbing compound not adsorbing strontium ions), so that the mesoporous silica supporting a strontium ion adsorbing compound is removed. Can be used repeatedly. That is, it can be recycled or reused many times.

Therefore, the total (total) strontium collection / recovery cost can be reduced. The mesoporous silica supporting the strontium ion-adsorbing compound adsorbed with the strontium ion of the present invention is very low in the order of ppb to ppm using a colorimetric method or UV-VIS-NIR spectroscopy. Since the concentration of strontium ions can also be detected, it can also be used as a strontium ion collector and concentration sensor.

FIG. 1 is a diagram showing a strontium recovery system of the present invention. FIG. 2 is a diagram showing a method for synthesizing HOM silica monolith. FIG. 3 is a diagram showing a method for producing a receptor DTDR and a structural formula of DTDR incorporating strontium. FIG. 4 shows the structural formula of receptor chlorophosphonazo 3 incorporating strontium. FIG. 5 is a diagram showing a method for producing a HOM carrying chlorophosphonazo 3 using a surface modification step. FIG. 6 is a graph showing the relationship between the UV-visible spectrum signal intensity of HOM-DDAB (CPP) -Sr and the pH value of the solution. FIG. 7 is a diagram showing an absorption spectrum and colorimetric analysis of HOM-DDAB (CPP) -Sr using strontium ion concentration as a parameter. FIG. 8 is a graph showing the relationship between the strontium ion concentration in the solution at pH = 11.0 and the absorbance (at λ = 585 nm) of the UV-visible spectrum of HOM-DDAB (CPP) -Sr. FIG. 9 is a table showing the applicable range of HOM-DDAB (CPP) -Sr of the present invention. FIG. 10 is a diagram schematically illustrating a strontium ion collection / separation process using a HOM-DTDR collector in which DTDR is supported on HOM silica. FIG. 11 is a graph showing the relationship between the UV-visible spectrum signal intensity of HOM-DTDR-Sr and the pH value of the solution. FIG. 12 is a diagram showing an absorption spectrum and colorimetric analysis of HOM-DTDR-Sr using strontium ion concentration as a parameter. FIG. 13 shows recovery of strontium (Sr) from a strontium ion-dissolved solution containing radioactive strontium and the like using mesoporous silica (HOMS) supporting CPP {DDAB (CPP)} or DTDR which is a strontium ion adsorbing compound of the present invention. It is a figure which shows the system to do.

The present invention provides strontium ion detection technology and strontium recovery technology using various chelates and other compounds having high selectivity and optical detection function. A feature of this technology is that it utilizes nano-sized surface states arranged at the atomic level of mesoporous materials composed of different atoms. The present invention is very excellent as a method for extracting strontium from wastes containing various active ions (cations and anions), surfactants, etc., water for daily use, and the environment. In particular, it is extremely excellent as a method for eliminating radioactive strontium, which has been a problem in recent years, from the environment.

The inner surface of mesoporous silica arranged at the nano level makes the strontium ion collector and sensor by controlling the environmental conditions such as pH and changing the fixation / dissociation state. Strontium ions can be reliably adsorbed by bonding between adjacent atoms and surface atoms having different electron orbital structures and compounds such as chelates. Furthermore, the nano-ordered ordered arrangement on the inner wall surface of the mesoporous material increases the charge transfer, so that optical changes that can be observed with the naked eye can be rapidly observed even with a very small amount of strontium adsorption at the ppb level (fast response). Occur.

Hereinafter, embodiments of the present invention will be described in detail.
FIG. 1 is a diagram showing a strontium recovery system of the present invention. First, highly ordered mesoporous silica (HOM silica (HOMS): High Ordered Mesoporous Silica; normally, HOM does not include silica, but in this specification etc. In this case, silica is also included unless otherwise specified.) Here, mesoporous silica is a kind of porous silica, which has pores (mesopores) having a substantially uniform and regular diameter called a mesopore region having a size of 2 nm to 50 nm. It is a group of porous materials that are known to have various properties depending on the type of network (spatial symmetry) created by the pores, the manufacturing method, and the like. However, in this patent application, porous silica having micropores (pores of 2 nm or less) smaller than mesopores or macropores (pores of 50 nm or more) larger than mesopores is also referred to as mesoporous silica.

The form of HOM used in the present invention includes a thin film form and a monolith form. The monolith form usually refers to various forms other than a thin film, such as fine particles, particles, block-like forms and the like. Highly ordered means a state in which cubic and hexagonal mesoporous structures are regularly arranged on the surface and inner wall surface in three dimensions, for example, cubic Ia3d, Pm3n, Fm3m and hexagonal P6m structures. When these structures are present in a wide range, a large amount of strontium ion-adsorbing compounds can be supported, and the total amount of strontium ion adsorption can be increased. Also, the larger the BET specific surface area of HOM, the better, but it is usually 400 m ² / g or more, preferably 500 m ² / g or more.

HOM silica can be synthesized by various methods. For example, in the sol-gel method using a surfactant as a template, when a surfactant is dissolved in an aqueous solution at a concentration equal to or higher than the critical micelle concentration, micelle particles having a certain size and structure are obtained depending on the type of the surfactant. It is formed. When left standing for a while, the micelle particles take a packed structure and become a colloidal crystal. When an organic silicon compound or the like serving as a silica source is added to the solution and a trace amount of acid or base is added as a catalyst, the sol-gel reaction proceeds in the gaps between the colloidal particles to form a silica gel skeleton. Finally, when fired at a high temperature, the surfactant used as a template is decomposed and removed to obtain pure highly ordered mesoporous silica (HOM silica). Further, for example, preferably, an organosilicon compound and a surfactant are mixed to form a lyotropic liquid crystal phase, and further, an aqueous acid solution is added to cause a hydrolysis reaction of the organosilicon compound in a short time, resulting in mesoporous After obtaining a composite product of silica and surfactant, a method is used in which the surfactant is removed to obtain HOM silica.

As the organic silicon compound, for example, silicon alkoxide such as tetramethylorthosilicate {also referred to as C4H12O4Si, TMOS (tetramethoxysilane)} or tetraethylorthosilicate {also referred to as C8H20O4Si, TEOS (tetraethoxysilane)} is used. (Because it is easier to remove methanol from ethanol by heating, vacuuming, etc. from the product, TMOS is preferable to TEOS rather than TEOS.) For the formation of HOM, in addition to organic silicon compounds, An inorganic silicon compound can also be used. For example, kanemite (NaHSi2O5 · 3H2O), sodium disilicate crystal (Na2Si2O5), macatite (NaHSi4O9 · 5H2O), eyeraite (NaHSi8O17 · XH2O), magadiite (Na2HSi14O29 · XH2O), KenyaO2 glass (Na2H2Si2O) Soda), glass, and amorphous sodium silicate can also be used. You may use these in mixture of 2 or more types.

Various surfactants can be used as templates. For example, a cationic, anionic, amphoteric or nonionic surfactant can be used. Examples of the cationic surfactant used as a template include primary amine salts, secondary amine salts, tertiary amine salts, and quaternary ammonium salts. Examples of the anionic surfactant used as a template include carboxylate, sulfate ester salt, sulfonate salt, phosphate ester salt, soap, higher alcohol sulfate ester salt, higher alkyl ether sulfate ester. Salts, sulfated oils, sulfated fatty acid esters, sulfated olefins, alkyl benzene sulfonates, alkyl naphthalene sulfonates, paraffin sulfonates and higher alcohol phosphate ester salts.

Examples of the amphoteric surfactant used as a template include sodium laurylaminopropionate, stearyldimethylbetaine, and lauryldihydroxyethylbetaine. Examples of the nonionic surfactant used as a template include polyoxyethylene alkyl ether, polyoxyethylene secondary alcohol ether, polyoxyethylene alkylphenyl ether, polyoxyethylene sterol ether, polyoxyethylene lanolin acid derivative, polyoxyethylene Examples include ether type compounds such as polyoxypropylene alkyl ether, polypropylene glycol, and polyethylene glycol, and nitrogen-containing types such as polyoxyethylene alkylamine. You may use these in mixture of 2 or more types.

The HOM structure (pore size, shape, crystal structure, etc.) can be controlled by changing the type of surfactant, so the crystal structure is highly ordered, the BET specific surface area is large, and the pore density is large. A surfactant capable of forming HOM is preferred. For example, polyoxyethylene (10) cetyl ether (Brij56: C16H33 (OCH2CH2) 10OH, C16EO10), triblock copolymer surfactant (eg, pluronic® P123: EO20PO70EO20, Pluronic® F108: EO141PO44O141) ) Can be used. Mixing with a weight ratio of Brij56: TMOS = 0.5 gives a cubic structure Pm3n, mixing with a weight ratio of P123: TMOS = 0.7-0.8 gives a cubic structure Ia3d, F108: weight ratio of TMOS = 0.7 To obtain a cubic structure Im3m cage silica structure.

FIG. 2 shows a method for synthesizing HOM (cubic Im3m) silica monolith. The HOM silica monolith was synthesized by employing the instantaneous direct template method with the copolymer surfactant F108 (EO ₁₄₁ PO ₄₄ EO ₁₄₁ ). Typically, mesoporous silica monoliths with cubic Im3m (HOM) cage-like mesopores add dodecane to the F108 / tetramethylorthosilicate (TMOS) mixed phase in a ratio of dodecane: F108: TMOS = 1: 2.8: 4. Was made using a microemulsion phase formed by This HOMS is a white powdery solid.

Next, in the second step, the strontium ion-adsorbing compound is supported on the HOM. At this stage, strontium ions (and other ions) are not adsorbed to the strontium ion adsorbing compound. (The term “strontium ion-adsorbing compound” is used to indicate that strontium ions are not adsorbed. Examples of the strontium ion-adsorbing compound used in the present invention include ion complexes, inorganic compounds, and organic compounds. Cellulose, protein, etc. The metal complexes include inorganic and organic metal complexes, metal carbonyl compounds, metal clusters and organometallic compounds, and chelate compounds.Basically, strontium ( A compound capable of adsorbing ions to the HOM, capable of releasing ions other than the target element strontium by chemical treatment, and then releasing the target element strontium by another chemical treatment. Strontium ion adsorption Compounds are strongly bonded to the HOM silica chemically, for example, via the OH groups.

The strontium ion-adsorptive compound is desirably a compound that selectively adsorbs strontium ions, which are target element ions to be recovered, in a large amount. For example, chelate compounds and other compounds that selectively bind to strontium ions can be used. By adjusting the pH value, temperature, concentration, etc. of a strontium ion-dissolved solution in which various ions (cations and anions) containing strontium and surfactants are dissolved, strontium, a target (metal) element, is added to the strontium ion-adsorbing compound. (Ions) can be selectively and preferentially adsorbed in large quantities. Further, since a compound such as a chelate compound can selectively adsorb a very small amount (for example, ppb order) of strontium, it is efficient even if the amount of strontium ions contained in the strontium ion solution is small. Selectively adsorb strontium ions.

For example, we have 4- (2-diazenyl-1,3,4-thiadiazole) -6-dodecylresorcinol {4- (2-diazenyl-1,3,4-thiadiazole) -6-dodecylresorcinol (DTDR)} ( It was found that the compound (hereinafter also referred to as receptor DTDR) selectively adsorbs strontium ions preferentially. (Receptor is originally a biological term “receptor”, but in this application, the term “receptor” may be used to mean an adsorbing compound that adsorbs a specific element (strontium) ion. is there.)

As will be described later, when this receptor DTDR is immersed in a solution containing strontium ions whose solution is adjusted to a specific pH value (strontium ion dissolving solution) and HOM silica supporting the receptor DTDR is immersed, the receptor DTDR has other pH values. Strontium ions are adsorbed in a larger amount and selectively than in solution. As the amount of adsorbed strontium ions increases, the color of the HOM silica carrying the receptor DTDR gradually increases from light brown to brown (strontium ion concentration 1 ppm) and dark brown (strontium ion concentration 5 ppm). To go. Since the color tone and the adsorbed strontium ion concentration have a correlation, the strontium ion concentration can be known from the color tone. That is, colorimetric analysis is possible. In particular, even a very small amount of strontium at the ppb to ppm level can be adsorbed, resulting in a change in color tone, so that an accurate concentration can be detected. By selectively immersing HOM silica (HOM-DTDR) carrying these receptor DTDRs in a solution containing strontium ions and other various ions (cations and anions) and surfactants, only strontium ions This means that the other various ions are hardly adsorbed. That is, HOM silica carrying a receptor DTDR (HOM-DTDR) has extremely excellent selectivity for strontium ion adsorption.

The strontium ion concentration can also be measured from the light absorption spectrum after strontium ion adsorption. That is, HOM silica carrying the receptor DTDR is also a strontium ion concentration detection sensor. This mesoporous silica (HOM-DTDR) carrying the receptor DTDR shows an absorption peak based on strontium adsorption in visible light having a wavelength of 450 nm to 500 nm in UV-visible spectroscopy when strontium ions are adsorbed. Since the strontium ion concentration has a correlation, by making a calibration curve in advance, the HOMS-DTDR is obtained from the absorption data of the wavelength in the UV-visible spectroscopy of HOM-DTDR that has adsorbed strontium ions. -The strontium ion concentration of Sr can be known. Moreover, this HOMS-DTDR-Sr selectively adsorbs strontium ions in the solution and hardly adsorbs other contained ions, so that it becomes a very sensitive strontium ion collector and concentration sensor. In particular, even a very small amount of strontium at the ppb to ppm level can be adsorbed, resulting in a change in spectrum, so that an accurate concentration can be detected.

An example of another strontium ion-adsorbing compound is Chlorophosphonazo-III, and other strontium ion-adsorbing compounds will be discovered from time to time. One or more of these strontium ion-adsorbing compounds can be supported on HOMS to produce a HOMS-receptor having the desired properties. These compounds adsorb (collect) strontium (ions) by incorporating strontium (ions) within and / or between the ring molecules. Therefore, it can be said that these strontium ion adsorbing compounds are chelate complexes. These strontium ion adsorbing compounds are compounds with extremely high selectivity because they hardly adsorb other anions and cations (including metal ions such as alkaline earth group metals). It is considered that strontium (ion) is adsorbed (bonded) to these compounds through covalent bonding.

There are various methods as a method (also referred to as a composite method) for supporting (modifying) such a strontium ion adsorbing compound on the HOM. For example, when the strontium ion-adsorbing compound to be held in the HOM is neutral, a reagent impregnation method (REACTIVE & FUNCTION POLYMERS, 49, 189 (2001), etc.) is used, and it is anionic. The cation exchange method is used, and if it is cationic, the anion exchange method is used. These compounding methods belong to known general technical fields, not special conditions and operations. Therefore, for the details of these general technical fields, it is possible to refer to reviews, literatures and the like regarding the solid adsorption field.

For example, mesoporous silica is surface-treated with a cationic organic reagent (for example, a cationic silylating agent) to impart a cationic functional group to the mesoporous silica, and then the cationic mesoporous silica and an anion are added. A method in which an aqueous solution or an alcohol solution of an ionic strontium ion adsorbing compound is contacted to adsorb the strontium ion adsorbing compound in mesoporous silica, an organic solvent solution in which the mesoporous silica and the strontium ion adsorbing compound are contacted, and an organic solvent Is removed by filtration or distillation, and the strontium ion-adsorbing compound is physically adsorbed and supported in mesoporous silica, the mesoporous silica is surface-treated using a silylating agent having a thiol group, Generated surface thiol By oxidizing the mesoporous silica, an anionic functional group is added to the mesoporous silica, and the anionic mesoporous silica is contacted with an aqueous solution of a cationic metal-adsorbing compound so that the strontium ion-adsorbing compound is contained in the mesoporous silica. The strontium ion-adsorbing compound is previously filled in the pores and on the surface, and then treated with an organic solvent solution of a cationic organic reagent, so that the strontium ion-adsorbing compound is placed in the pores and on the surface. Method of immobilization, by mixing strontium ion adsorbing compound and cationic organic reagent in advance, contacting the organic solvent solution of the obtained reagent complex with the silica, and removing only the organic solvent by filtration or distillation The method of supporting a strontium ion-adsorbing compound in the silica is used. It is.

For example, a two-step loading process is used to load the receptor chlorophosphonazo 3 (CPP) on HOMS. That is, first, HOMS-DDAB is prepared by functionalizing the HOM pore surface using dilauryl dimethyl ammonium bromide (DDAB). Next, HOMS-DDAB is added to the receptor chlorophosphonazo 3 (CPP) solution so that CPP is supported (modified) on DDAB of HOMS-DDAB, and HOMS-DDAB-CPP {HOMS-DDAB (CPP) Are also described}. In order to support the receptor DTDR on the HOM, the receptor DTDR is dissolved in ethanol, this solution is brought into contact with HOMS, and the receptor DTDR is impregnated into the HOMS. In this way, HOM silica (HOMS-DTDR) in which receptor DTDR is regularly and densely supported is completed. Efficient HOM silica loaded with receptor CPP {DDAB (CPP)} and DTDR in a high-purity solid state (powder) by evaporating (drying, heating, vacuuming, etc.) liquids such as alcohol and moisture. Can be produced well. In addition, the larger the porous (pore) density of the HOM silica, the higher the order of the crystal structure and the higher the BET specific surface area, the more receptors are regularly supported on the surface of the HOM silica and the inner walls of the pores. For example, preferably, a strontium ion-adsorptive compound such as receptor CPP {DDAB (CPP)} or DTDR on HOM silica having a wide range of structures such as cubic structures Im3m, Pm3n, Fm3m, Ia3d, hexagonal structure P6m, etc. To adsorb.

Naturally, the strontium ion-adsorbing compound alone can selectively adsorb strontium ions, which are target elements, but the strontium ion-adsorbing compound aggregates and cannot effectively use a functional group capable of adsorbing strontium ions. That is, even if the target element strontium ion is adsorbed to the functional group present on the surface of the aggregated (eg, particulate) strontium ion adsorbing compound substance, strontium inside the strontium ion adsorbing compound is diffused or permeated. Since the ion concentration decreases exponentially with respect to the distance (square), it is difficult for strontium ions to be adsorbed to all the functional groups of the strontium ion adsorbing compound inside the particulate matter. In addition, even if strontium ions are adsorbed to the functional group of the strontium ion adsorbing compound inside the particulate matter, it is difficult to take out (free or back-extract) the adsorbed strontium ions. . It is possible to diffuse strontium ions inside the particulate matter and take it out for a long time, but moving strontium ions inside the particulate matter over a long period of time results in poor productivity and Cannot be used.

On the other hand, mesoporous silica has a very large pore surface area and a highly ordered orientation structure. Therefore, a strontium ion adsorbing compound with strontium ion adsorbing compounds supported on the surface of the mesoporous silica and the inner wall of the pore Since the active compound is arranged in an orderly manner and bound, the strontium ion adsorption rate of the strontium ion adsorbing compound becomes very high. That is, each molecule of the strontium ion adsorbing compound can be used for strontium ion adsorption. The strontium ion dissolution solution and the free (back extraction) solution easily and quickly enter the surface and pores of the mesoporous silica, so it can be easily combined with the strontium ion adsorbing compound (reactive group) supported by HOMS. In addition, contact quickly. This means that the strontium ion-adsorbing compound supported on HOMS adsorbs strontium ions quickly when it comes into contact with the strontium ion solution. It also means that when adsorbed strontium ions are released, the adsorbed strontium ions are rapidly released if they come into contact with the free solution. Therefore, adsorption (collection) and release (separation) of strontium ions are extremely As a result, productivity is dramatically improved.

For example, in the case of a chelate resin alone, the surface atoms do not all have a chelate (functional group) effectively on the surface of the chelate resin, and the chelate reaction ends are discrete in atoms. It has become. When adsorbing strontium ions with a chelating resin alone, it is impossible to control which part of the chelating resin is attached. In addition, strontium ions are expected to be adsorbed (also referred to as extraction) to the chelate functional group in contact with the strontium ion-dissolved solution, but almost no strontium ions are adsorbed inside the chelate resin that is difficult to penetrate the strontium ion-dissolved solution. It is thought that it is not done. That is, the strontium ion adsorption efficiency is very poor. Furthermore, when releasing strontium ions adsorbed on the chelate resin (also referred to as back extraction), it becomes difficult to take out the strontium ions adsorbed inside the chelate resin.

Even when this chelate resin is repeatedly used, the efficiency of extraction and back-extraction of strontium ions becomes worse due to the influence of the residue in the chelate resin, and the performance of the chelate resin is greatly deteriorated by repeated use. On the other hand, those in which a chelate resin is supported on a HOM can form a chelate functional group on the surface of the HOM in a wide range using an atomic arrangement aligned with the large specific surface area of the HOM. In other words, the reaction end of the chelate is almost the same in HOM. In addition, the reaction end of the chelate is so large on the HOM surface and the inner wall of the pore that the conventional chelate resin alone cannot be realized. Since the chelate functional group selectively captures strontium ions or complex ions containing strontium ions, the adsorption efficiency of strontium ions becomes very high. In addition, the trapped strontium ions or complex ions containing strontium ions can be easily extracted by back extraction. Furthermore, when the chelate resin is used alone, the physical and / or chemical strength of the resin itself is insufficient, so the deterioration due to repeated use of the chelate resin is large. Since the physical and / or chemical strength of the HOM as the skeleton is sufficient, deterioration due to repeated use is small, and it can be used repeatedly, that is, reused any number of times.

In the third stage, an aqueous solution in which various ions (cations and anions) including strontium ions, a surfactant and the like are dissolved (this is called a strontium ion-dissolved solution) is prepared. This strontium ion-dissolved solution is, for example, a solution obtained by dissolving radioactive strontium-containing radioactive strontium in a domestic water or a domestic wastewater, or a radioactive strontium scattered from a nuclear facility or the like. In such a solution, various ions such as cations such as various metal ions and various anions and surfactants are dissolved in addition to strontium. If this solution contains solids, it is desirable to remove it in advance. This is because the HOM-MC probe immersed in this solution is a solid, and this is mixed with the solid content.

Therefore, a solution obtained by removing solids from this solution is a strontium ion dissolving solution. A strontium ion-dissolved solution is contacted with the strontium ion-dissolved solution by immersing HOM (hereinafter also referred to as HOM-MC) carrying a strontium ion-adsorbing compound (this is referred to as MC) at a high density in the strontium ion-dissolved solution. . By this contact, strontium ions are adsorbed on the HOM-MC. (This is HOM-MC-Sr-M (Sr: target element strontium (Sr), M: adsorbed ions other than strontium.)) Strontium ion adsorbing compounds under certain conditions (pH value, temperature Strontium ions, which are the target elements, are selectively and preferentially adsorbed under the conditions such as strontium ions, so that if the strontium ion-adsorbing compound is immersed in a strontium ion dissolving solution under the conditions, only the strontium that is the target element Can be obtained.

For example, HOM-MC can be brought into contact (including immersion) with a strontium ion-dissolved solution adjusted to a pH value that best adsorbs strontium ions, so that a large amount of strontium ions can be selectively adsorbed on HOM-MC. However, there is a possibility that a small amount of other ions M may be adsorbed due to slight fluctuations in conditions, etc., so by reducing the number of ions other than strontium, which is the target element, in the strontium ion dissolution solution in advance, other than strontium HOM-MC-Sr-M with a very small amount of adsorption of ions M can be obtained. For example, there is a method of precipitating and removing ions other than strontium ions by adjusting pH in a strontium ion solution or chemical treatment. Alternatively, there is also a method in which ions other than strontium ions are precipitated and removed using a compound that does not adsorb at least strontium ions (which may be prepared as appropriate HOM-MC).

In the case of the above-mentioned receptor CPP, strontium ions can be efficiently converted to HOM-MC {HOM-DDAB (CPP)} by adjusting the strontium ion solution to pH = 10.0 to 12.0, preferably pH = 10.5 to 11.5. Can be adsorbed. In the case of the above-mentioned receptor DTDR, the strontium ion solution is adjusted to pH = 7.0 to 11.0, preferably pH = 8.0 to 10.5, more preferably pH = 9.0 to 10.0, so that the strontium ion is converted to HOM-MC. (HOM-DTDR) can be adsorbed efficiently. It should be noted that HOM silica adsorbing strontium ions can be efficiently collected in a high-purity solid state (powder) by evaporating (heating, vacuuming, etc.) and then further drying a liquid such as ethanol or moisture.

In the fourth stage, HOM-MC-Sr-M adsorbing ions containing strontium ions that are target elements is immersed in a solution that can release ions other than strontium ions that are target elements, and strontium that is target elements. Ions other than ions are removed to form HOM-MC-Sr that adsorbs only the target element, strontium. Alternatively, in some cases, HOM-MC-Sr can be obtained by removing ions other than strontium, which is the target element, by adjusting conditions such as pH value, temperature, and solution concentration. If there is very little adsorption of ions other than the target element strontium (in this case, HOM-MC-Sr from the beginning), or if there is a method that can release only the target element strontium, the fourth The stage can be omitted. For example, in the case of the above-mentioned HOM-DDAB (CPP) carrying the receptor CPP or HOM-DTDR carrying the receptor DTDR, M is hardly adsorbed, that is, the state of HOM-DDAB (CPP) and DTDR-Sr. Therefore, the fourth stage can be omitted.

In the fifth stage, HOM-MC-Sr that has adsorbed almost only the target element strontium is immersed in a solution in which the target element strontium can be dissolved to dissolve the target element strontium ions. (Elution process) Alternatively, only the strontium ion, which is the target element, may be liberated by adjusting the conditions such as pH value, temperature, and solution concentration. Or the strontium ion which is a target element can be melt | dissolved by immersing in the solution which can release | release only the strontium ion which is a target element. In such a case, it is not always necessary to use HOM-MC-Sr that adsorbs only the target element strontium ions. The HOM-MC from which the target element strontium ions have been released from this solution is a solid and is removed by filtration. The HOM-MC removed as a solid can be used again.

Further, when strontium as the target element is separated from the eluent in which strontium is dissolved by the elution process by various methods (for example, molten salt electrolysis method or distillation method), strontium as the target element can be recovered. That is, the target element strontium was recovered from the environmental water in which strontium was dissolved. As a result, the solid HOM-MC can be filtered and reused and can be used again in the third stage. In addition, when strontium which is a target (metal) element is adsorbed to HOM-MC to make it HOM-MC-Sr, this process is performed from HOM-MC-Sr to Sr. Is released into HOM-MC, so it can be called back extraction (process).

From the strontium ion-dissolved solution in which strontium containing radioactive strontium, which is the target element obtained from the waste liquid from the nuclear facilities, the domestic water, and the environmental water, is obtained through the processes of the first stage to the fifth stage described above. The target element strontium can be recovered using highly ordered HOM silica (HOMS) carrying a strontium ion-adsorbing compound.

<Synthesis of HOM (cubic Ia3d) silica monolith>
FIG. 2 shows a method for synthesizing HOM (cubic Im3m) silica monolith. HOM silica monolith was synthesized by employing the instantaneous direct template method with copolymer surfactant F108 (EO ₁₄₁ PO ₄₄ EO ₁₄₁ ). A mesoporous silica monolith with cubic Im3m (HOM) cage-like mesopores is obtained by adding dodecane to the F108 / tetramethyl orthosilicate (TMOS) mixed phase in a ratio of dodecane: F108: TMOS = 1: 2.8: 4. Made using the formed microemulsion phase.

That is, 8.0 g of tetramethylorthosilicate (TMOS) and 5.6 g of surfactant F108 are placed in a round flask container, and 2.0 g of dodecane is added therein to completely dissolve the surfactant. Was stirred in warm water at about 50-60 ° C. for 5-10 minutes to obtain a homogeneous clear solution. When 4 g of pH 1.3 acidic aqueous solution (H ₂ O-HCl) is quickly added to this homogeneous mixed solution and evaporated, TMOS exothermic hydrolysis and concentration occur rapidly.

Since this exothermic hydrolysis / concentration reaction is continued in the exhaust by the rotary evaporator, the viscosity of the liquid material is increased, and the formed colored gel substance is formed in the reaction vessel. After evacuating for 10 minutes on a rotary evaporator, a translucent glassy monolith was collected and dried in an oven at 45 ° C. for 1 day. Thereafter, the surfactant and moisture were removed by baking at 450 ° C. for 8 hours, and a white powdery HOM (cubic Im3m) silica monolith was produced.

This HOM silica monolith has a very small pore size of 7 nm, a pore volume of 0.7 cm ³ / g, and a BET specific surface area of 700 m ² / g, as measured by nitrogen adsorption / desorption isotherm. Big. Also, X-ray diffraction patterns and electron microscopic analysis revealed that HOM silica monolith has an ordered cubic structure (Im3m) having a lattice constant of about 15.7 nm. Thus, the HOM silica produced by the above-described method is a highly ordered mesoporous silica having a very small pore size and a very large specific surface area.

<Receptor (1) used for recovery of radioactive strontium>
<Preparation of 4- (2-diazenyl-1,3,4-thiadiazole) -6-dodecylresorcinol {4- (2-diazenyl-1,3,4-thiadiazole) -6-dodecylresorcinol (DTDR)}>
FIG. 3 is a diagram showing a production method (reaction formula) of the receptor DTDR and a structural formula of DTDR incorporating strontium. About 0.05 mol of 2-amino-1,3,4-thiadiazol is dissolved in 40 ml of HCl, the solution is cooled to 0 ° C. and dissolved in water. 3.5 g NaNO ₂ was added slowly. The progress of this reaction was controlled by iodostarch paper. Finally, the diazonium salt solution was slowly poured into 3.4 g of a fully cooled solution of 6-dodecylresorcinol dissolved in 60 ml of 4N HCl. The resulting solution was then cooled at 0 ° C. for 30 minutes and 60 g sodium acetate solution dissolved in 180 ml water was added. This coupling reaction was carried out at 0 ° C. for 2 hours. A precipitate was formed, and this precipitate was washed with water. This precipitate is DTDR. As shown in FIG. 3, this DTDR is a strontium ion-adsorbing compound that can selectively adsorb strontium. Strontium (Sr) is incorporated into the cyclic molecular structure of DTDR. That is, DTDR is a chelate complex that preferentially adsorbs strontium. If strontium is separated (released), the original DTDR is restored. Thus, the adsorption / release reaction between strontium and DTDR is reversible. Thus, the receptor DTDR can be used to recover radioactive strontium.

<Receptor (2) used for recovery of radioactive strontium>
Receptor chlorophosphonazo-3 (hereinafter abbreviated as CPP) is manufactured industrially and is readily available. FIG. 4 shows the structural formula of receptor chlorophosphonazo 3 incorporating strontium. As shown in FIG. 4, this CPP is a strontium ion-adsorbing compound that can selectively adsorb strontium. Strontium (Sr) is incorporated into the cyclic molecular structure of CPP. That is, CPP is a chelate complex that preferentially adsorbs strontium. If strontium is separated (released), the original CPP is restored. Thus, the adsorption / release reaction between strontium and CPP is reversible. Therefore, the receptor chlorophosphonazo can be used for the recovery of radioactive strontium.

<Synthesis of HOM-probe material (1)>
<Preparation of HOM-DDAB-chlorophosphonazo 3 (collector)>
FIG. 5 is a diagram showing a method for producing a HOM carrying chlorophosphonazo 3 using a surface modification step. The HOM produced in Example 1 has a highly ordered cubic structure (Im3m) surface as shown in FIG. Since chlorophosphonazo 3 (CPP), which is a strontium-adsorbing compound, cannot be stably placed on the HOM, it cannot be directly supported (modified) on the HOM. Therefore, before supporting CPP on HOM, dimethylammonium dilauryl bromide (DDAB) is supported on HOM. DDAB is a type of cationic surfactant used to activate positively charged HOM pore surfaces. The role of this surfactant is an intermediate compound (intermediate regulator) for strontium to easily interact with and bind to the CPP on the HOM. That is, CPP is carried by HOM via DDAB.

In order to load CPP onto HOM via DDAB, we adopted a two-step loading process. As shown in FIG. 5, the surface of the HOM pore was first functionalized using dilauryl dimethyl ammonium bromide (DDAB). That is, a 0.1M ethanol solution of dimethylammonium dilauryl bromide was used for 1.0 g of HOM and stirred for 30 minutes. Thereafter, ethanol was evaporated by a rotary evaporator, and the solid matter was washed with water and then calcined at 650 ° C. for 6 hours.

Thus, as shown in FIG. 5, DDAB was supported on the highly ordered surface of HOM and the inner surface of the pores, and HOM-DDAB was produced. Second, 20 mg of chlorophosphonazo 3 was dissolved in 30 ml of water, to which 1.0 g of HOM-DDAB was added and stirred for 12 hours. After this time, the material was filtered and the solid product was washed until no elution was observed. After this, the material was dried at 65-70 ° C. for 5 hours, and then the material was ground into a powder and used for strontium removal under various experimental conditions. This material is HOM-DDAB (CPP) in which strontium-adsorbing compounds are regularly modified on the surface of activated HOM-DDAB as shown in FIG. When strontium is adsorbed to this HOM-DDAB (CPP), Sr is taken in (adsorbed) into CPP on HOM-DDAB (CPP) to become HOM-DDAB (CPP) -Sr, and Sr can be collected.

<Investigation of optimum pH value for strontium ion extraction>
It is an extremely important step to investigate the most efficient adsorption and collection of strontium under what environmental conditions the HOM (HOM-strontium probe) loaded with a strontium adsorbent (collector) agent (strontium collector) It is. We investigated the optimum environmental conditions (pH value of the solution) for strontium adsorption on the HOM-DDAB (CPP) collector.

The efficiency of (radioactive) strontium ion collectors with nanopores is affected by the pH value. The absorption spectrum of the probe charge transfer complex was carefully monitored over a wide range of aqueous pH values. We investigated using seven pH aqueous solutions (2.0, 3.5, 5.2, 7.0, 9.5, 11.0 and 12.5). Use pH adjustment solutions of either 0.01 M sulfuric acid or 0.2 M KCl-HCl for pH values 2.0 and 3.5, and CH ₃ COOH-CH ₃ COONa is used to adjust pH value 5.2. Used. 3-morpholinopropane sulfonic acid {3-morpholinopropane
sulfonic acid (MOPS)}, N-cyclohexyl-3-aminopropane-sulfonic acid {N-cyclohexyl-3-aminopropane sulfonic acid (CAPS)}, 2- (cyclohexylamino) ethanesulfonic acid {2- (cyclohexylamino) ethane sulfonic acid (CHES)} and KCl were used for pH 7.0, 9.5, 11.0 and 12.5, respectively, and pH was adjusted using 0.2 M NaOH. 2 ml of each pH solution was taken, 2 ppm of strontium (Sr ²⁺ ) was added thereto, and then a required amount of water was added to make a 10 ml solution. Thereafter, 6 mg of 6 mg of HOM-DDAB (CPP) collector was added, and the mixture was stirred for 1 hour and filtered. The solid material after filtration is HOM-DDAB (CPP) -Sr adsorbing strontium ions. The solid material was examined by UV-VIS-NIR Spectroscopy and an absorption spectrum was taken. Absorbance at a specific wavelength that particularly well represents strontium adsorption was plotted for each solid material.

FIG. 6 is a graph showing the relationship between the UV-visible spectrum signal intensity of HOM-DDAB (CPP) -Sr (measured at room temperature) and the pH value of the solution, from various pH value solutions in which 2 ppm of strontium ions are dissolved. HOM-DDAB (CPP) shows the pH value dependency of the absorbance of HOM-DDAB (CPP) -Sr adsorbed with strontium ions. In FIG. 6, the UV visible spectrum signal intensity (ratio) at a specific wavelength of HOM-DDAB (CPP) -Sr is plotted on the vertical axis, and the pH value of a solution in which 2 ppm of strontium ions are dissolved is plotted on the horizontal axis. The pH value solution with the highest signal intensity was used as the reference pH value. That is, the vertical axis in FIG. 6 represents the ratio to the signal intensity of an aqueous solution having a pH value of 11.0. As the amount of strontium in HOM-DDAB (CPP) -Sr increases, it is known that the absorbance in the UV-visible spectrum increases. Therefore, as can be seen from FIG. 6, the signal intensity data is the collector of strontium ions (adsorption) When HOM-DDAB (CPP) is used as the agent, the best pH value that best adsorbs strontium ions is 11.0. Considering measurement errors and variations, a good pH value is 9.5 to 12.5, preferably 10.0 to 12.0, and more preferably 10.5 to 11.5. From the colorimetric analysis data shown in the upper part of FIG. 6, the color tone of the HOM-DDAB (CPP) collector having a pH of 11.0 changes when adsorbing strontium ions (such as Sr2 ⁺ ). That is, HOM-DDAB (CPP) is a reddish amber color, but HOM-DDAB (CPP) -Sr is amber color. Thus, the HOM-DDAB (CPP) collector is a visual collector (collector).

<Investigation of sensitivity when extracting strontium from various concentrations of strontium solution using HOM-DDAB (CPP)>
Take 2 ml of pH 11.0 solution that best adsorbs strontium ions, add various concentrations (0.5 ppm-4.0 ppm) of strontium ions (Sr ²⁺ ), add an appropriate amount of water and add 10 ml with a glass test tube. Into solution. Thereafter, 6 mg of a HOM-DDAB (CPP) collector was added, shaken for 1 hour, and filtered at room temperature. The solid material was examined by UV-VIS-NIR Spectroscopy and an absorbance spectrum was taken.

FIG. 7 is a diagram showing an absorption spectrum and colorimetric analysis of HOM-DDAB (CPP) -Sr using strontium ion concentration as a parameter at room temperature. In FIG. 7, the horizontal axis represents the measurement wavelength, and the vertical axis represents the absorbance. The measurement wavelength range is 250 nm to 900 nm. As can be seen from FIG. 7, as the strontium ion concentration increases, the absorption spectrum intensity increases in almost all light in the wavelength region (30 nm to 700 nm). Accordingly, if UV-visible spectrum measurement of HOM-DDAB (CPP) -Sr is performed, the strontium ion concentration in the solution can be known from the absorbance.

Actually, when the relationship between the absorbance and the strontium ion concentration is examined at the wavelength (λ = 585 nm) at which the absorbance is greatest, which is related to the adsorption of strontium ions, it is as shown in FIG. That is, FIG. 8 is a graph showing the relationship between the strontium ion concentration in the solution at pH = 11.0 and the absorbance (at λ = 585 nm) of the ultraviolet visible spectrum of HOM-DDAB (CPP) -Sr. It is a calibration curve of concentration and absorbance (at λ = 585 nm). Thus, it can be clearly understood that the absorbance of the UV-visible spectrum of HOM-DDAB (CPP) -Sr increases as the strontium ion concentration in the solution increases. In other words, the strontium ion concentration in the solution can be known from the absorbance of the ultraviolet visible spectrum of HOM-DDAB (CPP) -Sr. Particularly in a place where the strontium ion concentration is low (50 μM or less), the linearity is good as shown in FIG. That is, the curve curve shown in FIG. 8 may be referred to as a calibration curve between absorption rate and concentration. Thus, the HOM probe (HOM-DDAB (CPP)) is an excellent collector and concentration detection sensor for strontium ions. These spectral changes indicate that CPP is an indicator of a strontium-receptor binding event to form a charge transfer complex. The measurement of the UV-visible spectrum was repeated 10 times, but there was almost no variation and the reproducibility was very good. The strontium ion concentration is calibrated based on a known sample.

FIG. 7 shows the relationship between the strontium ion concentration and the color tone of HOM-DDAB (CPP) -Sr, that is, colorimetric data. As shown in FIG. 7, the color tone of the solid material after filtration gradually increases from the reddish amber color (strontium ion concentration 0 ppb, that is, the color tone of the HOM-DDAB (CPP) collector) as the strontium ion concentration increases. It becomes amber (strontium ion concentration 2 ppm) and changes to a deeper amber (strontium ion concentration 4.0 ppm). Since this change in color tone is continuous, it is possible to know the strontium ion concentration from the color tone of the solid material {HOM-DDAB (CPP) -strontium} after filtration. Thus, also from the result of colorimetric analysis, the HOM probe {HOM-DDAB (CPP) -Sr} is an excellent collector and concentration detection sensor of strontium ions.

FIG. 9 is a table showing the applicable range of the HOM-DDAB (CPP) -Sr of the present invention obtained from the above examples. HOM-DDAB (CPP) HOM- DDAB when immersed collectors to strontium ions lysis solution (CPP) response time collectors to adsorb the strontium ion is about 2 minutes, detection limit 3.19x10 ^{-6 (mol.dm-3} ), The effective collection range is 0.5-4.0 ppm. The required amount of a HOM-DDAB (CPP) collector that adsorbs 1 g of strontium is 14 g. Moreover, the HOM-DDAB (CPP) collector which adsorb | sucked strontium returns to the original HOM-DDAB (CPP) collector by using an acidic solution or an alkaline solution as an elution solution. Moreover, since the HOM-DDAB (CPP) collector has a stable structure of the HOMS skeleton and can be used repeatedly, a large amount of strontium can be recovered with a small amount of material.

<HOM-DTDR [4- (2-diazenyl-1,3,4-thiadiazole) -6-dodecylresorcinol {4- (2-diazenyl-1,3,4-thiadiazole) -6-dodecylresorcinol (DTDR)}] Synthesis>
0.030 g of DTDR was dissolved in ethanol in a round flask and 1.0 g of HOM (Cage form) was added. The ethanol in the solution was removed by vacuuming at 45 ° C. connected to a rotary evaporator. After this, the material was washed and dried at 65-70 ° C. for 5 hours. This material was ground to a powder and was used to remove strontium under various experimental conditions. This material is HOM-DTDR carrying a strontium ion adsorbing compound.

FIG. 10 is a diagram schematically illustrating a strontium ion collection / separation process using a HOM-DTDR collector in which DTDR is supported on HOM silica. A HODR-DTDR collector is prepared by supporting DTDR on the surface of the highly ordered HOM silica carrier and the inner surface of the pores. This HOM-DTDR collector is brought into contact (immersion) with a strontium ion dissolving solution to adsorb strontium ions to the HOM-DTDR collector to obtain HOM-DTDR-Sr. That is, strontium ions (Sr ²⁺ ) are incorporated into the cyclic molecular structure of DTDR on the HOM-DTDR collector. This HOM-DTDR-Sr is contacted (immersed) in an appropriate elution solution to separate (release) strontium. As a result, the HOM-DTDR-Sr returns to the original HOM-DTDR and can be used again as a HOM-DTDR collector for collecting strontium. Since DTDR, which is a strontium ion adsorbing compound, can be directly supported on HOM silica, this supporting method may be called a direct supporting method. On the other hand, in the case of CPP, which is the aforementioned strontium ion adsorbing compound, CPP is supported on HOM silica via DDAB, and this supporting method can be called an indirect supporting method.

<Investigation of optimum pH value for strontium ion extraction>
Investigate what environmental conditions the HOM (HOM-strontium probe) carrying a strontium (ion) adsorbent (collector) agent (strontium (ion) collector) absorbs and collects strontium most efficiently This is an extremely important step. We investigated the optimum environmental conditions (solution pH value) for strontium adsorption on the HOM-DTDR collector.

The efficiency of a radioactive strontium ion collector with nanopores is affected by the pH value. The absorption spectrum of the probe charge transfer complex was carefully monitored over a wide range of aqueous pH values. We investigated using seven pH aqueous solutions (2.0, 3.5, 5.2, 7.0, 9.5, 11.0 and 12.5). CH ₃ COOH-CH ₃ COONa is used to adjust pH value 5.2 using pH adjustment solution of either 0.01M sulfuric acid or 0.2M KCl-HCl for pH value 2.0 and 3.5. It was. 3-morpholinopropane sulfonic acid {3-morpholinopropane
sulfonic acid (MOPS)}, N-cyclohexyl-3-aminopropane-sulfonic acid {N-cyclohexyl-3-aminopropane sulfonic acid (CAPS)}, 2- (cyclohexylamino) ethanesulfonic acid {2- (cyclohexylamino) ethane sulfonic acid (CHES)} and KCl were used for pH 7.0, 9.5, 11.0 and 12.5, respectively, and pH was adjusted using 0.2 M NaOH. 2 ml of each pH solution was taken, 3 ppm of strontium (Sr ²⁺ ) was added thereto, and then a required amount of water was added to make a 10 ml solution. Thereafter, 10 mg of HOM-DTDR collector was added, and the mixture was stirred for 1 hour and then filtered. The solid material after filtration is HOM-DTDR-Sr adsorbing strontium ions. The solid material was examined by UV-VIS-NIR Spectroscopy and an absorption spectrum was taken. Absorbance at a specific wavelength that particularly well represents strontium adsorption was plotted for each solid material.

FIG. 11 is a graph showing the relationship between the UV-visible spectrum signal intensity (room temperature measurement) of HOM-DTDR-Sr and the pH value of the solution. From various pH value solutions in which 3 ppm of strontium ions are dissolved, HOM-DTDR Shows the pH value dependence of the absorbance of HOM-DTDR-Sr adsorbing strontium ions. In FIG. 11, the UV visible spectrum signal intensity (ratio) at a specific wavelength of HOM-DTDR-Sr is plotted on the vertical axis, and the pH value of a solution in which 3 ppm of strontium ions are dissolved is plotted on the horizontal axis. The pH value solution with the highest signal intensity was used as the reference pH value. That is, the vertical axis in FIG. 11 represents a ratio to the signal intensity of an aqueous solution having a pH value of 9.5. Since it is known that the absorbance of the UV-visible spectrum increases as the amount of strontium in HOM-DTDR-Sr increases, as shown in FIG. 11, the signal intensity data is obtained as a collector (adsorbent) of strontium ions. When HOM-DTDR-Sr is used, the best pH value that best adsorbs strontium ions is 9.5. Considering measurement errors and variations, a good pH value is 7.0 to 11.0, preferably 8.0 to 10.5, and more preferably 9.0 to 10.0.

<Survey of sensitivity when extracting strontium from various concentrations of strontium solution using HOM-DTDR>
Take 2 ml of pH 9.5 solution that best adsorbs strontium ions, add various concentrations (0.5 ppm-5.0 ppm) of strontium ions (Sr ²⁺ ), add an appropriate amount of water, and use a glass test tube. Made 10 ml solution. Then, 10 mg of HOM-DTDR collector was added, shaken for 1 hour, and filtered at room temperature. The solid material was examined by UV-VIS-NIR Spectroscopy and an absorbance spectrum was taken.

FIG. 12 is a diagram showing an absorption spectrum and colorimetric analysis of HOM-DTDR-Sr using strontium ion concentration as a parameter at room temperature. The measurement wavelength range is 250 nm to 900 nm. In FIG. 12, the horizontal axis represents the measurement wavelength, and the vertical axis represents the absorbance. As can be seen from FIG. 12, as the strontium ion concentration increases, the absorption spectrum intensity increases in almost all light in the wavelength region (300 nm to 700 nm). Therefore, if the ultraviolet visible spectrum measurement of HOM-DTDR-Sr is performed, the strontium ion concentration in the solution can be known from the absorbance. For example, the strontium ion concentration in the solution can be determined fairly accurately by using the absorbance at a wavelength of 479 nm related to the adsorption of strontium.

FIG. 12 shows the relationship between the strontium ion concentration and the color tone of HOM-DTDR-Sr, that is, colorimetric data. As shown in FIG. 12, as the strontium ion concentration increases, the color tone of the solid material after filtration gradually increases from light brown (strontium ion concentration 0 ppb, that is, the color tone of the HOM-DTDR collector) to brown (strontium ion concentration). 1.0 ppm), and further changes to dark brown (strontium ion concentration 5.0 ppm). Since this change in color tone is continuous, it is possible to know the strontium ion concentration from the color tone of the solid material {HOM-DTDR-strontium} after filtration. Thus, also from the result of colorimetric analysis, the HOM probe (HOM-DTDR-Sr) is an excellent collector and concentration detection sensor of strontium ions.

When the strontium ion concentration of the solution before and after putting the HOM-DTDR collector of these samples was measured by ICP-OES (ICP emission spectroscopic analysis), strontium ions could be removed with a recovery rate of about 90%. By optimizing the conditions, the removal efficiency can be further increased, and the recovery rate can be close to 100%. Moreover, the HOM-DTDR collector (HOM-DTDR-Sr) which adsorb | sucked strontium returns to the original HOM-DTDR collector by using an acidic solution or an alkaline solution as an elution solution. Moreover, since the HOM-DTDR collector has a stable structure of the HOMS skeleton and can be used repeatedly, a large amount of strontium can be recovered with a small amount of material.

FIG. 13 shows recovery of strontium (Sr) from a strontium ion-dissolved solution containing radioactive strontium and the like using mesoporous silica (HOMS) supporting CPP {DDAB (CPP)} or DTDR which is a strontium ion adsorbing compound of the present invention. It is the figure which showed the system which performs. In the first stage, mesoporous silica (HOMS) is prepared, and in the second stage, strontium-adsorbing compound CPP {DDAB (CPP)} or DTDR is supported on HOMS, and HOMS-DDAB (CPP) collector or HOMS-DTDR collector. Is made. Next, in a third stage, HOMS-DDAB (CPP) or HOMS-DTDR is immersed (contacted) in a strontium (ion) solution containing strontium (which naturally contains radioactive strontium) and should be extracted (or collected). The target (metal) element strontium should be adsorbed (extracted and collected) on HOMS-DDAB (CPP) or HOMS-DTDR to produce HOMS-DDAB (CPP) -Sr or HOMS-DTDR-Sr. In the next fourth stage (fifth stage in FIG. 1), this HOMS-DDAB (CPP) -Sr or HOMS-DTDR-Sr is the target element by immersing it in a strontium elution solution such as an acidic solution or an alkaline solution. Isolate strontium. (HOMS-DDAB (CPP) and HOMS-DTDR selectively adsorb only Sr ions even if various ions (cations and anions) are dissolved, so the fourth step in FIG. 1 can be omitted.) The operation recovered or collected strontium. HOMS-DDAB (CPP) or HOMS-DTDR can be used again in the third stage and can be used any number of times by reusing the HOMS-DDAB (CPP) collector or HOMS-DTDR collector.

In terms of the colorimetric method, the color tone of the HOMS-DDAB (CPP) collector or HOMS-DTDR collector changes in the strontium ion solution in the third stage. This change in color tone depends on the strontium ion concentration of the strontium ion solution. Alternatively, the color tone of the HOMS-DDAB (CPP) collector or HOMS-DTDR collector varies depending on the concentration of strontium ions adsorbed thereto. Since the strontium ion adsorption speed to the HOMS-DDAB (CPP) collector or HOMS-DTDR collector is about several minutes, the HOMS-DDAB (CPP) collector (HOMS-DDAB) is filtered by filtration after the color change is completed. (CPP) -Sr) or HOMS-DTDR collector (which becomes HOMS-DTDR-Sr). This indicates that strontium ions in the strontium ion dissolution solution were collected in the HOMS-DDAB (CPP) collector or HOMS-DTDR collector.

When these HOMS-DDAB (CPP) -Sr or HOMS-DTDR-Sr are brought into contact with an elution (free, separated) solution capable of separating strontium from them, the color of the HOMS-DDAB (CPP) collector or HOMS-DTDR collector Changes again and returns to the original color. That is, it returned to HOMS-DDAB (CPP) or HOMS-DTDR which did not adsorb strontium. The HOMS-DDAB (CPP) collector or HOMS-DTDR collector has a very high extraction selectivity for strontium ions, and even if a large number of ions are contained, there is almost no effect on the effect, and the color tone of solids can be changed. Has little effect. Thus, a HOMS-DDAB (CPP) collector or HOMS-DTDR collector can be said to be a complete strontium collector or a complete strontium remover because it can collect all the strontium in solution and remove almost completely strontium. In this way, a HOMS-DDAB (CPP) collector or HOMS-DTDR collector can be used many times for the recovery of strontium ions using a colorimetric method.

As described above, it is possible to know how much strontium ions have been adsorbed by the HOMS-DDAB (CPP) collector or the HOMS-DTDR collector using the color change by the colorimetric method. In addition, if a HOMS-DDAB (CPP) collector or HOMS-DTDR collector is immersed in a strontium ion-dissolved solution and the HOMS-DDAB (CPP) collector or HOMS-DTDR collector is observed for the degree of discoloration, the end point is reached. The HOMS-DDAB (CPP) collector or the HOMS-DTDR collector is immersed in an aqueous solution containing strontium ions, the HOMS-DDAB (CPP) collector or the HOMS-DTDR collector is taken out of the aqueous solution, and the HOMS- Strontium ions can be eluted from DDAB (CPP) -Sr or HOMS-DTDR-Sr. When HOMS-DDAB (CPP) -Sr or HOMS-DTDR-Sr is put into a strontium ion elution solution, strontium is eluted and discolored, and the original HOMS-DDAB (CPP) or HOMS- not adsorbing strontium ions. Return to DTDR.

It can be confirmed from ICP-OES measurement that strontium ions are completely removed. Thus, the amount of adsorption of strontium ions can be determined using a colorimetric method, and end point detection is also possible. The HOMS-DDAB (CPP) collector or HOMS-DTDR collector is reversible for extraction / separation of strontium ions. Thus, the adsorption amount of strontium ions can be grasped only by the color tone, or it can be grasped that strontium ions are not adsorbed, so that not only rapid detection of strontium ions but also rapid recovery can be performed. As a result, productivity can be greatly improved. As described above, the HOMS-DDAB (CPP) collector or HOMS-DTDR collector can extract (collect) strontium by utilizing the change in color tone (colorimetric method). You can also. In addition, the color change (colorimetric method) and the above-described spectroscopic method can be automated to construct an automatic recovery system and perform continuous processing.

HOMS-DDAB (CPP) or HOMS-DTDR, or HOMS loaded with other strontium ion-adsorbing compounds has excellent selectivity, so even if metals other than strontium ions are contained in the strontium ion solution Alternatively, even if an anion ion or a surfactant is contained in the strontium ion solution, that is, even if these competing ions are present, the selectivity is very good, and only strontium ions are extracted or collected. Even if the amount of strontium ions is contained in a trace amount of ppb to ppm or in a large amount, and even if the content of other metal ions, anions or surfactants is contained in a trace amount or in a large amount, the present invention HOMS-DDAB (CPP) or HOMS-DTDR can selectively extract or collect only strontium ions.

One of the features of the present invention is that the inner wall of the mesoporous material is composed of an arbitrary composite oxide to create a state in which different kinds of atoms are aligned, and an appropriate chelate or compound is fixed thereto, thereby sensing and collecting. Is to do Strontium ion collectors such as HOMS-DDAB (CPP) collector and HOMS-DTDR collector manufactured by using the technology of the present invention adsorb strontium from waste (exhaust) liquid containing radioactive strontium, etc., or domestic (exhaust) water. Then, since it changes visually, strontium can be easily recovered. Moreover, the HOMS-DDAB (CPP) collector or HOMS-DTDR collector has high selectivity for strontium ions among various ions and has an optical response function. The HOMS-DDAB (CPP) collector or HOMS-DTDR collector of the present invention is extremely useful for extraction, removal, collection, recovery and detection of radioactive strontium that is particularly dangerous to humans.

As described above, the present invention allows a highly ordered mesoporous silica prepared from an organosilicon compound and a surfactant to carry a strontium ion adsorbing compound such as a chelate compound that selectively adsorbs a target element strontium ion. The mesoporous silica supporting the strontium ion adsorbing compound is brought into contact with a solution in which the target element strontium ions are dissolved, and the target element strontium ion is selectively converted into the strontium ion adsorbing compound supported on the mesoporous silica. Adsorb. Thereafter, the mesoporous silica supporting the strontium ion adsorbing compound adsorbing the target element strontium ions is chemically treated to release the target element strontium ion from the strontium ion adsorbing compound supported on the mesoporous silica, Collect strontium, the target element. The mesoporous silica supporting the strontium ion-adsorbing compound from which the target element strontium ions are released can be reused. The mesoporous silica supporting the strontium ion adsorbing compound can also be used as a strontium (ion) collector and a concentration detection sensor. Furthermore, it is possible to inspect whether or not (hazardous radioactive) strontium is dissolved in domestic water or waste liquid, and the concentration can be detected even at a very small concentration of ppb to ppm order. Furthermore, the (radioactive) strontium dissolved in domestic water or waste liquid can be adsorbed to reduce the (radioactive) strontium concentration to a very small concentration. In terms of radioactivity level, it can be reduced below the allowable limit. Therefore, it can also be used as a (radioactive) strontium removal filter.

In addition, it cannot be overemphasized that the said content can be applied to the said other part regarding that it can apply without contradiction also to the other part which did not describe the content described and demonstrated in a certain part of the specification. Moreover, the said embodiment and an Example are examples, and it can be carried out by changing variously within the range which does not deviate from a summary, and it cannot be overemphasized that the right range of this invention is not limited to the said embodiment.

The present invention relates to an industrial field relating to strontium collectors and sensors, an industrial field for removing strontium containing radioactive strontium from substances and materials containing various cations, anions and surfactants, and an industrial field for recovering strontium containing radioactive strontium Can be used.

Claims (22)

Adsorbability of strontium ions that can adsorb strontium ions and release adsorbed strontium ions from a solution in which various ions including strontium ions, which are target elements, are dissolved (strontium ion solution). Mesoporous silica bonded with a compound,
The strontium ion adsorbing compound is:
4- (2-diazenyl-1,3,4-thiadiazole) -6-dodecylresorcinol {4- (2-diazenyl-1,3,4-thiadiazole) -6-dodecylresorcinol (DTDR)} and / or chlorophosphonazo 3. Mesoporous silica characterized by being 3 (Chlorophosphonazo-III). The mesoporous silica according to claim 1, wherein in the case of the chlorophosphonazo 3, the mesoporous silica is bonded to mesoporous silica via dilauryl dimethyl ammonium bromide (DDAB). 3. The mesoporous silica according to claim 1, wherein the strontium ion-dissolved solution is a strontium ion-dissolved solution adjusted to a pH value at which strontium as a target element is maximally adsorbed. Wherein the in case of the DTDR of the pH value is 8.0 to 10.5, in the case of the Chlorophosphonazo 3 of the pH value is 10.0 to 12.0, claim 3. Mesoporous silica according to 3. The color tone of the mesoporous silica bonded with the strontium ion adsorbing compound before adsorbing strontium is changed by adsorbing strontium, and further returns to the original color when strontium is separated. 5. The mesoporous silica according to any one of 4 above .
The mesoporous silica according to any one of claims 1 to 5, wherein the strontium ion-dissolved solution contains radioactive strontium ions. A mesoporous silica bonded with a strontium ion-adsorbing compound is brought into contact with a strontium ion-dissolved solution containing a strontium ion as a target element, adjusted to a pH value that well adsorbs the strontium ion as a target element. A mesoporous silica comprising a step of adsorbing a strontium ion as a target element to a compound, and a step of releasing the strontium ion as a target element from the strontium ion adsorbing compound adsorbing the strontium ion as a target element A strontium recovery method used,
The strontium ion-adsorbing compound is 4- (2-diazenyl-1,3,4-thiadiazole) -6-dodecylresorcinol {4- (2-diazenyl-1,3,4-thiadiazole) -6-dodecylresorcinol (DTDR And / or chlorophosphonazo-3 (Chlorophosphonazo-III). 8. The method for recovering strontium according to claim 7 , wherein the chlorophosphonazo 3 is bonded to mesoporous silica via dilauryl dimethyl ammonium bromide (DDAB). . The method for recovering strontium according to claim 7 or 8 , further comprising a step of binding the strontium ion-adsorbing compound to mesoporous silica. 10. The method according to claim 7 , further comprising determining a concentration of strontium ions adsorbed on the mesoporous silica bonded with the strontium ion adsorbing compound using a colorimetric method. Strontium recovery method. The method for recovering strontium according to any one of claims 7 to 10 , wherein mesoporous silica bonded with a strontium ion adsorbing compound is reused. Wherein the in case of the DTDR the pH value is 8.0 to 10.5, in the case of the Chlorophosphonazo 3 of the pH value is 10.0 to 12.0, claim 7 Strontium recovery method of any one of -11 . Extracting strontium ions by using the change in color when the mesoporous silica bonded with the strontium ion adsorbing compound adsorbs strontium ions, and / or discoloring when the mesoporous silica adsorbing strontium ions elutes strontium ions The method for recovering strontium according to any one of claims 7 to 12 , wherein strontium ions are separated by returning to mesoporous silica bonded with a strontium ion adsorbing compound. A strontium ion collector based on mesoporous silica combined with a strontium ion adsorbing compound that collects strontium ions from a solution in which various ions including strontium ions are dissolved (strontium ion solution),
The strontium ion adsorbing compound is 4- (2-diazenyl-1,3,4-thiadiazole) -6-dodecylresorcinol {4- (2-diazenyl-1,3,4-thiadiazole) -6-dodecylresorcinol (DTDR) } And / or a strontium ion collector, characterized by being chlorophosphonazo-III. The strontium ion collection according to claim 14 , characterized in that, in the case of the chlorophosphonazo 3, it is bound to mesoporous silica through dilauryl dimethyl ammonium bromide (DDAB). Agent. The strontium ion collecting agent according to claim 14 or 15 , wherein strontium ions can be collected even in the presence of competing ions. The strontium ion-dissolving agent according to any one of claims 14 to 16, wherein the strontium ion dissolving solution contains radioactive strontium ions. A strontium ion concentration sensor based on mesoporous silica combined with a strontium ion-adsorptive compound. Color change of strontium ion (colorimetric method) or UV-VIS-NIR spectroscopy of strontium ion concentration A strontium ion concentration sensor characterized by detecting by:
The strontium ion adsorbing compound is 4- (2-diazenyl-1,3,4-thiadiazole) -6-dodecylresorcinol {4- (2-diazenyl-1,3,4-thiadiazole) -6-dodecylresorcinol (DTDR) } And / or a strontium ion concentration sensor, characterized in that it is chlorophosphonazo-III. 19. The strontium ion concentration according to claim 18 , wherein the chlorophosphonazo 3 is bonded to mesoporous silica via dilauryl dimethyl ammonium bromide (DDAB). Sensor. The strontium ion concentration sensor according to claim 18 or 19 , wherein the concentration of strontium ions is detected by applying UV-VIS-NIR spectroscopy while changing the wavelength of 250 nm to 900 nm. The strontium ion concentration sensor according to any one of claims 18 to 20 , wherein the strontium ion concentration is detected in the presence of competing ions. The strontium removal filter using the mesoporous silica of any one of Claims 1-6 .