JP5967748B2 - Mesoporous silica supporting cesium ion adsorbing compound and cesium collector, cesium recovery method, cesium ion collector, cesium ion concentration sensor and cesium removal filter using the same - Google Patents

Description

The present invention relates to mesoporous silica having a regular arrangement carrying a cesium (Cs) ion-adsorbing compound capable of selectively adsorbing cesium ions as a target element. Cesium (Cs) ion collector using mesoporous silica supporting cesium (Cs) ion-adsorbing compound that can collect and recover radioactive cesium (Cs), and cesium (Cs) ion adsorption supported on mesoporous silica The present invention relates to a method for efficiently and selectively recovering cesium (Cs) ions contained in a cesium (Cs) ion-dissolved solution using a functional compound. Furthermore, the present invention relates to a cesium (Cs) ion collector and sensor using mesoporous silica that detects cesium (Cs) ion concentration.

Cesium (element symbol Cs) is a soft, silver-white alkali metal that is highly chemically reactive and rich in ductility, and is naturally present in minerals such as polxite and carnal stone. One of the main uses of cesium is drilling and drilling water using cesium formate in the oil mining industry. In addition, since cesium is highly sensitive to light, it is applied to optoelectronic devices and used in televisions, movies, radars and musical instruments, and also used in arc tubes and light-emitting screens. As a noteworthy application, cesium 133 is used in a cesium atomic clock and is considered to be the most accurate unit of time. As chemical and biological applications of cesium, cesium nitrate is used as a medium in methacrylic resin catalysts, cesium chloride, etc. as a medium in density gradient centrifugation when separating and purifying nucleic acid (DNA, RNA) serum. Cesium is used as a catalyst for synthesizing polyoxyalkylene polyol used as a raw material for polyurethane. Although the use of cesium is still limited, its demand is increasing. Currently, it is produced industrially by distilling a mixture of cesium chloride and calcium or by distilling cesium hydroxide, carbonate, aluminate, etc. with magnesium as a reducing agent.

As described above, cesium (Cs) is a useful metal, but in nuclear power generation, radioactive isotopes such as cesium 137 ( ¹³⁷ Cs) and cesium 134 ( ¹³⁴ Cs) are generated from the fission reaction of uranium and plutonium. . Chernobyl nuclear power plant accident and the most recent of a large amount in the Fukushima nuclear power plant accident radioactive element cesium ¹³⁷ (137 Cs) and the like are released into the environment. Also, leakage from the reactor during normal operation into the environment is becoming a problem. In addition to direct radioactive cesium 137 from a nuclear reactor or the like, there is a problem that radioactive cesium 137 is indirectly generated. For example, iodine 137 (half-life 24.5 seconds), xenon 137 (half-life 3.82 minutes) and tellurium 137 (half-life 2.5 minutes) produced directly in thermal neutron fission of uranium 235 are more than cesium 137. It is a short-lived nuclide with a short half-life, but beta decays to cesium 137. Furthermore, accidents in which radioactive element cesium 137 used in γ-ray generators and the like are accidentally released to the environment have sometimes occurred. Since this radioactive element cesium 137 ( ¹³⁷ Cs) has a long half-life of 30.1 years, once released into the environment, organisms will be exposed for a long time, and there is concern about the effects of radioactive cesium 137 on the human body. Yes. Many of the cesium compounds such as radioactive cesium 137 are water-soluble, and the behavior in the living body is similar to that of potassium and the like and is easily taken into the living body. When entering the living body, radioactive cesium 137 is distributed throughout the body, causing internal exposure due to β (beta) ray decay.

Therefore, the removal of radioactive cesium (Cs) 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. If the chemical reaction in the reactor is not carefully controlled, the chemical reaction proceeds rapidly, the furnace pressure rises, and fuel rod corrosion occurs. 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 cesium (Cs) into the water that is cooling around the fuel rods. Radioactive cesium (Cs) circulates in the system together with cooling water and eventually exits the reactor to the environment, such as air, or becomes liquid and solid waste. Occasionally, the reactor gas capture system may release gas containing radioactive cesium (Cs) to the environment. In this way, even if there is no accident at this Fukushima nuclear power plant, even under strict management, leakage of radioactive materials not only from existing systems but also from waste and stored materials is inevitable, and a considerably long half-life Cesium radioactivity 137 has a radionuclide found quite frequently in soil and groundwater.

There are mainly three techniques for selectively removing cesium. The first approach uses tetraphenyl sodium borate to deposit cesium using subsequent cesium removal by cross-flow filtration. The second approach uses a non-organic adsorbent, crystalline silicon titanate, to collect cesium in a non-elutable ion exchange approach. The third approach uses specially designed crown ethers that are deployed within the organic extraction system. A cesium ion complex having a large crown ether has been studied in an aqueous solvent and a non-aqueous solvent (Non-patent Document 1), and also in a conductivity measurement method. (Non-patent Document 2) Further, the complex formation reaction in the mixed solvent system is only investigated to a very limited extent. (Non-Patent Document 3) It is interesting for us to study the effects of solvent properties and ring size crown on the interaction of metal ions with large crown ethers.

At present, organic ion exchange resins such as resorcinol-formaldehyde, Duolite CS-100 (registered trademark), and diphonix CS (registered trademark) are used as cesium ( Cs) Used for removal. Many studies so far have considered the use of traditional non-organic and organic ion exchangers for the separation of radionuclides. However, these ion exchanger methods are used to elute cesium ions, wash the ion exchanger or load the ion exchanger, and use a large amount of secondary waste or waste liquid from the solution used. Give birth. In addition, used ion exchangers become waste, non-organic materials can usually be used only once before disposal, and renewable materials have a short usable life. (Non-patent document 4) There is also a problem that it is difficult to selectively remove cesium ions.

As a method for removing cesium, a method of adding an alkali cation to a beta zeolite carrier has been studied. For example, the method of exchanging platinum supported on beta zeolite with cesium cations is important in the aromatization of n-hexane, and that platinum supported on beta zeolite was exchanged with alkali cations and alkaline earth cations. Has also been reported. (Non-Patent Document 5) However, the cesium removal method by such a replacement method has problems that the process is complicated (long) and that recycling and reuse are difficult. Moreover, it is difficult to selectively adsorb cesium by the method of directly supporting cesium on zeolite. As described above, various methods for selectively removing cesium ions have been studied, but a simple and inexpensive method capable of selectively removing a trace amount of radioactive cesium that affects the human body has not yet been found.

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 / removal approach is a simple technique that does not require complex equipment or a well-controlled environment, but for low concentration levels of radioactive cesium, low cost, good selectivity, rapid detection and radioactive cesium No visual collector has been developed yet that can eliminate this.

Radioactive cesium is present at concentrations well below the extraction limits of most commonly used processing methods, and the acceptable level of radioactive cesium in the human body is very low, so cesium 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 techniques that are rapid, cost effective, easy to use, and reliable for the measurement and extraction of trace cesium 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 prior patent documents and non-patent documents so far discloses a simple, rapid and accurate method for recovering cesium adsorbed on mesoporous silica.

JP2007-327886A JP2007-327887A

C.M.Goff, M.A.Matchette, N. Shabestary, S. Khazaeli, “Complexation of caesium and rubidium cations with crown ethers in N, N-dimethylformamide” Polyhedron 15 (1996) 3897-3903 M. Shamsipur, M. Saeidi, “Conductance study of binding of some Rb + and Cs + ions bymacrocyclicpolyethers in acetonitrile solution” J. Solution Chem. 29 (2000) 1187-1198 G. Rounaghi, A.I. Popov, “133Cs NMR study of Cs + ion complexes with dibenzo-21-crown-7 and dibenzo-24-crown-8 insome mixed solvents” Polyhedron 5 (1986) 1329–1333 M.A.Lilga, R.J.Ortha, J.P.H.Sukamtoa, S.D.Rassata, J.D.Gendersb, R. Gopa.Separation and Purification Technology 24 (2001) 451-466 G.E.Sntamaaria, J.M.Bautista, H. Silva, L. Munoz, N. Batina. “Cesium concentrationeffect on Pt / Cs beta zeolite / γ-aluminacatalysts for n-heptane conversion” .Applied Catalysis A: General 231 (2002) 117−123

As explained above, cesium (Cs) is used in various applications, but radioactive cesium such as cesium 137 ( ¹³⁷ Cs), which is a radioisotope, accumulates in the human body even in a trace amount on the order of ppb to ppm. Because it induces carcinogenic diseases by emitting radiation, it is necessary to exclude it from all environments such as waste water and soil as well as domestic water such as drinking water and washing water and the atmosphere.

Therefore, it is necessary to know what level of cesium (Cs) is contained in a solution such as domestic water or wastewater even in a small amount. However, there are few cesium (Cs) collectors or cesium concentration detection sensors that quickly and accurately measure a very small amount of cesium (Cs) on the order of ppb to ppm, and there is a problem that even if it is not possible to use it repeatedly. Also, since there are few collectors or sensors that selectively collect and detect cesium (Cs), solutions containing multiple elements and ions other than cesium (Cs) are affected by elements and ions other than cesium (Cs). Only the cesium (Cs) concentration cannot be measured accurately. Furthermore, when a very small amount of radioactive cesium is present in a solution such as domestic water or wastewater, it is necessary to remove the radioactive cesium, but there are few methods for removing cesium (Cs) from the ppb to the ppm order level. In the case of an ion exchange resin or the like, ions of the order of ppb to ppm can be removed, but there is a problem that only cesium (Cs) ions cannot be specified and removed. In other words, a highly selective substance that selectively removes only cesium (Cs) (ion) has not been found.

In addition, after removing cesium (Cs) with a recovery agent, there is a problem that it is difficult to effectively utilize the recovered cesium (Cs) because it is difficult to separate the cesium (Cs). Since cesium (Cs) is a rare metal and the producing countries are unevenly distributed, it is extremely important to collect and reuse cesium (Cs). Alternatively, if the collected cesium cannot be separated, there is also a problem that it is difficult to reuse the recovery agent. Therefore, the recovery agent that recovered cesium (Cs) can only be discarded as it is, and this secondary waste disposal method becomes a problem. In addition, there is a problem that the cost for collecting and recycling cesium (Cs) in solutions such as domestic water and wastewater is high. As described above, simple, low-cost, high-selectivity methods for detecting cesium (Cs) concentration in the environment, removing cesium (Cs) from the environment, and recovering and recycling useful cesium (Cs). There is an urgent need worldwide for a method with good accuracy and capable of high speed recovery.

The present invention relates to a compound capable of selectively adsorbing cesium (Cs) ions on mesoporous silica having a highly ordered structure (hereinafter referred to as cesium (Cs) ion adsorbing compound (or cesium (Cs) (ion ) (Collecting agent), cesium (Cs) ion collector, or simply collector, or cesium (Cs) (ion), meaning to capture cesium (Cs) ion captor or simply captor) Cesium (Cs) ions are adsorbed on the supported cesium (Cs) ion-adsorbing compound, and an efficient method for recovering the adsorbed cesium (Cs) and cesium (Cs) ion adsorption used in the method The present invention provides a mesoporous silica having a cesium (Cs) ion-adsorbing compound. Provided are a cesium (Cs) ion collector and a sensor capable of accurately detecting a cesium (Cs) ion concentration and using a mesoporous silica that has been measured in a minute amount on the order of ppb to ppm.

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 cesium (Cs) ion-adsorbing compound (the cesium (Cs) ion has not been adsorbed yet). The cesium (Cs) ion-adsorbing compound is a compound that can selectively adsorb cesium (Cs) ions. For example, a complex such as a chelate compound. (A compound that easily adsorbs specific element ions is referred to as an (element) ion-adsorbing compound in this application. Here, in the sense that specific ions that can be selectively adsorbed by the element ion-adsorbing compound are collected. In the present invention, the target element is cesium (Cs).) As a compound that selectively and preferentially adsorbs cesium (Cs) ions, for example, 2-dodecyl- 4-((Phenyl) diazenyl) resorcinol {2-dodecyl-4-((phenyl) diazenyl)
resorcinol (DPAR)}, 4- (2-diazenyl-1,3,4-thiadiazole) -6-dodecylresorcinol {4- (2-diazenyl-1,3,4-thiadiazole) -6-dodecylresorcinol (DTDR)} And pyrogallol red {Pyrogallol red (PR)}. These cesium (Cs) ion-adsorbing compounds are supported on mesoporous silica. (For example, these cesium (Cs) ion-adsorbing compounds are collectively referred to as MC, and mesoporous silica supporting MC is referred to as HOM-MC or HOMS-MC.) These may be supported alone in HOMS. A plurality of them may be mixed and supported on HOMS. Therefore, HOM-DPAR for DPAR, HOM-DTDR for DTDR, or HOM-PR for PR.

The cesium (Cs) (ion) adsorptive compound is supported (or modified) in an ion-dissolved solution in which various ions containing cesium (Cs) (including not only element ions but also other cations and anions) are dissolved. Mesoporous silica is brought into contact, and cesium (Cs) ions (such as Cs ⁺ ), which are target element ions, are adsorbed to the cesium (Cs) ion-adsorbing compound supported on the 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 that adsorbs cesium (Cs) ions is referred to as HOM-MC-Cs.) For example, in the case of the aforementioned HOM-DPAR, the pH value is 1.5 to 2.5, preferably 2.0. Alternatively, HOM-DPAR is a target element ion of cesium (Cs) by contacting with an ionic solution containing cesium (Cs) ions adjusted to a pH value of 9.0 to 10.0, preferably 9.5. Ions are preferentially and selectively adsorbed quickly. (HOM-DPAR adsorbing cesium (Cs) is referred to as HOM-DPAR-Cs.)

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

Moreover, since the main body (mesoporous silica carrying a cesium (Cs) ion-adsorbing compound) has not changed, the adsorbent (or collector (collector)) or extractant of the cesium (Cs) ion, which is the target element ion, is again used. Can be used. For example, by immersing HOM-MC-Cs in an acidic solution or an alkaline solution, cesium (Cs) can be eluted to form HOM-MC. HOM-MC from which cesium (Cs) has been separated can again be used as a cesium (Cs) ion adsorbent (collector or captor).

In the present invention, the cesium (Cs) 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), so that the cesium (Cs) ion adsorption Cesium (Cs) ions are easily and quickly adsorbed to the reactive group of the active compound. Therefore, not only the adsorption response speed is high, but also the cesium (Cs) ion adsorption efficiency to the cesium (Cs) ion adsorbing compound supported on mesoporous silica is the cesium to the single cesium (Cs) ion adsorbing compound. (Cs) It becomes much larger than the ion adsorption efficiency, and the amount of cesium (Cs) (ion) adsorption increases.

In addition, cesium (Cs) ions adsorbed on the cesium (Cs) (ion) adsorbing compound are also arranged in order and densely adsorbed, so that the adsorbed cesium (Cs) ions are easily released quickly (or separated, or Elution). Therefore, the release efficiency of cesium (Cs) ions is very high. Moreover, the cesium (Cs) ion-adsorbing compound can selectively adsorb cesium (Cs) ions in a large amount and rapidly by adjusting conditions such as the pH value of the cesium (Cs) ion-dissolved solution. Therefore, only cesium (Cs) (ions) can be efficiently recovered. In addition, cesium (Cs) ions in the order of ppb to ppm can be adsorbed and removed, so the concentration of cesium (Cs) ions contained in solutions such as domestic water and wastewater, soil and other ionic solutions is extremely small. It can be reduced to the level. Since trace amounts of radioactive cesium (Cs) in the environment, which has been a problem in recent years, can be efficiently and rapidly removed, the HOM-MC of the present invention is a useful material for maintaining the health of the human body and purifying the environment.

In addition, mesoporous silica carrying a cesium (Cs) ion-adsorbing compound has a strong skeleton, and the mesoporous silica skeleton can also be formed by supporting a cesium (Cs) ion-adsorbing compound or adsorbing cesium (Cs) ions. There is little change. Since the adsorbed cesium (Cs) ion can be almost completely released, it returns to its original state (mesoporous silica carrying a cesium (Cs) ion-adsorbing compound that does not adsorb cesium (Cs) ion), so cesium ( Cs) Mesoporous silica carrying an ion-adsorbing compound can be used repeatedly. That is, it can be recycled or reused many times.

Therefore, the total (total) cesium (Cs) collection / recovery cost can be reduced. In addition, mesoporous silica carrying a cesium (Cs) ion-adsorbing compound on which cesium (Cs) ions of the present invention are adsorbed is ppb--using a colorimetric method or UV-VIS-NIR spectroscopy. It can also be used as a cesium (Cs) ion collector and concentration sensor because it can detect cesium (Cs) ion concentrations at very low concentrations on the order of ppm.

FIG. 1 is a diagram showing a cesium (Cs) recovery system of the present invention. FIG. 2 is a diagram showing a method for synthesizing HOM silica monolith. FIG. 3 shows a method for synthesizing receptor DPAR. FIG. 4 shows a method for synthesizing the receptor DTDR. FIG. 5 is a diagram showing the structural formula of the receptor PR. FIG. 6 is a diagram showing a method for producing HOM-DPAR carrying receptor DPAR. FIG. 7 is a diagram showing a cesium (Cs) extraction flow by HOM-DPAR when DPAR is used as the cesium-adsorbing compound. FIG. 8 is a diagram showing a cesium (Cs) extraction flow by HOM-DPAR when DPAR is used as the cesium-adsorbing compound. FIG. 9 is a diagram showing the absorption spectrum and colorimetric analysis of UV-visible spectroscopy of solid HOM-DPAR-Cs adsorbed with cesium ions at pH 2.0. FIG. 10 is a diagram showing an absorption spectrum and a colorimetric analysis of UV-visible spectroscopy of solid HOM-DPAR-Cs adsorbed with cesium ions at pH 9.5. FIG. 11 is a diagram showing the absorption spectrum and colorimetric analysis results of HOM-DPAR-Cs that adsorbed cesium ions in the presence of competing ions at pH 2. FIG. 12 is a diagram showing the absorption spectrum and colorimetric analysis results of HOM-DPAR-Cs adsorbed with cesium ions in the presence of competing ions (such as NaCl) at pH 9.5 and UV-visible spectroscopy. FIG. 13 is a diagram showing an absorption spectrum and a colorimetric analysis result of the solid material HOM-DPAR-Cs after extraction of cesium ions extracted from a large-capacity cesium ion solution by UV-visible spectroscopy. FIG. 14 is a diagram showing an absorption spectrum and a colorimetric analysis result of the solid material HOM-DTDR-Cs extracted with cesium ions by ultraviolet visible spectroscopy. FIG. 15 is a diagram showing an absorption spectrum and a colorimetric analysis result of the solid material HOM-PR-Cs extracted with cesium ions by ultraviolet visible spectroscopy. FIG. 16 is a diagram showing absorption spectra of the solid material HOM-DPAR before and after elution of cesium ions by ultraviolet visible spectroscopy. FIG. 17 is a diagram showing a change in color tone of the solid material HOM-DPAR before and after elution of cesium ions. FIG. 18 is a table showing the concentration of cesium ion Cs (I) by ICP-MS analysis. FIG. 19 is a table showing the applicable range of cesium recovery of HOM-DPAR of the present invention. FIG. 20 is a diagram showing a system for recovering cesium from a cesium (Cs) ion-dissolved solution using mesoporous silica supporting a cesium ion-adsorbing compound of the present invention.

The present invention provides a cesium (Cs) ion detection technique and a cesium (Cs) recovery technique using various chelates and other compounds having high selectivity and an 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. INDUSTRIAL APPLICABILITY The present invention is very excellent as a method for extracting cesium (Cs) from wastes containing various active ions (cations and anions), surfactants, etc., domestic water and the environment. In particular, it is extremely excellent as a method for eliminating radioactive cesium, which has been a problem in recent years, from the environment.

The inner surface of mesoporous silica arranged at the nano level makes a cesium (Cs) ion collector and sensor by controlling the environmental conditions such as pH and changing the fixation / dissociation state. Cesium (Cs) ions can be reliably adsorbed by bonding between adjacent atoms and surface atoms having different electron orbital structures and compounds such as chelates. In addition, the nano-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 cesium (Cs) adsorption at the ppb level (high speed). Response) occurs.

Hereinafter, embodiments of the present invention will be described in detail.
FIG. 1 is a diagram showing a cesium (Cs) recovery system of the present invention. First of all, highly ordered mesoporous silica (HOM silica (HOMS): High Ordered Mesoporous Silica, usually, 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 cesium (Cs) ion-adsorbing compound can be supported, and the total amount of cesium (Cs) 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 ). Usually, the mesoporous silica monolith with cubic Im3m (HOM) cage-like mesopores is a ratio of F108 / tetramethylorthosilicate (Tetramethylorthosilicate (TMOS)) mixed with dodecane: F108: TMOS = 1: 2.8: 4 Was made using a microemulsion phase formed by addition at. This HOMS is a white powdery solid.

Next, in the second stage, the cesium (Cs) ion-adsorbing compound is supported on the HOM. At this stage, cesium (Cs) ions (and other ions) are not adsorbed to the cesium (Cs) ion-adsorbing compound. (As a term indicating that cesium ion {Cs (I)} is not adsorbed, it is referred to as a “cesium ion adsorbing compound.” As the cesium ion adsorbing compound used in the present invention, an ion complex, an inorganic compound or an organic compound is used. Also included are cesium (Cs) ion-adsorptive compounds such as cellulose, protein, etc. Examples of metal complexes include inorganic and organic metal complexes, metal carbonyl compounds, metal clusters and organometallic compounds, and chelate compounds. Basically, it is a compound that can adsorb cesium (Cs) (ion), can be supported on HOM, and can release ions other than cesium (Cs), which is the target element, by chemical treatment. It is a compound that can release cesium (Cs), the target element, by chemical treatment. Tightly bound to the HOM silica for example, through the OH group in manner.

The cesium (Cs) ion-adsorbing compound is desirably a compound that selectively adsorbs cesium (Cs) ions, which are target element ions to be recovered, in a large amount. For example, a chelate compound or other compound that selectively binds to cesium (Cs) ions can be used. Cesium (Cs) ion-adsorbing compounds by adjusting the pH value, temperature, concentration, etc. of cesium (Cs) ion-dissolved solutions in which various ions (cations and anions) containing cesium (Cs) and surfactants are dissolved The target (metal) element cesium (Cs) (ion) can be selectively and preferentially adsorbed in large quantities. In addition, since a compound such as a chelate compound can selectively adsorb a very small amount of cesium (Cs) (for example, on the order of ppb to ppm), cesium (Cs) ions dissolved in a cesium (Cs) ion solution ( Even if the amount of Cs) ions is small, cesium (Cs) ions are selectively and efficiently adsorbed.

For example, we have 2-dodecyl-4-((phenyl) diazenyl) resorcinol {2-dodecyl-4-((phenyl) diazenyl)
resorcinol (DPAR)} (hereinafter also referred to as receptor DPAR or captor DPAR) was found to selectively adsorb cesium (Cs) ions preferentially. (Receptor is originally a biological term “receptor”, but in this application, it means an ion-adsorbing compound that adsorbs a specific element (cesium (Cs)) ion. The term is sometimes used.)

This receptor DPAR is obtained by immersing HOM silica carrying the receptor DPAR in a solution containing cesium (Cs) ions (cesium (Cs) ion dissolving solution) whose solution is adjusted to a specific pH value. Cesium (Cs) ions are selectively adsorbed in a larger amount than in the solution of the value. As the amount of adsorbed cesium (Cs) ions increases, the color of the HOM silica supporting the receptor DPAR changes color, from light brown (non-adsorbed HOM-DPAR) to dark brown (cesium (Cs) ion concentration 5 ppm) And change. Since the color tone and the adsorbed cesium (Cs) ion concentration have a correlation, the cesium (Cs) ion concentration can be known from the color tone. That is, colorimetric analysis is possible. In particular, even a very small amount of cesium (Cs) at the ppb to ppm level can be adsorbed, resulting in a change in color tone, so that an accurate concentration can be detected. The meaning of selectively means that when HOM silica (HOM-DPAR) supporting these receptor DPARs is immersed in a solution containing cesium (Cs) ions and other various ions (cations and anions) and surfactants, It means that only cesium (Cs) ions are adsorbed and other various ions are hardly adsorbed. That is, HOM silica carrying a receptor DPAR (HOM-DPAR) has excellent selectivity for cesium (Cs) ion adsorption.

The cesium (Cs) ion concentration can also be measured from a light absorption spectrum after cesium (Cs) ion adsorption. That is, HOM silica carrying the receptor DPAR is also a cesium (Cs) ion concentration detection sensor. The mesoporous silica (HOM-DPAR) carrying this receptor DPAR absorbs cesium (Cs) ions, and in the visible light having a wavelength near 375 nm or 510 nm in UV-visible spectroscopy, an absorption peak based on cesium (Cs) adsorption. Since there is a correlation between the absorptance in this wavelength band and the cesium (Cs) ion concentration, the UV curve of HOM-DPAR that adsorbs cesium (Cs) ions can be obtained by creating a calibration curve in advance. The cesium (Cs) ion concentration of this HOMS-DPAR-Cs can be known from the absorptance data of the wavelength in the visible spectroscopy. Moreover, this HOMS-DPAR-Cs selectively adsorbs cesium (Cs) ions in the solution and hardly adsorbs other contained ions, so it becomes a very sensitive cesium (Cs) ion collector and concentration sensor. . In particular, even a very small amount of cesium (Cs) at the ppb to ppm level can be adsorbed, and as a result, a spectrum change occurs, so an accurate concentration can be detected.

Examples of other cesium (Cs) ion-adsorbing compounds include 4- (2-diazenyl-1,3,4-thiadiazole) -6-dodecylresorcinol {4- (2-diazenyl-1,3,4-thiadiazole ) -6-dodecylresorcinol (DTDR)} and Pyrogallol red (PR)}, and other cesium (Cs) ion-adsorbing compounds will be discovered from time to time. One or more of these cesium (Cs) ion-adsorbing compounds can be supported on HOMS to produce a HOMS-receptor having desired properties. These compounds adsorb (collect) cesium (Cs) (ions) by incorporating cesium (Cs) (ions) within and / or between the cyclic molecular structures. Therefore, it can be said that these cesium (Cs) ion adsorbing compounds are chelate complexes. These cesium (Cs) ion-adsorptive compounds are very highly selective compounds because they hardly adsorb other anions and cations (including metal ions such as alkali metals and alkaline earth metals). Cesium (Cs) (ion) is considered to be 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 cesium (Cs) ion-adsorbing compound on the HOM. For example, when the cesium (Cs) ion-adsorbing compound to be held in the HOM is neutral, a reagent impregnation method (REACTIVE & FUNCTION POLYMERS, 49, 189 (2001), etc.) is used, which is anionic. In some cases, a cation exchange method is used, and in some cases, an 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 alcohol solution of an ionic cesium (Cs) ion-adsorbing compound is contacted to adsorb the cesium (Cs) ion-adsorbing compound in mesoporous silica, organic of mesoporous silica and cesium (Cs) ion-adsorbing compound A method in which a cesium (Cs) ion-adsorbing compound is physically adsorbed and supported in mesoporous silica by contacting with a solvent solution and removing only the organic solvent by filtration or distillation. Mesoporous silica has a thiol group. Surface treatment with silylating agent, then thiol group on the surface to be generated Oxidation imparts an anionic functional group to the mesoporous silica, contacts the anionic mesoporous silica with an aqueous solution of a cationic metal adsorbing compound, and converts the cesium (Cs) ion adsorbing compound to mesoporous. A method of adsorbing in silica, cesium (Cs) ion adsorbing compound is filled in pores and surfaces in advance and then treated with an organic solvent solution of a cationic organic reagent to absorb cesium (Cs) ions A method of immobilizing a compound in the pores and on the surface, a cesium (Cs) ion-adsorbing compound and a cationic organic reagent are mixed in advance, and the organic solvent solution of the resulting reagent complex is brought into contact with the silica to form an organic A method of supporting the cesium (Cs) ion-adsorbing compound in the silica by removing only the solvent by filtration or distillation is used. .

For example, in order to support the receptor DTDR on the HOM, the receptor DTDR is dissolved in ethanol, and this solution is brought into contact with HOMS to impregnate the receptor DTDR into the HOMS. In this way, HOM silica (HOMS-DTDR) in which receptor DTDR is regularly and densely supported is completed. In addition, HOM silica carrying the receptor DTDR can be efficiently produced in a high-purity solid state (powder) by evaporating (heating, vacuuming, etc.) and then drying the liquid such as alcohol and moisture. 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, a cesium (Cs) ion-adsorptive compound such as receptor DTDR is preferably adsorbed on HOM silica having a wide range of structures such as cubic structures Im3m, Pm3n, Fm3m, Ia3d, and hexagonal structure P6m.

Naturally, the cesium (Cs) ion-adsorbing compound alone can selectively adsorb the target element cesium (Cs) ion, but the cesium (Cs) ion-adsorbing compound aggregates, so cesium (Cs) ion adsorption is possible. Functional groups cannot be used effectively. That is, even when the target element cesium (Cs) ion is adsorbed to the functional group present on the surface of the aggregated (eg, particulate) cesium (Cs) ion-adsorbing compound substance, Cs) The cesium (Cs) ion concentration inside the ion-adsorptive compound decreases exponentially with respect to the distance (square), so the functionality of the cesium (Cs) ion-adsorptive compound inside the particulate matter It is difficult for cesium (Cs) ions to be adsorbed on all groups. Moreover, even if cesium (Cs) ions are adsorbed to the functional group of the cesium (Cs) ion-adsorbing compound inside the particulate matter, the adsorbed cesium (Cs) ions are taken out (free or back-extracted). There is a problem that it is difficult. Although it is possible to diffuse cesium (Cs) ions inside the particulate matter and take it out for a long time, it is necessary to move the cesium (Cs) ions inside the particulate matter over a long period of time. Has poor productivity and cannot be used industrially.

In contrast, mesoporous silica has a very large pore surface area and a highly ordered orientation structure. Therefore, the mesoporous silica with a cesium (Cs) ion-adsorbing compound supported on the surface and pore inner wall is Since the cesium (Cs) ion-adsorptive compounds are arranged in an orderly manner and bonded, the cesium (Cs) ion-adsorptive compound has a very high cesium (Cs) ion adsorption rate. That is, each molecule of the cesium (Cs) ion-adsorptive compound can be used for cesium (Cs) ion adsorption. Cesium (Cs) ion-dissolved solution and free (back-extracted) solution easily and quickly enter the surface and pores of mesoporous silica, so the reaction of cesium (Cs) ion-adsorbing compound (supported by HOMS) Base) easily and quickly. This means that a cesium (Cs) ion-adsorbing compound supported on HOMS adsorbs cesium (Cs) ions quickly when it comes into contact with a cesium (Cs) ion solution. In addition, when the adsorbed cesium (Cs) ion is released, it also means that the adsorbed cesium (Cs) ion is released quickly if it comes into contact with the free solution. Collection) and release (separation) proceed very efficiently and rapidly, resulting in a dramatic improvement in productivity.

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. Even when the chelate resin alone adsorbs cesium (Cs) ions, it cannot be controlled to which part of the chelate resin. In addition, it is expected that cesium (Cs) ions will be adsorbed (also called extraction) to the chelate functional group in contact with the cesium (Cs) ion solution, but the cesium (Cs) ion solution does not easily penetrate. It is thought that cesium (Cs) ions are hardly adsorbed inside the chelate resin. That is, the cesium (Cs) ion adsorption efficiency is very poor. Further, when cesium (Cs) ions adsorbed on the chelate resin are liberated (also referred to as back extraction), it is difficult to extract the cesium (Cs) ions adsorbed inside the chelate resin.

Even when this chelate resin is used repeatedly, the efficiency of extraction and back-extraction of cesium (Cs) ions becomes worse due to the effects of residuals in the chelate resin, and the performance of the chelate resin deteriorates significantly with repeated use. End up. 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 cesium (Cs) ions or complex ions containing cesium (Cs) ions, the adsorption efficiency of cesium (Cs) ions becomes very high. Further, it becomes possible to easily extract the trapped cesium (Cs) ions or complex ions containing cesium (Cs) ions 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 cesium (Cs) ions, surfactants and the like are dissolved (this is called a cesium (Cs) ion-dissolved solution) is prepared. This cesium (Cs) ion-dissolved solution is, for example, radioactive cesium (Cs) containing nuclear cesium (Cs) coolant or waste liquid drained, or radioactive cesium (Cs) scattered from nuclear facilities, etc. dissolved in domestic water or domestic wastewater It is a solution. In such a solution, in addition to cesium (Cs), cations such as various metal ions, various ions such as various anions and surfactants are dissolved. 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 cesium (Cs) ion dissolving solution. Cesium (Cs) ions dissolved in a cesium (Cs) ion-dissolved solution with a cesium (Cs) ion-adsorbing compound (referred to as MC) at a high density (hereinafter also referred to as HOM-MC). Contact the lysis solution with HOM-MC. By this contact, cesium (Cs) ions are adsorbed on the HOM-MC. (This is HOM-MC-Cs-M (Cs: target element cesium (Cs) (Cs), M: adsorbed ions other than cesium (Cs).) Cesium (Cs) ion adsorbing compound is Because the target element cesium (Cs) ions are selectively and preferentially adsorbed under certain conditions (pH value, temperature, concentration, etc.), cesium is dissolved in the cesium (Cs) ion-dissolved solution under the conditions. If the (Cs) ion-adsorbing compound is immersed, HOM that adsorbs only the target element cesium (Cs) (ie, HOM-MC-Cs) can be obtained.

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

In the case of the above-mentioned receptor DPAR, for example, a cesium (Cs) ion-dissolved solution is pH = 1.5 to 2.5, preferably pH = 2.0, or pH = 9.0 to 10.0, preferably By adjusting the pH to 9.5, cesium (Cs) ions can be efficiently adsorbed on HOM-MC {HOM-DPAR}. In the case of the above receptor DTDR, by adjusting the cesium (Cs) ion solution to pH = 1.5 to 2.5, preferably pH = 2.0, the cesium (Cs) ion is converted to HOM-MC. (HOM-DTDR) can be adsorbed efficiently. In the case of the above receptor PR, the cesium (Cs) ion solution is adjusted to 9.0 to 10.0, preferably pH = 9.5, so that the cesium (Cs) ion is changed to HOM-MC ( HOM-PR) can be adsorbed efficiently. Incidentally, HOM silica adsorbed with cesium (Cs) ions can be efficiently collected in a high-purity solid state (powder) by evaporating (heating, vacuuming, etc.) liquid components such as ethanol and moisture and further drying.

In the fourth stage, HOM-MC-Cs-M adsorbing ions containing the target element cesium (Cs) ions is immersed in a solution that can release ions other than the target element cesium (Cs) ions. Then, ions other than the target element cesium (Cs) ion are removed to obtain HOM-MC-Cs in which only the target element cesium (Cs) is adsorbed. Alternatively, HOM-MC-Cs may be obtained by removing ions other than the target element cesium (Cs) by adjusting conditions such as pH value, temperature, and solution concentration. In addition, when adsorption of ions other than the target element cesium (Cs) is very small (in this case, it is HOM-MC-Cs from the beginning), or a method that can liberate only the target element cesium (Cs) If there is, the fourth step can be omitted. For example, in the case of the above-mentioned HOM-DPAR carrying receptor DPAR or HOM-DTDR carrying receptor DTDR or HOM-PR carrying receptor PR, M is hardly adsorbed, that is, HOM-DPAR, DTDR, Since the state is PR-Cs, the fourth step can be omitted.

In the fifth stage, HOM-MC-Cs that adsorbs only the target element cesium (Cs) is immersed in a solution in which the target element cesium (Cs) can be dissolved, and the target element cesium (Cs ) Dissolve ions. In some cases, only the cesium (Cs) ion, which is the target element, can be liberated by adjusting the conditions such as pH value, temperature, and solution concentration. Alternatively, the cesium (Cs) ion as the target element can be dissolved by immersing it in a solution that can liberate only the cesium (Cs) ion as the target element. In such a case, it is not always necessary to use HOM-MC-Cs that adsorbs only the cesium (Cs) ion that is the target element. The HOM-MC from which the target element cesium (Cs) 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.

In addition, when cesium (Cs), which is the target element, is separated from the eluate in which cesium (Cs) is dissolved by elution treatment by various methods (for example, molten salt electrolysis or distillation), the target element, cesium (Cs) Can be recovered. That is, the target element cesium (Cs) was recovered from the environmental water in which cesium (Cs) 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 cesium (Cs) which is a target (metal) element is adsorbed to HOM-MC and it is considered that extraction of cesium (Cs) which is a target element is HOM-MC-Cs, this process is HOM. -Since Cs is released from MC-Cs to form HOM-MC, it can also be called back extraction (step).

By going through the first to fifth steps described above, cesium (Cs) containing radioactive cesium (Cs), which is the target element obtained from waste liquid from nuclear facilities, domestic water and environmental water, is dissolved. The target element cesium (Cs) can be recovered from the obtained cesium (Cs) ion-dissolved solution using highly ordered HOM silica (HOMS) supporting a cesium (Cs) ion-adsorbing compound.

<Synthesis of HOM (cubic Ia3d) silica monolith>
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 ). 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, to put 8.0 g of tetramethylorthosilicate (TMOS) and 5.6 g of surfactant F108 in a round flask container, add 2.0 g of dodecane therein, and completely dissolve the surfactant, The flask container was kept in warm water at about 60 ° C. When 4 g of acidic aqueous solution (H ₂ O-HCl) having a pH of 1.3 is 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 on a rotary evaporator for 10 minutes, a translucent glassy monolith was collected and dried in an oven at 40 ° C. for 1 day. Thereafter, the solid material was calcined at 450 ° C. for 8 hours to remove the surfactant and moisture, 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 cesium (Cs)>
<2-dodecyl-4-((phenyl) diazenyl) resorcinol {2-dodecyl-4-((phenyl) diazenyl)
generation of resorcinol (DPAR)}
FIG. 3 is a diagram showing a synthesis method relating to the generation of receptor DPAR. About 0.05 mol of aniline is dissolved in 40 ml of HCl solution. The solution was cooled to 0 ° C. and 3.5 g NaNO ₂ dissolved in water was slowly added to the solution. The progress of the reaction was controlled by iodinated starch paper. Finally, the diazonium salt solution was slowly poured into a well-cooled solution of 3.4 g 6-dodecylresorcinol in 60 ml 4N HCl solution. The resulting solution was cooled at 0 ° C. for 30 minutes, after which an aqueous solution of 60 g sodium acetate in 180 ml water was added. This coupling reaction was carried out at 0 ° C. for 2 hours, and the produced precipitate was washed with water. This precipitate is DPAR.

<Receptor (2) used for recovery of radioactive cesium (Cs)>
<4- (2-diazenyl-1,3,4-thiadiazole) -6-dodecylresorcinol {4- (2-diazenyl-1,3,4-thiadiazole) -6-
Generation of dodecylresorcinol (DTDR)}
FIG. 4 is a diagram showing a synthesis method relating to the generation of the receptor DTDR. 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 well-cooled solution of 6-dodecylresorcinol 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. This DTDR is a cesium (Cs) ion-adsorbing compound capable of selectively adsorbing cesium (Cs). Cesium (Cs) is incorporated into the cyclic molecular structure of DTDR. That is, DTDR is a chelate complex that preferentially adsorbs cesium (Cs). If cesium (Cs) is separated (released), the original DTDR is restored. Thus, the adsorption / release reaction of cesium (Cs) and DTDR is reversible. Therefore, the receptor DTDR can be used for the recovery of radioactive cesium (Cs).

<Receptor (3) used for recovery of radioactive cesium (Cs)>
<Pyrogallol red (PR)}>
The structural formula of the receptor pyrogallol red {Pyrogallol red (PR)} is shown in FIG. This receptor PR is produced industrially and can be easily obtained, and a commercially available receptor PR was used in the present invention.

<Synthesis of HOM-probe material (1)>
<Production and properties of HOM-DPAR>
The method for synthesizing HOM-DPAR is shown below because the methods for preparing HOM-DPAR, DTDR, and PR by carrying HOM-sensor material, that is, HOM with receptors DPAR, DTDR, and PR are almost the same. FIG. 6 is a diagram showing a method for producing HOM-DPAR carrying receptor DPAR. 50 mg of 2-dodecyl-4-((phenyl) diazenyl) resorcinol (DPAR) was placed in an ethanol solution in a round flask, and 1 g of HOM-Cage (Cage-like HOMS) produced in Example 1 was added. The ethanol in the round flask was removed by connecting the flask to a rotary evaporator and slowly evacuating at 45-50 ° C. The viscous liquid in the flask changed to a colored gel material (solid product) within 2 hours. This material was dried at 65-70 ° C. for 5 hours, washed with warm water, and dried again at 65-70 ° C. The dried bulk powder was ground to a fine powder and this powdered material (HOM-DPAR) was used for cesium ion {Cs (I)} extraction in various experimental conditions.

The properties (BET specific surface area, pore volume, pore size) of HOM-DPAR can be determined from the nitrogen (N ₂ ) adsorption / desorption isotherm of this material. HOM-DPAR has a BET specific surface area of about 347.01 m ² g ⁻¹ , a pore volume of about 0.41 cm ³ g ⁻¹ , and a pore size of 5.4 nm. From these results, it can be seen that HOM-DPAR has a large BET specific surface area and a small pore size, and HOM-DPAR has a good adsorption site. Therefore, it can be seen that there are very many cesium ion adsorption sites.

<Synthesis of HOM-probe material (2)>
<Production and properties of HOM-DTDR>
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 cesium under various experimental conditions. This material is HOM-DTDR carrying DTDR which is a cesium ion adsorbing compound.

The characteristics (BET specific surface area, pore volume, pore size) of HOM-DTDR can be determined from the nitrogen (N ₂ ) adsorption / desorption isotherm of this material. HOM-DTDR has a BET specific surface area of about 422.26 m ² g ⁻¹ , a pore volume of about 0.48 cm ³ g ⁻¹ , and a pore size of 4.63 nm. From these results, it can be seen that HOM-DTDR has a large BET specific surface area and a small pore size, and HOM-DTDR has a good adsorption site. Therefore, it can be seen that there are very many cesium ion adsorption sites.

In this way, DTDR is supported on the surface of the highly ordered HOM silica carrier and the inner surface of the pores to produce a HOM-DTDR collector. This HOM-DTDR collector is brought into contact (immersion) with a cesium (Cs) ion-dissolved solution, and cesium (Cs) ions are adsorbed on the HOM-DTDR collector to obtain HOM-DTDR-Cs. That is, cesium ions (Cs ⁺ ) are incorporated into the cyclic molecular structure of DTDR on the HOM-DTDR collector. This HOM-DTDR-Cs is contacted (immersed) in an appropriate elution solution to separate (release) cesium (Cs). As a result, the HOM-DTDR-Cs returns to the original HOM-DTDR and can be used again as a HOM-DTDR collector for collecting cesium (Cs).

<Extraction of cesium ion Cs (I) using HOM-captor (DPAR)>
7 and 8 are diagrams showing a flow of cesium (Cs) extraction by HOM-DPAR when DPAR is used as the cesium-adsorbing compound {Captor}. FIG. 7 also shows a procedure for generating a HOM-DPAR by supporting the DPAR on the HOM. A considerable amount of the cesium solution was added to 4 ml of the pH-adjusted solution to obtain various concentrations (0.5 ppm to 5 ppm), and a necessary amount of water was added to make a 20 ml solution. To these aqueous solutions, 20 mg of solid HOM-DPAR prepared in Example 5 was added, stirred at 45-50 ° C. for 12 hours, and then filtered. The solid material after filtration was examined by UV-VIS-NIR Spectroscopy and an absorption spectrum was taken. Moreover, the colorimetric analysis was performed about the solid material after filtration.

Moreover, the cesium ion concentration of the solution before adding HOM-DPAR and the filtrate was measured by ICP-OES (ICP emission spectroscopic analysis). It was confirmed that cesium ions contained in the solution before adding HOM-DPAR were hardly contained in the filtrate. That is, it can be seen that most of the cesium ions in the solution were adsorbed on the HOM-DPAR. The cesium solution was prepared by dissolving 50.67 mg of cesium chloride CsCl2 in 200 ml of water. From this, an appropriate amount of cesium solution was taken to adjust the cesium concentration in the solution. For example, 5 ppm of Cs (I) was made by adding 500 μl from a 200 ppm stock bottle of cesium ions {Cs (I)}. Moreover, it experimented using various pH solutions. For example, for a pH 2 adjusted solution, 14.91 g of potassium chloride was dissolved in 1 L (1000 mL) H ₂ O and adjusted to pH 2 using hydrochloric acid (HCl). For pH 9.5, 0.2 M N-cyclohexyl-3-aminopropanesulfonic acid in 1 L (1000 mL) H ₂ O
acid (CAPS)} was added and adjusted to pH 9.5 using NaOH.

<Ultraviolet visible spectroscopy and colorimetric analysis in HOM-DPAR-Cs>
FIG. 9 shows the absorption spectrum (ultraviolet ray) of solid HOM-DPAR-Cs adsorbed with cesium ions obtained by immersing and filtering HOM-DPAR in aqueous solutions having various cesium concentrations at pH 2. It is a figure which shows a visible spectroscopy analysis and a colorimetric analysis. When HOM-DPAR adsorbs cesium to become HOM-DPAR-Cs, the absorption spectrum changes, and the absorbance (absorbance) in the wavelength range (250 nm to 700 nm) (the measurement wavelength in the actual measuring apparatus is 250 nm to 900 nm). It can be seen that it tends to be smaller. In particular, it can be seen that there is a change in intensity (peak value) of the absorption band of HOM-DPAR near the wavelength of 375 nm. This intensity change is considered to be based on the adsorption of cesium. It can also be seen that the color tone of HOM-DPAR changes when it adsorbs cesium and becomes HOM-DPAR-Cs. That is, HOM-DPAR (not adsorbing Cs) shows a light brown color, but HOM-DPAR-Cs adsorbing cesium has a dark brown color. In particular, it tends to increase as the cesium concentration increases. (The results of colorimetric analysis (color tone of solid matter) are cesium concentrations of 0, 5 ppm, 2.5 ppm, 1.5 ppm, 0.5 ppm, 5 ppm Cs + 5 ppm Ions from the left.) From these results, HOM adsorbed cesium -By examining the absorption spectrum of UV-visible spectroscopy of DPAR-Cs, it can be determined whether cesium (Cs) has been adsorbed, and the concentration of adsorbed cesium (Cs) can also be determined. In addition, if the color tone of HOM-DPAR-Cs with adsorbed cesium is analyzed and the color tone of the solid matter is examined, it can be determined whether or not cesium (Cs) has been adsorbed, and the concentration of adsorbed cesium (Cs) can also be known. Can do.

FIG. 10 shows the absorption spectrum of UV-visible spectroscopy of the solid material HOM-DPAR-Cs adsorbed with cesium obtained after immersing and filtering HOM-DPAR in aqueous solutions having various cesium concentrations at pH 9.5. It is a figure which shows a colorimetric analysis. When HOM-DPAR adsorbs cesium to become HOM-DPAR-Cs, the absorption spectrum changes, and the absorbance (absorbance) in the wavelength range (250 nm to 700 nm) (the measurement wavelength in the actual measuring apparatus is 250 nm to 900 nm). It can be seen that it tends to be smaller. In particular, it can be seen that there is an intensity change (peak value) of the absorption band of HOM-DPAR near the wavelength of 510 nm. This intensity change is considered to be based on the adsorption of cesium. It can also be seen that the color tone of HOM-DPAR changes when it adsorbs cesium and becomes HOM-DPAR-Cs. That is, HOM-DPAR (not adsorbing Cs) shows a light brown color, but HOM-DPAR-Cs adsorbing cesium is pink. In particular, it tends to increase as the cesium concentration increases. (The results of colorimetric analysis (color tone of solid matter) are cesium concentrations of 5 ppm, 2.5 ppm, 1.5 ppm, 0.5 ppm, 5 ppm Cs + 5 ppm Ions from the left.) From these results, HOM− adsorbed cesium ions By examining the absorption spectrum of UV-visible spectroscopy of DPAR-Cs, it can be determined whether or not cesium (Cs) has been adsorbed, and the concentration of adsorbed cesium (Cs) can also be determined. In addition, if the color tone of HOM-DPAR-Cs with adsorbed cesium is analyzed and the color tone of the solid matter is examined, it can be determined whether or not cesium (Cs) has been adsorbed, and the concentration of adsorbed cesium (Cs) can also be known. Can do.
(“5 ppm Cs + 5 ppm Ions” in FIGS. 9 and 10 means a solution containing 5 ppm cesium (Cs) and 5 ppm NaCl, LiCl, KI, MaCl 2, and CaCl 2.)

<Removal of cesium ions from HOM-DPAR in the presence of disturbing ions (pH 2 solution)>
Take 4 ml of pH 2 solution, pour into a 50 ml beaker, add 5 ppm Cs ¹⁺ (500 μl from 200 ppm stock bottle), and add (NaCl, LiCl, KI, MgCl 2, and CaCl 2) ions to this solution. After adding 5 ppm (200 μl from a 200 ppm stock solution bottle of each solution), the solution is made up to 20 ml using deionized water to produce a multiple ion solution containing alkali metal ions and alkaline earth ions in addition to cesium ions. . To this multiple ion solution, 20 mg of HOM-DPAR is added, stirred at 50-60 ° C. for 12 hours, and then filtered. From the results of ICP-MS analysis (ICP mass spectrometry), the filtrate did not contain cesium ions Cs (I), and element ions other than cesium ions were detected in the filtrate. The solid matter after filtration was examined by UV-VIS-NIR Spectroscopy, and an absorption spectrum was taken. Moreover, the colorimetric analysis was performed about the solid material after filtration.

FIG. 11 shows the absorption spectrum and colorimetric analysis results of HOM-DPAR-Cs adsorbing cesium ion {Cs (II)} in the presence of competing ions (NaCl, etc.) using a HOM-DPAR captor in pH 2 solution. Indicates. As can be seen from the results of the absorption spectrum, when cesium ions are contained, the absorptance (absorbance) is smaller than when no cesium ions are contained. In addition, even if ions other than cesium ions are included, there is no significant difference in the curve shape, and it can be seen that even if there are competing ions, they are not significantly affected. Furthermore, an absorption peak at a wavelength of 375 nm related to cesium ion adsorption appears in both. It can be seen from the results of colorimetric analysis that there is a similar tendency. That is, HOM-DPAR not adsorbing cesium ions has a light brown color tone, but the color tone of HOM-DPAR-Cs is darker in both cases of cesium ions alone and in the presence of multiple ions.

<Removal of cesium ions of HOM-DPAR in the presence of disturbing ions (pH 9.5 solution)>
Take 4 ml of pH 9.5 solution, pour into a 50 ml beaker and add 0.1 M sodium dodecyl sulfate {sodium
Add 2 ml dodecyl sulfate (SDS). Add 5 ppm Cs ¹⁺ (500 μl from 200 ppm stock bottle) and add 5 ppm from each ion of (NaCl, LiCl, KI, MgCl 2, and CaCl 2) to this solution (200 μl from 200 ppm stock bottle for each solution). After the addition, the solution is made up to 20 ml using deionized water, and a solution of a plurality of ions containing alkali metal ions and alkaline earth ions in addition to cesium ions is prepared. To this multiple ion solution, 20 mg of HOM-DPAR is added, stirred at 50-60 ° C. for 12 hours, and then filtered. From the results of ICP-MS analysis (ICP mass spectrometry), the filtrate did not contain cesium Cs (I), and element ions other than cesium ions were detected in the filtrate. The solid matter after filtration was examined by UV-VIS-NIR Spectroscopy, and an absorption spectrum was taken. Moreover, the colorimetric analysis was performed about the solid material after filtration.

FIG. 12 is obtained by UV-visible spectroscopy of HOM-DPAR-Cs in which cesium ions {Cs (II)} are adsorbed in the presence of competing ions (NaCl, etc.) using a HOM-DPAR captor in a pH 9.5 solution. An absorption spectrum and a colorimetric analysis result are shown. As can be seen from the results of the absorption spectrum, when cesium ions are contained, the absorptance (absorbance) is smaller than when no cesium ions are contained. In addition, even if ions other than cesium ions are included, there is no significant difference in the curve shape, and it can be seen that even if there are competing ions, they are not significantly affected. Furthermore, an absorption peak at a wavelength of 510 nm related to cesium ion adsorption appears in both. It can be seen from the results of colorimetric analysis that there is a similar tendency. Compared to FIG. 11, the selectivity of cesium Cs at pH 2 from the absorption spectrum and the colorimetric analysis results (particularly, in the colorimetric analysis results, the change in color tone of multiple ions and cesium single ions is smaller in the solution at pH 2) It can be seen that is better than pH 9.5.

<Extraction of cesium ions with HOM-DPAR in large volume cesium ion solution>
In the above embodiment, the cesium ion dissolving solution is a small amount (20 ml). However, when applied at an actual treatment site, a considerably large amount of treated water is used. Therefore, cesium adsorption was investigated when HOM-DPAR, which is the cesium adsorption material of the present invention, was used in a large amount of cesium ion solution. First, 160 ml of pH 2 adjusted solution was taken and poured into a 1000 ml beaker, and then 5 ppm of cesium ion Cs (I) (20 ml from a 200 ppm stock solution bottle of cesium ion Cs (I)) was added, followed by the required amount of deionization. Water was added to adjust the cesium ion dissolving solution to an 800 ml solution. Thereafter, 500 mg of a HOM-DPAR capter was added to this cesium ion solution, stirred at 50-60 ° C. for 24 hours, and then filtered.

FIG. 13 is a diagram showing an absorption spectrum and a colorimetric analysis result of the solid material HOM-DPAR-Cs after extraction of cesium ions extracted from a large-capacity cesium ion solution by UV-visible spectroscopy. As can be seen from FIG. 13, the absorbance of HOM-DPAR-Cs adsorbing cesium ions is considerably smaller than the absorbance of HOM-DPAR before adsorbing cesium ions, indicating that a large amount of cesium ions was adsorbed. The color tone of the solid material also changed before and after the adsorption of cesium ions, indicating that a large amount of cesium ions was adsorbed. Further, from the measurement by IPC-MS (IPC mass spectrometry), the filtrate contained almost no cesium ion Cs (I). From this, it was found that HOM-DPAR can adsorb a large amount of cesium ions and remove cesium ions almost completely from a large-capacity cesium ion solution using HOM-DPAR. . That is, it was confirmed that the level is practically acceptable. Thus, the HOM probe (HOM-DPAR) is an excellent collector and concentration detection sensor for cesium (Cs) ions.

<Extraction of cesium ions by HOM-DTDR in a large volume cesium ion solution>
Cesium adsorption was investigated when HOM-DTDR, which is the cesium adsorbing material of the present invention, was used in a large amount of cesium ion dissolving solution. After taking 160 ml of pH 2 adjusted solution and injecting it into a 1000 ml beaker, add 5 ppm of cesium Cs (I) (20 ml from a 200 ppm stock solution bottle of cesium ion Cs (I)), then add the required amount of deionized water. The cesium ion solution was adjusted to an 800 ml solution. Thereafter, 500 mg of a HOM-DTDR captor was added to the cesium ion solution, stirred at 50-60 ° C. for 24 hours, and then filtered.

FIG. 14 is a diagram showing an absorption spectrum and a colorimetric analysis result of the solid material HOM-DTDR-Cs after extraction of cesium ions extracted from a large-capacity cesium ion solution by UV-visible spectroscopy. As can be seen from FIG. 14, the absorbance of HOM-DTDR-Cs adsorbing cesium ions is considerably smaller than the absorbance of HOM-DTDR before adsorbing cesium ions, indicating that a large amount of cesium ions was adsorbed. Further, the color tone of the solid material also changed before and after the adsorption of cesium ions (changed from yellow to tan), indicating that a large amount of cesium ions was adsorbed. Further, from the measurement of IPC-MS, the filtrate contained almost no cesium ion Cs (I). From this, it was found that HOM-DTDR can adsorb a large amount of cesium ions from a large volume of cesium ion solution using HOM-DTDR, and can remove cesium ions almost completely. . That is, it was confirmed that the level is practically acceptable. Thus, the HOM probe (HOM-DTDR) is an excellent collector and concentration detection sensor for cesium (Cs) ions.

<Extraction of cesium ions by HOM-PR in a large volume cesium ion solution>
Cesium adsorption was investigated when HOM-PR, which is the cesium adsorption material of the present invention, was used in a large amount of cesium ion solution. After taking 160 ml of pH 9.5 adjusted solution and pouring it into a 1000 ml beaker, 0.1M sodium dodecyl sulfate {sodium
Add 40 ml of dodecyl sulfate (SDS). Next, 5 ppm of cesium Cs (I) (20 ml from a 200 ppm stock solution bottle of cesium ions Cs (I)) was added, and then a necessary amount of deionized water was added to adjust the cesium ion solution to an 800 ml solution. Then, 400 mg of HOM-PR capter was added to this cesium ion solution, stirred at 50-60 ° C. for 24 hours and filtered.

FIG. 15 is a diagram showing an absorption spectrum and a colorimetric analysis result of the solid material HOM-PR-Cs after the extraction of cesium ions from a large-capacity cesium ion solution by UV-visible spectroscopy. As can be seen from FIG. 15, the absorbance of HOM-PR-Cs adsorbing cesium ions is considerably smaller than the absorbance of HOM-PR before adsorbing cesium ions, indicating that a large amount of cesium ions was adsorbed. In addition, the color tone of the solid material also changed before and after adsorption of cesium ions (changed from ultra-thin purple to light purple), indicating that a large amount of cesium ions was adsorbed. Further, from the measurement of IPC-MS, the filtrate contained almost no cesium ion Cs (I). From this, it was found that HOM-PR can adsorb a large amount of cesium ions and remove cesium ions almost completely even from a large volume of cesium ion solution using HOM-PR. . That is, it was confirmed that the level is practically acceptable. Thus, the HOM probe (HOM-PR) is an excellent collector and concentration detection sensor for cesium (Cs) ions.

<Cesium recovery>
After adsorbing cesium ions Cs (I) from a cesium-dissolved solution (pH 9.5) to HOM-DPAR (Examples 7 and 8, cesium adsorption concentration 5 ppm), solid material adsorbing cesium ions Cs (I) (HOM-DPAR) -Cs) 20 mg is 20 ml of 0.01M HNO ₃ elution solution in a 50 ml beaker (20 μl of concentrated nitric acid HNO ₃ (60-61%) dissolved in 20 ml of deionized water to make 0.01 M HNO ₃ ) And stir for 5 minutes. This solution was then filtered.

FIG. 16 shows an absorption spectrum obtained by solid material HOM-DPAR ultraviolet-visible spectroscopy before and after releasing (or also separating or eluting) cesium ions Cs (I). FIG. 17 shows an enlarged view of the colorimetric analysis result shown in FIG. 16, that is, the change in color tone of the solid material HOM-DPAR before and after liberation (also referred to as separation or elution) of cesium Cs (I). FIG. 16A is pink in color tone of the solid material HOM-DPAR-Cs after cesium ion adsorption. FIG. 16B shows a light brown color of the solid material after liberation of cesium ions, which is close to the color tone of the solid material HOM-DPAR before cesium ion adsorption. Thus, it is considered that HOM-DPAR-Cs released cesium ion Cs (I) and returned to HOM-DPAR by the elution solution treatment of 0.01M HNO ₃ . The absorption spectrum by the UV-visible spectroscopy in FIG. 16 shows the result that there is not much change due to the elution process (the absorbance in the case of HOM-DPAR-Cs before elution is almost the same as the absorbance after release). Further ingenuity is required for sample volume and sample processing. Actually, it is considered that it approaches the absorption spectrum curve of HOM-DPAR before adsorbing cesium ions. Further, as can be seen from FIG. 16, the HOM-DPAR capter retains a large amount of DPAR ligand compound on the pore surface, and the HOM-DPAR capter can be recycled / reused. Further, it was confirmed by ICP-MS analysis (ICP mass spectrometry) of the filtrate that 90% or more of HOM-DPAR-Cs was recovered. By optimizing the conditions, the removal efficiency can be further increased, and the recovery rate can be close to 100%. Since the elution solution can be sufficiently removed with 0.01 M HNO ₃ having a very low concentration, the recovery cost is low.

<ICP-MS analysis by cesium ion adsorption by HOM-DPAR>
After taking 160 ml of pH 2 adjusted solution and injecting it into a 1000 ml beaker, adding 4.5 ppm of cesium ion Cs (I) (18 ml from a 200 ppm stock solution bottle of cesium ion Cs (I)), then the required amount of deionized Water was added to adjust the cesium ion dissolving solution to an 800 ml solution. Thereafter, 500 mg of a HOM-DPAR capter was added to this cesium ion solution, stirred at 50-60 ° C. for 24 hours, and then filtered. The filtrate was subjected to ICP-MS analysis (ICP mass spectrometry) to measure the cesium ion concentration.

Also, 160 ml of pH 9.5 adjustment solution is taken and poured into a 1000 ml beaker, and then 40 ml of 0.1 M dodecyl sulfate (SDS) is added. Next, after adding 4.5 ppm of cesium ion Cs (I) (18 ml from a 200 ppm stock solution bottle of cesium ion Cs (I)), add a necessary amount of deionized water to adjust the cesium ion solution to an 800 ml solution. did. Thereafter, 500 mg of a HOM-DPAR capter was added to this cesium ion solution, stirred at 50-60 ° C. for 24 hours, and then filtered. The filtrate was subjected to ICP-MS analysis (ICP mass spectrometry) and the cesium ion concentration was measured.

FIG. 18 shows the cesium ion Cs (I) concentration by ICP-MS analysis (ICP mass spectrometry). The cesium ion concentration before addition of HOM-DPAR was 4.5 ppm (as intended), but the cesium ion concentration in the filtrate after addition of HOM-DPAR was 0.1 ppm at pH 2 and pH 9 .5 was below the detection limit (<0.1 ppm). From these results, it was confirmed that HOM-DPAR can adsorb almost 100% of cesium ions. Therefore, the HOM-DPAR of the present invention is a very excellent cesium adsorbent. In addition, ions close to cesium such as alkali ions other than cesium and alkaline earth metal ions (similar in ionic valence and chemical / physical properties) are hardly adsorbed, and thus are excellent in selectivity. Also, HOM-DTDR and HOM-PR supporting other cesium ion adsorbing compounds have obtained the same results as HOM-DPAR, so HOM-DTDR and HOM-PR are also very excellent cesium adsorbents. It is an adsorbent with excellent selectivity.

FIG. 19 is a table showing the application range of cesium recovery of the HOM-DPAR of the present invention obtained from the above examples, that is, the efficiency and extraction parameters of cesium ions {Cs (I)}. Extraction time for the HOM-DPAR collector to adsorb cesium (Cs) ions when the HOM-DPAR collector is immersed in a cesium (Cs) ion solution (time until almost complete (97% or more) cesium ions are adsorbed) ) Has a detection limit of 0.5 ppm which can be detected visually for 12 hours. The required amount of a HOM-DPAR collector that adsorbs 1 g of cesium (Cs) is 10 g. The HOM-DPAR collector adsorbed cesium (Cs), by using a HNO ₃ as an eluting solution, returned to the original HOM-DPAR collectors. It can also be eluted with 0.01M HNO ₃ . Moreover, since the HOM-DPAR collector has a stable structure of the HOMS skeleton and can be used repeatedly, a large amount of cesium (Cs) can be recovered with a small amount of material.

FIG. 20 shows a cesium (Cs) ion-dissolving compound of the present invention, a cesium (Cs) ion-dissolved solution containing radioactive cesium (Cs) and the like using mesoporous silica (HOMS) carrying DPAR, DTDR, or PR. It is the figure which showed the system which collect | recovers (Cs). This figure summarizes the present invention described so far. In one step, mesoporous silica (HOMS) is prepared, and in the second step, cesium (Cs) ion-adsorbing compound DPAR, DTDR, or PR is supported on HOMS, and HOMS-DPAR collector, HOMS-DTDR collector, or HOMS-PR. Make a collector. Next, in a third stage, cesium (Cs) (this cesium (Cs) also includes radioactive cesium (Cs)) and cesium (Cs) (ion) dissolved solution containing other ions are dissolved in HOMS-DPAR or HOMS-DTDR. Or HOMS-PR is immersed (contacted), and the target (metal) element cesium (Cs) to be extracted (or collected) is adsorbed on HOMS-DPAR, HOMS-DTDR, or HOMS-PR (extraction, collection). HOMS-DPAR-Cs or HOMS-DTDR-Cs or HOMS-PR-Cs. In the next fourth stage (fifth stage in FIG. 1), the HOMS-DPAR-Cs or HOMS-DTDR-Cs or HOMS-PR-Cs is immersed in a cesium (Cs) elution solution such as an acidic solution or an alkaline solution. Then, the target element cesium (Cs) is separated. (HOMS-DPAR, HOMS-DTDR, and HOMS-PR selectively adsorb only Cs ions even if various ions (cations and anions) are dissolved, so the fourth step in FIG. 1 can be omitted.) The cesium (Cs) was recovered or collected by the operation of. The HOMS-DPAR or HOMS-DTDR or HOMS-PR can be used again in the third stage and can be used any number of times by reusing the HOMS-DPAR collector or HOMS-DTDR collector or HOMS-PR collector.

From the viewpoint of the colorimetric method, the color tone of the HOMS-DPAR collector, HOMS-DTDR collector, or HOMS-PR collector changes in the cesium (Cs) ion-dissolved solution in the third stage. This change in color tone varies depending on the concentration of cesium (Cs) ions in the cesium (Cs) ion solution. Alternatively, the color tone of the HOMS-DPAR collector, HOMS-DTDR collector, or HOMS-PR collector varies depending on the concentration of cesium (Cs) ions adsorbed thereto. Since the cesium (Cs) ion adsorption speed to the HOMS-DPAR collector, the HOMS-DTDR collector, or the HOMS-PR collector is quickly performed, the HOMS-DPAR collector (HOMS-DPAR-Cs) is obtained by filtration or the like when the color change is completed. Or HOMS-DTDR collector (becomes HOMS-DTDR-Cs) or HOMS-PR collector (becomes HOMS-PR-Cs). This indicates that cesium (Cs) ions in the cesium (Cs) ion dissolution solution were collected by the HOMS-DPAR collector, the HOMS-DTDR collector, or the HOMS-PR collector.

When these HOMS-DPAR-Cs or HOMS-DTDR-Cs or HOMS-PR-Cs are contacted with an elution (free, separated) solution capable of separating cesium (Cs) from these materials, the HOMS-DPAR collector or HOMS -The color tone of the DTDR collector or HOMS-PR collector changes again and returns to the original color tone. That is, it returned to HOMS-DPAR, HOMS-DTDR, or HOMS-PR that did not adsorb cesium (Cs). The HOMS-DPAR collector, HOMS-DTDR collector, or HOMS-PR collector has a very high selectivity for extraction of cesium (Cs) ions, and even if a large number of ions are contained, there is almost no influence on the effect thereof. It hardly affects the color tone change. Therefore, since the HOMS-DPAR collector or HOMS-DTDR collector or HOMS-PR collector can collect all the cesium (Cs) in the solution and almost completely remove cesium (Cs), the complete cesium (Cs) collector Or it can be said to be a complete cesium (Cs) remover. In this way, a HOMS-DPAR collector or HOMS-DTDR collector or HOMS-PR collector can be used many times for the recovery of cesium (Cs) ions using a colorimetric method.

As described above, it is possible to know how much cesium (Cs) ions have been adsorbed by the HOMS-DPAR collector, the HOMS-DTDR collector, or the HOMS-PR collector using the color change by the colorimetric method. In addition, immerse the HOMS-DPAR collector, HOMS-DTDR collector, or HOMS-PR collector in a cesium (Cs) ion dissolution solution to determine the degree of discoloration of the HOMS-DPAR collector, HOMS-DTDR collector, or HOMS-PR collector. For example, since cesium (Cs) ions of a certain concentration or more are adsorbed, the immersion of the HOMS-DPAR collector, HOMS-DTDR collector, or HOMS-PR collector into the aqueous solution containing cesium (Cs) ions is stopped, and the HOMS- Remove the DPAR collector or HOMS-DTDR collector or HOMS-PR collector. As a result, cesium (Cs) ions can be eluted from HOMS-DPAR-Cs, HOMS-DTDR-Cs, or HOMS-PR-Cs in the next step. When HOMS-DPAR-Cs or HOMS-DTDR-Cs or HOMS-PR-Cs is put into a cesium (Cs) ion elution solution, cesium (Cs) is eluted and discolored, and cesium (Cs) ions are not adsorbed. Return to the original HOMS-DPAR or HOMS-DTDR or HOMS-PR.

The complete removal of cesium (Cs) ions can also be confirmed from ICP-OES or ICP-MS measurements. In this way, the amount of adsorption of cesium (Cs) ions can be determined using the colorimetric method, and the end point can be detected. The HOMS-DPAR collector or HOMS-DTDR collector or HOMS-PR collector is reversible for extraction / separation of cesium (Cs) ions and can be used repeatedly. In this way, the amount of adsorption of cesium (Cs) ions can be grasped only by color tone, or it can be grasped that cesium (Cs) ions are not adsorbed, so that not only rapid detection of cesium (Cs) ions but also rapid recovery Can be performed. As a result, productivity can be greatly improved. As described above, a HOMS-DPAR collector, a HOMS-DTDR collector, a HOMS-PR collector, or the like can extract (collect) cesium (Cs) by utilizing a change in color tone (colorimetric method). It can also be called a visual collector. 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-DPAR or HOMS-DTDR, or HOMS-PR, or HOMS carrying another cesium (Cs) ion-adsorbing compound has very good selectivity, so that metals other than cesium (Cs) ions are cesium ( Even if it is contained in the Cs) ion solution, or if anion ions or surfactants are contained in the cesium (Cs) ion solution, that is, even if these competing ions are present Extracts or collects only cesium (Cs) ions. Even if the amount of cesium (Cs) ion is a trace amount or a larger amount of ppb to ppm, and the content of other metal ions, anions or surfactants is a trace amount or a larger amount The HOMS-DPAR or HOMS-DTDR or HOMS-PR collector of the present invention can selectively extract or collect only cesium (Cs) 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 A cesium (Cs) ion collector such as a HOMS-DPAR collector, a HOMS-DTDR collector, or a HOMS-PR collector produced by using the technology of the present invention is a waste (exhaust) liquid containing radioactive cesium (Cs), etc. When cesium (Cs) is adsorbed from waste, waste water, etc., it visually changes, so cesium (Cs) can be easily recovered. Moreover, a HOMS-DPAR collector, a HOMS-DTDR collector, a HOMS-PR collector, or the like has high selectivity with respect to cesium (Cs) ions among various ions, and has an optical response function. The HOMS-DPAR collector, HOMS-DTDR collector, HOMS-PR collector and the like of the present invention are extremely useful for extraction, removal, collection, recovery and detection of radioactive cesium (Cs) that is particularly dangerous to the human body (living body).

As described above, the present invention provides a cesium (Cs) ion such as a chelate compound that selectively adsorbs the target element cesium (Cs) ion to highly ordered mesoporous silica prepared from an organosilicon compound and a surfactant. An adsorbent compound is supported, and the mesoporous silica supporting the cesium (Cs) ion adsorbent compound is brought into contact with a solution in which the target element cesium (Cs) ion is dissolved, and the target element cesium (Cs) ion It is selectively adsorbed on a cesium (Cs) ion-adsorbing compound supported on mesoporous silica. After that, mesoporous silica carrying a cesium (Cs) ion-adsorbing compound that adsorbs cesium (Cs) ions as a target element was chemically treated, and cesium (Cs) ions as a target element were carried on mesoporous silica. The cesium (Cs) ion-adsorbing compound is liberated and the target element cesium (Cs) is recovered. The mesoporous silica supporting the cesium (Cs) ion-adsorbing compound from which the target element cesium (Cs) ion is released can be reused. The mesoporous silica supporting the cesium (Cs) ion-adsorbing compound can also be used as a cesium (Cs) (ion) collector and a concentration detection sensor. Furthermore, it is possible to inspect whether (harmful radioactivity) cesium (Cs) is dissolved in domestic water or waste liquid, and it is possible to detect even a very small concentration of ppb to ppm order. Furthermore, (radioactive) cesium (Cs) dissolved in domestic water or waste liquid can be adsorbed to reduce the (radioactive) cesium (Cs) 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) cesium (Cs) removal filter. For example, when there is a possibility that radioactive cesium is contained in drinking water, if a filter using mesoporous silica carrying a cesium ion-adsorbing compound of the present invention is attached to a drinking water faucet, the radioactive cesium is contained in this filter. Drinking water that has been adsorbed and reduced to a concentration below an acceptable limit can be obtained. If this filter is also treated with an eluent that elutes cesium ions, it can be recycled / reused.

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 related to cesium (Cs) collectors and sensors, an industrial field to remove cesium (Cs) containing radioactive cesium (Cs) from substances and materials containing various cations, anions and surfactants, and radioactive materials. It can be used in the industrial field for recovering cesium (Cs) containing cesium (Cs).

Claims (18)

Cesium ions adsorbing cesium ions that can adsorb cesium ions and liberate the adsorbed cesium ions from a solution in which various ions containing the target element cesium (Cs) are dissolved (cesium ion solution) Mesoporous silica carrying an adsorbent compound ,
The cesium ion adsorbing compound is 2-dodecyl-4-((phenyl) diazenyl) resorcinol {2-dodecyl-4-((phenyl) diazenyl) resorcinol (DPAR)},
4- (2-diazenyl-1,3,4-thiadiazole) -6-dodecylresorcinol {4- (2-diazenyl-1,3,4-thiadiazole) -6-dodecylresorcinol (DTDR)}, or
Pyrogallol red {Pyrogallol red (PR)}
Mesoporous silica, characterized in that it is at least one selected from: The mesoporous silica supporting the cesium ion adsorbing compound is brought into contact with a cesium ion dissolving solution adjusted to a pH value at which the target element cesium is well adsorbed, and the target element is added to the cesium ion adsorbing compound adsorbed on the mesoporous silica. The mesoporous silica according to claim 1 , which adsorbs cesium ions. In the case of the DPAR, the pH value is 1.5 to 2.5, in the case of the DTDR, the pH value is 1.5 to 2.5, and in the case of the PR, the pH value is 9. The mesoporous silica according to claim 2 , wherein the mesoporous silica is 0 to 10.0. The color tone of the mesoporous silica supporting the cesium ion-adsorbing compound before adsorbing cesium is discolored by adsorbing cesium, and the color tone is changed when cesium is further separated, and the original color tone is restored . The mesoporous silica according to any one of claims 1 to 3 . A cesium collector for collecting cesium (Cs) from a cesium ion-dissolved solution using the mesoporous silica according to any one of claims 1 to 4 . The cesium collector according to claim 5, wherein the cesium ion dissolution solution contains radioactive cesium. A mesoporous silica supporting a cesium ion-adsorbing compound is brought into contact with a cesium ion-dissolved solution containing the target element cesium ion, adjusted to a pH value that adsorbs the target element cesium ion well, and the cesium ion adsorption property including the step of liberating steps, and from <br/> the cesium ion adsorbent compounds that cesium ions adsorbed is the target element cesium ions is the target element to selectively adsorb the cesium ion is the target element compound A cesium recovery method using mesoporous silica characterized by comprising :
The cesium ion adsorbing compound is 2-dodecyl-4-((phenyl) diazenyl) resorcinol {2-dodecyl-4-((phenyl) diazenyl) resorcinol (DPAR)},
4- (2-diazenyl-1,3,4-thiadiazole) -6-dodecylresorcinol {4- (2-diazenyl-1,3,4-thiadiazole) -6-dodecylresorcinol (DTDR)}, or
Pyrogallol red {Pyrogallol red (PR)}
A method for recovering cesium, wherein the method is at least one selected from the group consisting of: The method for recovering cesium according to claim 7, further comprising a step of supporting the cesium ion-adsorbing compound on mesoporous silica. The method for recovering cesium according to claim 7 or 8 , further comprising a step of determining a concentration of cesium ions adsorbed on mesoporous silica supporting a cesium ion adsorbing compound using a colorimetric method. The method for recovering cesium according to any one of claims 7 to 9 , wherein mesoporous silica supporting a cesium ion adsorbing compound is reused. In the case of the DPAR, the pH value is 1.5 to 2.5, in the case of the DTDR, the pH value is 1.5 to 2.5, and in the case of the PR, the pH value is 9. It is 0-10.0, The cesium collection | recovery method of any one of Claims 7-10 characterized by the above-mentioned. Extraction of cesium ions using the change in color when the mesoporous silica supporting the cesium ion-adsorbing compound adsorbs cesium ions and / or discoloration when the mesoporous silica adsorbing cesium ions elutes cesium ions The cesium recovery method according to any one of claims 7 to 11 , wherein cesium ions are separated by returning to mesoporous silica supporting a cesium ion-adsorbing compound. A cesium ion collector based on mesoporous silica combined with a cesium ion adsorbing compound that collects cesium ions from a solution in which various ions containing cesium are dissolved (cesium ion solution),
The cesium ion adsorbing compound is 2-dodecyl-4-((phenyl) diazenyl) resorcinol {2-dodecyl-4-((phenyl) diazenyl) resorcinol (DPAR)},
4- (2-diazenyl-1,3,4-thiadiazole) -6-dodecylresorcinol {4- (2-diazenyl-1,3,4-thiadiazole) -6-dodecylresorcinol (DTDR)}, or
Pyrogallol red {Pyrogallol red (PR)}
At least one selected from:
Cesium ion collector. Characterized in that it is also possible to collect the cesium ions in the presence of competing ions, cesium ions collection agent according to claim 13. A cesium ion concentration sensor based on mesoporous silica loaded with a cesium ion-adsorbing compound, with cesium ion concentration changing color (colorimetric method) or cesium ion concentration UV-VIS-NIR spectroscopy A cesium ion concentration sensor, characterized by detecting by:
The cesium ion adsorbing compound is 2-dodecyl-4-((phenyl) diazenyl) resorcinol {2-dodecyl-4-((phenyl) diazenyl) resorcinol (DPAR)},
4- (2-diazenyl-1,3,4-thiadiazole) -6-dodecylresorcinol {4- (2-diazenyl-1,3,4-thiadiazole) -6-dodecylresorcinol (DTDR)}, or
Pyrogallol red {Pyrogallol red (PR)}
At least one selected from:
Cesium ion concentration sensor. The cesium ion concentration sensor according to claim 15, wherein the concentration of cesium ions is detected by a UV-VIS-NIR spectroscopic spectrum in a wavelength range of 250 nm to 900 nm .
The cesium ion concentration sensor according to claim 15 or 16, wherein the cesium ion concentration is detected in the presence of competing ions. The cesium removal filter using the mesoporous silica of any one of Claims 1-4.