JP6691415B2 - Method for producing cesium and / or strontium adsorbent - Google Patents
Method for producing cesium and / or strontium adsorbent Download PDFInfo
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- 239000003463 adsorbent Substances 0.000 title claims description 53
- 229910052712 strontium Inorganic materials 0.000 title claims description 46
- CIOAGBVUUVVLOB-UHFFFAOYSA-N strontium atom Chemical compound [Sr] CIOAGBVUUVVLOB-UHFFFAOYSA-N 0.000 title claims description 40
- 238000004519 manufacturing process Methods 0.000 title claims description 29
- 229910052792 caesium Inorganic materials 0.000 title claims description 25
- TVFDJXOCXUVLDH-UHFFFAOYSA-N caesium atom Chemical compound [Cs] TVFDJXOCXUVLDH-UHFFFAOYSA-N 0.000 title claims description 18
- 229910052783 alkali metal Inorganic materials 0.000 claims description 37
- 150000001340 alkali metals Chemical class 0.000 claims description 35
- 239000003795 chemical substances by application Substances 0.000 claims description 34
- KRKNYBCHXYNGOX-UHFFFAOYSA-N citric acid Chemical compound OC(=O)CC(O)(C(O)=O)CC(O)=O KRKNYBCHXYNGOX-UHFFFAOYSA-N 0.000 claims description 27
- 239000002994 raw material Substances 0.000 claims description 23
- 238000000034 method Methods 0.000 claims description 22
- 239000002253 acid Substances 0.000 claims description 15
- 229910052700 potassium Inorganic materials 0.000 claims description 14
- 229910052708 sodium Inorganic materials 0.000 claims description 14
- 238000010306 acid treatment Methods 0.000 claims description 10
- 150000008044 alkali metal hydroxides Chemical group 0.000 claims description 4
- -1 alkali metal salt Chemical class 0.000 claims description 2
- 150000001735 carboxylic acids Chemical class 0.000 claims 5
- 238000001179 sorption measurement Methods 0.000 description 31
- 239000010936 titanium Substances 0.000 description 25
- HEMHJVSKTPXQMS-UHFFFAOYSA-M Sodium hydroxide Chemical compound [OH-].[Na+] HEMHJVSKTPXQMS-UHFFFAOYSA-M 0.000 description 24
- 150000001732 carboxylic acid derivatives Chemical class 0.000 description 23
- KWYUFKZDYYNOTN-UHFFFAOYSA-M Potassium hydroxide Chemical compound [OH-].[K+] KWYUFKZDYYNOTN-UHFFFAOYSA-M 0.000 description 22
- 239000008187 granular material Substances 0.000 description 22
- 239000011734 sodium Substances 0.000 description 21
- 239000000047 product Substances 0.000 description 20
- 230000000052 comparative effect Effects 0.000 description 19
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 19
- 239000000243 solution Substances 0.000 description 18
- 239000007864 aqueous solution Substances 0.000 description 17
- 238000005469 granulation Methods 0.000 description 12
- 230000003179 granulation Effects 0.000 description 12
- 239000013535 sea water Substances 0.000 description 12
- 239000011230 binding agent Substances 0.000 description 11
- 239000002245 particle Substances 0.000 description 11
- 229910004298 SiO 2 Inorganic materials 0.000 description 10
- 239000013618 particulate matter Substances 0.000 description 10
- 238000012360 testing method Methods 0.000 description 10
- FAPWRFPIFSIZLT-UHFFFAOYSA-M Sodium chloride Chemical compound [Na+].[Cl-] FAPWRFPIFSIZLT-UHFFFAOYSA-M 0.000 description 8
- 238000002441 X-ray diffraction Methods 0.000 description 8
- 235000015165 citric acid Nutrition 0.000 description 8
- RMAQACBXLXPBSY-UHFFFAOYSA-N silicic acid Chemical compound O[Si](O)(O)O RMAQACBXLXPBSY-UHFFFAOYSA-N 0.000 description 8
- 239000002002 slurry Substances 0.000 description 8
- 235000011121 sodium hydroxide Nutrition 0.000 description 8
- XJDNKRIXUMDJCW-UHFFFAOYSA-J titanium tetrachloride Chemical compound Cl[Ti](Cl)(Cl)Cl XJDNKRIXUMDJCW-UHFFFAOYSA-J 0.000 description 8
- 238000011156 evaluation Methods 0.000 description 7
- 239000000203 mixture Substances 0.000 description 7
- 239000004745 nonwoven fabric Substances 0.000 description 7
- 235000011118 potassium hydroxide Nutrition 0.000 description 7
- 235000012239 silicon dioxide Nutrition 0.000 description 7
- 238000011282 treatment Methods 0.000 description 7
- 239000007788 liquid Substances 0.000 description 6
- 239000002904 solvent Substances 0.000 description 6
- 239000000463 material Substances 0.000 description 5
- 238000005259 measurement Methods 0.000 description 5
- 238000003756 stirring Methods 0.000 description 5
- 239000004111 Potassium silicate Substances 0.000 description 4
- 239000004115 Sodium Silicate Substances 0.000 description 4
- 229910010413 TiO 2 Inorganic materials 0.000 description 4
- RTAQQCXQSZGOHL-UHFFFAOYSA-N Titanium Chemical compound [Ti] RTAQQCXQSZGOHL-UHFFFAOYSA-N 0.000 description 4
- 150000001339 alkali metal compounds Chemical class 0.000 description 4
- 229910052910 alkali metal silicate Inorganic materials 0.000 description 4
- 238000004458 analytical method Methods 0.000 description 4
- 150000001875 compounds Chemical class 0.000 description 4
- 229920001577 copolymer Polymers 0.000 description 4
- 238000001027 hydrothermal synthesis Methods 0.000 description 4
- 230000001771 impaired effect Effects 0.000 description 4
- 229910052913 potassium silicate Inorganic materials 0.000 description 4
- 235000019353 potassium silicate Nutrition 0.000 description 4
- 239000000843 powder Substances 0.000 description 4
- 239000011780 sodium chloride Substances 0.000 description 4
- 229910052911 sodium silicate Inorganic materials 0.000 description 4
- NTHWMYGWWRZVTN-UHFFFAOYSA-N sodium silicate Chemical compound [Na+].[Na+].[O-][Si]([O-])=O NTHWMYGWWRZVTN-UHFFFAOYSA-N 0.000 description 4
- DGAQECJNVWCQMB-PUAWFVPOSA-M Ilexoside XXIX Chemical compound C[C@@H]1CC[C@@]2(CC[C@@]3(C(=CC[C@H]4[C@]3(CC[C@@H]5[C@@]4(CC[C@@H](C5(C)C)OS(=O)(=O)[O-])C)C)[C@@H]2[C@]1(C)O)C)C(=O)O[C@H]6[C@@H]([C@H]([C@@H]([C@H](O6)CO)O)O)O.[Na+] DGAQECJNVWCQMB-PUAWFVPOSA-M 0.000 description 3
- MUBZPKHOEPUJKR-UHFFFAOYSA-N Oxalic acid Chemical compound OC(=O)C(O)=O MUBZPKHOEPUJKR-UHFFFAOYSA-N 0.000 description 3
- ZLMJMSJWJFRBEC-UHFFFAOYSA-N Potassium Chemical compound [K] ZLMJMSJWJFRBEC-UHFFFAOYSA-N 0.000 description 3
- 238000006243 chemical reaction Methods 0.000 description 3
- 239000013078 crystal Substances 0.000 description 3
- 238000001035 drying Methods 0.000 description 3
- 238000010828 elution Methods 0.000 description 3
- 239000000706 filtrate Substances 0.000 description 3
- 238000002354 inductively-coupled plasma atomic emission spectroscopy Methods 0.000 description 3
- 238000002156 mixing Methods 0.000 description 3
- 239000011591 potassium Substances 0.000 description 3
- NNHHDJVEYQHLHG-UHFFFAOYSA-N potassium silicate Chemical compound [K+].[K+].[O-][Si]([O-])=O NNHHDJVEYQHLHG-UHFFFAOYSA-N 0.000 description 3
- CURLTUGMZLYLDI-UHFFFAOYSA-N Carbon dioxide Chemical compound O=C=O CURLTUGMZLYLDI-UHFFFAOYSA-N 0.000 description 2
- OFOBLEOULBTSOW-UHFFFAOYSA-N Malonic acid Chemical compound OC(=O)CC(O)=O OFOBLEOULBTSOW-UHFFFAOYSA-N 0.000 description 2
- MCMNRKCIXSYSNV-UHFFFAOYSA-N Zirconium dioxide Chemical compound O=[Zr]=O MCMNRKCIXSYSNV-UHFFFAOYSA-N 0.000 description 2
- GNKTZDSRQHMHLZ-UHFFFAOYSA-N [Si].[Si].[Si].[Ti].[Ti].[Ti].[Ti].[Ti] Chemical compound [Si].[Si].[Si].[Ti].[Ti].[Ti].[Ti].[Ti] GNKTZDSRQHMHLZ-UHFFFAOYSA-N 0.000 description 2
- 238000000975 co-precipitation Methods 0.000 description 2
- HNPSIPDUKPIQMN-UHFFFAOYSA-N dioxosilane;oxo(oxoalumanyloxy)alumane Chemical compound O=[Si]=O.O=[Al]O[Al]=O HNPSIPDUKPIQMN-UHFFFAOYSA-N 0.000 description 2
- 238000001125 extrusion Methods 0.000 description 2
- 238000001914 filtration Methods 0.000 description 2
- 208000022041 growing teratoma syndrome Diseases 0.000 description 2
- XLYOFNOQVPJJNP-UHFFFAOYSA-M hydroxide Chemical compound [OH-] XLYOFNOQVPJJNP-UHFFFAOYSA-M 0.000 description 2
- JVTAAEKCZFNVCJ-UHFFFAOYSA-N lactic acid Chemical compound CC(O)C(O)=O JVTAAEKCZFNVCJ-UHFFFAOYSA-N 0.000 description 2
- 229910052751 metal Inorganic materials 0.000 description 2
- 239000002184 metal Substances 0.000 description 2
- 230000002572 peristaltic effect Effects 0.000 description 2
- 239000004033 plastic Substances 0.000 description 2
- 229920003023 plastic Polymers 0.000 description 2
- 239000011148 porous material Substances 0.000 description 2
- BWHMMNNQKKPAPP-UHFFFAOYSA-L potassium carbonate Substances [K+].[K+].[O-]C([O-])=O BWHMMNNQKKPAPP-UHFFFAOYSA-L 0.000 description 2
- 230000002285 radioactive effect Effects 0.000 description 2
- 239000000941 radioactive substance Substances 0.000 description 2
- 229920005989 resin Polymers 0.000 description 2
- 239000011347 resin Substances 0.000 description 2
- CDBYLPFSWZWCQE-UHFFFAOYSA-L sodium carbonate Substances [Na+].[Na+].[O-]C([O-])=O CDBYLPFSWZWCQE-UHFFFAOYSA-L 0.000 description 2
- 238000005507 spraying Methods 0.000 description 2
- 239000010457 zeolite Substances 0.000 description 2
- BJEPYKJPYRNKOW-REOHCLBHSA-N (S)-malic acid Chemical compound OC(=O)[C@@H](O)CC(O)=O BJEPYKJPYRNKOW-REOHCLBHSA-N 0.000 description 1
- BVKZGUZCCUSVTD-UHFFFAOYSA-L Carbonate Chemical compound [O-]C([O-])=O BVKZGUZCCUSVTD-UHFFFAOYSA-L 0.000 description 1
- 229920002134 Carboxymethyl cellulose Polymers 0.000 description 1
- 239000004354 Hydroxyethyl cellulose Substances 0.000 description 1
- 101100496858 Mus musculus Colec12 gene Proteins 0.000 description 1
- 229920000459 Nitrile rubber Polymers 0.000 description 1
- 229920003171 Poly (ethylene oxide) Polymers 0.000 description 1
- 239000002202 Polyethylene glycol Substances 0.000 description 1
- 239000004372 Polyvinyl alcohol Substances 0.000 description 1
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 description 1
- 229910021536 Zeolite Inorganic materials 0.000 description 1
- 230000032683 aging Effects 0.000 description 1
- 239000003513 alkali Substances 0.000 description 1
- 229910000288 alkali metal carbonate Inorganic materials 0.000 description 1
- 150000008041 alkali metal carbonates Chemical class 0.000 description 1
- 150000004703 alkoxides Chemical class 0.000 description 1
- BJEPYKJPYRNKOW-UHFFFAOYSA-N alpha-hydroxysuccinic acid Natural products OC(=O)C(O)CC(O)=O BJEPYKJPYRNKOW-UHFFFAOYSA-N 0.000 description 1
- AZDRQVAHHNSJOQ-UHFFFAOYSA-N alumane Chemical group [AlH3] AZDRQVAHHNSJOQ-UHFFFAOYSA-N 0.000 description 1
- PNEYBMLMFCGWSK-UHFFFAOYSA-N aluminium oxide Inorganic materials [O-2].[O-2].[O-2].[Al+3].[Al+3] PNEYBMLMFCGWSK-UHFFFAOYSA-N 0.000 description 1
- 239000003125 aqueous solvent Substances 0.000 description 1
- 239000000440 bentonite Substances 0.000 description 1
- 229910000278 bentonite Inorganic materials 0.000 description 1
- SVPXDRXYRYOSEX-UHFFFAOYSA-N bentoquatam Chemical compound O.O=[Si]=O.O=[Al]O[Al]=O SVPXDRXYRYOSEX-UHFFFAOYSA-N 0.000 description 1
- 239000006227 byproduct Substances 0.000 description 1
- 239000001569 carbon dioxide Substances 0.000 description 1
- 229910002092 carbon dioxide Inorganic materials 0.000 description 1
- 239000001768 carboxy methyl cellulose Substances 0.000 description 1
- 235000010948 carboxy methyl cellulose Nutrition 0.000 description 1
- 229920003090 carboxymethyl hydroxyethyl cellulose Polymers 0.000 description 1
- 239000008112 carboxymethyl-cellulose Substances 0.000 description 1
- 238000005341 cation exchange Methods 0.000 description 1
- 239000003153 chemical reaction reagent Substances 0.000 description 1
- 239000004927 clay Substances 0.000 description 1
- 239000008119 colloidal silica Substances 0.000 description 1
- 238000007906 compression Methods 0.000 description 1
- 230000006835 compression Effects 0.000 description 1
- YPHMISFOHDHNIV-FSZOTQKASA-N cycloheximide Chemical compound C1[C@@H](C)C[C@H](C)C(=O)[C@@H]1[C@H](O)CC1CC(=O)NC(=O)C1 YPHMISFOHDHNIV-FSZOTQKASA-N 0.000 description 1
- 238000004090 dissolution Methods 0.000 description 1
- 239000005038 ethylene vinyl acetate Substances 0.000 description 1
- 230000001747 exhibiting effect Effects 0.000 description 1
- 239000000835 fiber Substances 0.000 description 1
- 238000010335 hydrothermal treatment Methods 0.000 description 1
- 235000019447 hydroxyethyl cellulose Nutrition 0.000 description 1
- 239000012535 impurity Substances 0.000 description 1
- 239000004615 ingredient Substances 0.000 description 1
- 238000005342 ion exchange Methods 0.000 description 1
- NLYAJNPCOHFWQQ-UHFFFAOYSA-N kaolin Chemical compound O.O.O=[Al]O[Si](=O)O[Si](=O)O[Al]=O NLYAJNPCOHFWQQ-UHFFFAOYSA-N 0.000 description 1
- 229910052622 kaolinite Inorganic materials 0.000 description 1
- 239000004310 lactic acid Substances 0.000 description 1
- 235000014655 lactic acid Nutrition 0.000 description 1
- 239000004816 latex Substances 0.000 description 1
- 229920000126 latex Polymers 0.000 description 1
- 238000011866 long-term treatment Methods 0.000 description 1
- 230000007774 longterm Effects 0.000 description 1
- 239000001630 malic acid Substances 0.000 description 1
- 235000011090 malic acid Nutrition 0.000 description 1
- 150000002739 metals Chemical class 0.000 description 1
- 239000011259 mixed solution Substances 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 229910052758 niobium Inorganic materials 0.000 description 1
- 239000010955 niobium Substances 0.000 description 1
- GUCVJGMIXFAOAE-UHFFFAOYSA-N niobium atom Chemical compound [Nb] GUCVJGMIXFAOAE-UHFFFAOYSA-N 0.000 description 1
- 239000003960 organic solvent Substances 0.000 description 1
- 235000006408 oxalic acid Nutrition 0.000 description 1
- 238000005453 pelletization Methods 0.000 description 1
- 229920001200 poly(ethylene-vinyl acetate) Polymers 0.000 description 1
- 229920000058 polyacrylate Polymers 0.000 description 1
- 229920000728 polyester Polymers 0.000 description 1
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- 229920005596 polymer binder Polymers 0.000 description 1
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- 229920000098 polyolefin Polymers 0.000 description 1
- 229920002451 polyvinyl alcohol Polymers 0.000 description 1
- 229910000027 potassium carbonate Inorganic materials 0.000 description 1
- 235000011181 potassium carbonates Nutrition 0.000 description 1
- 238000003825 pressing Methods 0.000 description 1
- 238000012545 processing Methods 0.000 description 1
- 238000004445 quantitative analysis Methods 0.000 description 1
- 230000005855 radiation Effects 0.000 description 1
- 229910000029 sodium carbonate Inorganic materials 0.000 description 1
- 239000007787 solid Substances 0.000 description 1
- 239000007921 spray Substances 0.000 description 1
- 238000001694 spray drying Methods 0.000 description 1
- 229910001427 strontium ion Inorganic materials 0.000 description 1
- PWYYWQHXAPXYMF-UHFFFAOYSA-N strontium(2+) Chemical group [Sr+2] PWYYWQHXAPXYMF-UHFFFAOYSA-N 0.000 description 1
- 229920003048 styrene butadiene rubber Polymers 0.000 description 1
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Landscapes
- Solid-Sorbent Or Filter-Aiding Compositions (AREA)
- Silicates, Zeolites, And Molecular Sieves (AREA)
Description
本発明は、セシウム及び／又はストロンチウム吸着剤の製造方法に関し、特に海水中のストロンチウムを効率的に分離又は回収しうる吸着剤の製造方法に関する。 The present invention relates to a method for producing a cesium and / or strontium adsorbent, and particularly to a method for producing an adsorbent capable of efficiently separating or recovering strontium in seawater.
従来、放射性物質を含む排水の処理技術としては共沈処理が知られている（下記特許文献１参照）。しかし、水溶性である放射性ストロンチウム及び放射性セシウムについては、前記共沈処理は有効ではなく、現在、ゼオライトなどの無機系吸着剤による吸着除去が行われている（下記特許文献２参照）。 Conventionally, coprecipitation treatment has been known as a technique for treating wastewater containing radioactive substances (see Patent Document 1 below). However, with respect to water-soluble radioactive strontium and radioactive cesium, the coprecipitation treatment is not effective, and at present, adsorption removal using an inorganic adsorbent such as zeolite is performed (see Patent Document 2 below).
セシウム及び／又はストロンチウムの吸着性についてこれまでに研究されている無機系吸着材の一つとして、結晶性シリコチタネートが挙げられる。結晶性シリコチタネートは、Ｔｉ／Ｓｉ比が１：１のもの、５：１２のもの、２：１のもの等、複数種類の組成のものが知られているが、その他に、Ｔｉ／Ｓｉ比が４：３である結晶性シリコチタネートが存在することが知られている。非特許文献１には、Ｔｉ源としてＴｉ（ＯＥＴ）４というアルコキシドを用い、Ｓｉ源としてコロイダルシリカを用いた水熱処理により製造した製造物３Ｂ及び３Ｃは、そのＸ線回折パターンから、３次元的な８員環構造を有していること、この構造の結晶性シリコチタネートは、理想的にはＡ４Ｔｉ４Ｓｉ３Ｏ１６（ＡはＮａ、Ｋ等）で表される組成を有することを報告し、この構造の結晶性シリコチタネートにＧｒａｃｅ ｔｉｔａｎｉｕｍ ｓｉｌｉｃａｔｅ（ＧＴＳ−１）と名付けている。また、非特許文献２にはＴｉ／Ｓｉ比が４：３である結晶性シリコチタネートを、Ｔｉ／Ｓｉ比が０．３２の混合溶液に水熱合成処理を行うことにより製造した旨が記載されている。同文献には、合成した結晶性シリコチタネートが、ストロンチウムイオン交換能を有する旨が記載されている。
また、セシウム及びストロンチウムを両方吸着できる吸着剤として、本出願人は先に、Ａ4Ｔｉ4Ｓｉ3Ｏ16・ｎＨ2Ｏ（ＡはＮａ及び／又はＫであり、ｎは０〜８の数を示す。）で表される結晶性シリコチタネートと、Ａ4Ｔｉ9Ｏ20・ｍＨ2Ｏ（ＡはＮａ及び／又はＫであり、ｍは０〜１０の数を示す。）で表されるチタン酸塩とを含む組成物を報告している（下記特許文献３参照）。
Crystalline silicotitanate is one of the inorganic adsorbents that have been studied so far for the adsorption of cesium and / or strontium. Crystalline silicotitanate is known to have a plurality of compositions such as a Ti / Si ratio of 1: 1, 5:12, and 2: 1. It is known that there is crystalline silicotitanate having a ratio of 4: 3. In Non-Patent Document 1, products 3B and 3C manufactured by hydrothermal treatment using an alkoxide of Ti (OET) 4 as a Ti source and colloidal silica as a Si source are three-dimensional from their X-ray diffraction patterns. Has a unique 8-membered ring structure, and the crystalline silicotitanate of this structure ideally has a composition represented by A 4 Ti 4 Si 3 O 16 (A is Na, K, etc.). It has been reported that the crystalline silicotitanate of this structure is named Grace titanium silicate (GTS-1). Further, Non-Patent Document 2 describes that crystalline silicotitanate having a Ti / Si ratio of 4: 3 was produced by subjecting a mixed solution having a Ti / Si ratio of 0.32 to hydrothermal synthesis. ing. The literature describes that the synthesized crystalline silicotitanate has strontium ion exchange ability.
Further, as an adsorbent capable of adsorbing both cesium and strontium, the present applicant has previously described A 4 Ti 4 Si 3 O 16 .nH 2 O (A is Na and / or K, and n is a number from 0 to 8). Of the crystalline silicotitanate and A 4 Ti 9 O 20 .mH 2 O (A is Na and / or K, and m is a number from 0 to 10). A composition containing a titanate has been reported (see Patent Document 3 below).
上記のとおり、従来、Ｔｉ／Ｓｉ比が４：３である結晶性シリコチタネートに関するセシウム及び／又はストロンチウム吸着性能が報告されているものの、更なるストロンチウムやセシウムの吸着性能の向上が望まれている。特にストロンチウムを低濃度で含む液を効率的に吸着する吸着剤が求められているところ、Ｔｉ／Ｓｉ比が４：３である結晶性シリコチタネートを用いた従来の吸着剤は、ストロンチウムを低濃度で含む液からのストロンチウム吸着性能について十分なものと言い難い。
したがって本発明の課題は、上記課題を解決できる吸着剤の工業的に有利な製造方法を提供することにある。
As described above, although the cesium and / or strontium adsorption performance of a crystalline silicotitanate having a Ti / Si ratio of 4: 3 has been reported in the past, further improvement of the strontium and cesium adsorption performance is desired. . In particular, there is a demand for an adsorbent that efficiently adsorbs a liquid containing strontium in a low concentration. However, a conventional adsorbent using a crystalline silicotitanate having a Ti / Si ratio of 4: 3 has a low strontium concentration. It is hard to say that the adsorption performance of strontium from the liquid containing in is sufficient.
Therefore, an object of the present invention is to provide an industrially advantageous manufacturing method of an adsorbent that can solve the above problems.
本発明者は、前記課題を解決するために鋭意研究を重ねた結果、Ｔｉ／Ｓｉ比が４：３である結晶性シリコチタネート即ちＡ4Ｔｉ4Ｓｉ3Ｏ16・ｎＨ2Ｏ（ＡはＮａ及び／又はＫであり、ｎは０〜８の数を示す。）で表される結晶性シリコチタネートを含有し特定の酸処理に供した吸着剤は、驚くべきことに、低濃度でのストロンチウムの吸着効率が高いことを見出した。 The present inventor has conducted extensive studies in order to solve the above-mentioned problems, and as a result, a crystalline silicotitanate having a Ti / Si ratio of 4: 3, that is, A 4 Ti 4 Si 3 O 16 .nH 2 O (A is Na And / or K, and n is a number from 0 to 8), and the adsorbent containing a crystalline silicotitanate represented by the following formula is surprisingly low in strontium. It was found that the adsorption efficiency of
即ち本発明は、一般式；Ａ４Ｔｉ４Ｓｉ３Ｏ１６・ｎＨ２Ｏ（式中、ＡはＮａ及びＫから選ばれる１種又は２種のアルカリ元素を示す。ｎは０〜８の数を示す。）で表される結晶性シリコチタネートを含む原料を、有機カルボン酸に接触させる酸処理を行い、次いで、得られた酸処理物をアルカリ金属剤に接触させる、セシウム及び／又はストロンチウム吸着剤の製造方法を提供するものである。 That is, the present invention has the general formula: The number of A 4 Ti 4 Si 3 O 16 · nH 2 O ( In the formula, A .n is 0-8 showing one or two or alkaline element selected from Na and K The raw material containing the crystalline silicotitanate represented by the formula (1) is subjected to an acid treatment by bringing it into contact with an organic carboxylic acid, and then the obtained acid-treated product is brought into contact with an alkali metal agent, which adsorbs cesium and / or strontium. A method for producing an agent is provided.
本発明の方法で製造されたセシウム及び／又はストロンチウム吸着剤は、特に、ストロンチウムを低濃度で含有する水等の媒体から、ストロンチウムを効率よく吸着できる。
また、本発明のセシウム及び／又はストロンチウム吸着剤の製造方法によれば、前記のセシウム及び／又はストロンチウム吸着剤を工業的に有利な方法で製造することができる。
The cesium and / or strontium adsorbent produced by the method of the present invention can adsorb strontium efficiently from a medium such as water containing strontium at a low concentration.
Further, according to the method for producing a cesium and / or strontium adsorbent of the present invention, the above cesium and / or strontium adsorbent can be produced by an industrially advantageous method.
まず、本発明の製造方法で得られる吸着剤について説明する。本発明の製造方法で得られるセシウム及び／又はストロンチウム吸着剤（以下、単に「本発明の吸着剤」と記載する場合もある）は、一般式；Ａ４Ｔｉ４Ｓｉ３Ｏ１６・ｎＨ２Ｏ（式中、ＡはＮａ及びＫから選ばれる１種又は２種のアルカリ元素を示す。ｎは０〜８の数を示す。）で表される結晶性シリコチタネートを含有する。以下では、この結晶性シリコチタネートをＧＴＳ（Ｇｒａｃｅ ｔｉｔａｎｉｕｍ ｓｉｌｉｃａｔｅ）とも記載する。なお、前記のＡ４Ｔｉ４Ｓｉ３Ｏ１６・ｎＨ２Ｏは、一般式；Ｎａ4Ｔｉ4Ｓｉ3Ｏ16・ｎＨ2Ｏ、（ＮａxＫ(1-x)）4Ｔｉ4Ｓｉ3Ｏ16・ｎＨ2Ｏ及びＫ4Ｔｉ4Ｓｉ3Ｏ16・ｎＨ2Ｏ（これらの式中、ｘは０超１未満の数を示し、ｎは０〜８の数を示す。）として表すこともできる。ＡがＮａ及びＫの両方を含む場合、Ｎａ4Ｔｉ4Ｓｉ3Ｏ16・ｎＨ2Ｏ及びＫ4Ｔｉ4Ｓｉ3Ｏ16・ｎＨ2Ｏ（これらの式中、ｘは０超１未満の数を示し、ｎは０〜２を示す。）を含有していても良く、（ＮａxＫ(1-x)）4Ｔｉ4Ｓｉ3Ｏ16・ｎＨ2Ｏを含有していても良い。 First, the adsorbent obtained by the production method of the present invention will be described. The cesium and / or strontium adsorbent obtained by the production method of the present invention (hereinafter sometimes simply referred to as “the adsorbent of the present invention”) has a general formula: A 4 Ti 4 Si 3 O 16 · nH 2 O (In the formula, A represents one or two kinds of alkali elements selected from Na and K. n represents a number of 0 to 8.), and the crystalline silicotitanate is contained. Below, this crystalline silicotitanate is also described as GTS (Grace titanium silicate). The above A 4 Ti 4 Si 3 O 16 · nH 2 O has the general formula: Na 4 Ti 4 Si 3 O 16 · nH 2 O, (Na x K (1-x) ) 4 Ti 4 Si 3 O. It may also be expressed as 16 · nH 2 O and K 4 Ti 4 Si 3 O 16 · nH 2 O (wherein x represents a number greater than 0 and less than 1 and n represents a number from 0 to 8). it can. When A contains both Na and K, Na 4 Ti 4 Si 3 O 16 .nH 2 O and K 4 Ti 4 Si 3 O 16 .nH 2 O (where x is a number greater than 0 and less than 1) , And n represents 0 to 2), and may contain (Na x K (1-x) ) 4 Ti 4 Si 3 O 16 .nH 2 O.
本発明の製造方法で得られるセシウム及び／又はストロンチウム吸着剤は、上記一般式におけるＡが、Ｋであるか、Ｎａ及びＫであることが、セシウム及びストロンチウムの吸着性能を高めやすいために好ましい。 In the cesium and / or strontium adsorbent obtained by the production method of the present invention, it is preferable that A in the above general formula is K or Na and K because the adsorption performance of cesium and strontium can be easily enhanced.
本発明の製造方法で得られる吸着剤は、ＧＴＳによるセシウム及び／又はストロンチウムの吸着性能を高く維持する観点から、Ｃｕ−ＫαをＸ線源に用いて回折角（２θ）が５°以上８０°以下の範囲でＸ線回析測定したときに、ＧＴＳの結晶構造に特徴的なピークが観察されることが好ましい。例えば本発明の製造方法で得られる吸着剤は上記走査範囲におけるメーンピークとして、１０°以上１３°以下の範囲にＧＴＳの結晶構造に由来するメーンピークが観察されることが好ましい。 The adsorbent obtained by the production method of the present invention has a diffraction angle (2θ) of 5 ° or more and 80 ° using Cu-Kα as an X-ray source from the viewpoint of maintaining high adsorption performance of cesium and / or strontium by GTS. It is preferable that a peak characteristic of the crystal structure of GTS is observed when X-ray diffraction measurement is performed in the following range. For example, in the adsorbent obtained by the production method of the present invention, it is preferable that a main peak derived from the crystal structure of GTS is observed in the range of 10 ° to 13 ° as the main peak in the above scanning range.
本発明の製造方法で得られる吸着剤は、更に、後述するＧＴＳを含む原料に起因して含有される一般式；Ａ１ ４Ｔｉ９Ｏ２０・ｍＨ２Ｏ（式中、Ａ１はＮａ、Ｋ及びＣｓから選ばれる１種又は２種の金属を示し、ｍは０〜１０の数を示す。）で表されるチタン酸塩を含有していてもよい。 Adsorbent obtained by the process of the present invention, further, the general formula is contained due to the raw material containing GTS to be described later; in A 1 4 Ti 9 O 20 · mH 2 O ( wherein, A 1 is Na, It may contain a titanate represented by 1 or 2 metals selected from K and Cs, and m represents a number of 0 to 10.).
本発明の吸着剤の製造方法は、ＧＴＳを含む原料（以下、「ＧＴＳ含有原料」と言うこともある）を、有機カルボン酸に接触させる酸処理を行い、次いで、得られた酸処理物をアルカリ金属剤に接触させることを特徴の一つとするものである。 In the method for producing an adsorbent of the present invention, a raw material containing GTS (hereinafter sometimes referred to as “GTS-containing raw material”) is subjected to an acid treatment in which it is brought into contact with an organic carboxylic acid, and then the obtained acid-treated product is treated. One of the features is that it is brought into contact with an alkali metal agent.
ＧＴＳ含有原料の好適な製造方法の例を以下説明するが、ＧＴＳ含有原料の製造方法はこれに限定されるものではない。
＜ＧＴＳ含有原料の好適な製造方法＞
本製造方法は、ケイ酸源と、アルカリ金属化合物、四塩化チタン及び水を混合して混合ゲルを製造する第一工程と、第一工程により得られた混合ゲルを水熱反応させる第二工程とを有する。第一工程においてはケイ酸源と、アルカリ金属化合物、四塩化チタン及び水に加えて混合させて混合ゲルを得る。
An example of a suitable method for producing the GTS-containing raw material will be described below, but the method for producing the GTS-containing raw material is not limited to this.
<Preferable method for producing GTS-containing raw material>
The present production method comprises a silicic acid source, a first step of producing a mixed gel by mixing an alkali metal compound, titanium tetrachloride and water, and a second step of hydrothermally reacting the mixed gel obtained in the first step. Have and. In the first step, a silicic acid source, an alkali metal compound, titanium tetrachloride and water are added and mixed to obtain a mixed gel.
第一工程において用いられるケイ酸源としては、例えば、ケイ酸ナトリウム、ケイ酸カリウム等のケイ酸アルカリが挙げられる。また、ケイ酸アルカリ（すなわちケイ酸のアルカリ金属塩）をカチオン交換することにより得られる活性ケイ酸も用いることができる。 Examples of the silicic acid source used in the first step include alkali silicates such as sodium silicate and potassium silicate. Further, active silicic acid obtained by cation exchange of alkali silicate (that is, alkali metal salt of silicic acid) can also be used.
第一工程において用いられるアルカリ金属化合物としては、例えば、ナトリウム、カリウムを含有する化合物である。ナトリウムを含有する化合物としては、水酸化ナトリウム、炭酸ナトリウムが挙げられる。またカリウムを含有する化合物としては、水酸化カリウムや炭酸カリウムが挙げられる。これらの化合物のうち、炭酸塩を用いると炭酸ガスが発生する一方、水酸化物にはそのようなガスの発生がない水酸化物という利点を有する。 The alkali metal compound used in the first step is, for example, a compound containing sodium and potassium. Examples of the compound containing sodium include sodium hydroxide and sodium carbonate. Further, examples of the compound containing potassium include potassium hydroxide and potassium carbonate. Among these compounds, when carbonate is used, carbon dioxide gas is generated, while hydroxide has an advantage that hydroxide does not generate such gas.
第一工程において、下記モル比で表される組成の混合ゲルとなるようにケイ酸源、アルカリ金属化合物、四塩化チタン及び水を混合することが、目的とするＧＴＳの収率を満足すべき程度に高くすることができ、かつＧＴＳ以外の不純物の副生物を抑制できる観点から好ましい。
（ＴｉＯ２）/ＳｉＯ２＝１．２５〜１．６０、好ましくは１．３０〜１．５０ Ａ２Ｏ/ＳｉＯ２＝０．８０〜１．０５、好ましくは０．８５〜１．００ Ｈ２Ｏ/ＳｉＯ２＝６５〜１００、好ましくは７５〜９０。
In the first step, mixing the silicic acid source, the alkali metal compound, titanium tetrachloride and water so that the mixed gel has the composition represented by the following molar ratio should satisfy the target GTS yield. It is preferable from the viewpoint that it can be increased to some extent and that byproducts of impurities other than GTS can be suppressed.
(TiO 2 ) / SiO 2 = 1.25 to 1.60, preferably 1.30 to 1.50 A 2 O / SiO 2 = 0.80 to 1.05, preferably 0.85 to 1.00 H 2 O / SiO 2 = 65-100, preferably 75-90.
なお、ケイ酸源として、ケイ酸ナトリウムやケイ酸カリウム等のケイ酸アルカリを用いた場合には、ケイ酸アルカリに含まれるアルカリ金属成分であるナトリウムやカリウムは同時にＮａＯＨやＫＯＨとみなされ、アルカリ成分でもある。したがって、前記のＡ２Ｏは全てのアルカリ成分の和として計算される。 When an alkali silicate such as sodium silicate or potassium silicate is used as the silicic acid source, sodium and potassium which are alkali metal components contained in the alkali silicate are regarded as NaOH and KOH at the same time, and It is also an ingredient. Therefore, the above A 2 O is calculated as the sum of all alkaline components.
第一工程により得られた混合ゲルは、後述する第二工程である水熱反応を行う前に、０．５時間以上２時間以下の時間にわたり、２０℃以上１００℃以下で熟成を行うことが、均一な生成物を得る点で好ましい。熟成工程は、例えば静置状態で行ってもよく、あるいはラインミキサーなどを用いた撹拌状態で行ってもよい。 The mixed gel obtained in the first step may be aged at 20 ° C. or higher and 100 ° C. or lower for 0.5 hours or longer and 2 hours or shorter before the hydrothermal reaction which is the second step described later. It is preferable in that a uniform product is obtained. The aging step may be performed, for example, in a stationary state or in a stirring state using a line mixer or the like.
本製造方法では、第一工程において得られた前記混合ゲルを、第二工程である水熱反応に付してＧＴＳ含有原料を得る。水熱反応としては、結晶性シリコチタネートが合成できる条件であればよい。通常、オートクレーブ中で好ましくは１２０℃以上２００℃以下、更に好ましくは１４０℃以上１８０℃以下の温度において、好ましくは６時間以上１００時間以下、更に好ましくは１２時間以上８０時間以下の時間にわたって、加圧下に反応させる。 In this manufacturing method, the mixed gel obtained in the first step is subjected to a hydrothermal reaction in the second step to obtain a GTS-containing raw material. The hydrothermal reaction may be carried out under the condition that crystalline silicotitanate can be synthesized. Usually, in an autoclave, the temperature is preferably 120 ° C. or higher and 200 ° C. or lower, more preferably 140 ° C. or higher and 180 ° C. or lower, preferably 6 hours or longer and 100 hours or shorter, and more preferably 12 hours or longer and 80 hours or shorter. React under pressure.
上記で得られるＧＴＳ含有原料には、製造方法に起因して、更に一般式；Ａ１ ４Ｔｉ９Ｏ２０・ｍＨ２Ｏ（式中、Ａ１はＮａ、Ｋ及びＣｓから選ばれる１種又は２種の金属を示し、ｍは０〜１０の数を示す。）で表されるチタン酸塩が含有されていてもよい。 Due to the production method, the GTS-containing raw material obtained above has a general formula; A 1 4 Ti 9 O 20 .mH 2 O (wherein A 1 is one selected from Na, K and Cs, or 2 types of metal are shown, m shows the number of 0-10.) The titanate represented by these may be contained.
得られたＧＴＳ含有原料は粉末状、顆粒状、顆粒以外の成形体（球状、円柱状）等のいずれであってもよい。例えば含水状態のＧＴＳ含有原料を複数の開孔が形成された開孔部材から押出成形して棒状成形体を得、得られた該棒状成形体を乾燥させて柱状にしたり、乾燥させた該棒状成形体を球状に成形したり、解砕又は粉砕して粒子状とすることができる。このような押出成形（押出造粒）のほか、例えば撹拌混合造粒、転動造粒、破砕造粒、流動層造粒、噴霧乾燥造粒（スプレードライ）、圧縮造粒等の各種造粒方法を採用することができる。造粒の過程において必要に応じ、結合剤成分や溶媒を添加してもよい。結合剤成分としては、例えばシリカゾル、アルミナゾル、ジルコニアゾルなどの無機バインダー；ベントナイト、カオリナイトなどの粘土系バインダー；カルボキシメチルセルロース、ヒドロキシエチルセルロースなどのセルロース系バインダー；ポリエチレングリコール、ポリエチレンオキサイドなどの高分子バインダーなどを用いることができる。これらの結合剤成分は１種を単独で、又は２種以上を組み合わせて用いることができる。造粒されたＧＴＳ含有原料に占める結合剤成分の好ましい割合は上述した吸着剤中の結合剤成分の好ましい割合と同様である。溶媒としては、各種の水性溶媒や有機溶媒を用いることができる。 The GTS-containing raw material thus obtained may be in the form of powder, granules, molded bodies other than granules (spherical, cylindrical), or the like. For example, a GTS-containing raw material in a water-containing state is extruded from an opening member having a plurality of openings to obtain a rod-shaped molded body, and the obtained rod-shaped molded body is dried into a columnar shape or the dried rod-shaped body. The molded body can be molded into a spherical shape, or can be crushed or crushed into a particle shape. In addition to such extrusion molding (extrusion granulation), various granulations such as stirring and mixing granulation, tumbling granulation, crushing granulation, fluidized bed granulation, spray drying granulation (spray dry), and compression granulation. The method can be adopted. If necessary, a binder component or a solvent may be added during the granulation process. Examples of the binder component include inorganic binders such as silica sol, alumina sol and zirconia sol; clay-based binders such as bentonite and kaolinite; cellulosic binders such as carboxymethyl cellulose and hydroxyethyl cellulose; polymer binders such as polyethylene glycol and polyethylene oxide. Can be used. These binder components may be used alone or in combination of two or more. The preferable ratio of the binder component in the granulated GTS-containing raw material is the same as the preferable ratio of the binder component in the adsorbent described above. As the solvent, various aqueous solvents and organic solvents can be used.
造粒装置によって造粒された造粒体は、これ乾燥させ、必要に応じて焼成した後、粒度調整を行って次の有機カルボン酸処理に供する。造粒体の形状や大きさは、該造粒体を吸着容器や充填塔に充填した状態で、ストロンチウム及び／又はセシウムを含む処理水を通水するのに適応するように適宜調整することが好ましい。造粒体の大きさに関しては、ＪＩＳ Ｚ８８０１規格による標準フルイによって測定された粒径が好ましくは２００μｍ以上１０００μｍ以下であり、更に好ましくは３００μｍ以上６００μｍ以下である。この範囲の粒径を有する造粒体から得られる吸着剤を用いると、例えば該吸着剤を吸着塔に充填した場合に、目詰まりが起こりにくくなるという利点がある。 The granulated product granulated by the granulating device is dried and, if necessary, calcined, and then subjected to particle size adjustment and subjected to the next organic carboxylic acid treatment. The shape and size of the granule may be appropriately adjusted so as to be suitable for passing treated water containing strontium and / or cesium in a state where the granule is packed in an adsorption container or a packed tower. preferable. Regarding the size of the granulated product, the particle size measured by a standard sieve according to JIS Z8801 standard is preferably 200 μm or more and 1000 μm or less, and more preferably 300 μm or more and 600 μm or less. The use of an adsorbent obtained from a granulated product having a particle size in this range has an advantage that clogging is less likely to occur when the adsorbent is packed in an adsorption tower.
また、ＧＴＳ含有原料は造粒過程に供さずに、粉末状等の未成形体の状態のまま有機カルボン酸及びアルカリ金属剤と接触させてもよい。 Further, the GTS-containing raw material may be brought into contact with the organic carboxylic acid and the alkali metal agent in the state of an unmolded body such as a powder, without being subjected to the granulation process.
ＧＴＳ含有原料を処理する有機カルボン酸としては、クエン酸、リンゴ酸、乳酸、シュウ酸、マロン酸等が挙げられる。これらは１種又は２種以上を組み合わせて用いることができる。中でもクエン酸を用いると、ニオブ溶出量が高く、望ましい低濃度域のストロンチウム吸着性能を有する吸着剤を製造しやすい観点から好ましい。 Examples of the organic carboxylic acid for treating the GTS-containing raw material include citric acid, malic acid, lactic acid, oxalic acid and malonic acid. These can be used alone or in combination of two or more. Among them, citric acid is preferable from the viewpoint of high elution amount of niobium and easy production of an adsorbent having a desired low concentration range of strontium adsorption performance.
有機カルボン酸は溶媒に溶解させて使用することが好ましい。この場合の溶媒としては、水が挙げられる。得られる溶液中の有機カルボン酸の濃度は、望ましいストロンチウム吸着性能を有する吸着剤を効率よく得る観点から０．０５ｍｏｌ／Ｌ以上が好ましい。また溶液中の有機カルボン酸の濃度は、ＧＴＳの過度の溶解を防止するという観点から１ｍｏｌ／Ｌ以下が好ましい。これらの観点から、溶液中の有機カルボン酸の濃度は０．１ｍｏｌ／Ｌ以上０．５ｍｏｌ／Ｌ以下がより一層好ましく、０．１ｍｏｌ／Ｌ以上０．３ｍｏｌ／Ｌ以下が特に好ましい。 The organic carboxylic acid is preferably used by dissolving it in a solvent. The solvent in this case may be water. The concentration of the organic carboxylic acid in the obtained solution is preferably 0.05 mol / L or more from the viewpoint of efficiently obtaining an adsorbent having a desired strontium adsorption performance. Further, the concentration of the organic carboxylic acid in the solution is preferably 1 mol / L or less from the viewpoint of preventing excessive dissolution of GTS. From these viewpoints, the concentration of the organic carboxylic acid in the solution is more preferably 0.1 mol / L or more and 0.5 mol / L or less, and particularly preferably 0.1 mol / L or more and 0.3 mol / L or less.
ＧＴＳ含有原料を有機カルボン酸と接触させる際の有機カルボン酸の温度としては、望ましいストロンチウム吸着性能を有する吸着剤を効率よく得る観点から５℃以上であることが好ましい。またこの時の有機カルボン酸の温度は、高温の酸処理によりＧＴＳの吸着性能を損なうことを防止する観点から、８０℃以下であることが好ましい。これらの観点から有機カルボン酸の温度は１５℃以上６０℃以下がより一層好ましく、２０℃以上５０℃以下が特に好ましい。 The temperature of the organic carboxylic acid when the GTS-containing raw material is brought into contact with the organic carboxylic acid is preferably 5 ° C. or higher from the viewpoint of efficiently obtaining an adsorbent having a desired strontium adsorption performance. The temperature of the organic carboxylic acid at this time is preferably 80 ° C. or lower from the viewpoint of preventing the GTS adsorption performance from being impaired by the high temperature acid treatment. From these viewpoints, the temperature of the organic carboxylic acid is more preferably 15 ° C. or higher and 60 ° C. or lower, and particularly preferably 20 ° C. or higher and 50 ° C. or lower.
ＧＴＳ含有原料を有機カルボン酸と接触させる時間としては、有機カルボン酸の温度が上記範囲であることを前提として、望ましいストロンチウム吸着性能を有する吸着剤を効率よく得る観点から０．５時間以上であることが好ましい。またこの時間は、長時間の酸処理によりＧＴＳの吸着性能を損なうことを防止する観点から、２時間以下であることが好ましい。これらの観点から接触時間は０．５時間以上１．５時間以下がより一層好ましい。 The time for contacting the GTS-containing raw material with the organic carboxylic acid is 0.5 hours or more from the viewpoint of efficiently obtaining an adsorbent having a desirable strontium adsorption performance, assuming that the temperature of the organic carboxylic acid is in the above range. It is preferable. Further, this time is preferably 2 hours or less from the viewpoint of preventing the GTS adsorption performance from being impaired by long-term acid treatment. From these viewpoints, the contact time is more preferably 0.5 hours or more and 1.5 hours or less.
ＧＴＳ含有原料を有機カルボン酸と接触させる方法としては、ＧＴＳ含有原料を有機カルボン酸溶液中に分散させたり、浸漬させたりする方法のほか、ＧＴＳ含有原料に有機カルボン酸溶液をスプレーする方法、あるいはＧＴＳ含有原料をカラムに充填し、有機カルボン酸を溶解した溶液をカラムに通水する方法等が挙げられる。ＧＴＳ含有原料を有機カルボン酸溶液に分散させたり、浸漬させたりする場合には、適宜撹拌を行っても良い。有機カルボン酸溶液に分散させたり、浸漬させたりする場合、得られるスラリー中の吸着剤の濃度を３質量％以上１５質量％以下、特に５質量％以上１０質量％以下とすることが効率よい酸処理のために好ましい。 As the method of contacting the GTS-containing raw material with the organic carboxylic acid, a method of dispersing the GTS-containing raw material in the organic carboxylic acid solution or immersing it, a method of spraying the GTS-containing raw material with the organic carboxylic acid solution, or Examples include a method in which a GTS-containing raw material is packed in a column and a solution in which an organic carboxylic acid is dissolved is passed through the column. When the GTS-containing raw material is dispersed or immersed in the organic carboxylic acid solution, appropriate stirring may be performed. When dispersed or immersed in an organic carboxylic acid solution, it is efficient to adjust the concentration of the adsorbent in the obtained slurry to 3% by mass or more and 15% by mass or less, particularly 5% by mass or more and 10% by mass or less. Preferred for processing.
有機カルボン酸と接触させた酸処理物を、アルカリ金属剤と接触させる。ＧＴＳ中の細孔中に存在するプロトンはストロンチウムと置換しがたい。このため、クエン酸処理後のＧＴＳ含有原料をアルカリ金属剤で処理して、ＧＴＳ中の細孔中に存在するプロトンをストロンチウムと交換可能なアルカリ金属と置換させる必要がある。アルカリ金属剤としては、アルカリ金属水酸化物やアルカリ金属炭酸塩等が挙げられ、特にアルカリ金属水酸化物が価格や取り扱いやすさ（溶解性）の観点から好ましい。アルカリ金属水酸化物の中でも、扱いやすさや価格の観点から水酸化ナトリウムが好ましい。酸処理物は水等で洗浄した後にアルカリ金属剤と接触させることが好ましい。 The acid-treated product brought into contact with the organic carboxylic acid is brought into contact with the alkali metal agent. The protons present in the pores of GTS are difficult to replace with strontium. Therefore, it is necessary to treat the GTS-containing raw material after the citric acid treatment with an alkali metal agent to replace the protons present in the pores of GTS with an alkali metal capable of exchanging strontium. Examples of the alkali metal agents include alkali metal hydroxides and alkali metal carbonates, and alkali metal hydroxides are particularly preferable from the viewpoints of price and ease of handling (solubility). Among the alkali metal hydroxides, sodium hydroxide is preferable from the viewpoint of easy handling and price. The acid-treated product is preferably washed with water or the like and then brought into contact with an alkali metal agent.
アルカリ金属剤は溶媒に溶解させて用いることが好ましく、その場合の溶媒としては、有機カルボン酸を溶解させる溶媒と同様のものを用いることができる。アルカリ金属剤を溶解してなる溶液中のアルカリ金属剤の濃度は、望ましいストロンチウム吸着性能を有する吸着剤を効率よく得る観点から０．１ｍｏｌ／Ｌ以上が好ましい。また溶液中のアルカリ金属剤の濃度は、プロトン置換後の洗浄の容易性の観点から２．０ｍｏｌ／Ｌ以下が好ましい。これらの観点から、溶液中のアルカリ金属剤の濃度は０．２ｍｏｌ／Ｌ以上１．５ｍｏｌ／Ｌ以下がより一層好ましく、０．３ｍｏｌ／Ｌ以上１．０ｍｏｌ／Ｌ以下が特に好ましい。 The alkali metal agent is preferably used by dissolving it in a solvent, and in that case, the same solvent as that for dissolving the organic carboxylic acid can be used. The concentration of the alkali metal agent in the solution prepared by dissolving the alkali metal agent is preferably 0.1 mol / L or more from the viewpoint of efficiently obtaining an adsorbent having a desired strontium adsorption performance. Further, the concentration of the alkali metal agent in the solution is preferably 2.0 mol / L or less from the viewpoint of ease of washing after proton substitution. From these viewpoints, the concentration of the alkali metal agent in the solution is more preferably 0.2 mol / L or more and 1.5 mol / L or less, and particularly preferably 0.3 mol / L or more and 1.0 mol / L or less.
酸処理物をアルカリ金属剤と接触させる際のアルカリ金属剤の温度としては、５℃以上であれば良い。また酸処理物をアルカリ金属剤と接触させる際のアルカリ金属剤の温度は、高温のアルカリ金属剤処理によりＧＴＳの吸着性能を損なうことを防止する観点から、８０℃以下であることが好ましい。これらの観点から前記のアルカリ金属剤の温度は５℃以上５０℃以下がより一層好ましく、５℃以上４０℃以下が特に好ましい。 The temperature of the alkali metal agent when contacting the acid-treated product with the alkali metal agent may be 5 ° C. or higher. The temperature of the alkali metal agent when the acid-treated product is brought into contact with the alkali metal agent is preferably 80 ° C. or lower from the viewpoint of preventing the GTS adsorption performance from being impaired by the high temperature alkali metal agent treatment. From these viewpoints, the temperature of the alkali metal agent is more preferably 5 ° C. or higher and 50 ° C. or lower, and particularly preferably 5 ° C. or higher and 40 ° C. or lower.
酸処理物をアルカリ金属剤と接触させる時間としては、アルカリ金属剤の温度が上記範囲であることを前提として、望ましいストロンチウム吸着性能を有する吸着剤を効率よく得る観点から０．５時間以上であることが好ましい。またこの時間は、長時間のアルカリ金属剤による処理によりＧＴＳの吸着性能を損なうことを防止する観点から、２時間以下であることが好ましい。これらの観点から酸処理物をアルカリ金属剤と接触させる接触時間は０．５時間以上１．５時間以下がより一層好ましい。 The time for contacting the acid-treated product with the alkali metal agent is 0.5 hours or more from the viewpoint of efficiently obtaining an adsorbent having a desired strontium adsorption performance, assuming that the temperature of the alkali metal agent is in the above range. It is preferable. Further, this time is preferably 2 hours or less from the viewpoint of preventing the GTS adsorption performance from being impaired by the long-term treatment with the alkali metal agent. From these viewpoints, the contact time for contacting the acid-treated product with the alkali metal agent is more preferably 0.5 hours or more and 1.5 hours or less.
酸処理物をアルカリ金属剤と接触させる方法としては、酸処理物をアルカリ金属剤の溶液中に分散させたり、浸漬させたりする方法のほか、酸処理物にアルカリ金属剤の溶液をスプレーする方法、あるいは酸処理物をカラムに充填し、アルカリ金属剤を溶解した溶液をカラムに通水する方法等が挙げられる。酸処理物をアルカリ金属剤の溶液に分散させたり、浸漬させたりする場合には、適宜撹拌を行っても良い。酸処理物をアルカリ金属剤溶液に分散させたり、浸漬させたりする場合、得られるスラリー中の吸着剤の濃度を３質量％以上１５質量％以下、特に５質量％以上１０質量％以下とすることが効率よいアルカリ金属剤処理のために好ましい。 As a method of bringing the acid-treated product into contact with the alkali metal agent, a method of dispersing the acid-treated product in the solution of the alkali metal agent or immersing it, or a method of spraying the solution of the alkali metal agent on the acid-treated product Alternatively, a method in which an acid-treated product is packed in a column and a solution in which an alkali metal agent is dissolved is passed through the column can be used. When the acid-treated product is dispersed or dipped in a solution of an alkali metal agent, appropriate stirring may be performed. When the acid-treated product is dispersed or dipped in an alkali metal agent solution, the concentration of the adsorbent in the obtained slurry should be 3% by mass or more and 15% by mass or less, particularly 5% by mass or more and 10% by mass or less. Is preferable for efficient alkali metal agent treatment.
上記のアルカリ金属剤処理後に得られた処理物は、適宜後、ろ過し、乾燥させて使用することができる。乾燥は８０℃以上１５０℃以下で２時間以上１２時間以下行うことが好ましい。 The treated product obtained after the above-mentioned treatment with an alkali metal agent can be used after appropriately filtering and drying. Drying is preferably performed at 80 ° C. or higher and 150 ° C. or lower for 2 hours or more and 12 hours or less.
得られた吸着剤はそのままの状態で用いることができる。また、吸着剤が粉末状等の未成形体である場合は、この後に、上述したＧＴＳ含有材料の造粒過程と同様の造粒過程による造粒を行ってもよい。好ましい造粒体の粒径は、ＧＴＳ含有材料の造粒体の好ましい粒径として上記で述べた粒径と同様である。 The adsorbent obtained can be used as it is. Further, when the adsorbent is an unmolded body such as a powder, granulation may be performed thereafter by the same granulation process as that of the GTS-containing material described above. The preferred particle size of the granulate is similar to the particle size described above as the preferred particle size of the GTS-containing material granulate.
また、本発明の製造方法で得られた吸着剤は、これを例えば不織布などの各種の吸着シートやマットに使用する場合、そのまま粉末状体として材料を加工する際に添加することにより用いられる。不織布に吸着剤を固定する具体的な方法としては、粉末状の吸着剤を、エマルジョン化した樹脂バインダーとともに、水に分散させ、これに、不織布を含浸添着させたのち乾燥する方法が挙げられる。この樹脂バインダーとしては、例えば、ラテックスバインダ、ポリアクリレート、ポリメタクリレート、アクリレートの共重合体、メタクリレートの共重合体、スチレンブタジエン共重合体、スチレンアクリル共重合体、エチレンビニルアセテート共重合体、ニトリルゴム、アクリルニトリルブタジエン共重合体、ポリビニルアルコールなどが挙げられる。不織布としては例えばポリエステル及び／又はポリオレフィン繊維で構成されるものが用いられる。
このように吸着剤を塗布した不織布を、例えば吸着剤を塗布した面を内側にして巻回した形態とすることによっても、水処理に好適に用いることができる。
When the adsorbent obtained by the production method of the present invention is used in various adsorbent sheets or mats such as nonwoven fabrics, the adsorbent is added as it is when the material is processed into a powder form. As a specific method of fixing the adsorbent to the non-woven fabric, there is a method of dispersing the powdery adsorbent together with an emulsified resin binder in water, impregnating and impregnating the non-woven fabric, and then drying. Examples of the resin binder include latex binder, polyacrylate, polymethacrylate, acrylate copolymer, methacrylate copolymer, styrene-butadiene copolymer, styrene-acryl copolymer, ethylene vinyl acetate copolymer, nitrile rubber. , Acrylonitrile-butadiene copolymer, polyvinyl alcohol and the like. As the non-woven fabric, one made of polyester and / or polyolefin fiber is used.
The non-woven fabric coated with the adsorbent as described above can be preferably used for water treatment also by forming the non-woven fabric into a form in which the surface coated with the adsorbent is wound inside.
上述したセシウム又は／及びストロンチウム吸着剤の製造方法によって得られる顆粒状の吸着剤や粉末状体として不織布に固定させた吸着剤は、放射性物質吸着剤を充填してなる吸着容器及び吸着塔を有する水処理システムの吸着剤として好適に使用することができる。特に、本発明の製造方法で得られた吸着剤はストロンチウムが低濃度である液におけるストロンチウム吸着性能に優れたものである。ここでいう低濃度とは、本発明の製造方法で得られた吸着剤の性能を充分に発揮する観点、及び、求められる用途に対応する観点から、吸着対象の液中のストロンチウムが０．０１ｐｐｍ以上１０ｐｐｍ以下であることが好ましく、０．０５ｐｐｍ以上５ｐｐｍ以下であることがより好ましく、０．１ｐｐｍ以上５ｐｐｍ以下であることが特に好ましい。 A granular adsorbent obtained by the method for producing a cesium and / or strontium adsorbent described above or an adsorbent fixed to a nonwoven fabric as a powdery body has an adsorption container and an adsorption tower filled with a radioactive substance adsorbent. It can be suitably used as an adsorbent for a water treatment system. In particular, the adsorbent obtained by the production method of the present invention has excellent strontium adsorption performance in a liquid having a low concentration of strontium. The low concentration here means that the strontium in the liquid to be adsorbed is 0.01 ppm from the viewpoint of sufficiently exhibiting the performance of the adsorbent obtained by the production method of the present invention, and from the viewpoint of meeting the required application. It is preferably 10 ppm or more and 10 ppm or less, more preferably 0.05 ppm or more and 5 ppm or less, and particularly preferably 0.1 ppm or more and 5 ppm or less.
以下に、実施例及び比較例により本発明を具体的に説明するが、本発明はこれらに限定されるものではない。特に断らない限り「％」は「質量％」を表す。実施例及び比較例で使用した評価装置及び評価方法並びに使用材料は以下のとおりである。 Hereinafter, the present invention will be specifically described with reference to Examples and Comparative Examples, but the present invention is not limited thereto. Unless otherwise specified, “%” represents “mass%”. The evaluation devices and evaluation methods used in the examples and comparative examples, and the materials used are as follows.
＜評価装置及び評価方法＞
・Ｘ線回折：Ｂｒｕｋｅｒ社 Ｄ８ ＡｄｖａｎｃｅＳを用いた。線源としてＣｕ−Ｋαを用いた。測定条件は、管電圧４０ｋＶ、管電流４０ｍＡ、走査速度０．１°／ｓｅｃとした。
・ＩＣＰ−ＡＥＳ：Ｖａｒｉａｎ社７２０−ＥＳを用いた。Ｓｒの測定波長は２１６．５９６ｎｍとしてＳｒの吸着試験を行った。標準試料はＮａＣｌを０．３％含有したＣｓ：１００ｐｐｍ、５０ｐｐｍ及び１０ｐｐｍの水溶液、並びにＮａＣｌを０．３％含有したＳｒ：１００ｐｐｍ、１０ｐｐｍ及び１ｐｐｍの水溶液を使用した。
・ＸＲＦ：蛍光Ｘ線装置（装置名：ＺＳＸ１００ｅ、管球：Ｒｈ（４ｋＷ）、雰囲気：真空、分析窓：Ｂｅ（３０μｍ）、測定モード：ＳＱＸ分析（ＥＺスキャン）、測定径：３０ｍｍφ、（株）リガク製）で全元素測定した。測定用試料は、適当な容器（アルミリング等）に入れ、ダイスで挟みこんでからプレス機で１０ＭＰａの圧力をかけてペレット化することにより得た。
<Evaluation device and evaluation method>
X-ray diffraction: D8 AdvanceS manufactured by Bruker was used. Cu-Kα was used as the radiation source. The measurement conditions were a tube voltage of 40 kV, a tube current of 40 mA, and a scanning speed of 0.1 ° / sec.
-ICP-AES: Varian 720-ES was used. The measurement wavelength of Sr was 216.5596 nm, and an Sr adsorption test was conducted. As standard samples, Cs containing 0.3% of NaCl: 100 ppm, 50 ppm and 10 ppm aqueous solution, and Sr containing 0.3% of NaCl: 100 ppm, 10 ppm and 1 ppm aqueous solution were used.
XRF: fluorescent X-ray device (device name: ZSX100e, tube: Rh (4 kW), atmosphere: vacuum, analysis window: Be (30 μm), measurement mode: SQX analysis (EZ scan), measurement diameter: 30 mmφ, (stock ) Made by Rigaku Co., Ltd. The sample for measurement was obtained by putting it in an appropriate container (aluminum ring or the like), sandwiching it with a die, and then pelletizing it by applying a pressure of 10 MPa with a pressing machine.
＜使用材料＞
・３号ケイ酸ソーダ：日本化学工業株式会社製（ＳｉＯ2：２８．５％、Ｎａ2Ｏ：９．２％、Ｈ2Ｏ：６２．３％、ＳｉＯ2／Ｎａ2Ｏ＝３．１）。
・２５％液体苛性ソーダ：工業用２５％水酸化ナトリウム（ＮａＯＨ：２５％、Ｈ2Ｏ：７５％）。
・四塩化チタン水溶液：株式会社大阪チタニウムテクノロジーズ社製３６．４８％水溶液
・８５％苛性カリ：固体試薬 水酸化カリウム（ＫＯＨ：８５％）
・ケイ酸カリ：日本化学工業株式会社製（ＳｉＯ２：２６．５％、Ｋ２Ｏ：１３．５％、Ｈ２Ｏ：６０．０％
・模擬海水１：Ｓｒ及びＣｓをそれぞれ１００ｐｐｍ含有した０．３％ＮａＣｌ水溶液を模擬海水とした。模擬海水は、ＮａＣｌ（９９．５％）：３．０１５１ｇ、ＳｒＣｌ・６Ｈ２Ｏ（９９％）：０．３０７４ｇ、ＣｓＮＯ３（９９％）：０．１４８１ｇ、Ｈ２Ｏ：９９６．５２９４ｇを混合して得た。
・模擬海水２：人工海水（富田製薬製「マリンアート」１ｋｇをイオン交換水２５Ｌに溶解したもの）を１／２０に希釈し、Ｓｒを３ｐｐｍ、Ｃｓを１０ｐｐｍ含有した水溶液を模擬海水とした。
<Materials used>
・ No. 3 sodium silicate: manufactured by Nippon Kagaku Kogyo Co., Ltd. (SiO 2 : 28.5%, Na 2 O: 9.2%, H 2 O: 62.3%, SiO 2 / Na 2 O = 3.1) ).
25% liquid caustic soda: industrial 25% sodium hydroxide (NaOH: 25%, H 2 O: 75%).
・ Titanium tetrachloride aqueous solution: Osaka Titanium Technologies Co., Ltd. 36.48% aqueous solution ・ 85% caustic potash: solid reagent potassium hydroxide (KOH: 85%)
- potassium silicate: manufactured by Nippon Chemical Industrial Co., Ltd. (SiO 2: 26.5%, K 2 O: 13.5%, H 2 O: 60.0%
Simulated sea water 1: A 0.3% NaCl aqueous solution containing 100 ppm each of Sr and Cs was used as simulated sea water. The simulated seawater was mixed with NaCl (99.5%): 3.0151 g, SrCl.6H 2 O (99%): 0.3074 g, CsNO 3 (99%): 0.1481 g, and H 2 O: 996.5294 g. I got it.
Simulated seawater 2: Artificial seawater (1 kg of "Marine Art" manufactured by Tomita Pharmaceutical Co., Ltd. dissolved in 25 L of ion-exchanged water) was diluted to 1/20, and an aqueous solution containing 3 ppm of Sr and 10 ppm of Cs was used as simulated seawater.
〔比較例１〕
（１）第一工程
ケイ酸カリ６４．５ｇ、８５％苛性カリ１２６．７ｇ及びイオン交換水２１０．２ｇを混合し撹拌して混合水溶液を得た。この混合水溶液に、四塩化チタン水溶液２０３．３ｇをペリスタポンプで３０分にわたって連続的に添加して混合ゲルを製造した。当該混合ゲルは、四塩化チタン水溶液の添加後、１時間にわたり７０℃で混合して熟成した。
[Comparative Example 1]
(1) First Step 64.5 g of potassium silicate, 126.7 g of 85% potassium hydroxide and 210.2 g of ion-exchanged water were mixed and stirred to obtain a mixed aqueous solution. 203.3 g of an aqueous titanium tetrachloride solution was continuously added to this mixed aqueous solution for 30 minutes by a peristaltic pump to produce a mixed gel. The mixed gel was aged at 70 ° C. for 1 hour after the addition of the titanium tetrachloride aqueous solution.
（２）第二工程
第一工程で得られた混合ゲルをオートクレーブに入れ、１．５時間かけて１７０℃に昇温したのち、この温度を維持しながら静置下に７２時間反応を行った。反応後のスラリーをろ過し、得られたケーキを直径０．６μｍの円形の開孔部材で押出成形した後、乾燥し、分級して粒度が３００μｍ以上６００μｍ以下の粒状物を得た。
(2) Second step The mixed gel obtained in the first step was placed in an autoclave, heated to 170 ° C over 1.5 hours, and then allowed to stand for 72 hours while maintaining this temperature. . After the reaction, the slurry was filtered, and the obtained cake was extrusion-molded with a circular aperture member having a diameter of 0.6 μm, dried and classified to obtain granules having a particle size of 300 μm or more and 600 μm or less.
〔実施例１〕
比較例１で得られた粒状物を、０．１ｍｏｌ／Ｌクエン酸水溶液に分散させ、これを５０℃で２時間撹拌した。スラリー中の粒状物の濃度は５．０％とした。クエン酸処理終了後、粒状物をイオン交換水で置換洗浄したのち、１．０ｍｏｌ／Ｌ苛性カリ水溶液に分散させ、常温（２５℃）で１時間撹拌した。スラリー中の粒状物の濃度は５．０％とした。終了後に粒状物をイオン交換水で置換洗浄したのち、ろ過し、１１０℃で３時間乾燥後、フルイで分級して粒度が３００μｍ以上６００μｍ以下の粒状物を得た。
[Example 1]
The granular material obtained in Comparative Example 1 was dispersed in a 0.1 mol / L aqueous citric acid solution, and this was stirred at 50 ° C. for 2 hours. The concentration of the particulate matter in the slurry was 5.0%. After the citric acid treatment was completed, the particulate matter was replaced and washed with ion-exchanged water, dispersed in a 1.0 mol / L aqueous potassium hydroxide solution, and stirred at room temperature (25 ° C.) for 1 hour. The concentration of the particulate matter in the slurry was 5.0%. After the completion, the particulate matter was replaced and washed with ion-exchanged water, filtered, dried at 110 ° C. for 3 hours, and then classified with a sieve to obtain a particulate matter having a particle size of 300 μm or more and 600 μm or less.
〔比較例２〕
比較例１で得られた粒状物を、クエン酸水溶液の代わりに、イオン交換水に分散させた以外は、実施例1と同様にして粒状物を得た。
[Comparative Example 2]
A granular material was obtained in the same manner as in Example 1 except that the granular material obtained in Comparative Example 1 was dispersed in ion-exchanged water instead of the citric acid aqueous solution.
〔比較例３〕
（１）第一工程
３号ケイ酸ソーダ６０ｇ、苛性ソーダ水溶液２２４．３ｇ、８５％苛性カリ３４．６ｇ及びイオン交換水８２．５ｇを混合し撹拌して混合水溶液を得た。この混合水溶液に、四塩化チタン水溶液２０３．３ｇをペリスタポンプで０．５時間にわたって連続的に添加して混合ゲルを製造した。当該混合ゲルは、四塩化チタン水溶液の添加後、１時間にわたり室温（２５℃）で静置熟成した。
[Comparative Example 3]
(1) First Step 60 g of No. 3 sodium silicate, 224.3 g of an aqueous solution of caustic soda, 34.6 g of 85% caustic potash and 82.5 g of ion-exchanged water were mixed and stirred to obtain a mixed aqueous solution. 203.3 g of titanium tetrachloride aqueous solution was continuously added to this mixed aqueous solution by a peristaltic pump over 0.5 hours to produce a mixed gel. The mixed gel was allowed to stand and age at room temperature (25 ° C.) for 1 hour after the addition of the titanium tetrachloride aqueous solution.
（２）第二工程
第一工程で得られた混合ゲルをオートクレーブに入れ、１時間かけて１７０℃に昇温したのち、この温度を維持しながら撹拌下に９６時間反応を行った。反応後のスラリーをろ過し、得られたケーキを直径０．６μｍの円形の開孔部材で押出成形した後、乾燥し、分級して粒度が３００μｍ以上６００μｍ以下の粒状物を得た。
(2) Second Step The mixed gel obtained in the first step was placed in an autoclave and heated to 170 ° C. over 1 hour, and then the reaction was carried out for 96 hours while stirring while maintaining this temperature. After the reaction, the slurry was filtered, and the obtained cake was extrusion-molded with a circular aperture member having a diameter of 0.6 μm, dried and classified to obtain granules having a particle size of 300 μm or more and 600 μm or less.
〔実施例２〕
比較例３で得られた粒状物を、０．１ｍｏｌ／Ｌクエン酸水溶液に分散させ、これを５０℃で１時間撹拌した。スラリー中の粒状物の濃度は５％とした。クエン酸処理終了後、粒状物をイオン交換水で置換洗浄したのち、１ｍｏｌ／Ｌ苛性ソーダ水溶液に分散させ、常温（２５℃）で１時間撹拌した。スラリー中の粒状物の濃度は５％とした。終了後に粒状物をイオン交換水で置換洗浄したのち、ろ過し、１１０℃で３時間乾燥後、フルイで分級して粒度が３００μｍ以上６００μｍ以下の粒状物を得た。
[Example 2]
The granular material obtained in Comparative Example 3 was dispersed in a 0.1 mol / L citric acid aqueous solution, and this was stirred at 50 ° C. for 1 hour. The concentration of the particulate matter in the slurry was 5%. After the completion of the citric acid treatment, the particulate matter was replaced and washed with ion-exchanged water, dispersed in a 1 mol / L caustic soda aqueous solution, and stirred at room temperature (25 ° C.) for 1 hour. The concentration of the particulate matter in the slurry was 5%. After the completion, the particulate matter was replaced and washed with ion-exchanged water, filtered, dried at 110 ° C. for 3 hours, and then classified with a sieve to obtain a particulate matter having a particle size of 300 μm or more and 600 μm or less.
比較例１〜３、実施例１及び２で得られた粒状物を以下（１）〜（３）の評価に供した。
〔評価〕
（１）Ｘ線回折測定を行った。比較例１及び３、並びに実施例１及び２の粒状物より得られたＸ線回折チャートをそれぞれ、図１及び図２に示す。
The granular materials obtained in Comparative Examples 1 to 3 and Examples 1 and 2 were subjected to the following evaluations (1) to (3).
[Evaluation]
(1) X-ray diffraction measurement was performed. The X-ray diffraction charts obtained from the granular materials of Comparative Examples 1 and 3 and Examples 1 and 2 are shown in FIGS. 1 and 2, respectively.
（２）組成分析
比較例１〜３、実施例１及び２の粒状物中のＫ２Ｏ、Ｎａ２Ｏ、ＳｉＯ２及びＴｉＯ２の含有量（質量％）を上記条件のＸＲＦにて、半定量分析法であるＳＱＸ法で計算することで算出した。この算出したＫ２Ｏ、Ｎａ２Ｏ、ＳｉＯ２及びＴｉＯ２の含有量をもとに、ＳｉＯ２／ＴｉＯ２及びＡ２Ｏ／ＳｉＯ２を求めた。結果を表１に示す。
（３）上記（１）のＸ線回折チャート及び上記の（２）の組成分析から判断される組成を表１に示す。
(2) Composition analysis The content (mass%) of K 2 O, Na 2 O, SiO 2 and TiO 2 in the granular materials of Comparative Examples 1 to 3 and Examples 1 and 2 was measured by XRF under the above conditions. It was calculated by the SQX method, which is a quantitative analysis method. Based on the calculated contents of K 2 O, Na 2 O, SiO 2 and TiO 2 , SiO 2 / TiO 2 and A 2 O / SiO 2 were obtained. The results are shown in Table 1.
(3) Table 1 shows the composition judged from the X-ray diffraction chart of the above (1) and the composition analysis of the above (2).
比較例１〜３、実施例１及び２で得られた粒状物を以下の＜Ｃｓ及びＳｒバッチ吸着試験＞に供した。
＜Ｃｓ及びＳｒバッチ吸着試験＞
粒状物を、１００ｍｌのポリ容器に０．５ｇ取り、上記模擬海水１（１００．００ｇ）を添加し、蓋をした後、内容物を振り混ぜた。内容物の振り混ぜは、ポリ容器の倒立を１０回行うことにより行った。その後、静置して２４時間経過した後、再び内容物を振り混ぜ、５Ｃのろ紙でろ過し、ろ過によって得られたろ液を採取した。
。採取されたろ液を対象として、ＩＣＰ−ＡＥＳを用い、ろ液中のＣｓ及びＳｒの含有量を測定した。その結果を以下の表２に示す。
The granular materials obtained in Comparative Examples 1 to 3 and Examples 1 and 2 were subjected to the following <Cs and Sr batch adsorption test>.
<Cs and Sr batch adsorption test>
0.5 g of the granular material was placed in a 100 ml plastic container, the above-mentioned simulated seawater 1 (100.00 g) was added, and after covering the lid, the contents were shaken and mixed. The contents were shaken by inverting the plastic container 10 times. Then, after standing still for 24 hours, the contents were shaken again and filtered with 5C filter paper, and the filtrate obtained by filtration was collected.
. The content of Cs and Sr in the filtrate was measured for the collected filtrate using ICP-AES. The results are shown in Table 2 below.
また比較例１〜３、実施例１〜２で得られた粒状物を以下の＜Ｓｒカラム吸着試験＞に供した。
＜Ｓｒカラム吸着試験＞
カラムとして内径φ１２ｍｍのものを用いた。このカラムに高さが４．５ｃｍ（容積５ｍｌ）となるように、吸着剤試料を充填した。カラムに、上記模擬海水２を通液した。通液流量は、１６．７（ｍｌ／ｍｉｎ）、ＬＶ＝８．９（ｍ／ｈ）、ＳＶ＝２００（１／ｈ）とした。定期的にサンプリングした試験液におけるストロンチウム濃度をＩＣＰ−ＡＥＳにて測定し、初期ストロンチウム濃度Ｃｏに対する通液後ストロンチウム濃度Ｃの比率（Ｃｏ／Ｃ）を求めた。縦軸にＣ／Ｃｏで表される数値を示し、横軸に前記の容量５ｍｌに対する模擬海水の総通液容量（Ｂ．Ｖ．）を示したものを図３及び図４に示す。
Further, the granular materials obtained in Comparative Examples 1 to 3 and Examples 1 and 2 were subjected to the following <Sr column adsorption test>.
<Sr column adsorption test>
A column having an inner diameter of 12 mm was used. The adsorbent sample was packed in the column so that the height was 4.5 cm (volume 5 ml). The simulated seawater 2 was passed through the column. The flow rate was 16.7 (ml / min), LV = 8.9 (m / h), and SV = 200 (1 / h). The strontium concentration in the test liquid sampled periodically was measured by ICP-AES, and the ratio (Co / C) of the strontium concentration C after passing to the initial strontium concentration Co was determined. 3 and 4 show the numerical value represented by C / Co on the vertical axis and the total flow-through volume (BV) of simulated seawater for the above-mentioned volume of 5 ml on the horizontal axis.
表２に示すように、Ｓｒ及びＣｓを高濃度で含有する模擬海水１を用いて行ったバッチ試験では、各実施例で得られたＧＴＳは比較例のＧＴＳと同程度のレベルでＳｒ及びＣｓを吸着できることが判る。一方、Ｓｒが低濃度の模擬海水２を用いて行ったカラム試験では、図３及び図４に示すように、ＧＴＳを含有し且つＴｉ溶出量が特定量以下の実施例１及び２の吸着剤は、溶出量が特定量超の比較例１〜３の吸着剤に比べ、低濃度におけるストロンチウム吸着能が大幅に高いことが判る。 As shown in Table 2, in the batch test performed using the simulated seawater 1 containing high concentrations of Sr and Cs, the GTSs obtained in each Example were at the same level as the GTSs of the Comparative Examples. It is understood that can be adsorbed. On the other hand, in the column test conducted using the simulated seawater 2 having a low concentration of Sr, as shown in FIGS. 3 and 4, the adsorbents of Examples 1 and 2 containing GTS and having a Ti elution amount of not more than a specific amount. In comparison with the adsorbents of Comparative Examples 1 to 3 in which the elution amount exceeds a specific amount, the strontium adsorption capacity at a low concentration is significantly higher.
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