JP7400716B2 - Inorganic ion exchanger and its manufacturing method, and method for purifying water containing radioactive strontium - Google Patents
Inorganic ion exchanger and its manufacturing method, and method for purifying water containing radioactive strontium Download PDFInfo
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- JP7400716B2 JP7400716B2 JP2020531334A JP2020531334A JP7400716B2 JP 7400716 B2 JP7400716 B2 JP 7400716B2 JP 2020531334 A JP2020531334 A JP 2020531334A JP 2020531334 A JP2020531334 A JP 2020531334A JP 7400716 B2 JP7400716 B2 JP 7400716B2
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- JP
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- Prior art keywords
- ion exchanger
- inorganic ion
- alkali metal
- powder
- strontium
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
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- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 title claims description 99
- 229910001410 inorganic ion Inorganic materials 0.000 title claims description 90
- 229910001868 water Inorganic materials 0.000 title claims description 84
- 229910052712 strontium Inorganic materials 0.000 title claims description 66
- CIOAGBVUUVVLOB-UHFFFAOYSA-N strontium atom Chemical compound [Sr] CIOAGBVUUVVLOB-UHFFFAOYSA-N 0.000 title claims description 66
- 238000000034 method Methods 0.000 title claims description 26
- 230000002285 radioactive effect Effects 0.000 title claims description 25
- 238000004519 manufacturing process Methods 0.000 title claims description 18
- 239000000843 powder Substances 0.000 claims description 74
- 229910000288 alkali metal carbonate Inorganic materials 0.000 claims description 43
- 150000008041 alkali metal carbonates Chemical class 0.000 claims description 43
- RTAQQCXQSZGOHL-UHFFFAOYSA-N Titanium Chemical compound [Ti] RTAQQCXQSZGOHL-UHFFFAOYSA-N 0.000 claims description 37
- 229910052783 alkali metal Inorganic materials 0.000 claims description 35
- -1 alkali metal hydrogen carbonates Chemical class 0.000 claims description 32
- 238000000634 powder X-ray diffraction Methods 0.000 claims description 19
- 238000001179 sorption measurement Methods 0.000 claims description 19
- 239000007864 aqueous solution Substances 0.000 claims description 13
- 229910052751 metal Inorganic materials 0.000 claims description 13
- 239000002184 metal Substances 0.000 claims description 13
- 150000003609 titanium compounds Chemical class 0.000 claims description 13
- GWEVSGVZZGPLCZ-UHFFFAOYSA-N Titan oxide Chemical compound O=[Ti]=O GWEVSGVZZGPLCZ-UHFFFAOYSA-N 0.000 claims description 11
- 239000010936 titanium Substances 0.000 claims description 11
- 238000005406 washing Methods 0.000 claims description 11
- 238000009826 distribution Methods 0.000 claims description 10
- 229910052700 potassium Inorganic materials 0.000 claims description 9
- 150000001875 compounds Chemical class 0.000 claims description 7
- 238000001035 drying Methods 0.000 claims description 7
- 229910052744 lithium Inorganic materials 0.000 claims description 7
- 239000002253 acid Substances 0.000 claims description 6
- 229910052936 alkali metal sulfate Inorganic materials 0.000 claims description 5
- 229910052708 sodium Inorganic materials 0.000 claims description 5
- OGIDPMRJRNCKJF-UHFFFAOYSA-N titanium oxide Inorganic materials [Ti]=O OGIDPMRJRNCKJF-UHFFFAOYSA-N 0.000 claims description 5
- 229910010413 TiO 2 Inorganic materials 0.000 claims description 4
- 238000002156 mixing Methods 0.000 claims description 4
- 229910052719 titanium Inorganic materials 0.000 claims description 3
- 239000013078 crystal Substances 0.000 description 38
- LLZRNZOLAXHGLL-UHFFFAOYSA-J titanic acid Chemical compound O[Ti](O)(O)O LLZRNZOLAXHGLL-UHFFFAOYSA-J 0.000 description 24
- 238000004458 analytical method Methods 0.000 description 19
- 239000000203 mixture Substances 0.000 description 18
- 239000004570 mortar (masonry) Substances 0.000 description 18
- 239000008367 deionised water Substances 0.000 description 15
- 229910021641 deionized water Inorganic materials 0.000 description 15
- 238000005259 measurement Methods 0.000 description 14
- BWHMMNNQKKPAPP-UHFFFAOYSA-L potassium carbonate Chemical compound [K+].[K+].[O-]C([O-])=O BWHMMNNQKKPAPP-UHFFFAOYSA-L 0.000 description 14
- 238000006243 chemical reaction Methods 0.000 description 13
- 230000000052 comparative effect Effects 0.000 description 12
- 238000001644 13C nuclear magnetic resonance spectroscopy Methods 0.000 description 11
- 229910052799 carbon Inorganic materials 0.000 description 11
- 229910052739 hydrogen Inorganic materials 0.000 description 11
- 239000000047 product Substances 0.000 description 11
- MWEXRLZUDANQDZ-RPENNLSWSA-N (2s)-3-hydroxy-n-[11-[4-[4-[4-[11-[[2-[4-[(2r)-2-hydroxypropyl]triazol-1-yl]acetyl]amino]undecanoyl]piperazin-1-yl]-6-[2-[2-(2-prop-2-ynoxyethoxy)ethoxy]ethylamino]-1,3,5-triazin-2-yl]piperazin-1-yl]-11-oxoundecyl]-2-[4-(3-methylsulfanylpropyl)triazol-1-y Chemical compound N1=NC(CCCSC)=CN1[C@@H](CO)C(=O)NCCCCCCCCCCC(=O)N1CCN(C=2N=C(N=C(NCCOCCOCCOCC#C)N=2)N2CCN(CC2)C(=O)CCCCCCCCCCNC(=O)CN2N=NC(C[C@@H](C)O)=C2)CC1 MWEXRLZUDANQDZ-RPENNLSWSA-N 0.000 description 10
- CURLTUGMZLYLDI-UHFFFAOYSA-N Carbon dioxide Chemical compound O=C=O CURLTUGMZLYLDI-UHFFFAOYSA-N 0.000 description 10
- 238000005469 granulation Methods 0.000 description 10
- 230000003179 granulation Effects 0.000 description 10
- 238000010438 heat treatment Methods 0.000 description 10
- 238000012360 testing method Methods 0.000 description 10
- 238000001107 thermogravimetry coupled to mass spectrometry Methods 0.000 description 10
- CDBYLPFSWZWCQE-UHFFFAOYSA-L Sodium Carbonate Chemical compound [Na+].[Na+].[O-]C([O-])=O CDBYLPFSWZWCQE-UHFFFAOYSA-L 0.000 description 8
- PNEYBMLMFCGWSK-UHFFFAOYSA-N aluminium oxide Inorganic materials [O-2].[O-2].[O-2].[Al+3].[Al+3] PNEYBMLMFCGWSK-UHFFFAOYSA-N 0.000 description 8
- 239000010410 layer Substances 0.000 description 8
- 239000007789 gas Substances 0.000 description 7
- 239000011229 interlayer Substances 0.000 description 7
- 229910000027 potassium carbonate Inorganic materials 0.000 description 7
- 235000011181 potassium carbonates Nutrition 0.000 description 7
- OTYBMLCTZGSZBG-UHFFFAOYSA-L potassium sulfate Chemical compound [K+].[K+].[O-]S([O-])(=O)=O OTYBMLCTZGSZBG-UHFFFAOYSA-L 0.000 description 7
- 229910052939 potassium sulfate Inorganic materials 0.000 description 7
- 235000011151 potassium sulphates Nutrition 0.000 description 7
- 239000000941 radioactive substance Substances 0.000 description 7
- 150000001340 alkali metals Chemical class 0.000 description 6
- 150000002500 ions Chemical class 0.000 description 6
- XGZVUEUWXADBQD-UHFFFAOYSA-L lithium carbonate Chemical compound [Li+].[Li+].[O-]C([O-])=O XGZVUEUWXADBQD-UHFFFAOYSA-L 0.000 description 6
- 239000011734 sodium Substances 0.000 description 6
- ZLMJMSJWJFRBEC-UHFFFAOYSA-N Potassium Chemical compound [K] ZLMJMSJWJFRBEC-UHFFFAOYSA-N 0.000 description 5
- 239000001569 carbon dioxide Substances 0.000 description 5
- 229910002092 carbon dioxide Inorganic materials 0.000 description 5
- 238000005342 ion exchange Methods 0.000 description 5
- 229960003975 potassium Drugs 0.000 description 5
- 239000011591 potassium Substances 0.000 description 5
- UIIMBOGNXHQVGW-UHFFFAOYSA-M Sodium bicarbonate Chemical compound [Na+].OC([O-])=O UIIMBOGNXHQVGW-UHFFFAOYSA-M 0.000 description 4
- 239000003463 adsorbent Substances 0.000 description 4
- 238000005119 centrifugation Methods 0.000 description 4
- NJLLQSBAHIKGKF-UHFFFAOYSA-N dipotassium dioxido(oxo)titanium Chemical compound [K+].[K+].[O-][Ti]([O-])=O NJLLQSBAHIKGKF-UHFFFAOYSA-N 0.000 description 4
- 238000005192 partition Methods 0.000 description 4
- 239000002901 radioactive waste Substances 0.000 description 4
- 229910052701 rubidium Inorganic materials 0.000 description 4
- 238000003756 stirring Methods 0.000 description 4
- BVKZGUZCCUSVTD-UHFFFAOYSA-L Carbonate Chemical compound [O-]C([O-])=O BVKZGUZCCUSVTD-UHFFFAOYSA-L 0.000 description 3
- WHXSMMKQMYFTQS-UHFFFAOYSA-N Lithium Chemical compound [Li] WHXSMMKQMYFTQS-UHFFFAOYSA-N 0.000 description 3
- OKKJLVBELUTLKV-UHFFFAOYSA-N Methanol Chemical compound OC OKKJLVBELUTLKV-UHFFFAOYSA-N 0.000 description 3
- HEMHJVSKTPXQMS-UHFFFAOYSA-M Sodium hydroxide Chemical compound [OH-].[Na+] HEMHJVSKTPXQMS-UHFFFAOYSA-M 0.000 description 3
- 229910052792 caesium Inorganic materials 0.000 description 3
- 239000008187 granular material Substances 0.000 description 3
- 239000011736 potassium bicarbonate Substances 0.000 description 3
- 229910000028 potassium bicarbonate Inorganic materials 0.000 description 3
- 235000015497 potassium bicarbonate Nutrition 0.000 description 3
- TYJJADVDDVDEDZ-UHFFFAOYSA-M potassium hydrogencarbonate Chemical compound [K+].OC([O-])=O TYJJADVDDVDEDZ-UHFFFAOYSA-M 0.000 description 3
- 229940086066 potassium hydrogencarbonate Drugs 0.000 description 3
- GROMGGTZECPEKN-UHFFFAOYSA-N sodium metatitanate Chemical compound [Na+].[Na+].[O-][Ti](=O)O[Ti](=O)O[Ti]([O-])=O GROMGGTZECPEKN-UHFFFAOYSA-N 0.000 description 3
- 239000000243 solution Substances 0.000 description 3
- 239000000126 substance Substances 0.000 description 3
- 239000012085 test solution Substances 0.000 description 3
- 239000004408 titanium dioxide Substances 0.000 description 3
- XJDNKRIXUMDJCW-UHFFFAOYSA-J titanium tetrachloride Chemical compound Cl[Ti](Cl)(Cl)Cl XJDNKRIXUMDJCW-UHFFFAOYSA-J 0.000 description 3
- KRHYYFGTRYWZRS-UHFFFAOYSA-N Fluorane Chemical compound F KRHYYFGTRYWZRS-UHFFFAOYSA-N 0.000 description 2
- GRYLNZFGIOXLOG-UHFFFAOYSA-N Nitric acid Chemical compound O[N+]([O-])=O GRYLNZFGIOXLOG-UHFFFAOYSA-N 0.000 description 2
- 239000004115 Sodium Silicate Substances 0.000 description 2
- 229910021536 Zeolite Inorganic materials 0.000 description 2
- MCMNRKCIXSYSNV-UHFFFAOYSA-N Zirconium dioxide Chemical compound O=[Zr]=O MCMNRKCIXSYSNV-UHFFFAOYSA-N 0.000 description 2
- 230000015572 biosynthetic process Effects 0.000 description 2
- 235000012241 calcium silicate Nutrition 0.000 description 2
- 229910052918 calcium silicate Inorganic materials 0.000 description 2
- OYACROKNLOSFPA-UHFFFAOYSA-N calcium;dioxido(oxo)silane Chemical compound [Ca+2].[O-][Si]([O-])=O OYACROKNLOSFPA-UHFFFAOYSA-N 0.000 description 2
- 239000003729 cation exchange resin Substances 0.000 description 2
- 229940023913 cation exchange resins Drugs 0.000 description 2
- 238000007796 conventional method Methods 0.000 description 2
- 238000012937 correction Methods 0.000 description 2
- 230000018044 dehydration Effects 0.000 description 2
- 238000006297 dehydration reaction 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
- 230000000694 effects Effects 0.000 description 2
- 238000011049 filling Methods 0.000 description 2
- 229910001385 heavy metal Inorganic materials 0.000 description 2
- 238000007602 hot air drying Methods 0.000 description 2
- 239000007788 liquid Substances 0.000 description 2
- 229910052808 lithium carbonate Inorganic materials 0.000 description 2
- 229910000032 lithium hydrogen carbonate Inorganic materials 0.000 description 2
- HQRPHMAXFVUBJX-UHFFFAOYSA-M lithium;hydrogen carbonate Chemical compound [Li+].OC([O-])=O HQRPHMAXFVUBJX-UHFFFAOYSA-M 0.000 description 2
- 229910017604 nitric acid Inorganic materials 0.000 description 2
- DCKVFVYPWDKYDN-UHFFFAOYSA-L oxygen(2-);titanium(4+);sulfate Chemical compound [O-2].[Ti+4].[O-]S([O-])(=O)=O DCKVFVYPWDKYDN-UHFFFAOYSA-L 0.000 description 2
- VLTRZXGMWDSKGL-UHFFFAOYSA-N perchloric acid Chemical compound OCl(=O)(=O)=O VLTRZXGMWDSKGL-UHFFFAOYSA-N 0.000 description 2
- 230000005855 radiation Effects 0.000 description 2
- 239000013535 sea water Substances 0.000 description 2
- 238000000926 separation method Methods 0.000 description 2
- 239000010865 sewage Substances 0.000 description 2
- 229910000030 sodium bicarbonate Inorganic materials 0.000 description 2
- 235000017557 sodium bicarbonate Nutrition 0.000 description 2
- 229910000029 sodium carbonate Inorganic materials 0.000 description 2
- NTHWMYGWWRZVTN-UHFFFAOYSA-N sodium silicate Chemical compound [Na+].[Na+].[O-][Si]([O-])=O NTHWMYGWWRZVTN-UHFFFAOYSA-N 0.000 description 2
- 229910052911 sodium silicate Inorganic materials 0.000 description 2
- 239000002689 soil Substances 0.000 description 2
- 229910000348 titanium sulfate Inorganic materials 0.000 description 2
- 235000020681 well water Nutrition 0.000 description 2
- 239000002349 well water Substances 0.000 description 2
- 239000010457 zeolite Substances 0.000 description 2
- BHPQYMZQTOCNFJ-UHFFFAOYSA-N Calcium cation Chemical compound [Ca+2] BHPQYMZQTOCNFJ-UHFFFAOYSA-N 0.000 description 1
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 1
- 229920002134 Carboxymethyl cellulose Polymers 0.000 description 1
- UFHFLCQGNIYNRP-UHFFFAOYSA-N Hydrogen Chemical compound [H][H] UFHFLCQGNIYNRP-UHFFFAOYSA-N 0.000 description 1
- 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 1
- FYYHWMGAXLPEAU-UHFFFAOYSA-N Magnesium Chemical compound [Mg] FYYHWMGAXLPEAU-UHFFFAOYSA-N 0.000 description 1
- 101100496858 Mus musculus Colec12 gene Proteins 0.000 description 1
- 239000004372 Polyvinyl alcohol Substances 0.000 description 1
- 239000004113 Sepiolite Substances 0.000 description 1
- PMZURENOXWZQFD-UHFFFAOYSA-L Sodium Sulfate Chemical compound [Na+].[Na+].[O-]S([O-])(=O)=O PMZURENOXWZQFD-UHFFFAOYSA-L 0.000 description 1
- 229930006000 Sucrose Natural products 0.000 description 1
- 239000004809 Teflon Substances 0.000 description 1
- 229920006362 Teflon® Polymers 0.000 description 1
- 238000013019 agitation Methods 0.000 description 1
- 229910001583 allophane Inorganic materials 0.000 description 1
- WMGSQTMJHBYJMQ-UHFFFAOYSA-N aluminum;magnesium;silicate Chemical compound [Mg+2].[Al+3].[O-][Si]([O-])([O-])[O-] WMGSQTMJHBYJMQ-UHFFFAOYSA-N 0.000 description 1
- ANBBXQWFNXMHLD-UHFFFAOYSA-N aluminum;sodium;oxygen(2-) Chemical compound [O-2].[O-2].[Na+].[Al+3] ANBBXQWFNXMHLD-UHFFFAOYSA-N 0.000 description 1
- HPTYUNKZVDYXLP-UHFFFAOYSA-N aluminum;trihydroxy(trihydroxysilyloxy)silane;hydrate Chemical compound O.[Al].[Al].O[Si](O)(O)O[Si](O)(O)O HPTYUNKZVDYXLP-UHFFFAOYSA-N 0.000 description 1
- 229960000892 attapulgite Drugs 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
- MTAZNLWOLGHBHU-UHFFFAOYSA-N butadiene-styrene rubber Chemical compound C=CC=C.C=CC1=CC=CC=C1 MTAZNLWOLGHBHU-UHFFFAOYSA-N 0.000 description 1
- ZMCUDHNSHCRDBT-UHFFFAOYSA-M caesium bicarbonate Chemical compound [Cs+].OC([O-])=O ZMCUDHNSHCRDBT-UHFFFAOYSA-M 0.000 description 1
- FJDQFPXHSGXQBY-UHFFFAOYSA-L caesium carbonate Chemical compound [Cs+].[Cs+].[O-]C([O-])=O FJDQFPXHSGXQBY-UHFFFAOYSA-L 0.000 description 1
- 229910000024 caesium carbonate Inorganic materials 0.000 description 1
- 229910001424 calcium ion Inorganic materials 0.000 description 1
- 239000000378 calcium silicate Substances 0.000 description 1
- XFWJKVMFIVXPKK-UHFFFAOYSA-N calcium;oxido(oxo)alumane Chemical compound [Ca+2].[O-][Al]=O.[O-][Al]=O XFWJKVMFIVXPKK-UHFFFAOYSA-N 0.000 description 1
- 238000001460 carbon-13 nuclear magnetic resonance spectrum Methods 0.000 description 1
- BVKZGUZCCUSVTD-UHFFFAOYSA-N carbonic acid Chemical class OC(O)=O BVKZGUZCCUSVTD-UHFFFAOYSA-N 0.000 description 1
- 239000001768 carboxy methyl cellulose Substances 0.000 description 1
- 235000010948 carboxy methyl cellulose Nutrition 0.000 description 1
- 239000008112 carboxymethyl-cellulose Substances 0.000 description 1
- 239000000919 ceramic Substances 0.000 description 1
- 239000003153 chemical reaction reagent Substances 0.000 description 1
- 239000002734 clay mineral Substances 0.000 description 1
- 238000002485 combustion reaction Methods 0.000 description 1
- 238000007906 compression Methods 0.000 description 1
- 230000006835 compression Effects 0.000 description 1
- 238000011109 contamination Methods 0.000 description 1
- 229910052878 cordierite Inorganic materials 0.000 description 1
- 238000013480 data collection Methods 0.000 description 1
- UKGZHELIUYCPTO-UHFFFAOYSA-N dicesium;oxygen(2-);titanium(4+) Chemical compound [O-2].[O-2].[O-2].[Ti+4].[Cs+].[Cs+] UKGZHELIUYCPTO-UHFFFAOYSA-N 0.000 description 1
- 235000014113 dietary fatty acids Nutrition 0.000 description 1
- JSKIRARMQDRGJZ-UHFFFAOYSA-N dimagnesium dioxido-bis[(1-oxido-3-oxo-2,4,6,8,9-pentaoxa-1,3-disila-5,7-dialuminabicyclo[3.3.1]nonan-7-yl)oxy]silane Chemical compound [Mg++].[Mg++].[O-][Si]([O-])(O[Al]1O[Al]2O[Si](=O)O[Si]([O-])(O1)O2)O[Al]1O[Al]2O[Si](=O)O[Si]([O-])(O1)O2 JSKIRARMQDRGJZ-UHFFFAOYSA-N 0.000 description 1
- 238000001125 extrusion Methods 0.000 description 1
- 239000000194 fatty acid Substances 0.000 description 1
- 229930195729 fatty acid Natural products 0.000 description 1
- 239000000706 filtrate Substances 0.000 description 1
- 239000012530 fluid Substances 0.000 description 1
- 239000010797 grey water Substances 0.000 description 1
- 229910052621 halloysite Inorganic materials 0.000 description 1
- 239000001257 hydrogen Substances 0.000 description 1
- GPRLSGONYQIRFK-UHFFFAOYSA-N hydron Chemical compound [H+] GPRLSGONYQIRFK-UHFFFAOYSA-N 0.000 description 1
- KEDRKJFXBSLXSI-UHFFFAOYSA-M hydron;rubidium(1+);carbonate Chemical compound [Rb+].OC([O-])=O KEDRKJFXBSLXSI-UHFFFAOYSA-M 0.000 description 1
- 238000001027 hydrothermal synthesis Methods 0.000 description 1
- 238000001095 inductively coupled plasma mass spectrometry Methods 0.000 description 1
- 238000002354 inductively-coupled plasma atomic emission spectroscopy Methods 0.000 description 1
- 229910001872 inorganic gas Inorganic materials 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
- 239000004816 latex Substances 0.000 description 1
- 229920000126 latex Polymers 0.000 description 1
- 239000011777 magnesium Substances 0.000 description 1
- 229910052749 magnesium Inorganic materials 0.000 description 1
- HCWCAKKEBCNQJP-UHFFFAOYSA-N magnesium orthosilicate Chemical compound [Mg+2].[Mg+2].[O-][Si]([O-])([O-])[O-] HCWCAKKEBCNQJP-UHFFFAOYSA-N 0.000 description 1
- 239000000391 magnesium silicate Substances 0.000 description 1
- 229910052919 magnesium silicate Inorganic materials 0.000 description 1
- 235000019792 magnesium silicate Nutrition 0.000 description 1
- 238000004949 mass spectrometry Methods 0.000 description 1
- 239000000463 material Substances 0.000 description 1
- 238000007909 melt granulation Methods 0.000 description 1
- 238000002844 melting Methods 0.000 description 1
- 230000008018 melting Effects 0.000 description 1
- 239000012528 membrane Substances 0.000 description 1
- 229920000620 organic polymer Polymers 0.000 description 1
- 229910052625 palygorskite Inorganic materials 0.000 description 1
- 239000002245 particle Substances 0.000 description 1
- 239000008188 pellet Substances 0.000 description 1
- 230000000704 physical effect Effects 0.000 description 1
- 229920002451 polyvinyl alcohol Polymers 0.000 description 1
- 150000003112 potassium compounds Chemical class 0.000 description 1
- 229910001414 potassium ion Inorganic materials 0.000 description 1
- 238000001556 precipitation Methods 0.000 description 1
- 238000010298 pulverizing process Methods 0.000 description 1
- 238000000746 purification Methods 0.000 description 1
- 238000004445 quantitative analysis Methods 0.000 description 1
- 238000011084 recovery Methods 0.000 description 1
- 230000000717 retained effect Effects 0.000 description 1
- 238000005096 rolling process Methods 0.000 description 1
- IGLNJRXAVVLDKE-UHFFFAOYSA-N rubidium atom Chemical compound [Rb] IGLNJRXAVVLDKE-UHFFFAOYSA-N 0.000 description 1
- WPFGFHJALYCVMO-UHFFFAOYSA-L rubidium carbonate Chemical compound [Rb+].[Rb+].[O-]C([O-])=O WPFGFHJALYCVMO-UHFFFAOYSA-L 0.000 description 1
- 229910000026 rubidium carbonate Inorganic materials 0.000 description 1
- 229910052624 sepiolite Inorganic materials 0.000 description 1
- 235000019355 sepiolite Nutrition 0.000 description 1
- 150000004760 silicates Chemical class 0.000 description 1
- RMAQACBXLXPBSY-UHFFFAOYSA-N silicic acid Chemical compound O[Si](O)(O)O RMAQACBXLXPBSY-UHFFFAOYSA-N 0.000 description 1
- 235000012239 silicon dioxide Nutrition 0.000 description 1
- 239000002002 slurry Substances 0.000 description 1
- 229910001388 sodium aluminate Inorganic materials 0.000 description 1
- 235000019795 sodium metasilicate Nutrition 0.000 description 1
- 235000019794 sodium silicate Nutrition 0.000 description 1
- 229910052938 sodium sulfate Inorganic materials 0.000 description 1
- 235000011152 sodium sulphate Nutrition 0.000 description 1
- 239000007787 solid Substances 0.000 description 1
- 239000007921 spray Substances 0.000 description 1
- 229910001631 strontium chloride Inorganic materials 0.000 description 1
- AHBGXTDRMVNFER-UHFFFAOYSA-L strontium dichloride Chemical compound [Cl-].[Cl-].[Sr+2] AHBGXTDRMVNFER-UHFFFAOYSA-L 0.000 description 1
- 239000005720 sucrose Substances 0.000 description 1
- 238000009423 ventilation Methods 0.000 description 1
Images
Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
- B01J39/00—Cation exchange; Use of material as cation exchangers; Treatment of material for improving the cation exchange properties
- B01J39/08—Use of material as cation exchangers; Treatment of material for improving the cation exchange properties
- B01J39/09—Inorganic material
-
- G—PHYSICS
- G21—NUCLEAR PHYSICS; NUCLEAR ENGINEERING
- G21F—PROTECTION AGAINST X-RADIATION, GAMMA RADIATION, CORPUSCULAR RADIATION OR PARTICLE BOMBARDMENT; TREATING RADIOACTIVELY CONTAMINATED MATERIAL; DECONTAMINATION ARRANGEMENTS THEREFOR
- G21F9/00—Treating radioactively contaminated material; Decontamination arrangements therefor
- G21F9/04—Treating liquids
- G21F9/06—Processing
- G21F9/12—Processing by absorption; by adsorption; by ion-exchange
Description
本発明は、無機イオン交換体及びその製造方法に関する。また、本発明は、該無機イオン交換体を用いる、放射性ストロンチウムを含有する水の浄化方法に関する。 The present invention relates to an inorganic ion exchanger and a method for manufacturing the same. The present invention also relates to a method for purifying water containing radioactive strontium using the inorganic ion exchanger.
原子力発電設備の事故等で排出された放射性廃液中の放射性物質の除去や有価元素の回収のために、合成ゼオライト系吸着剤や陽イオン交換樹脂を用いる方法の他、チタン酸アルカリ金属化合物をイオン交換体として用いる方法が提案されている。
イオン交換体として用いるチタン酸アルカリ金属化合物としては、ＴｉＯ５三角両錐体の連鎖構造を有する層状構造チタン酸アルカリ金属化合物と、ＴｉＯ６八面体の連鎖構造を有する層状チタン酸アルカリ金属塩とからなる多孔質チタネート（特許文献１）、ケイ酸源と、ナトリウム及び／又はカリウム化合物と、四塩化チタンと、水とを混合して混合ゲルを得、該混合ゲルを水熱反応させて得られる結晶性シリコチタネート（特許文献２）等が知られている。チタン酸アルカリ金属化合物として、四チタン酸カリウムＫ２Ｔｉ４Ｏ９は、結晶の層間に水を取り込むことにより、カリウムイオンをカルシウムイオンと交換できることが知られている（非特許文献１）。In order to remove radioactive substances and recover valuable elements from radioactive waste fluid discharged from nuclear power plant accidents, etc., in addition to methods using synthetic zeolite adsorbents and cation exchange resins, alkali metal titanate compounds are used as ions. A method of using it as an exchanger has been proposed.
The alkali metal titanate compounds used as ion exchangers include layered alkali metal titanates having a TiO 5 triangular bipyramidal chain structure and layered alkali metal titanates having a TiO 6 octahedral chain structure. Porous titanate (Patent Document 1), a silicic acid source, a sodium and/or potassium compound, titanium tetrachloride, and water are mixed to obtain a mixed gel, and the mixed gel is subjected to a hydrothermal reaction. Crystalline silicotitanate (Patent Document 2) and the like are known. As an alkali metal titanate compound, potassium tetratitanate K 2 Ti 4 O 9 is known to be able to exchange potassium ions with calcium ions by incorporating water between the crystal layers (Non-Patent Document 1).
しかしながら、従来の合成ゼオライト系吸着剤や陽イオン交換樹脂を用いる方法や、従来のチタン酸アルカリ金属化合物をイオン交換体として用いる方法では、放射性ストロンチウム除去能が十分ではないという課題があった。
本発明が解決しようとする課題は、放射性ストロンチウムが基準値以下になるまで放射性ストロンチウムを除去することができる無機イオン交換体、及び該無機イオン交換体の製造方法、並びに該無機イオン交換体を用いる、放射性ストロンチウムを含有する水の浄化方法を提供することにある。However, conventional methods using synthetic zeolite-based adsorbents and cation exchange resins, and conventional methods using alkali metal titanate compounds as ion exchangers, have a problem in that the ability to remove radioactive strontium is not sufficient.
The problems to be solved by the present invention are an inorganic ion exchanger capable of removing radioactive strontium until the radioactive strontium becomes below a standard value, a method for producing the inorganic ion exchanger, and a method using the inorganic ion exchanger. An object of the present invention is to provide a method for purifying water containing radioactive strontium.
本発明者は、結晶構造内に、アルカリ金属塩およびアルカリ金属炭酸塩からなる群から選ばれる少なくとも１種を含有する層状チタン酸塩を含む無機イオン交換体が、高いイオン交換能を有し、放射性ストロンチウムを含有する水から高い効率で放射性ストロンチウムを除去できることを見出し、本発明を完成するに至った。 The present inventor has discovered that an inorganic ion exchanger containing a layered titanate containing at least one selected from the group consisting of alkali metal salts and alkali metal carbonates in its crystal structure has high ion exchange ability, The present inventors have discovered that radioactive strontium can be removed with high efficiency from water containing radioactive strontium, and have completed the present invention.
即ち、本発明は、以下の［１］～［１０］に関する。
［１］結晶構造内に、アルカリ金属炭酸塩およびアルカリ金属炭酸水素塩からなる群から選ばれる少なくとも１種を含有する層状チタン酸塩を含む無機イオン交換体。
［２］前記層状チタン酸塩が、ｘＡ２Ｏ・ＴｉＯ２・ｙＨ２Ｏ・ｚＡ２ＣＯ３（ＡはＬｉ、Ｋ、Ｎａ、Ｒｂ及びＣｓから選ばれる少なくとも１種の元素を表し、ｘ、ｙ、ｚは、それぞれ０．０２≦ｘ≦２．０、ｙ≧０．０５、ｚ≧０．０１５の数値を表す）で表されることを特徴とする［１］に記載の無機イオン交換体。
［３］前記層状チタン酸塩が、ＣｕＫα線を用いて測定した粉末Ｘ線回折パターンにおいて、回折角（２θ）が１°以上８°以下の範囲に極大点のある回折ピークを有することを特徴とする［１］または［２］に記載の無機イオン交換体。
［４］前記層状チタン酸塩が、前記回折ピークの半値幅が２θで３°以上である低結晶性の化合物であることを特徴とする［３］に記載の無機イオン交換体。
［５］ｐＨが１２以上のアルカリ性ストロンチウム水溶液に分散させたときに、下記式（１）で表される分配係数Ｋｄが３００００ｍｌ／ｇ以上であることを特徴とする［１］～［４］のいずれか一項に記載の無機イオン交換体。That is, the present invention relates to the following [1] to [10].
[1] An inorganic ion exchanger containing a layered titanate containing at least one selected from the group consisting of alkali metal carbonates and alkali metal hydrogen carbonates in its crystal structure.
[2] The layered titanate is composed of xA 2 O・TiO 2・yH 2 O・zA 2 CO 3 (A represents at least one element selected from Li, K, Na, Rb and Cs, x, The inorganic ion exchange method according to [1], wherein y and z represent numerical values of 0.02≦x≦2.0, y≧0.05, and z≧0.015, respectively. body.
[3] The layered titanate has a diffraction peak with a maximum point in the range of a diffraction angle (2θ) of 1° or more and 8° or less in a powder X-ray diffraction pattern measured using CuKα rays. The inorganic ion exchanger according to [1] or [2].
[4] The inorganic ion exchanger according to [3], wherein the layered titanate is a low-crystalline compound in which the half-width of the diffraction peak is 3° or more in 2θ.
[5] The composition of [1] to [4], characterized in that when dispersed in an alkaline strontium aqueous solution having a pH of 12 or more, the distribution coefficient Kd expressed by the following formula (1) is 30,000 ml/g or more. The inorganic ion exchanger according to any one of the items.
Ｋｄ＝Ｑｅｑ／Ｃｅｑ・・・（１）
（式（１）中、Ｋｄは分配係数（ｍｌ／ｇ）、Ｃｅｑは平衡到達時の水溶液中のストロンチウム濃度（ｍｏｌ／ｍｌ）、Ｑｅｑは平衡到達時の無機イオン交換体の単位重量当たりのストロンチウム吸着量（ｍｏｌ／ｇ）をそれぞれ表す）
［６］［１］～［５］のいずれか一項に記載の無機イオン交換体の製造方法であって、以下の工程（１）及び工程（２）を順次行うことを特徴とする無機イオン交換体の製造方法。
工程（１）：チタン化合物の粉末と過剰量の、アルカリ金属炭酸塩およびアルカリ金属炭酸水素塩からなる群から選ばれる少なくとも1種の粉末とを混合する工程
工程（２）：前記工程（１）で得られた混合物を７００℃以上１５００℃以下で加熱する工程
［７］さらに以下の工程（３）及び工程（４）を順次行うことを特徴とする［６］に記載の無機イオン交換体の製造方法。
工程（３）：前記工程（２）で得られた無機イオン交換体を水で洗浄する工程
工程（４）：前記工程（３）で洗浄後の無機イオン交換体を乾燥する工程
［８］前記チタン化合物が、酸化チタン、メタチタン酸、アルカリ金属チタン酸塩、および金属チタンからなる群から選ばれる少なくとも１種であることを特徴とする［６］又は［７］に記載の無機イオン交換体の製造方法。
［９］前記工程（１）において、アルカリ金属硫酸塩の粉末をさらに混合することを特徴とする［６］～［８］のいずれか一項に記載の無機イオン交換体の製造方法。
［１０］［１］～［５］のいずれか一項に記載の無機イオン交換体に、放射性ストロンチウムを含有する水を接触させる工程と、前記接触後の水から前記無機イオン交換体を分離する工程とを順次行うことを特徴とする、放射性ストロンチウムを含有する水の浄化方法。Kd=Qeq/Ceq...(1)
(In formula (1), Kd is the distribution coefficient (ml/g), Ceq is the strontium concentration in the aqueous solution (mol/ml) when equilibrium is reached, and Qeq is the strontium per unit weight of the inorganic ion exchanger when equilibrium is reached. Each represents the adsorption amount (mol/g)
[6] A method for producing an inorganic ion exchanger according to any one of [1] to [5], characterized in that the following steps (1) and (2) are performed sequentially. Method of manufacturing an exchanger.
Step (1): A step of mixing a titanium compound powder and an excess amount of at least one powder selected from the group consisting of alkali metal carbonates and alkali metal hydrogen carbonates. Step (2): Step (1) above. Step [7] of heating the mixture obtained in 700° C. or higher and lower than 1500° C. The inorganic ion exchanger according to [6], further comprising sequentially performing the following steps (3) and (4). Production method.
Step (3): Washing the inorganic ion exchanger obtained in step (2) with water Step (4): Drying the inorganic ion exchanger after washing in step (3) [8] Said The inorganic ion exchanger according to [6] or [7], wherein the titanium compound is at least one selected from the group consisting of titanium oxide, metatitanic acid, alkali metal titanate, and metal titanium. Production method.
[9] The method for producing an inorganic ion exchanger according to any one of [6] to [8], characterized in that in step (1), alkali metal sulfate powder is further mixed.
[10] A step of bringing water containing radioactive strontium into contact with the inorganic ion exchanger according to any one of [1] to [5], and separating the inorganic ion exchanger from the water after the contact. A method for purifying water containing radioactive strontium, the method comprising sequentially performing the following steps.
本発明の無機イオン交換体は、高いイオン交換能を有し、放射性物質を含有する水から高い効率で放射性物質を除去することができる。このため、放射性廃液から放射性物質を除去する際に、無機イオン交換体としての使用量を削減でき、浄化コストの削減及び放射性廃棄物の量を低減することができる。また、本発明の無機イオン交換体は、井戸水などからの重金属除去、海水などからの有価資源回収、汚染土上からの有害物質除去などにも使用することができる。 The inorganic ion exchanger of the present invention has high ion exchange ability and can remove radioactive substances from water containing radioactive substances with high efficiency. Therefore, when removing radioactive substances from radioactive waste liquid, the amount used as an inorganic ion exchanger can be reduced, and purification costs and the amount of radioactive waste can be reduced. Furthermore, the inorganic ion exchanger of the present invention can be used for removing heavy metals from well water, etc., recovering valuable resources from seawater, etc., removing harmful substances from contaminated soil, etc.
＜無機イオン交換体＞
本発明の無機イオン交換体は、結晶構造内に、アルカリ金属炭酸塩およびアルカリ金属炭酸水素塩からなる群から選ばれる少なくとも１種を含有する層状チタン酸塩を含む。
前記層状チタン酸塩の結晶構造内に含有されるアルカリ金属炭酸塩としては、例えば、炭酸リチウム、炭酸ナトリウム、炭酸カリウム、炭酸ルビジウム、炭酸セシウム等が挙げられ、これらは、単独で含有されていてもよいし、２種以上が組み合わされて含有されていてもよい。
また、前記層状チタン酸塩の結晶構造内に含有されるアルカリ金属炭酸水素塩としては、例えば、炭酸水素リチウム、炭酸水素ナトリウム、炭酸水素カリウム、炭酸水素ルビジウム、炭酸水素セシウム等が挙げられ、これらは、単独で含有されていてもよいし、２種以上が組み合わされて含有されていてもよい。<Inorganic ion exchanger>
The inorganic ion exchanger of the present invention includes a layered titanate containing at least one selected from the group consisting of alkali metal carbonates and alkali metal hydrogen carbonates in its crystal structure.
Examples of the alkali metal carbonate contained in the crystal structure of the layered titanate include lithium carbonate, sodium carbonate, potassium carbonate, rubidium carbonate, cesium carbonate, etc. or a combination of two or more types may be contained.
Further, examples of the alkali metal hydrogen carbonate contained in the crystal structure of the layered titanate include lithium hydrogen carbonate, sodium hydrogen carbonate, potassium hydrogen carbonate, rubidium hydrogen carbonate, cesium hydrogen carbonate, etc. may be contained alone or in combination of two or more.
本発明の無機イオン交換体の形態としては、特に制限はなく、粉末状、顆粒状、粒子状、円柱状、球状、ペレット状、ハニカム成型体、多孔質成型体等を挙げることができ、さらに、アルミナ、ジルコニア、コージェライトなどの支持体の上に担持されたものでもよい。イオン交換体は、一般的には、カラムに充填して放射性廃液などを通液する方法で用いられるため、１ｍｍ程度の大きさの顆粒状または粒子状で、水と長時間接触しても脆化しない形態であることが好ましい。
本発明の無機イオン交換体における前記層状チタン酸塩としては、ｘＡ２Ｏ・ＴｉＯ２・ｙＨ２Ｏ・ｚＡ２ＣＯ３（ＡはＬｉ、Ｋ、Ｎａ、Ｒｂ及びＣｓから選ばれる少なくとも１種の元素を表し、ｘ、ｙ、ｚは、それぞれ０．０２≦ｘ≦２．０、ｙ≧０．０５、ｚ≧０．０１５の数値を表す）で表される層状チタン酸塩であることが好ましい。ここで、ｘは、０．０５≦ｘ≦１．０であることが好ましく、０．１≦ｘ≦０．５であることがより好ましい。ｙは、０．０５≦ｙ≦３．０であることが好ましく、０．１≦ｙ≦２．０であることがより好ましい。ｚは、０．０１５≦ｚ≦１．５であることが好ましく、０．０２≦ｚ≦１．０であることがより好ましい。The form of the inorganic ion exchanger of the present invention is not particularly limited, and may include powder, granules, particulates, cylinders, spheres, pellets, honeycomb molded bodies, porous molded bodies, etc. , alumina, zirconia, cordierite, or the like. Ion exchangers are generally used by filling a column and passing radioactive waste liquid through it, so they are in the form of granules or particles with a size of about 1 mm, and are not brittle even if they come in contact with water for a long time. Preferably, it is in a form that does not change.
The layered titanate in the inorganic ion exchanger of the present invention is xA 2 O・TiO 2・yH 2 O・zA 2 CO 3 (A is at least one selected from Li, K, Na, Rb and Cs). x, y, and z represent the numerical values of 0.02≦x≦2.0, y≧0.05, and z≧0.015, respectively). preferable. Here, x preferably satisfies 0.05≦x≦1.0, more preferably 0.1≦x≦0.5. It is preferable that y is 0.05≦y≦3.0, and more preferably 0.1≦y≦2.0. It is preferable that z is 0.015≦z≦1.5, and more preferably 0.02≦z≦1.0.
なお、前記ｚＡ２ＣＯ３は、ｚＡＨＣＯ３であってもよく、この場合の水素イオンは、ｙＨ２Ｏから得られる。従って、前記ｚＡ２ＣＯ３がｚＡＨＣＯ３である場合は、前記層状チタン酸塩は、ｘＡ２Ｏ・ＴｉＯ２・（ｙ－ｚ）Ｈ２Ｏ・ｚＡＨＣＯ３・ｚＡＯＨ（ＡはＬｉ、Ｋ、Ｎａ、Ｒｂ及びＣｓから選ばれる少なくとも１種の元素を表し、ｘ、ｙ、ｚは、それぞれ０．０２≦ｘ≦２．０、ｙ≧０．０５、ｚ≧０．０１５の数値を表す）となる。In addition, the said zA2CO3 may be zAHCO3 , and the hydrogen ion in this case is obtained from yH2O . Therefore, when the zA 2 CO 3 is zAHCO 3 , the layered titanate is xA 2 O・TiO 2・(yz)H 2 O・zAHCO 3・zAOH (A is Li, K, Na , represents at least one element selected from Rb and Cs, and x, y, and z represent numerical values of 0.02≦x≦2.0, y≧0.05, and z≧0.015, respectively). Become.
前記層状チタン酸塩は、ＣｕＫα線を用いて測定した粉末Ｘ線回折パターンにおいて、回折角（２θ）が１°以上８°以下、好ましくは２°以上７°以下の範囲に極大点のある回折ピークを有することが好ましい。前記粉末Ｘ線回折パターンにおいて、回折角（２θ）が１°以上８°以下、好ましくは２°以上７°以下の範囲に極大点のある回折ピークを有する層状チタン酸塩は、チタン酸の層間距離が、１．１ｎｍ～８．８ｎｍ、好ましくは、１．３ｎｍ～４．４ｎｍとなる。前記回折ピークの回折角（２θ）は、実際の粉末Ｘ線回折で得られた回折ピークパターンをベースライン補正した、回折パターンより算出することができる。このベースライン補正は、算出対象の回折角度範囲に回折ピークを有さない化合物で得られたバックグランド曲線をフィッテングさせることにより行うことができる。 The layered titanate has a powder X-ray diffraction pattern measured using CuKα radiation, with a diffraction angle (2θ) having a maximum point in the range of 1° or more and 8° or less, preferably 2° or more and 7° or less. It is preferable to have a peak. In the powder X-ray diffraction pattern, the layered titanate having a diffraction peak with a maximum point in the range of a diffraction angle (2θ) of 1° or more and 8° or less, preferably 2° or more and 7° or less, The distance is 1.1 nm to 8.8 nm, preferably 1.3 nm to 4.4 nm. The diffraction angle (2θ) of the diffraction peak can be calculated from a diffraction pattern obtained by baseline-correcting a diffraction peak pattern obtained by actual powder X-ray diffraction. This baseline correction can be performed by fitting a background curve obtained with a compound that does not have a diffraction peak in the diffraction angle range to be calculated.
また、前記層状チタン酸塩は、前記回折ピークの半値幅が２θで３°以上である低結晶性であることが好ましい。前記回折ピークの半値幅が広くなる程、結晶性が低くなり、前記回折ピークの半値幅が狭くなる程、結晶性が高くなる。本発明における層状チタン酸塩は、前記回折ピークの半値幅が２θで３°以上である低結晶性の化合物であることが好ましく、３°以上１０°以下である低結晶性の化合物がより好ましい。 Further, it is preferable that the layered titanate has low crystallinity such that the half width of the diffraction peak is 3° or more in 2θ. The wider the half width of the diffraction peak, the lower the crystallinity, and the narrower the half width of the diffraction peak, the higher the crystallinity. The layered titanate in the present invention is preferably a low-crystalline compound in which the half-width of the diffraction peak is 3° or more in 2θ, more preferably a low-crystalline compound in which the half-value width of the diffraction peak is 3° or more and 10° or less. .
前記回折ピークの半値幅は、実際の粉末Ｘ線回折で得られた回折ピークパターンをベースライン補正した、回折パターンより算出することができる。このベースライン補正は、算出対象の回折角度範囲に回折ピークを有さない化合物で得られたバックグランド曲線をフィッテングさせることにより行うことができる。また、前記回折ピークパターンが、他の回折ピークと重なり合っている場合は、ピーク分離を行った後に半値幅を求めることができる。ピーク分離は、ガウス型の基本波形の重ね合わせにより近似し、重なりあったピークのそれぞれをカーブフィッテングすることにより行うことができる。 The half-width of the diffraction peak can be calculated from a diffraction pattern obtained by baseline-correcting a diffraction peak pattern obtained by actual powder X-ray diffraction. This baseline correction can be performed by fitting a background curve obtained with a compound that does not have a diffraction peak in the diffraction angle range to be calculated. Furthermore, when the diffraction peak pattern overlaps with other diffraction peaks, the half-width can be determined after performing peak separation. Peak separation can be performed by approximating Gaussian fundamental waveforms by superimposing them and performing curve fitting on each of the overlapped peaks.
本発明の無機イオン交換体は、上記の通り、層状チタン酸塩の結晶構造内に、アルカリ金属炭酸塩およびアルカリ金属炭酸水素塩からなる群から選ばれる少なくとも１種を含んでおり、このアルカリ金属炭酸塩またはアルカリ金属炭酸水素塩の介在により、チタン酸の層間距離が広がった構造を有している。従来の層状チタン酸塩を含む無機イオン交換体は、チタン酸の層間に水分子を含んだ構造を有し、チタン酸の層間距離が広がっているが、本発明の無機イオン交換体は、チタン酸の層間に、アルカリ金属炭酸塩およびアルカリ金属炭酸水素塩からなる群から選ばれる少なくとも１種を含むことにより、従来の水分子をチタン酸の層間に含む無機イオン交換体よりも、さらに多くの水分子を含み得るため、チタン酸の層間距離がさらに広がった構造を形成し得るためと推定される。 As described above, the inorganic ion exchanger of the present invention contains at least one selected from the group consisting of alkali metal carbonates and alkali metal hydrogen carbonates in the crystal structure of the layered titanate, and the alkali metal It has a structure in which the interlayer distance of titanic acid is widened due to the presence of carbonate or alkali metal hydrogen carbonate. Conventional inorganic ion exchangers containing layered titanates have a structure that contains water molecules between the layers of titanic acid, and the distance between the layers of titanic acid is wide; however, the inorganic ion exchanger of the present invention By including at least one member selected from the group consisting of alkali metal carbonates and alkali metal hydrogen carbonates between the acid layers, more water molecules can be contained between the titanic acid layers than in conventional inorganic ion exchangers that contain water molecules between the titanic acid layers. It is presumed that this is because the titanic acid can form a structure in which the interlayer distance is further widened since it may contain water molecules.
また、本発明の無機イオン交換体は、さらに水分子を結晶構造内に取り込むことができる。すなわち、本発明の無機イオン交換体は、層状チタン酸塩の結晶構造内に、アルカリ金属炭酸塩およびアルカリ金属炭酸水素塩からなる群から選ばれる少なくとも１種と水分子とを含有するものも包含する。水分子と、アルカリ金属炭酸塩およびアルカリ金属炭酸水素塩からなる群から選ばれる少なくとも１種とを両方含む場合は、水分子のみ、または、アルカリ金属炭酸塩およびアルカリ金属炭酸水素塩からなる群から選ばれる少なくとも１種のみを含む場合に比べて、本発明の技術的効果が相乗的に発現することが期待できる。 Furthermore, the inorganic ion exchanger of the present invention can further incorporate water molecules into its crystal structure. That is, the inorganic ion exchanger of the present invention also includes those containing at least one selected from the group consisting of alkali metal carbonates and alkali metal hydrogen carbonates and water molecules in the crystal structure of the layered titanate. do. When it contains both water molecules and at least one selected from the group consisting of alkali metal carbonates and alkali metal hydrogen carbonates, only water molecules or from the group consisting of alkali metal carbonates and alkali metal hydrogen carbonates It can be expected that the technical effects of the present invention will be expressed synergistically compared to the case where only at least one selected species is included.
＜無機イオン交換体の分配係数＞
本発明の無機イオン交換体を、ストロンチウムを含む水溶液に分散させると、無機イオン交換体中のアルカリ金属が、水溶液中のストロンチウムと交換反応し、ストロンチウムが無機イオン交換体に取り込まれ、ストロンチウムが取り込まれた無機イオン交換体が生成し得る。この反応は下記式に示す平衡反応であり、平衡がストロンチウムの取り込みの側（右側）へ傾く程、ストロンチウムの取り込み量が高くなり得る。<Partition coefficient of inorganic ion exchanger>
When the inorganic ion exchanger of the present invention is dispersed in an aqueous solution containing strontium, the alkali metal in the inorganic ion exchanger undergoes an exchange reaction with strontium in the aqueous solution, and strontium is incorporated into the inorganic ion exchanger. Inorganic ion exchangers can be produced. This reaction is an equilibrium reaction represented by the following formula, and the more the equilibrium tilts toward the side of strontium uptake (to the right), the higher the amount of strontium uptake can become.
無機イオン交換体のストロンチウム取り込み能は、該無機イオン交換体をｐＨが１２以上のアルカリ性ストロンチウム水溶液に分散させたときの、下記式（１）で表される分配係数Ｋｄで表すことができる。
Ｋｄ＝Ｑｅｑ／Ｃｅｑ・・・（１）
（式（１）中、Ｋｄは分配係数（ｍｌ／ｇ）、Ｃｅｑは上記平衡反応における平衡到達時の溶液中のストロンチウム濃度（ｍｏｌ／ｍｌ）、Ｑｅｑは上記平衡反応における平衡到達時の無機イオン交換体の単位重量当たりのストロンチウム吸着量（ｍｏｌ／ｇ）をそれぞれ表す）
上記平衡反応において、平衡到達時は、本発明の無機イオン交換体を、ストロンチウムを含む水溶液に分散させた後、水溶液中のストロンチウム濃度を測定して、濃度の変化がなくなる時間を求めることにより確認することができるが、通常は、３～５時間である。The strontium uptake ability of an inorganic ion exchanger can be expressed by the distribution coefficient Kd expressed by the following formula (1) when the inorganic ion exchanger is dispersed in an alkaline strontium aqueous solution having a pH of 12 or more.
Kd=Qeq/Ceq...(1)
(In formula (1), Kd is the distribution coefficient (ml/g), Ceq is the strontium concentration in the solution (mol/ml) when equilibrium is reached in the above equilibrium reaction, and Qeq is the inorganic ion when equilibrium is reached in the above equilibrium reaction. Each represents the amount of strontium adsorbed per unit weight of the exchanger (mol/g)
In the above equilibrium reaction, when equilibrium is reached, it is confirmed by dispersing the inorganic ion exchanger of the present invention in an aqueous solution containing strontium, measuring the strontium concentration in the aqueous solution, and determining the time when the concentration stops changing. However, it is usually 3 to 5 hours.
本発明の無機イオン交換体の分配係数Ｋｄは、３００００ｍｌ／ｇ以上であることが好ましく、１０００００ｍｌ／ｇ以上であることがより好ましく、５０００００ｍｌ／ｇ以上であることが更に好ましい。
上記の平衡反応において、分配係数Ｋｄが高い程、平衡はストロンチウムの取り込みの側（右側）へ傾き、ストロンチウムの取り込み能が高くなる。上記の通り、本発明の無機イオン交換体の分配係数Ｋｄは高いため、高いストロンチウム取り込み能を有している。
なお、本明細書においては、イオン交換体が、イオン交換によりストロンチウムを取り込む現象を、ストロンチウム吸着と呼ぶ。The distribution coefficient Kd of the inorganic ion exchanger of the present invention is preferably 30,000 ml/g or more, more preferably 100,000 ml/g or more, and even more preferably 500,000 ml/g or more.
In the above equilibrium reaction, the higher the partition coefficient Kd, the more the equilibrium tilts toward the strontium uptake side (to the right), and the higher the strontium uptake ability becomes. As mentioned above, since the inorganic ion exchanger of the present invention has a high partition coefficient Kd, it has a high strontium uptake ability.
Note that in this specification, the phenomenon in which an ion exchanger takes in strontium through ion exchange is referred to as strontium adsorption.
＜無機イオン交換体の製造方法＞
本発明の無機イオン交換体は、以下の工程（１）及び工程（２）を順次行うことにより製造することができる。
工程（１）：チタン化合物の粉末と過剰量の、アルカリ金属炭酸塩およびアルカリ金属炭酸水素塩からなる群から選ばれる少なくとも１種の粉末とを混合する工程
工程（２）：前記工程（１）で得られた混合物を７００℃以上１５００℃以下で加熱する工程<Method for manufacturing inorganic ion exchanger>
The inorganic ion exchanger of the present invention can be manufactured by sequentially performing the following steps (1) and (2).
Step (1): A step of mixing a titanium compound powder and an excess amount of at least one kind of powder selected from the group consisting of alkali metal carbonates and alkali metal hydrogen carbonates. Step (2): Step (1) above. A step of heating the mixture obtained in 700°C or more and 1500°C or less
工程（１）は、チタン化合物の粉末と過剰量の、アルカリ金属炭酸塩およびアルカリ金属炭酸水素塩からなる群から選ばれる少なくとも１種（以下、アルカリ金属炭酸塩等ともいう）の粉末とを混合する工程である。チタン化合物の粉末と混合するアルカリ金属炭酸塩等の粉末量は、チタン化合物の粉末量よりも過剰であれば、特に制限はないが、チタン化合物をチタン元素換算１００ｍｏｌ％に対して、１２０ｍｏｌ％以上であることが好ましく、１５０ｍｏｌ％以上であることがより好ましく、２００ｍｏｌ％以上であることがさらに好ましい。 Step (1) is to mix a titanium compound powder and an excess amount of at least one powder selected from the group consisting of alkali metal carbonates and alkali metal hydrogen carbonates (hereinafter also referred to as alkali metal carbonates, etc.). This is the process of The amount of powder such as alkali metal carbonate to be mixed with the powder of the titanium compound is not particularly limited as long as it is in excess of the amount of the powder of the titanium compound, but the amount of the titanium compound should be 120 mol% or more relative to 100 mol% in terms of titanium element. It is preferably 150 mol% or more, more preferably 200 mol% or more.
本発明の無機イオン交換体の製造方法に用いられる、アルカリ金属炭酸塩およびアルカリ金属炭酸水素塩としては、前述のアルカリ金属炭酸塩およびアルカリ金属炭酸水素塩が挙げられる。本発明の無機イオン交換体の製造方法に用いられる前記チタン化合物としては、酸化チタン、メタチタン酸、アルカリ金属チタン酸塩、金属チタン等が挙げられ、これらは、単独で用いてもよいし、２種以上を組み合わせて用いてもよい。アルカリ金属チタン酸塩としては、チタン酸リチウム、チタン酸ナトリウム、チタン酸カリウム、チタン酸ルビジウム、チタン酸セシウム等が挙げられる。 Examples of the alkali metal carbonates and alkali metal hydrogen carbonates used in the method for producing an inorganic ion exchanger of the present invention include the aforementioned alkali metal carbonates and alkali metal hydrogen carbonates. Examples of the titanium compound used in the method for producing an inorganic ion exchanger of the present invention include titanium oxide, metatitanic acid, alkali metal titanate, metal titanium, etc., and these may be used alone or in combination. You may use combinations of more than one species. Examples of the alkali metal titanate include lithium titanate, sodium titanate, potassium titanate, rubidium titanate, and cesium titanate.
前記工程（１）において、工程（２）における加熱温度よりも融点の高いアルカリ金属硫酸塩の粉末をさらに混合することにより、工程（２）において、高温で溶融したアルカリ金属炭酸塩中で反応前のチタン化合物が沈殿して反応ムラが生じることが抑制される。更に、工程（２）において反応後の化合物および過剰のアルカリ金属炭酸塩の融液がアルカリ金属硫酸塩粉末に浸み込んだ状態で冷却されることにより、それらが固化するとともに収縮する際に製造容器との界面に隙間ができ、前記工程（２）において得られる生成物を製造容器から取り出しやすくすることができる。アルカリ金属硫酸塩としては、特に制限はなく、例えば、硫酸カリウム、硫酸ナトリウム等が挙げられる。 In step (1), by further mixing an alkali metal sulfate powder with a melting point higher than the heating temperature in step (2), in step (2), the reaction temperature in the alkali metal carbonate molten at high temperature is Precipitation of the titanium compound and occurrence of reaction unevenness is suppressed. Furthermore, in step (2), the compound after the reaction and the excess alkali metal carbonate melt soak into the alkali metal sulfate powder and are cooled, so that when they solidify and shrink, the production A gap is formed at the interface with the container, and the product obtained in step (2) can be easily taken out from the production container. The alkali metal sulfate is not particularly limited and includes, for example, potassium sulfate, sodium sulfate, and the like.
工程（２）は、前記工程（１）で得られた混合物を７００℃以上１５００℃以下で加熱する工程である。加熱時間は、３０分間～１００時間が好ましい。チタン化合物の粉末と過剰量のアルカリ金属炭酸塩等の粉末との混合物を７００℃以上１５００℃以下で加熱することにより、チタン化合物がアルカリ金属炭酸塩と反応して層状チタン酸塩が生成すると共に、層状チタン酸塩の結晶構造内にアルカリ金属炭酸塩を含有させることができる。なお、工程（２）において、アルカリ金属炭酸水素塩は、高温で分解してアルカリ金属炭酸塩となる。 Step (2) is a step of heating the mixture obtained in step (1) above at 700° C. or higher and 1500° C. or lower. The heating time is preferably 30 minutes to 100 hours. By heating a mixture of a titanium compound powder and an excess amount of powder such as an alkali metal carbonate at a temperature of 700°C or more and 1500°C or less, the titanium compound reacts with the alkali metal carbonate to form a layered titanate. , an alkali metal carbonate can be included within the crystal structure of the layered titanate. In addition, in step (2), the alkali metal hydrogen carbonate is decomposed at high temperature to become an alkali metal carbonate.
この反応は、炭酸ガスが脱離する反応であるため、系内の炭酸ガス濃度が高くなると反応が阻害され、目的とは別の生成物が生じるなどの不具合が生じる。そのため、加熱に使用する容器や装置は、炭酸ガスを効率的に排気できる構造や仕組みとなっていることが好ましい。例えば、容器は、通気のための切り欠きのあるものが好ましく、加熱装置としては排気を吸引して外気を少しずつ取り込む仕組みのあるものが好ましい。 Since this reaction is a reaction in which carbon dioxide gas is eliminated, when the concentration of carbon dioxide gas in the system increases, the reaction is inhibited, causing problems such as the production of products other than the intended ones. Therefore, it is preferable that the container or device used for heating has a structure or mechanism that can efficiently exhaust carbon dioxide gas. For example, the container preferably has a notch for ventilation, and the heating device preferably has a mechanism for sucking in exhaust gas and gradually introducing outside air.
前記工程（１）及び工程（２）を順次行うことによって、結晶構造内に、アルカリ金属炭酸塩およびアルカリ金属炭酸水素塩から選ばれる少なくとも１種を含有する層状チタン酸塩を含む無機イオン交換体を得ることができる。
ここで、アルカリ金属炭酸水素塩は、工程（２）で結晶構造内に含有されたアルカリ金属炭酸塩の一部が、空気中などから供給される水分子および二酸化炭素と反応して生成したものである。
このようにして得られる無機イオン交換体は、結晶構造内に水分子を含有していない層状チタン酸塩を含む無機イオン交換体である。本発明の無機イオン交換体は、さらに以下の工程（３）及び工程（４）を順次行うことにより、結晶構造内にさらに水分子を含有する層状チタン酸塩を含む無機イオン交換体を製造することができる。
工程（３）：前記工程（２）で得られた無機イオン交換体を水で洗浄する工程
工程（４）：前記工程（３）で洗浄後の無機イオン交換体を乾燥する工程By sequentially performing the steps (1) and (2), an inorganic ion exchanger containing a layered titanate containing at least one selected from alkali metal carbonates and alkali metal hydrogen carbonates in its crystal structure can be obtained. can be obtained.
Here, the alkali metal hydrogen carbonate is produced by a part of the alkali metal carbonate contained in the crystal structure in step (2) reacting with water molecules and carbon dioxide supplied from the air etc. It is.
The inorganic ion exchanger thus obtained is an inorganic ion exchanger containing a layered titanate that does not contain water molecules within its crystal structure. The inorganic ion exchanger of the present invention is produced by sequentially performing the following steps (3) and (4) to produce an inorganic ion exchanger containing a layered titanate that further contains water molecules in its crystal structure. be able to.
Step (3): A step of washing the inorganic ion exchanger obtained in the above step (2) with water. Step (4): A step of drying the inorganic ion exchanger after washing in the above step (3).
前記工程（３）は、前記工程（２）で得られた無機イオン交換体を水で洗浄し、無機イオン交換体の結晶構造の外にある余分なアルカリ金属炭酸塩を除去する工程である。前記工程（２）で得られた無機イオン交換体を水で洗浄することにより、無機イオン交換体の結晶構造の外にある余分なアルカリ金属炭酸塩を除去すると同時に、層状チタン酸塩の結晶構造内に水分子が取り込まれ、チタン酸の層間距離がさらに広がった構造となる。 The step (3) is a step of washing the inorganic ion exchanger obtained in the step (2) with water to remove excess alkali metal carbonate outside the crystal structure of the inorganic ion exchanger. By washing the inorganic ion exchanger obtained in step (2) with water, excess alkali metal carbonate outside the crystal structure of the inorganic ion exchanger is removed, and at the same time, the crystal structure of the layered titanate is changed. Water molecules are taken into the titanic acid, resulting in a structure in which the interlayer distance of titanic acid is further expanded.
洗浄の効率を上げるために、前記工程（２）で得られた生成物は、工程（３）の前に解砕しておくことが好ましい。解砕装置としては、ジョークラッシャー、ロールクラッシャー、ハンマーミルなどを用いることができる。
前記工程（３）において、イオン交換体の結晶構造内に存在するアルカリ金属炭酸塩等が除去されないように、水での洗浄は穏やかにすることが好ましい。即ち、適量の水で洗浄したり、高温でない水で洗浄したりすることで、結晶構造内での水分子をより多く保持することができる。例えば、水での洗浄は、工程（２）の生成物の重量に対して３～１０倍の重量の常温の水でスラリー化し、次いで脱水し、更に得られた脱水ケーキの重量に対して３～１０倍の重量の常温の水を通水する方法、或いは、前記スラリー化と脱水を２～３回繰り返す方法が好ましい。In order to increase the efficiency of washing, the product obtained in step (2) is preferably crushed before step (3). As the crushing device, a jaw crusher, roll crusher, hammer mill, etc. can be used.
In step (3), it is preferable to wash gently with water so as not to remove alkali metal carbonates and the like present in the crystal structure of the ion exchanger. That is, by washing with an appropriate amount of water or washing with water at a low temperature, more water molecules can be retained within the crystal structure. For example, washing with water involves slurrying the product in step (2) with 3 to 10 times the weight of room temperature water, followed by dehydration, and then 3 to 10 times the weight of the product in step (2). A method of passing 10 times the weight of water at room temperature, or a method of repeating the slurry formation and dehydration 2 to 3 times is preferred.
前記工程（４）は、前記工程（３）で洗浄後の無機イオン交換体を乾燥する工程である。水分子のみを完全に除去して、アルカリ金属炭酸塩等のみを結晶構造内に残すようにしてもよいが、アルカリ金属炭酸塩等だけでなく、水分子も結晶構造内に残すようにした方が、アルカリ金属炭酸塩等のみを結晶構造内に残すよりは、チタン酸の層間をより広くすることができ、本発明の技術的効果の発現を最大化することができる。したがって、前記工程（３）で層状チタン酸塩の結晶構造内に取り込まれた水分子を、前記工程（４）により前記無機イオン交換体を乾燥させてもなお結晶構造内に残存させるために、乾燥条件は、穏やかにすることが好ましい。乾燥条件としては、１００℃以下での温風乾燥が好ましく、５０℃以下での温風乾燥がより好ましい。
前記工程（３）および前記工程（４）においては、結晶構造内に取り込まれた水分子の一部と、結晶構造内に存在するアルカリ金属炭酸塩の一部と、水中または空気中から供給される二酸化炭素とが反応し、アルカリ金属炭酸水素塩が更に生成することがある。The step (4) is a step of drying the inorganic ion exchanger washed in the step (3). Although it is possible to completely remove only the water molecules and leave only the alkali metal carbonates, etc. in the crystal structure, it is better to leave not only the alkali metal carbonates, etc., but also the water molecules in the crystal structure. However, rather than leaving only the alkali metal carbonate or the like in the crystal structure, the gap between the titanic acid layers can be made wider, and the technical effects of the present invention can be maximized. Therefore, in order to cause the water molecules incorporated into the crystal structure of the layered titanate in step (3) to remain in the crystal structure even after drying the inorganic ion exchanger in step (4), It is preferable that the drying conditions be mild. As the drying conditions, hot air drying at 100°C or lower is preferred, and hot air drying at 50°C or lower is more preferred.
In the step (3) and the step (4), a part of the water molecules incorporated into the crystal structure, a part of the alkali metal carbonate present in the crystal structure, and a part of the alkali metal carbonate supplied from water or air are combined. may react with carbon dioxide to further form alkali metal bicarbonate.
工程（４）で得られた無機イオン交換体の乾燥物は、必要に応じ解砕または粉砕して粉末状とすることができる。また、得られた無機イオン交換体の粉末を、造粒助剤を用いて造粒処理を行い、造粒体としてもよい。造粒処理方法としては、特に制限はなく、転動造粒法、流動層造粒法、混合撹拌造粒法、押出造粒法、融解造粒法、噴霧造粒法、圧縮造粒法、粉砕造粒法等が挙げられる。造粒助剤としては、例えば、ベントナイト、アタパルジャイト、セピオライト、アロフェン、ハロイサイト、イモゴライト、カオリナイト等の粘土鉱物；ケイ酸ナトリウム、ケイ酸カルシウム、ケイ酸マグネシウム、メタケイ酸ナトリウム、メタケイ酸カルシウム、メタケイ酸マグネシウム、メタケイ酸アルミン酸ナトリウム、メタケイ酸アルミン酸カルシウム、メタケイ酸アルミン酸マグネシウムなどのケイ酸塩化合物；ポリビニルアルコール、カルボキシメチルセルロース、ショ糖脂肪酸エステル、ブタジエン－スチレンラテックス、フッ素樹脂などの有機高分子等が挙げられる。これらは１種を単独で用いてもよいし、２種以上を混合して用いてもよい。 The dried inorganic ion exchanger obtained in step (4) can be crushed or pulverized to a powder form, if necessary. Alternatively, the obtained inorganic ion exchanger powder may be granulated using a granulation aid to form a granule. There are no particular restrictions on the granulation treatment method, and examples include rolling granulation, fluidized bed granulation, mixed agitation granulation, extrusion granulation, melt granulation, spray granulation, compression granulation, Examples include pulverization and granulation methods. Examples of granulation aids include clay minerals such as bentonite, attapulgite, sepiolite, allophane, halloysite, imogolite, and kaolinite; sodium silicate, calcium silicate, magnesium silicate, sodium metasilicate, calcium metasilicate, and metasilicate. Silicate compounds such as magnesium, sodium aluminate metasilicate, calcium aluminate metasilicate, and magnesium aluminate metasilicate; organic polymers such as polyvinyl alcohol, carboxymethyl cellulose, sucrose fatty acid ester, butadiene-styrene latex, fluororesin, etc. can be mentioned. These may be used alone or in combination of two or more.
＜放射性ストロンチウムを含有する水の浄化方法＞
本発明の無機イオン交換体を用いて、放射性物質を含有する水、具体的には放射性ストロンチウムを含有する水を浄化し、水中に含まれる放射性ストロンチウムを除去することができる。前記放射性ストロンチウムを含む水の浄化方法は、本発明の無機イオン交換体に放射性ストロンチウムを含有する水を接触させる工程と、前記接触後に得られた水から前記無機イオン交換体を分離する工程とを順次行うことにより実施することができる。<Method for purifying water containing radioactive strontium>
Using the inorganic ion exchanger of the present invention, water containing radioactive substances, specifically water containing radioactive strontium, can be purified to remove radioactive strontium contained in the water. The method for purifying water containing radioactive strontium includes the steps of bringing water containing radioactive strontium into contact with the inorganic ion exchanger of the present invention, and separating the inorganic ion exchanger from the water obtained after the contact. It can be implemented by performing the steps sequentially.
本発明の放射性ストロンチウムを含有する水の浄化方法において、本発明の無機イオン交換体に放射性ストロンチウムを含有する水を接触させる方法は、特に制限はなく、例えば、前記無機イオン交換体をカラム等の容器に充填して、放射性ストロンチウムを含む水を通塔させる方法や、放射性ストロンチウムを含有する水に、本発明の無機イオン交換体を分散させる方法等が挙げられる。 In the method for purifying water containing radioactive strontium of the present invention, there is no particular restriction on the method of bringing the water containing radioactive strontium into contact with the inorganic ion exchanger of the present invention. Examples include a method of filling a container and passing water containing radioactive strontium through a tower, and a method of dispersing the inorganic ion exchanger of the present invention in water containing radioactive strontium.
前記放射性ストロンチウムを含有する水の浄化方法において、本発明の無機イオン交換体に放射性ストロンチウムを含有する水を接触後に得られた水から前記無機イオン交換体を分離する方法は、本発明の無機イオン交換体に放射性ストロンチウムを含有する水を接触後に得られた水から前記無機イオン交換体を分離できれば特に制限はなく、例えば、前記無機イオン交換体をカラム等の容器に充填して、放射性ストロンチウムを含有する水を通塔させる場合は、そのまま通過した水を分取すればよく、放射性ストロンチウムを含有する水に、本発明の無機イオン交換体を分散させる場合は、分散された無機イオン交換体を、上部または下部にストレーナー構造を有する容器を用いて無機イオン交換体を前記接触後の水から分離すること等により行うことができる。 In the method for purifying water containing radioactive strontium, the method for separating the inorganic ion exchanger from the water obtained after contacting the inorganic ion exchanger of the present invention with the water containing radioactive strontium is carried out using the inorganic ion exchanger of the present invention. There is no particular restriction as long as the inorganic ion exchanger can be separated from the water obtained after contacting the exchanger with water containing radioactive strontium. When water containing water is passed through the column, it is sufficient to separate the water that has passed through the column as it is, and when the inorganic ion exchanger of the present invention is dispersed in water containing radioactive strontium, the dispersed inorganic ion exchanger is This can be carried out by separating the inorganic ion exchanger from the water after the contact using a container having a strainer structure at the upper or lower part.
以下に実施例を比較例と共に挙げて本発明を詳細に説明するが、本発明はそれら実施例によって何ら限定されるものではない。以下の実施例と比較例において、得られたチタン酸塩の組成および物性の測定は下記によった。 EXAMPLES The present invention will be described in detail below using Examples and Comparative Examples, but the present invention is not limited to these Examples in any way. In the following Examples and Comparative Examples, the composition and physical properties of the obtained titanate were measured as follows.
＜金属元素組成分析＞
フッ酸と硝酸と過塩素酸との混酸を用い、テフロン（登録商標）製耐圧密閉容器内で１４０℃に加熱して試料を分解し、硝酸溶液としてから、ＩＣＰ－ＭＳにて金属元素の含有量を分析した。<Metal element composition analysis>
Using a mixed acid of hydrofluoric acid, nitric acid, and perchloric acid, the sample is decomposed by heating to 140°C in a pressure-tight airtight container made of Teflon (registered trademark) to form a nitric acid solution, and the metal element content is determined using ICP-MS. The amount was analyzed.
＜Ｃ、Ｈ含有量測定＞
ＪＩＳ Ｍ ８８１９の方法に従い、固体中炭素水素分析計を用いて、燃焼温度９２０℃の条件にて、ＣおよびＨの含有量を分析した。<C, H content measurement>
According to the method of JIS M 8819, the content of C and H was analyzed using a solid carbon hydrogen analyzer at a combustion temperature of 920°C.
＜粉末Ｘ線回折＞
（株）リガク製の粉末Ｘ線回折装置ＲＩＮＴ２２００ ＵＬＴＩＭＡ ＩＶを用い、線源
として、Ｃｕ管球［波長１．５４１８４１Å（Ｋα）］を用いて、角度（２θ）１°から２０°までの回折パターンを得た。そして、この角度範囲に回折ピークを有さないアナターゼ型二酸化チタン粉末の測定で得られたバックグラウンド曲線をフィッテングさせて補正した上で、最低角度（２θ）の回折ピークの位置および半値幅を求めた。<Powder X-ray diffraction>
Using a powder X-ray diffractometer RINT2200 ULTIMA IV manufactured by Rigaku Co., Ltd. and a Cu tube [wavelength 1.541841 Å (Kα)] as a radiation source, diffraction patterns were obtained at angles (2θ) from 1° to 20°. I got it. Then, after fitting and correcting the background curve obtained from the measurement of anatase-type titanium dioxide powder that does not have a diffraction peak in this angle range, the position and half-value width of the diffraction peak at the lowest angle (2θ) are determined. Ta.
＜ＴＧ－ＭＳ分析＞
（株）リガク製の粉示差熱天秤－光イオン化質量分析同時測定システム Ｔｈｅｒｍｏ Ｍａｓｓ Ｐｈｏｔｏを用い、室温から毎分１０℃で２００℃まで昇温したときの発生ガスを分析した。そして、（株）リガク発行のＴｈｅｒｍｏ Ｍａｓｓ Ｐｈｏｔｏ測定データ集に記載の無機ガスの簡易定量法を用いて、発生ガス量を求めた。<TG-MS analysis>
Using a powder differential thermal balance-photoionization mass spectrometry simultaneous measurement system Thermo Mass Photo manufactured by Rigaku Co., Ltd., the gas generated when the temperature was raised from room temperature to 200°C at 10°C per minute was analyzed. Then, the amount of gas generated was determined using the simple quantitative method for inorganic gas described in the Thermo Mass Photo measurement data collection published by Rigaku Co., Ltd.
＜１３Ｃ－ＮＭＲ＞
ＪＥＯＬ ＲＥＳＯＮＡＮＣＥ製のＪＮＭ－ＥＣＡ６００を用い、共鳴周波数１５０ＭＨｚとし、回転数１０ｋＨｚのＭＡＳ（シングルパルス）にて固体高分解能１３Ｃ－ＮＭＲ測定を行った。炭酸塩ピークの同定は、試薬炭酸塩の測定により得られた共鳴ピーク位置との比較により行った。 <13C-NMR>
Solid-state high-resolution 13 C-NMR measurement was performed using JNM-ECA600 manufactured by JEOL RESONANCE with a resonance frequency of 150 MHz and MAS (single pulse) at a rotation speed of 10 kHz. The carbonate peak was identified by comparison with the resonance peak position obtained by measuring the reagent carbonate.
＜ストロンチウム吸着試験＞
脱イオン水１Ｌに、塩化ストロンチウム（ＳｒＣｌ２）０．０９０５ｇを溶解させ、次いで４８％水酸化ナトリウム水溶液６．２５ｇを加えてよく混ぜ、試験溶液とした。この試験溶液５０ｍｌに、試料０．０５ｇを入れ、ラボシェーカーで１０時間振とうさせた。
振とう後、試験溶液をメンブレンフィルターにより濾過し、濾液中の残留ストロンチウム量をＩＣＰ－ＯＥＳ（パーキンエルマー製Ｏｐｔｉｍａ ８３００）を用いて定量し、分配係数Ｋｄ（ｍｌ／ｇ）を下記式により求めた。<Strontium adsorption test>
0.0905 g of strontium chloride (SrCl 2 ) was dissolved in 1 L of deionized water, and then 6.25 g of a 48% aqueous sodium hydroxide solution was added and mixed well to obtain a test solution. 0.05 g of the sample was added to 50 ml of this test solution, and the mixture was shaken using a lab shaker for 10 hours.
After shaking, the test solution was filtered with a membrane filter, and the amount of residual strontium in the filtrate was determined using ICP-OES (PerkinElmer Optima 8300), and the distribution coefficient Kd (ml/g) was determined using the following formula. .
（実施例１）
無水炭酸カリウム粉末２７．６ｇ（Ｋとして４００ｍｍｏｌ）と、硫酸カリウム粉末３５ｇと、アナターゼ型二酸化チタン粉末８．０ｇ（Ｔｉとして１００ｍｍｏｌ）とを乳鉢でよく混合し、アルミナルツボに入れて９５０℃で２０時間加熱した。生成物を乳鉢で粗解砕し、５００ｇの脱イオン水に懸濁させ、１時間撹拌した。次いで、減圧ろ過し、脱水ケーキとなったところで、減圧ろ過を続けながら、１００ｇの脱イオン水でリンス洗浄した。脱水したウエットケーキに、２０ｍｌのメタノールを通液して水と置換し、次いで、常温で風乾し、白色の粉末を得た。得られた白色粉末について、前記金属元素組成分析とＣ、Ｈ含有量測定結果を行ったところ、組成は次の式で表せることが分かった。
０．２４Ｋ２Ｏ・ＴｉＯ２・１．０Ｈ２Ｏ・０．０８６Ｋ２ＣＯ３
(Example 1)
27.6 g of anhydrous potassium carbonate powder (400 mmol as K), 35 g of potassium sulfate powder, and 8.0 g of anatase-type titanium dioxide powder (100 mmol as Ti) were thoroughly mixed in a mortar, placed in an alumina crucible, and heated at 950°C for 20 minutes. heated for an hour. The product was crushed in a mortar, suspended in 500 g of deionized water, and stirred for 1 hour. Next, it was filtered under reduced pressure, and when it became a dehydrated cake, it was rinsed with 100 g of deionized water while continuing to filter under reduced pressure. 20 ml of methanol was passed through the dehydrated wet cake to replace water, and then air-dried at room temperature to obtain a white powder. When the obtained white powder was subjected to the above-mentioned metal element composition analysis and C and H content measurement results, it was found that the composition can be expressed by the following formula.
0.24K2O・TiO2 ・ 1.0H2O・0.086K2CO3
次に、得られた白色粉末について、前記粉末Ｘ線回折測定を行ったところ、図１に示す回折パターンが得られた。回折角８°以下に極大点を有するブロードなピークが観察され、層状物質の層間が不規則に広がった構造であることが示唆された。最低角回折線のピーク位置は６．８°で、その半値幅は２θで５．２°であった。
さらに、得られた白色粉末について、前記ＴＧ－ＭＳ分析を行ったところ、１３％の重量減少があり、発生ガスはＨ２Ｏと同定された。
また、得られた白色粉末について、１３Ｃ－ＮＭＲを分析したところ、図２に示すチャートが得られ、化学シフトが１７０ｐｐｍの位置に炭酸カリウムに帰属される鋭いピークが得られた。
さらに、前記ストロンチウム吸着試験を行ったところ、分配係数Ｋｄは１００万ｍｌ／ｇであった。
以上の分析結果を表１に示す。表１に示した結果より、上記で得られた白色粉末は、結晶構造内に炭酸カリウムおよび炭酸水素カリウムからなる群から選ばれる少なくとも１種と水とを含有する、低結晶性の層状チタン酸カリウムであると推定され、優れたストロンチウム吸着能を有していた。Next, the obtained white powder was subjected to powder X-ray diffraction measurement, and the diffraction pattern shown in FIG. 1 was obtained. A broad peak with a maximum point at a diffraction angle of 8° or less was observed, suggesting a structure in which the interlayers of the layered material were spread irregularly. The peak position of the lowest angle diffraction line was 6.8°, and its half width was 5.2° at 2θ.
Further, when the obtained white powder was subjected to the above-mentioned TG-MS analysis, there was a weight decrease of 13%, and the generated gas was identified as H 2 O.
Further, when the obtained white powder was analyzed by 13 C-NMR, the chart shown in FIG. 2 was obtained, and a sharp peak attributed to potassium carbonate was obtained at a chemical shift of 170 ppm.
Furthermore, when the strontium adsorption test was conducted, the distribution coefficient Kd was 1 million ml/g.
The above analysis results are shown in Table 1. From the results shown in Table 1, the white powder obtained above is a low-crystalline layered titanic acid containing water and at least one member selected from the group consisting of potassium carbonate and potassium hydrogen carbonate in its crystal structure. It was presumed to be potassium and had excellent strontium adsorption ability.
（実施例２）
無水炭酸カリウム粉末１０．４ｇ（Ｋとして１５０ｍｍｏｌ）と、硫酸カリウム粉末１３ｇと、メタチタン酸粉末９．８ｇ（Ｔｉとして１００ｍｍｏｌ）とを乳鉢でよく混合し、アルミナルツボに入れて９００℃で２０時間加熱した。生成物を乳鉢で粗解砕し、３５０ｇの脱イオン水に懸濁させ、１時間撹拌した。次いで、減圧ろ過し、脱水ケーキとなったところで、減圧ろ過を続けながら、１００ｇの脱イオン水でリンス洗浄した。洗浄したケーキを、５０℃で温風乾燥し、白色粉末を得た。得られた白色粉末について、金属元素組成分析、Ｃ、Ｈ含有量測定、粉末Ｘ線回折、ＴＧ－ＭＳ分析、１３Ｃ－ＮＭＲ及びストロンチウム吸着試験を行った。その結果を表１に示す。表１に示した結果より、得られた白色粉末は、結晶構造内に炭酸カリウムおよび炭酸水素カリウムからなる群から選ばれる少なくとも１種と水とを含有する、低結晶性の層状チタン酸カリウムであると推定され、優れたストロンチウム吸着能を有していた。(Example 2)
10.4 g of anhydrous potassium carbonate powder (150 mmol as K), 13 g of potassium sulfate powder, and 9.8 g of metatitanic acid powder (100 mmol as Ti) were mixed well in a mortar, placed in an alumina crucible, and heated at 900°C for 20 hours. did. The product was crushed in a mortar, suspended in 350 g of deionized water, and stirred for 1 hour. Next, it was filtered under reduced pressure, and when it became a dehydrated cake, it was rinsed with 100 g of deionized water while continuing to filter under reduced pressure. The washed cake was dried with hot air at 50°C to obtain a white powder. The obtained white powder was subjected to metal element composition analysis, C and H content measurement, powder X-ray diffraction, TG-MS analysis, 13 C-NMR, and strontium adsorption test. The results are shown in Table 1. From the results shown in Table 1, the obtained white powder is a low-crystalline layered potassium titanate containing at least one member selected from the group consisting of potassium carbonate and potassium hydrogen carbonate and water in its crystal structure. It was estimated that the strontium adsorbent had excellent strontium adsorption ability.
（実施例３）
無水炭酸ナトリウム粉末２１．２ｇを水２００ｍｌに溶解し、常温で撹拌しながら、１０重量％硫酸チタン水溶液２４０ｇ（Ｔｉとして１００ｍｍｏｌ）を３０分間かけて滴下した。生成した水酸化チタンを遠心分離で回収し、１００℃で蒸発乾固させた後、乳鉢ですり潰して水酸化チタン粉末１１．３ｇを得た。この水酸化チタン粉末全量と、無水炭酸ナトリウム粉末１５．９ｇ（Ｎａとして３００ｍｍｏｌ）と、硫酸カリウム粉末２５ｇとを乳鉢でよく混合し、アルミナルツボに入れて９００℃で２０時間加熱した。生成物を乳鉢で粗解砕し、５００ｇの脱イオン水に懸濁させ、１時間撹拌した。次いで、減圧ろ過し、脱水ケーキとなったところで、減圧ろ過を続けながら、１００ｇの脱イオン水でリンス洗浄した。洗浄したケーキを、５０℃で温風乾燥し、白色粉末を得た。得られた白色粉末について、金属元素組成分析、Ｃ、Ｈ含有量測定、粉末Ｘ線回折、ＴＧ－ＭＳ分析、１３Ｃ－ＮＭＲ及びストロンチウム吸着試験を行った。その結果を表１に示す。表１に示した結果より、得られた白色粉末は、結晶構造内に炭酸ナトリウムおよび炭酸水素ナトリウムからなる群から選ばれる少なくとも１種と水とを含有する、低結晶性の層状チタン酸ナトリウムであると推定され、優れたストロンチウム吸着能を有していた。(Example 3)
21.2 g of anhydrous sodium carbonate powder was dissolved in 200 ml of water, and while stirring at room temperature, 240 g of a 10% by weight titanium sulfate aqueous solution (100 mmol as Ti) was added dropwise over 30 minutes. The produced titanium hydroxide was collected by centrifugation, evaporated to dryness at 100°C, and then ground in a mortar to obtain 11.3 g of titanium hydroxide powder. The entire amount of this titanium hydroxide powder, 15.9 g of anhydrous sodium carbonate powder (300 mmol as Na), and 25 g of potassium sulfate powder were thoroughly mixed in a mortar, placed in an alumina crucible, and heated at 900° C. for 20 hours. The product was crushed in a mortar, suspended in 500 g of deionized water, and stirred for 1 hour. Next, it was filtered under reduced pressure, and when it became a dehydrated cake, it was rinsed with 100 g of deionized water while continuing to filter under reduced pressure. The washed cake was dried with hot air at 50°C to obtain a white powder. The obtained white powder was subjected to metal element composition analysis, C and H content measurement, powder X-ray diffraction, TG-MS analysis, 13 C-NMR, and strontium adsorption test. The results are shown in Table 1. From the results shown in Table 1, the obtained white powder is a low-crystalline layered sodium titanate containing at least one member selected from the group consisting of sodium carbonate and sodium bicarbonate and water in its crystal structure. It was estimated that the strontium adsorbent had excellent strontium adsorption ability.
（実施例４）
無水炭酸リチウム粉末１４．９ｇを水２００ｍｌに溶解して７０℃に加熱し、撹拌しながら、１０重量％四塩化チタン水溶液１９０ｇ（Ｔｉとして１００ｍｍｏｌ）を３０分間かけて滴下した。生成した水酸化チタンを遠心分離で回収し、１００℃で蒸発乾固させた後、乳鉢ですり潰して水酸化チタン粉末１２．８ｇを得た。この水酸化チタン粉末全量と、無水炭酸リチウム粉末９．２ｇ（Ｌｉとして２５０ｍｍｏｌ）と、硫酸カリウム粉末２５ｇとを乳鉢でよく混合し、アルミナルツボに入れて９００℃で２０時間加熱した。生成物を乳鉢で粗解砕し、５００ｇの脱イオン水に懸濁させ、１時間撹拌した。次いで、減圧ろ過し、脱水ケーキとなったところで、減圧ろ過を続けながら、１００ｇの脱イオン水でリンス洗浄した。洗浄したケーキを、５０℃で温風乾燥し、白色粉末を得た。得られた白色粉末について、金属元素組成分析、Ｃ、Ｈ含有量測定、粉末Ｘ線回折、ＴＧ－ＭＳ分析、１３Ｃ－ＮＭＲ及びストロンチウム吸着試験を行った。その結果を表１に示す。表１に示した結果より、得られた白色粉末は、結晶構造内に炭酸リチウムおよび炭酸水素リチウムからなる群から選ばれる少なくとも１種と水とを含有する、低結晶性の層状構造チタン酸リチウムであると推定され、優れたストロンチウム吸着能を有していた。(Example 4)
14.9 g of anhydrous lithium carbonate powder was dissolved in 200 ml of water and heated to 70° C., and while stirring, 190 g of a 10% by weight titanium tetrachloride aqueous solution (100 mmol as Ti) was added dropwise over 30 minutes. The produced titanium hydroxide was collected by centrifugation, evaporated to dryness at 100°C, and then ground in a mortar to obtain 12.8 g of titanium hydroxide powder. The entire amount of this titanium hydroxide powder, 9.2 g of anhydrous lithium carbonate powder (250 mmol as Li), and 25 g of potassium sulfate powder were thoroughly mixed in a mortar, placed in an alumina crucible, and heated at 900° C. for 20 hours. The product was crushed in a mortar, suspended in 500 g of deionized water, and stirred for 1 hour. Next, it was filtered under reduced pressure, and when it became a dehydrated cake, it was rinsed with 100 g of deionized water while continuing to filter under reduced pressure. The washed cake was dried with hot air at 50°C to obtain a white powder. The obtained white powder was subjected to metal element composition analysis, C and H content measurement, powder X-ray diffraction, TG-MS analysis, 13 C-NMR, and strontium adsorption test. The results are shown in Table 1. From the results shown in Table 1, the obtained white powder has a low crystalline layered structure of lithium titanate containing at least one member selected from the group consisting of lithium carbonate and lithium hydrogen carbonate and water in its crystal structure. It was estimated that it had excellent strontium adsorption ability.
（比較例１）
無水炭酸カリウム粉末３．５ｇ（Ｋとして５０ｍｍｏｌ）と、アナターゼ型二酸化チタン粉末８．０ｇ（Ｔｉとして１００ｍｍｏｌ）をと乳鉢でよく混合し、アルミナルツボに入れて８００℃で４８時間加熱し、白色粉末を得た。ただし、加熱１６時間毎に一旦冷却し、乳鉢でよくすり潰した。得られた白色粉末について、金属元素組成分析、Ｃ、Ｈ含有量測定、粉末Ｘ線回折、ＴＧ－ＭＳ分析、１３Ｃ－ＮＭＲ及びストロンチウム吸着試験を行った。その結果を表１に示す。表１に示した結果より、得られた白色粉末は、結晶構造内にアルカリ金属炭酸塩およびアルカリ金属炭酸酸塩を含有しない、層状四チタン酸カリウムであると推定された。(Comparative example 1)
3.5 g of anhydrous potassium carbonate powder (50 mmol as K) and 8.0 g of anatase-type titanium dioxide powder (100 mmol as Ti) were mixed well in a mortar, placed in an alumina crucible, and heated at 800°C for 48 hours to form a white powder. I got it. However, after every 16 hours of heating, the mixture was cooled and thoroughly ground in a mortar. The obtained white powder was subjected to metal element composition analysis, C and H content measurement, powder X-ray diffraction, TG-MS analysis, 13 C-NMR, and strontium adsorption test. The results are shown in Table 1. From the results shown in Table 1, it was estimated that the obtained white powder was layered potassium tetratitanate containing no alkali metal carbonate or alkali metal carbonate in its crystal structure.
（比較例２）
比較例１で得られたチタン酸カリウム１ｇを６０ｇの脱イオン水に懸濁させ、４８時間撹拌した。次いで、減圧ろ過し、脱水ケーキとなったところで、減圧ろ過を続けながら、１０ｇの脱イオン水でリンス洗浄した。洗浄したケーキを、室温で風乾し、白色粉末を得た。得られた白色粉末について、金属元素組成分析、Ｃ、Ｈ含有量測定、粉末Ｘ線回折、ＴＧ－ＭＳ分析、１３Ｃ－ＮＭＲ及びストロンチウム吸着試験を行った。その結果を表１に示す。表１に示した結果より、得られた白色粉末は、層状結晶である四チタン酸カリウムの層間から一部のカリウムが溶出するとともに、水とオキソニウムイオンとが導入され、層間が規則的に広がっているが、結晶構造内にアルカリ金属炭酸塩およびアルカリ金属炭酸酸塩を含有しない、層状チタン酸カリウムであると推定された。(Comparative example 2)
1 g of potassium titanate obtained in Comparative Example 1 was suspended in 60 g of deionized water and stirred for 48 hours. Next, it was filtered under reduced pressure, and when it became a dehydrated cake, it was rinsed with 10 g of deionized water while continuing to filter under reduced pressure. The washed cake was air-dried at room temperature to obtain a white powder. The obtained white powder was subjected to metal element composition analysis, C and H content measurement, powder X-ray diffraction, TG-MS analysis, 13 C-NMR, and strontium adsorption test. The results are shown in Table 1. From the results shown in Table 1, the white powder obtained is such that some potassium is eluted from between the layers of potassium tetratitanate, which is a layered crystal, and water and oxonium ions are introduced, resulting in regular interlayer formation. It was presumed to be a layered potassium titanate that does not contain alkali metal carbonates or alkali metal carbonates in its crystal structure.
（比較例３）
無水炭酸ナトリウム粉末２１．２ｇを水２００ｍｌに溶解し、常温で撹拌しながら、１０重量％硫酸チタン水溶液２４０ｇ（Ｔｉとして１００ｍｍｏｌ）を３０分間かけて滴下した。生成した水酸化チタンを遠心分離で回収し、１００℃で蒸発乾固させた後、乳鉢ですり潰して水酸化チタン粉末１１．３ｇを得た。この水酸化チタン粉末全量と、無水炭酸ナトリウム粉末３．７ｇ（Ｎａとして７０ｍｍｏｌ）と、硫酸カリウム粉末２５ｇとを乳鉢でよく混合し、アルミナルツボに入れて９００℃で２０時間加熱した。生成物を乳鉢で粗解砕し、５００ｇの脱イオン水に懸濁させ、１時間撹拌した。次いで、減圧ろ過し、脱水ケーキとなったところで、減圧ろ過を続けながら、１００ｇの脱イオン水でリンス洗浄した。洗浄したケーキを、５０℃で温風乾燥し、白色粉末を得た。得られた白色粉末について、金属元素組成分析、Ｃ、Ｈ含有量測定、粉末Ｘ線回折、ＴＧ－ＭＳ分析、１３Ｃ－ＮＭＲ及びストロンチウム吸着試験を行った。その結果を表１に示す。表１に示した結果より、得られた白色粉末は、結晶構造内にアルカリ金属炭酸塩およびアルカリ金属炭酸酸塩を含有しない、トンネル構造のチタン酸ナトリウムであると推定された。(Comparative example 3)
21.2 g of anhydrous sodium carbonate powder was dissolved in 200 ml of water, and while stirring at room temperature, 240 g of a 10% by weight titanium sulfate aqueous solution (100 mmol as Ti) was added dropwise over 30 minutes. The produced titanium hydroxide was collected by centrifugation, evaporated to dryness at 100°C, and then ground in a mortar to obtain 11.3 g of titanium hydroxide powder. The entire amount of this titanium hydroxide powder, 3.7 g of anhydrous sodium carbonate powder (70 mmol as Na), and 25 g of potassium sulfate powder were thoroughly mixed in a mortar, placed in an alumina crucible, and heated at 900° C. for 20 hours. The product was crushed in a mortar, suspended in 500 g of deionized water, and stirred for 1 hour. Next, it was filtered under reduced pressure, and when it became a dehydrated cake, it was rinsed with 100 g of deionized water while continuing to filter under reduced pressure. The washed cake was dried with hot air at 50°C to obtain a white powder. The obtained white powder was subjected to metal element composition analysis, C and H content measurement, powder X-ray diffraction, TG-MS analysis, 13 C-NMR, and strontium adsorption test. The results are shown in Table 1. From the results shown in Table 1, it was estimated that the obtained white powder was sodium titanate with a tunnel structure that did not contain an alkali metal carbonate or an alkali metal carbonate in its crystal structure.
（比較例４）
無水炭酸リチウム粉末１４．９ｇを水２００ｍｌに溶解して７０℃に加熱し、攪拌しながら、１０重量％四塩化チタン水溶液１９０ｇ（Ｔｉとして１００ｍｍｏｌ）を３０分間かけて滴下した。生成した水酸化チタンを遠心分離で回収し、１００℃で蒸発乾固させた後、乳鉢ですり潰して水酸化チタン粉末１２．８ｇを得た。この水酸化チタン粉末全量と、無水炭酸リチウム粉末７．４ｇ（Ｌｉとして２００ｍｍｏｌ）と、硫酸カリウム粉末２５ｇとを乳鉢でよく混合し、アルミナルツボに入れて９００℃で２０時間加熱した。生成物を乳鉢で粗解砕し、５００ｇの脱イオン水に懸濁させ、１時間攪拌した。次いで、減圧ろ過し、脱水ケーキとなったところで、減圧ろ過を続けながら、１００ｇの脱イオン水でリンス洗浄した。洗浄したケーキを、５０℃で温風乾燥し、白色粉末を得た。得られた白色粉末について、金属元素組成分析、Ｃ、Ｈ含有量測定、粉末Ｘ線回折、ＴＧ－ＭＳ分析、１３Ｃ－ＮＭＲ及びストロンチウム吸着試験を行った。その結果を表１に示す。表１に示した結果より、得られた白色粉末は、結晶構造内にアルカリ金属炭酸塩およびアルカリ金属炭酸酸塩を含有しない、層状チタン酸リチウムであると推定された。(Comparative example 4)
14.9 g of anhydrous lithium carbonate powder was dissolved in 200 ml of water and heated to 70° C., and while stirring, 190 g of a 10% by weight titanium tetrachloride aqueous solution (100 mmol as Ti) was added dropwise over 30 minutes. The produced titanium hydroxide was collected by centrifugation, evaporated to dryness at 100°C, and then ground in a mortar to obtain 12.8 g of titanium hydroxide powder. The entire amount of this titanium hydroxide powder, 7.4 g of anhydrous lithium carbonate powder (200 mmol as Li), and 25 g of potassium sulfate powder were thoroughly mixed in a mortar, placed in an alumina crucible, and heated at 900° C. for 20 hours. The product was crushed in a mortar, suspended in 500 g of deionized water, and stirred for 1 hour. Next, it was filtered under reduced pressure, and when it became a dehydrated cake, it was rinsed with 100 g of deionized water while continuing to filter under reduced pressure. The washed cake was dried with hot air at 50°C to obtain a white powder. The obtained white powder was subjected to metal element composition analysis, C and H content measurement, powder X-ray diffraction, TG-MS analysis, 13 C-NMR, and strontium adsorption test. The results are shown in Table 1. From the results shown in Table 1, it was estimated that the obtained white powder was layered lithium titanate containing no alkali metal carbonate or alkali metal carbonate in its crystal structure.
表１に示したように、１３Ｃ－ＮＭＲの結果、実施例１～４の層状チタン酸塩は、いずれもＣＯ３に帰属できるピークが確認され、結晶構造内にアルカリ金属炭酸塩およびアルカリ金属炭酸水素塩からなる群から選ばれる少なくとも１種が含有されることが確認された。それに対して、比較例１～４のチタン酸塩は、いずれもアルカリ金属炭酸塩およびアルカリ金属炭酸水素塩を含んでいなかった。
また、ストロンチウム吸着試験の結果、実施例１～４の層状チタン酸塩は、上記の分配係数がいずれも５００００ｍｌ／ｇ以上であり、高いストロンチウム吸着能を有することが確認された。それに対して、比較例１～４のチタン酸塩は、分配係数が５０ｍｌ／ｇ以下であり、ストロンチウム吸着能において劣っていた。As shown in Table 1, as a result of 13 C-NMR, the layered titanates of Examples 1 to 4 all had peaks that could be attributed to CO 3 , and contained alkali metal carbonates and alkali metals in their crystal structures. It was confirmed that at least one selected from the group consisting of hydrogen carbonates was contained. In contrast, none of the titanates of Comparative Examples 1 to 4 contained alkali metal carbonate or alkali metal hydrogen carbonate.
Further, as a result of the strontium adsorption test, it was confirmed that the layered titanates of Examples 1 to 4 all had the above-mentioned distribution coefficients of 50,000 ml/g or more, and had high strontium adsorption ability. In contrast, the titanates of Comparative Examples 1 to 4 had partition coefficients of 50 ml/g or less and were inferior in strontium adsorption ability.
また、粉末Ｘ線回折の結果、実施例１～４の層状チタン酸塩は、いずれも回折角（２θ）が１°以上８°以下の範囲に極大点のある回折ピークを有しており、チタン酸の層間距離が広いことが確認された。それに対して、比較例１～４のチタン酸塩は、回折角（２θ）が８°を超えており、チタン酸の層間距離が、実施例１～４の層状チタン酸塩と比較して狭くなっていた。 Further, as a result of powder X-ray diffraction, the layered titanates of Examples 1 to 4 all have diffraction peaks with maximum points in the range of diffraction angles (2θ) of 1° or more and 8° or less, It was confirmed that the interlayer distance of titanic acid was wide. In contrast, the titanates of Comparative Examples 1 to 4 have diffraction angles (2θ) exceeding 8°, and the interlayer distance of titanic acid is narrower than that of the layered titanates of Examples 1 to 4. It had become.
また、実施例１～４の層状チタン酸塩は、粉末Ｘ線回折の回折ピークの半値幅が２θで、いずれも３°以上であり、低結晶性のチタン酸塩であることが確認された。それに対して、比較例１～４のチタン酸塩は、粉末Ｘ線回折の回折ピークの半値幅が２θで、いずれも１°以下であり、結晶性が高いチタン酸塩であることが確認された。
さらに、実施例１～４の層状チタン酸塩は、ＴＧ－ＭＳの結果、結晶構造内に水を含むことが確認された。それに対し、比較例１、２および４のチタン酸塩は、結晶構造内に水を含んでいなかった。In addition, the layered titanates of Examples 1 to 4 had a half-value width of the diffraction peak in powder X-ray diffraction of 2θ, which was 3° or more in each case, and it was confirmed that the layered titanates were low-crystalline titanates. . On the other hand, in the titanates of Comparative Examples 1 to 4, the half-width of the diffraction peak in powder X-ray diffraction is 2θ, which is 1° or less, and it is confirmed that the titanates have high crystallinity. Ta.
Further, as a result of TG-MS, it was confirmed that the layered titanates of Examples 1 to 4 contained water in their crystal structures. In contrast, the titanates of Comparative Examples 1, 2, and 4 did not contain water in their crystal structures.
本発明の無機イオン交換体は、高いイオン交換能を有し、放射性物質を含有する水から高い効率で放射性物質を除去することができる。このため、例えば、井戸水、湖沼水、河川水、雨水、湧水、上下水道水、工場上水・中水・下水などの各種の水などからの重金属除去、海水などからの有価資源回収、汚染土壌からの有害物質除去などにも使用することができる。 The inorganic ion exchanger of the present invention has high ion exchange ability and can remove radioactive substances from water containing radioactive substances with high efficiency. For this reason, for example, heavy metal removal from various types of water such as well water, lake water, river water, rainwater, spring water, water and sewage water, factory water, gray water, and sewage, recovery of valuable resources from seawater, etc., and contamination. It can also be used to remove harmful substances from soil.
Claims (8)
Ｋｄ＝Ｑｅｑ／Ｃｅｑ・・・（１）
（式（１）中、Ｋｄは分配係数（ｍｌ／ｇ）、Ｃｅｑは平衡到達時の水溶液中のストロンチウム濃度（ｍｏｌ／ｍｌ）、Ｑｅｑは平衡到達時の無機イオン交換体の単位重量当たりのストロンチウム吸着量（ｍｏｌ／ｇ）をそれぞれ表す） According to any one of claims 1 to 3, the distribution coefficient expressed by the following formula (1) is 30,000 ml/g or more when dispersed in an alkaline strontium aqueous solution having a pH of 12 or more. inorganic ion exchanger.
Kd=Qeq/Ceq...(1)
(In formula (1), Kd is the distribution coefficient (ml/g), Ceq is the strontium concentration in the aqueous solution (mol/ml) when equilibrium is reached, and Qeq is the strontium per unit weight of the inorganic ion exchanger when equilibrium is reached. Each represents the adsorption amount (mol/g)
工程（１）：チタン化合物の粉末と過剰量の、アルカリ金属炭酸塩およびアルカリ金属炭酸水素塩からなる群から選ばれる少なくとも１種の粉末とを混合する工程
工程（２）：前記工程（１）で得られた混合物を７００℃以上１５００℃以下で加熱する工程
工程（３）：前記工程（２）で得られた無機イオン交換体を水で洗浄する工程
工程（４）：前記工程（３）で得られた洗浄後の無機イオン交換体を１００℃以下での温風乾燥する工程 A method for producing an inorganic ion exchanger according to any one of claims 1 to 4, comprising sequentially performing the following steps (1), (2), (3), and (4). A method for producing a featured inorganic ion exchanger.
Step (1): A step of mixing a titanium compound powder and an excess amount of at least one kind of powder selected from the group consisting of alkali metal carbonates and alkali metal hydrogen carbonates. Step (2): Step (1) above. Step (3): Washing the inorganic ion exchanger obtained in Step (2) with water Step (4): Step (3) A step of drying the washed inorganic ion exchanger obtained by hot air at a temperature of 100°C or less.
る請求項５又は６に記載の無機イオン交換体の製造方法。 The method for producing an inorganic ion exchanger according to claim 5 or 6, characterized in that in the step (1), alkali metal sulfate powder is further mixed.
有する水を接触させる工程と、前記接触後の水から前記無機イオン交換体を分離する工程
とを順次行うことを特徴とする、放射性ストロンチウムを含有する水の浄化方法。 A step of bringing water containing radioactive strontium into contact with the inorganic ion exchanger according to any one of claims 1 to 4, and a step of separating the inorganic ion exchanger from the water after the contact are performed sequentially. A method for purifying water containing radioactive strontium, characterized by:
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| WO2017086056A1 (en) | 2015-11-18 | 2017-05-26 | 国立大学法人香川大学 | Strontium ion adsorbent and method for producing same |
| JP2017209594A (en) | 2016-05-23 | 2017-11-30 | 株式会社クボタ | Ion-exchange material, ion exchanger, ion adsorption device, water treatment system, production method of ion-exchange material, and production method of ion exchanger |
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| JPWO2020017538A1 (en) | 2021-08-02 |
| WO2020017538A1 (en) | 2020-01-23 |
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