JP2015007634A - RADIOACTIVE Cs ADSORBENT AND METHOD OF MANUFACTURING THE SAME - Google Patents
RADIOACTIVE Cs ADSORBENT AND METHOD OF MANUFACTURING THE SAME Download PDFInfo
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- JP2015007634A JP2015007634A JP2014150468A JP2014150468A JP2015007634A JP 2015007634 A JP2015007634 A JP 2015007634A JP 2014150468 A JP2014150468 A JP 2014150468A JP 2014150468 A JP2014150468 A JP 2014150468A JP 2015007634 A JP2015007634 A JP 2015007634A
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- Prior art keywords
- adsorbent
- radioactive
- prussian blue
- ions
- hydroxide
- Prior art date
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- 239000003463 adsorbent Substances 0.000 title claims abstract description 104
- 230000002285 radioactive effect Effects 0.000 title claims abstract description 68
- 238000004519 manufacturing process Methods 0.000 title claims abstract description 25
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims abstract description 67
- DCYOBGZUOMKFPA-UHFFFAOYSA-N iron(2+);iron(3+);octadecacyanide Chemical compound [Fe+2].[Fe+2].[Fe+2].[Fe+3].[Fe+3].[Fe+3].[Fe+3].N#[C-].N#[C-].N#[C-].N#[C-].N#[C-].N#[C-].N#[C-].N#[C-].N#[C-].N#[C-].N#[C-].N#[C-].N#[C-].N#[C-].N#[C-].N#[C-].N#[C-].N#[C-] DCYOBGZUOMKFPA-UHFFFAOYSA-N 0.000 claims abstract description 38
- 229960003351 prussian blue Drugs 0.000 claims abstract description 38
- 239000013225 prussian blue Substances 0.000 claims abstract description 38
- -1 iron salt compound Chemical class 0.000 claims abstract description 33
- VTLYFUHAOXGGBS-UHFFFAOYSA-N Fe3+ Chemical compound [Fe+3] VTLYFUHAOXGGBS-UHFFFAOYSA-N 0.000 claims abstract description 31
- 238000000034 method Methods 0.000 claims abstract description 27
- 239000007864 aqueous solution Substances 0.000 claims abstract description 22
- XLYOFNOQVPJJNP-UHFFFAOYSA-M hydroxide Chemical compound [OH-] XLYOFNOQVPJJNP-UHFFFAOYSA-M 0.000 claims abstract description 20
- 150000001768 cations Chemical class 0.000 claims abstract description 16
- 230000036961 partial effect Effects 0.000 claims abstract description 15
- 229910052723 transition metal Inorganic materials 0.000 claims abstract description 14
- 150000003624 transition metals Chemical class 0.000 claims abstract description 12
- 150000007661 iron cyano complex Chemical class 0.000 claims abstract description 8
- XEEYBQQBJWHFJM-UHFFFAOYSA-N iron Substances [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 claims description 41
- 239000000706 filtrate Substances 0.000 claims description 21
- 238000003786 synthesis reaction Methods 0.000 claims description 11
- 230000015572 biosynthetic process Effects 0.000 claims description 10
- 238000001914 filtration Methods 0.000 claims description 8
- PXHVJJICTQNCMI-UHFFFAOYSA-N Nickel Chemical compound [Ni] PXHVJJICTQNCMI-UHFFFAOYSA-N 0.000 claims description 5
- 238000001035 drying Methods 0.000 claims description 4
- HCHKCACWOHOZIP-UHFFFAOYSA-N Zinc Chemical compound [Zn] HCHKCACWOHOZIP-UHFFFAOYSA-N 0.000 claims description 3
- 239000010949 copper Substances 0.000 claims description 3
- 239000011701 zinc Substances 0.000 claims description 3
- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical compound [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 claims description 2
- 229910052793 cadmium Inorganic materials 0.000 claims description 2
- BDOSMKKIYDKNTQ-UHFFFAOYSA-N cadmium atom Chemical compound [Cd] BDOSMKKIYDKNTQ-UHFFFAOYSA-N 0.000 claims description 2
- 229910017052 cobalt Inorganic materials 0.000 claims description 2
- 239000010941 cobalt Substances 0.000 claims description 2
- GUTLYIVDDKVIGB-UHFFFAOYSA-N cobalt atom Chemical compound [Co] GUTLYIVDDKVIGB-UHFFFAOYSA-N 0.000 claims description 2
- 229910052802 copper Inorganic materials 0.000 claims description 2
- WPBNNNQJVZRUHP-UHFFFAOYSA-L manganese(2+);methyl n-[[2-(methoxycarbonylcarbamothioylamino)phenyl]carbamothioyl]carbamate;n-[2-(sulfidocarbothioylamino)ethyl]carbamodithioate Chemical compound [Mn+2].[S-]C(=S)NCCNC([S-])=S.COC(=O)NC(=S)NC1=CC=CC=C1NC(=S)NC(=O)OC WPBNNNQJVZRUHP-UHFFFAOYSA-L 0.000 claims description 2
- 229910052759 nickel Inorganic materials 0.000 claims description 2
- 229910052725 zinc Inorganic materials 0.000 claims description 2
- 150000003841 chloride salts Chemical class 0.000 claims 1
- 150000002823 nitrates Chemical class 0.000 claims 1
- 150000003467 sulfuric acid derivatives Chemical class 0.000 claims 1
- 229910001417 caesium ion Inorganic materials 0.000 abstract description 59
- 239000000243 solution Substances 0.000 abstract description 20
- 230000008569 process Effects 0.000 abstract description 9
- 230000002194 synthesizing effect Effects 0.000 abstract description 5
- CWYNVVGOOAEACU-UHFFFAOYSA-N Fe2+ Chemical compound [Fe+2] CWYNVVGOOAEACU-UHFFFAOYSA-N 0.000 abstract description 3
- 238000012360 testing method Methods 0.000 description 37
- 230000000052 comparative effect Effects 0.000 description 27
- 238000003756 stirring Methods 0.000 description 26
- 239000013078 crystal Substances 0.000 description 25
- 150000002500 ions Chemical class 0.000 description 23
- 239000007788 liquid Substances 0.000 description 21
- 238000006243 chemical reaction Methods 0.000 description 20
- 238000001179 sorption measurement Methods 0.000 description 20
- 239000010410 layer Substances 0.000 description 19
- HEMHJVSKTPXQMS-UHFFFAOYSA-M Sodium hydroxide Chemical compound [OH-].[Na+] HEMHJVSKTPXQMS-UHFFFAOYSA-M 0.000 description 15
- 239000013535 sea water Substances 0.000 description 15
- 239000002585 base Substances 0.000 description 13
- 239000002253 acid Substances 0.000 description 12
- 239000012153 distilled water Substances 0.000 description 12
- 239000000047 product Substances 0.000 description 11
- 239000011521 glass Substances 0.000 description 10
- 230000007062 hydrolysis Effects 0.000 description 10
- 238000006460 hydrolysis reaction Methods 0.000 description 10
- 230000003993 interaction Effects 0.000 description 9
- NQXWGWZJXJUMQB-UHFFFAOYSA-K iron trichloride hexahydrate Chemical compound O.O.O.O.O.O.[Cl-].Cl[Fe+]Cl NQXWGWZJXJUMQB-UHFFFAOYSA-K 0.000 description 9
- 239000000203 mixture Substances 0.000 description 9
- 239000003795 chemical substances by application Substances 0.000 description 8
- ARUVKPQLZAKDPS-UHFFFAOYSA-L copper(II) sulfate Chemical compound [Cu+2].[O-][S+2]([O-])([O-])[O-] ARUVKPQLZAKDPS-UHFFFAOYSA-L 0.000 description 8
- 229910000366 copper(II) sulfate Inorganic materials 0.000 description 8
- 239000011734 sodium Substances 0.000 description 8
- 239000004480 active ingredient Substances 0.000 description 7
- 125000004093 cyano group Chemical group *C#N 0.000 description 7
- 239000006185 dispersion Substances 0.000 description 7
- 230000000694 effects Effects 0.000 description 7
- 239000011229 interlayer Substances 0.000 description 7
- 229910001415 sodium ion Inorganic materials 0.000 description 7
- 239000000126 substance Substances 0.000 description 7
- QAOWNCQODCNURD-UHFFFAOYSA-N Sulfuric acid Chemical compound OS(O)(=O)=O QAOWNCQODCNURD-UHFFFAOYSA-N 0.000 description 6
- 229910021536 Zeolite Inorganic materials 0.000 description 6
- HNPSIPDUKPIQMN-UHFFFAOYSA-N dioxosilane;oxo(oxoalumanyloxy)alumane Chemical compound O=[Si]=O.O=[Al]O[Al]=O HNPSIPDUKPIQMN-UHFFFAOYSA-N 0.000 description 6
- 238000004770 highest occupied molecular orbital Methods 0.000 description 6
- ISPYRSDWRDQNSW-UHFFFAOYSA-L manganese(II) sulfate monohydrate Chemical compound O.[Mn+2].[O-]S([O-])(=O)=O ISPYRSDWRDQNSW-UHFFFAOYSA-L 0.000 description 6
- 238000005259 measurement Methods 0.000 description 6
- 239000000049 pigment Substances 0.000 description 6
- 239000000843 powder Substances 0.000 description 6
- 239000010457 zeolite Substances 0.000 description 6
- 150000007513 acids Chemical class 0.000 description 5
- AIYUHDOJVYHVIT-UHFFFAOYSA-M caesium chloride Chemical compound [Cl-].[Cs+] AIYUHDOJVYHVIT-UHFFFAOYSA-M 0.000 description 5
- 229910001424 calcium ion Inorganic materials 0.000 description 5
- 238000009792 diffusion process Methods 0.000 description 5
- 229910052751 metal Inorganic materials 0.000 description 5
- 239000002184 metal Substances 0.000 description 5
- 239000002244 precipitate Substances 0.000 description 5
- 238000000967 suction filtration Methods 0.000 description 5
- JFSUDVTVQZUDOP-UHFFFAOYSA-N tetrasodium;iron(2+);hexacyanide;decahydrate Chemical compound O.O.O.O.O.O.O.O.O.O.[Na+].[Na+].[Na+].[Na+].[Fe+2].N#[C-].N#[C-].N#[C-].N#[C-].N#[C-].N#[C-] JFSUDVTVQZUDOP-UHFFFAOYSA-N 0.000 description 5
- LWAVGNJLLQSNNN-UHFFFAOYSA-N (2,5-dioxopyrrolidin-1-yl) 4-azidobenzoate Chemical compound C1=CC(N=[N+]=[N-])=CC=C1C(=O)ON1C(=O)CCC1=O LWAVGNJLLQSNNN-UHFFFAOYSA-N 0.000 description 4
- NAWXUBYGYWOOIX-SFHVURJKSA-N (2s)-2-[[4-[2-(2,4-diaminoquinazolin-6-yl)ethyl]benzoyl]amino]-4-methylidenepentanedioic acid Chemical compound C1=CC2=NC(N)=NC(N)=C2C=C1CCC1=CC=C(C(=O)N[C@@H](CC(=C)C(O)=O)C(O)=O)C=C1 NAWXUBYGYWOOIX-SFHVURJKSA-N 0.000 description 4
- VEXZGXHMUGYJMC-UHFFFAOYSA-N Hydrochloric acid Chemical compound Cl VEXZGXHMUGYJMC-UHFFFAOYSA-N 0.000 description 4
- 239000011362 coarse particle Substances 0.000 description 4
- 150000001875 compounds Chemical class 0.000 description 4
- 238000002474 experimental method Methods 0.000 description 4
- 229910052742 iron Inorganic materials 0.000 description 4
- 229910001425 magnesium ion Inorganic materials 0.000 description 4
- 230000007246 mechanism Effects 0.000 description 4
- VEXZGXHMUGYJMC-UHFFFAOYSA-M Chloride anion Chemical compound [Cl-] VEXZGXHMUGYJMC-UHFFFAOYSA-M 0.000 description 3
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 description 3
- 230000009471 action Effects 0.000 description 3
- 239000003513 alkali Substances 0.000 description 3
- 239000002131 composite material Substances 0.000 description 3
- NMCUIPGRVMDVDB-UHFFFAOYSA-L iron dichloride Chemical compound Cl[Fe]Cl NMCUIPGRVMDVDB-UHFFFAOYSA-L 0.000 description 3
- 238000002360 preparation method Methods 0.000 description 3
- 229910052708 sodium Inorganic materials 0.000 description 3
- 229910021580 Cobalt(II) chloride Inorganic materials 0.000 description 2
- 229910021503 Cobalt(II) hydroxide Inorganic materials 0.000 description 2
- XFXPMWWXUTWYJX-UHFFFAOYSA-N Cyanide Chemical compound N#[C-] XFXPMWWXUTWYJX-UHFFFAOYSA-N 0.000 description 2
- TWRXJAOTZQYOKJ-UHFFFAOYSA-L Magnesium chloride Chemical compound [Mg+2].[Cl-].[Cl-] TWRXJAOTZQYOKJ-UHFFFAOYSA-L 0.000 description 2
- CSNNHWWHGAXBCP-UHFFFAOYSA-L Magnesium sulfate Chemical compound [Mg+2].[O-][S+2]([O-])([O-])[O-] CSNNHWWHGAXBCP-UHFFFAOYSA-L 0.000 description 2
- PWHULOQIROXLJO-UHFFFAOYSA-N Manganese Chemical compound [Mn] PWHULOQIROXLJO-UHFFFAOYSA-N 0.000 description 2
- 229910021586 Nickel(II) chloride Inorganic materials 0.000 description 2
- WCUXLLCKKVVCTQ-UHFFFAOYSA-M Potassium chloride Chemical compound [Cl-].[K+] WCUXLLCKKVVCTQ-UHFFFAOYSA-M 0.000 description 2
- FAPWRFPIFSIZLT-UHFFFAOYSA-M Sodium chloride Chemical compound [Na+].[Cl-] FAPWRFPIFSIZLT-UHFFFAOYSA-M 0.000 description 2
- QAOWNCQODCNURD-UHFFFAOYSA-L Sulfate Chemical compound [O-]S([O-])(=O)=O QAOWNCQODCNURD-UHFFFAOYSA-L 0.000 description 2
- XLOMVQKBTHCTTD-UHFFFAOYSA-N Zinc monoxide Chemical compound [Zn]=O XLOMVQKBTHCTTD-UHFFFAOYSA-N 0.000 description 2
- QKDIMNPUZPNYGB-UHFFFAOYSA-N [Cu](C#N)C#N.[Fe] Chemical compound [Cu](C#N)C#N.[Fe] QKDIMNPUZPNYGB-UHFFFAOYSA-N 0.000 description 2
- 239000011149 active material Substances 0.000 description 2
- 229910001413 alkali metal ion Inorganic materials 0.000 description 2
- 229910001420 alkaline earth metal ion Inorganic materials 0.000 description 2
- 150000008064 anhydrides Chemical class 0.000 description 2
- 229920006318 anionic polymer Polymers 0.000 description 2
- 150000001450 anions Chemical class 0.000 description 2
- 238000004774 atomic orbital Methods 0.000 description 2
- 239000003638 chemical reducing agent Substances 0.000 description 2
- GVPFVAHMJGGAJG-UHFFFAOYSA-L cobalt dichloride Chemical compound [Cl-].[Cl-].[Co+2] GVPFVAHMJGGAJG-UHFFFAOYSA-L 0.000 description 2
- ASKVAEGIVYSGNY-UHFFFAOYSA-L cobalt(ii) hydroxide Chemical compound [OH-].[OH-].[Co+2] ASKVAEGIVYSGNY-UHFFFAOYSA-L 0.000 description 2
- ORTQZVOHEJQUHG-UHFFFAOYSA-L copper(II) chloride Chemical compound Cl[Cu]Cl ORTQZVOHEJQUHG-UHFFFAOYSA-L 0.000 description 2
- 238000001514 detection method Methods 0.000 description 2
- 238000010586 diagram Methods 0.000 description 2
- 238000010828 elution Methods 0.000 description 2
- 238000001704 evaporation Methods 0.000 description 2
- 238000006703 hydration reaction Methods 0.000 description 2
- AMWRITDGCCNYAT-UHFFFAOYSA-L hydroxy(oxo)manganese;manganese Chemical compound [Mn].O[Mn]=O.O[Mn]=O AMWRITDGCCNYAT-UHFFFAOYSA-L 0.000 description 2
- 230000001771 impaired effect Effects 0.000 description 2
- 238000009616 inductively coupled plasma Methods 0.000 description 2
- 238000009830 intercalation Methods 0.000 description 2
- RBTARNINKXHZNM-UHFFFAOYSA-K iron trichloride Chemical compound Cl[Fe](Cl)Cl RBTARNINKXHZNM-UHFFFAOYSA-K 0.000 description 2
- 239000011777 magnesium Substances 0.000 description 2
- QMMRZOWCJAIUJA-UHFFFAOYSA-L nickel dichloride Chemical compound Cl[Ni]Cl QMMRZOWCJAIUJA-UHFFFAOYSA-L 0.000 description 2
- 230000001590 oxidative effect Effects 0.000 description 2
- 239000002245 particle Substances 0.000 description 2
- 229910001414 potassium ion Chemical group 0.000 description 2
- 238000001556 precipitation Methods 0.000 description 2
- 230000002829 reductive effect Effects 0.000 description 2
- 239000013049 sediment Substances 0.000 description 2
- GEHJYWRUCIMESM-UHFFFAOYSA-L sodium sulfite Chemical compound [Na+].[Na+].[O-]S([O-])=O GEHJYWRUCIMESM-UHFFFAOYSA-L 0.000 description 2
- 230000006641 stabilisation Effects 0.000 description 2
- 238000011105 stabilization Methods 0.000 description 2
- 239000006228 supernatant Substances 0.000 description 2
- UTYXJYFJPBYDKY-UHFFFAOYSA-N tetrapotassium;iron(2+);hexacyanide;trihydrate Chemical compound O.O.O.[K+].[K+].[K+].[K+].[Fe+2].N#[C-].N#[C-].N#[C-].N#[C-].N#[C-].N#[C-] UTYXJYFJPBYDKY-UHFFFAOYSA-N 0.000 description 2
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 description 1
- IOGACBCZESMECN-UHFFFAOYSA-N C(#N)[Fe+].[Fe+2] Chemical compound C(#N)[Fe+].[Fe+2] IOGACBCZESMECN-UHFFFAOYSA-N 0.000 description 1
- BVKZGUZCCUSVTD-UHFFFAOYSA-L Carbonate Chemical compound [O-]C([O-])=O BVKZGUZCCUSVTD-UHFFFAOYSA-L 0.000 description 1
- JJLJMEJHUUYSSY-UHFFFAOYSA-L Copper hydroxide Chemical compound [OH-].[OH-].[Cu+2] JJLJMEJHUUYSSY-UHFFFAOYSA-L 0.000 description 1
- 239000005750 Copper hydroxide Substances 0.000 description 1
- 229910021592 Copper(II) chloride Inorganic materials 0.000 description 1
- VMQMZMRVKUZKQL-UHFFFAOYSA-N Cu+ Chemical compound [Cu+] VMQMZMRVKUZKQL-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
- 229910021577 Iron(II) chloride Inorganic materials 0.000 description 1
- 229910021578 Iron(III) chloride Inorganic materials 0.000 description 1
- 229910002651 NO3 Inorganic materials 0.000 description 1
- 229910021260 NaFe Inorganic materials 0.000 description 1
- NHNBFGGVMKEFGY-UHFFFAOYSA-N Nitrate Chemical compound [O-][N+]([O-])=O NHNBFGGVMKEFGY-UHFFFAOYSA-N 0.000 description 1
- BPQQTUXANYXVAA-UHFFFAOYSA-N Orthosilicate Chemical group [O-][Si]([O-])([O-])[O-] BPQQTUXANYXVAA-UHFFFAOYSA-N 0.000 description 1
- 229910019142 PO4 Inorganic materials 0.000 description 1
- NPYPAHLBTDXSSS-UHFFFAOYSA-N Potassium ion Chemical group [K+] NPYPAHLBTDXSSS-UHFFFAOYSA-N 0.000 description 1
- 229910018557 Si O Inorganic materials 0.000 description 1
- FKNQFGJONOIPTF-UHFFFAOYSA-N Sodium cation Chemical group [Na+] FKNQFGJONOIPTF-UHFFFAOYSA-N 0.000 description 1
- 239000004809 Teflon Substances 0.000 description 1
- 229920006362 Teflon® Polymers 0.000 description 1
- 230000002378 acidificating effect Effects 0.000 description 1
- 239000000654 additive Substances 0.000 description 1
- 230000000996 additive effect Effects 0.000 description 1
- 230000002776 aggregation Effects 0.000 description 1
- 238000004220 aggregation Methods 0.000 description 1
- 229910052783 alkali metal Inorganic materials 0.000 description 1
- 150000001340 alkali metals Chemical class 0.000 description 1
- DIZPMCHEQGEION-UHFFFAOYSA-H aluminium sulfate (anhydrous) Chemical compound [Al+3].[Al+3].[O-]S([O-])(=O)=O.[O-]S([O-])(=O)=O.[O-]S([O-])(=O)=O DIZPMCHEQGEION-UHFFFAOYSA-H 0.000 description 1
- 239000010426 asphalt Substances 0.000 description 1
- 238000006664 bond formation reaction Methods 0.000 description 1
- PLLZRTNVEXYBNA-UHFFFAOYSA-L cadmium hydroxide Chemical compound [OH-].[OH-].[Cd+2] PLLZRTNVEXYBNA-UHFFFAOYSA-L 0.000 description 1
- 229910052792 caesium Inorganic materials 0.000 description 1
- TVFDJXOCXUVLDH-UHFFFAOYSA-N caesium atom Chemical compound [Cs] TVFDJXOCXUVLDH-UHFFFAOYSA-N 0.000 description 1
- 230000015556 catabolic process Effects 0.000 description 1
- 238000005341 cation exchange Methods 0.000 description 1
- 239000004927 clay Substances 0.000 description 1
- 239000000701 coagulant Substances 0.000 description 1
- 229910001956 copper hydroxide Inorganic materials 0.000 description 1
- MPTQRFCYZCXJFQ-UHFFFAOYSA-L copper(II) chloride dihydrate Chemical compound O.O.[Cl-].[Cl-].[Cu+2] MPTQRFCYZCXJFQ-UHFFFAOYSA-L 0.000 description 1
- 230000007797 corrosion Effects 0.000 description 1
- 238000005260 corrosion Methods 0.000 description 1
- 238000004132 cross linking Methods 0.000 description 1
- 150000004691 decahydrates Chemical class 0.000 description 1
- 230000003247 decreasing effect Effects 0.000 description 1
- 229910001873 dinitrogen Inorganic materials 0.000 description 1
- 239000000975 dye Substances 0.000 description 1
- 238000003912 environmental pollution Methods 0.000 description 1
- 238000011156 evaluation Methods 0.000 description 1
- 230000008020 evaporation Effects 0.000 description 1
- 238000004880 explosion Methods 0.000 description 1
- 239000010419 fine particle Substances 0.000 description 1
- 239000008187 granular material Substances 0.000 description 1
- 238000010438 heat treatment Methods 0.000 description 1
- 229910001385 heavy metal Inorganic materials 0.000 description 1
- 150000004679 hydroxides Chemical class 0.000 description 1
- 230000006872 improvement Effects 0.000 description 1
- 230000002401 inhibitory effect Effects 0.000 description 1
- 238000005342 ion exchange Methods 0.000 description 1
- 150000002505 iron Chemical class 0.000 description 1
- FBAFATDZDUQKNH-UHFFFAOYSA-M iron chloride Chemical compound [Cl-].[Fe] FBAFATDZDUQKNH-UHFFFAOYSA-M 0.000 description 1
- 230000000670 limiting effect Effects 0.000 description 1
- 229910001629 magnesium chloride Inorganic materials 0.000 description 1
- 159000000003 magnesium salts Chemical class 0.000 description 1
- 229910052943 magnesium sulfate Inorganic materials 0.000 description 1
- 235000019341 magnesium sulphate Nutrition 0.000 description 1
- 229910052748 manganese Inorganic materials 0.000 description 1
- 239000011572 manganese Substances 0.000 description 1
- 239000000463 material Substances 0.000 description 1
- AIBQNUOBCRIENU-UHFFFAOYSA-N nickel;dihydrate Chemical compound O.O.[Ni] AIBQNUOBCRIENU-UHFFFAOYSA-N 0.000 description 1
- NBIIXXVUZAFLBC-UHFFFAOYSA-K phosphate Chemical compound [O-]P([O-])([O-])=O NBIIXXVUZAFLBC-UHFFFAOYSA-K 0.000 description 1
- 239000010452 phosphate Substances 0.000 description 1
- XAEFZNCEHLXOMS-UHFFFAOYSA-M potassium benzoate Chemical compound [K+].[O-]C(=O)C1=CC=CC=C1 XAEFZNCEHLXOMS-UHFFFAOYSA-M 0.000 description 1
- 239000001103 potassium chloride Substances 0.000 description 1
- 235000011164 potassium chloride Nutrition 0.000 description 1
- LDQICAMJIICDLF-UHFFFAOYSA-N potassium;iron(2+);iron(3+);hexacyanide Chemical compound [K+].[Fe+2].[Fe+3].N#[C-].N#[C-].N#[C-].N#[C-].N#[C-].N#[C-] LDQICAMJIICDLF-UHFFFAOYSA-N 0.000 description 1
- 230000001376 precipitating effect Effects 0.000 description 1
- 238000011002 quantification Methods 0.000 description 1
- 230000009257 reactivity Effects 0.000 description 1
- 239000000377 silicon dioxide Substances 0.000 description 1
- LIVNPJMFVYWSIS-UHFFFAOYSA-N silicon monoxide Inorganic materials [Si-]#[O+] LIVNPJMFVYWSIS-UHFFFAOYSA-N 0.000 description 1
- 239000010802 sludge Substances 0.000 description 1
- 239000002002 slurry Substances 0.000 description 1
- 239000011780 sodium chloride Substances 0.000 description 1
- 159000000000 sodium salts Chemical class 0.000 description 1
- 235000010265 sodium sulphite Nutrition 0.000 description 1
- 238000007614 solvation Methods 0.000 description 1
- 238000001291 vacuum drying Methods 0.000 description 1
- 238000005406 washing Methods 0.000 description 1
- 239000002699 waste material Substances 0.000 description 1
- 239000011787 zinc oxide Substances 0.000 description 1
- NWONKYPBYAMBJT-UHFFFAOYSA-L zinc sulfate Chemical compound [Zn+2].[O-]S([O-])(=O)=O NWONKYPBYAMBJT-UHFFFAOYSA-L 0.000 description 1
- 229910000368 zinc sulfate Inorganic materials 0.000 description 1
- 229960001763 zinc sulfate Drugs 0.000 description 1
Landscapes
- Solid-Sorbent Or Filter-Aiding Compositions (AREA)
Abstract
Description
本発明は、放射性Ｃｓ汚染水中の放射性Ｃｓイオンを吸着するための放射性Ｃｓ吸着剤及びその製造方法に関する。 The present invention relates to a radioactive Cs adsorbent for adsorbing radioactive Cs ions in radioactive Cs-contaminated water and a method for producing the same.
２０１１年３月１１日の福島第１原発の爆発により大量の放射性セシウムＣｓが環境中に放出され、東日本の広域に亘り甚大な被害を齎した。特に、半減期がそれぞれ２年、３０年と永い放射性Ｃｓ１３４とＣｓ１３７による環境汚染は深刻であり、それらを除去するため、様々な技術が使用されてきた。例えば、放射性Ｃｓ汚染水のＣｓイオンの除去にゼオライトやプルシアンブルー色素顔料などの吸着剤が使用されている。 The explosion of the Fukushima Daiichi nuclear power plant on March 11, 2011 released a large amount of radioactive cesium Cs into the environment, causing serious damage over a wide area in eastern Japan. In particular, environmental pollution due to radioactive Cs134 and Cs137 having a long half-life of 2 years and 30 years, respectively, is serious, and various techniques have been used to remove them. For example, adsorbents such as zeolite and Prussian blue pigment are used to remove Cs ions from radioactive Cs contaminated water.
ゼオライトは多孔質の吸着剤で比較的大きな比表面積を有し、該表面のシリケート基Ｓｉ−Ｏ-による陽イオン交換作用によりＣｓイオンを捕捉するのであるが、汚染水にＮａイオンやＫイオン、Ｃａイオン、Ｍｇイオン、Ｃａイオンなどが高濃度に存在すると、これら陽イオンとの平衡作用によって捕捉したＣｓイオンが脱離するなど、Ｃｓイオンを選択的に吸着できないという問題があった。 Zeolite has a relatively large specific surface area with a porous adsorbent, silicate groups of the surface Si-O - but by it to capture the Cs ions by cation exchange action, Na ions and K ions in contaminated water, When Ca ions, Mg ions, Ca ions, and the like are present at high concentrations, there is a problem that Cs ions cannot be selectively adsorbed, for example, Cs ions captured by an equilibrium action with these cations are desorbed.
一方、プルシアンブルー色素顔料は、Ｃｓイオンを選択的に吸着することができ、海水のようにＮａイオン、Ｋイオン、Ｍｇイオンなどの陽イオンを含む汚染水を処理する場合であっても、これらの陽イオンによる阻害作用の影響はゼオライトと比較して小さい。 On the other hand, Prussian blue pigments can selectively adsorb Cs ions, and even when treating contaminated water containing cations such as Na ions, K ions and Mg ions like seawater. The influence of the inhibitory action by cations is small compared to zeolite.
しかし、プルシアンブルー色素顔料を吸着剤として用いる場合、９９％以上のＣｓ除去率を得るためには２４時間以上の時間が必要であるという問題があった。
また、プルシアンブルー色素顔料は微粉体の状態で用いられるため、Ｃｓイオンを吸着させても濾過によって取り除くことが困難である（篩目を通過してしまう）。そのため、沈殿・濾過工程では硫酸バンドなどの凝集剤の併用が必須であった。
However, when Prussian blue pigment is used as an adsorbent, there is a problem that it takes 24 hours or more to obtain a Cs removal rate of 99% or more.
In addition, since the Prussian blue pigment is used in a fine powder state, it is difficult to remove it by filtration even if Cs ions are adsorbed (passes through a sieve mesh). For this reason, in the precipitation / filtration process, it is essential to use a coagulant such as a sulfuric acid band.
このように、ゼオライトなど多孔質の吸着剤は比表面積が大きくカチオン吸着速度に優れるが、Ｃｓイオン選択性に問題があり、他方、ＰＢはＣｓイオン選択性に優れるが、遅い吸着速度に欠点があった。 Thus, a porous adsorbent such as zeolite has a large specific surface area and an excellent cation adsorption rate, but has a problem in Cs ion selectivity, while PB has an excellent Cs ion selectivity but has a drawback in a slow adsorption rate. there were.
この点、大きな比表面積を有し、吸着特性、Ｃｓイオン選択性ともに優れた吸着剤の開発も行われており、例えば、メソポーラスシリカ粒子表面にアンカー分子を介して、銅―鉄シアン化錯体を担持させ優れたＣｓイオン吸着性能を有する吸着剤が開発されている（非特許文献１参照）。 In this respect, an adsorbent having a large specific surface area and excellent adsorption characteristics and Cs ion selectivity has been developed. For example, a copper-iron cyanide complex is formed on the surface of mesoporous silica particles via an anchor molecule. Adsorbents that are supported and have excellent Cs ion adsorption performance have been developed (see Non-Patent Document 1).
しかし、銅−鉄シアン錯体をシリカ表面に繋ぐアンカーに高価なシリル化剤を使用するため、大量のＣｓ汚染水を処理するにはコスト面で問題があった。 However, since an expensive silylating agent is used as an anchor for linking the copper-iron cyanide complex to the silica surface, there is a problem in terms of cost in treating a large amount of Cs-contaminated water.
そこで、本発明は、放射性Ｃｓ汚染水からＣｓイオンを低コストで迅速かつ効率的に除去することのできる放射性Ｃｓ吸着剤及びその製造方法を提供することを目的とする。 Then, an object of this invention is to provide the radioactive Cs adsorption agent which can remove Cs ion from radioactive Cs contaminated water quickly and efficiently at low cost, and its manufacturing method.
本発明者らは、上記課題を解決するために、以下の如き検討・考察を行った。 In order to solve the above problems, the present inventors have made the following examinations and considerations.
すなわち、まず、従来吸着剤として用いられてきたプルシアンブルーの理想的な組成式はＦｅ(III)4[Ｆｅ(II)(ＣＮ)6]3であるが、例えば、ヘキサシアン鉄(II)イオンのナトリウム塩Ｎａ4Ｆｅ(II)(ＣＮ)6やカリウム塩Ｋ4Ｆｅ(II)(ＣＮ)6を用いたプルシアンブルーの合成ではＦｅ(III)の一部がナトリウムイオンやカリウムイオンに置き換えられた形の可溶性プルシアンブルーＮａＦｅ(III)Ｆｅ(II)(ＣＮ)6やＫＦｅ(III)Ｆｅ(II)(ＣＮ)6が生成する。プルシアンブルーの結晶構造はＦｅ(III)やＮａイオン、或いはＫイオンが面心立方体格子を形成し、各辺の中点、及び面心立方体の中心にＦｅ(II)が位置している。そしてシアノ基ＣＮがＦｅ(III)、或いはＭ(I)とＦｅ(II)の間に位置している。
Ｃｓイオンが水溶液中でプルシアンブルー結晶体に捕捉されるためにはＣｓイオンが該結晶格子内を拡散してゆき、結晶内のアルカリイオン、或いはカリウムイオンと置換する必要がある。つまり、プルシアンブルー色素顔料によるＣｓイオンの吸着速度はＣｓイオンの該結晶格子内への拡散が律速になっているものと考えられる。
しかし、結晶格子内でのＣｓイオンの拡散係数は極めて小さいため、Ｃｓイオンに対する優れた吸着選択性にも係わらず、結晶構造が成長したプルシアンブルー色素がＣｓ汚染水からＣｓイオンを効果的に吸着・除去するには２４時間以上の時間を要していたものと理解される。
That is, first, the ideal composition formula of Prussian blue that has been used as an adsorbent in the past is Fe (III) 4 [Fe (II) (CN) 6 ] 3. For example, hexacyan iron (II) ion In the synthesis of Prussian blue using sodium salt Na 4 Fe (II) (CN) 6 and potassium salt K 4 Fe (II) (CN) 6 , part of Fe (III) was replaced with sodium ion or potassium ion. Forms of soluble Prussian blue NaFe (III) Fe (II) (CN) 6 and KFe (III) Fe (II) (CN) 6 are formed. In the Prussian blue crystal structure, Fe (III), Na ions, or K ions form a face-centered cubic lattice, and Fe (II) is located at the midpoint of each side and at the center of the face-centered cube. The cyano group CN is located between Fe (III) or M (I) and Fe (II).
In order for Cs ions to be trapped in the Prussian blue crystal in an aqueous solution, the Cs ions must diffuse in the crystal lattice and be replaced with alkali ions or potassium ions in the crystal. That is, it is considered that the adsorption rate of Cs ions by the Prussian blue pigment is the rate limiting of diffusion of Cs ions into the crystal lattice.
However, since the diffusion coefficient of Cs ions in the crystal lattice is extremely small, Prussian blue dye with a grown crystal structure effectively adsorbs Cs ions from Cs-contaminated water, despite excellent adsorption selectivity for Cs ions.・ It is understood that it took more than 24 hours to remove.
以上の点を踏まえてさらに鋭意検討を重ねた結果、従来のプルシアンブルー色素顔料のように結晶構造が成長した形ではなく、分子及び／又はクラスターの状態で六方晶の結晶構造をとるＭｅ(II)(ＯＨ)2（但し、Ｍｅ(II)は２価の遷移金属である）で表される水酸化物を共存させて、プルシアンブルーを不溶化させることが、本発明の上記課題を解決するにおいて重要であることを見出し、本発明を完成するに至った。 As a result of further intensive studies based on the above points, Me (II) which has a hexagonal crystal structure in a molecular and / or cluster state, not a crystal structure grown like a conventional Prussian blue pigment. ) (OH) 2 (wherein Me (II) is a divalent transition metal) to coexist and insolubilize Prussian blue in solving the above-mentioned problems of the present invention. The present invention has been found to be important, and the present invention has been completed.
すなわち、本発明にかかる放射性Ｃｓ吸着剤は、Ｍ(I)3xＦｅ(III)4-x［Ｆｅ(II)（ＣＮ）6］3で表されるプルシアンブルー（但し、Ｍ(I)は１価のカチオンでｘは０又は１である）の分子及び／又はそのクラスターと、Ｍｅ(II)(ＯＨ)2で表される水酸化物又はその部分酸化物（但し、Ｍｅ(II)は２価の遷移金属である）との複合体を有効成分とする、ことを特徴とする。
また、本発明にかかる放射性Ｃｓ吸着剤の製造方法は、水中で、Ｍ(I)4Ｆｅ(II)（ＣＮ）6及び／又はＭ(I)3Ｆｅ(III)（ＣＮ）6で表される鉄シアノ錯体（但し、Ｍ(I)は１価のカチオンである）と、２価及び／又は３価の鉄塩化合物とを反応させることによりプルシアンブルーを合成する工程（以下、便宜上、工程（Ａ）と記すことがある）と、前記プルシアンブルーの水溶液にＭｅ(II)(ＯＨ)2で表される水酸化物（但し、Ｍｅ(II)は２価の遷移金属である）を含有させる工程（以下、便宜上、工程（Ｂ）と記すことがある）とを含む、ことを特徴とする。
なお、以下では、「Ｍ(I)3xＦｅ(III)4-x［Ｆｅ(II)（ＣＮ）6］3で表されるプルシアンブルー」を単に「ＰＢ」と略記し、「Ｍｅ(II)(ＯＨ)2で表される水酸化物」を単に「Ｍｅ(II)(ＯＨ)2」と略記し、「Ｍｅ(II)Ｏで表される酸化物」を単に「Ｍｅ(II)Ｏ」と略記することがある。
That is, the radioactive Cs adsorbent according to the present invention is Prussian blue represented by M (I) 3x Fe (III) 4-x [Fe (II) (CN) 6 ] 3 (where M (I) is 1). A valent cation and x is 0 or 1) and / or a cluster thereof, and a hydroxide represented by Me (II) (OH) 2 or a partial oxide thereof (where Me (II) is 2 It is characterized by comprising a complex with a valent transition metal) as an active ingredient.
A method of manufacturing a radioactive Cs adsorbent according to the present invention, in water, expressed in M (I) 4 Fe (II ) (CN) 6 and / or M (I) 3 Fe (III ) (CN) 6 A process of synthesizing Prussian blue by reacting an iron cyano complex (where M (I) is a monovalent cation) and a divalent and / or trivalent iron salt compound (hereinafter referred to as a process for convenience) (A) may contain a hydroxide represented by Me (II) (OH) 2 in the Prussian blue aqueous solution (where Me (II) is a divalent transition metal). (Hereinafter, for convenience, may be referred to as a step (B)).
In the following, “Prussian blue represented by M (I) 3x Fe (III) 4-x [Fe (II) (CN) 6 ] 3 ” is simply abbreviated as “PB” and “Me (II) The “hydroxide represented by (OH) 2 ” is simply abbreviated as “Me (II) (OH) 2 ”, and the “oxide represented by Me (II) O” is simply “Me (II) O”. May be abbreviated.
本発明の放射性Ｃｓ吸着剤によれば、放射性Ｃｓイオンを低コストで迅速かつ高効率に吸着除去することができる。
また、本発明の放射性Ｃｓ吸着剤の製造方法によれば、上記の如き優れた性能を有する放射性Ｃｓ吸着剤を製造することができる。
According to the radioactive Cs adsorbent of the present invention, radioactive Cs ions can be adsorbed and removed quickly and efficiently at low cost.
Moreover, according to the manufacturing method of the radioactive Cs adsorbent of this invention, the radioactive Cs adsorbent which has the above outstanding performances can be manufactured.
以下、本発明にかかる放射性Ｃｓ吸着剤及びその製造方法について詳しく説明するが、本発明の範囲はこれらの説明に拘束されることはなく、以下の例示以外についても、本発明の趣旨を損なわない範囲で適宜変更実施し得る。 Hereinafter, although the radioactive Cs adsorbent concerning this invention and its manufacturing method are demonstrated in detail, the scope of the present invention is not restrained by these description and does not impair the meaning of this invention except the following illustrations. Changes can be made as appropriate within the range.
〔放射性Ｃｓ吸着剤〕
本発明の放射性Ｃｓ吸着剤は、下記ＰＢの分子及び／又はそのクラスターと下記水酸化物又はその部分酸化物との複合体を有効成分とする。
[Radioactive Cs adsorbent]
The radioactive Cs adsorbent of the present invention contains a complex of the following PB molecule and / or cluster thereof and the following hydroxide or partial oxide thereof as an active ingredient.
＜ＰＢ＞
本発明におけるＰＢは、Ｍ(I)3xＦｅ(III)4-x［Ｆｅ(II)（ＣＮ）6］3で表される。
ここで、Ｍ(I)は１価のカチオンであり、例えば、Ｌｉ+、Ｎａ+、Ｋ+、ＮＨ4 +などが挙げられるが、好ましくは、Ｎａ+及び／又はＫ+である。
また、ｘは０又は１である。
<PB>
PB in the present invention is represented by M (I) 3x Fe (III) 4-x [Fe (II) (CN) 6 ] 3 .
Here, M (I) is a monovalent cation, and examples thereof include Li + , Na + , K + , NH 4 + and the like, preferably Na + and / or K + .
X is 0 or 1.
＜水酸化物又はその部分酸化物＞
本発明における水酸化物は、Ｍｅ(II)(ＯＨ)2（但し、Ｍｅ(II)は２価の遷移金属である）で表される。
<Hydroxide or its partial oxide>
The hydroxide in the present invention is represented by Me (II) (OH) 2 (where Me (II) is a divalent transition metal).
ここで、Ｍｅ(II)としては、水酸化物が六方晶の結晶構造をとる２価の遷移金属であれば特に限定されないが、例えば、マンガン、鉄、コバルト、ニッケル、銅、亜鉛、カドミウムなどが好ましく挙げられる。 Here, Me (II) is not particularly limited as long as the hydroxide is a divalent transition metal having a hexagonal crystal structure. For example, manganese, iron, cobalt, nickel, copper, zinc, cadmium, etc. Is preferred.
また、本発明において、水酸化物の部分酸化物とは、複合体を構成するＭｅ(II)(ＯＨ)2の一部が縮合してＭｅ(II)Ｏとなっているものである。例えば、乾燥状態では、Ｍｅ(II)(ＯＨ)2の一部がＭｅ(II)Ｏの状態となっていることが多いが、この場合でも、水中では、水和によりＭｅ(II)(ＯＨ)2の状態になるため、結局、放射性Ｃｓ吸着剤の有効成分としての作用という観点から見たとき、六方晶の結晶構造が維持される限度において、Ｍｅ(II)(ＯＨ)2とＭｅ(II)Ｏとは同等と評価できる（この点については、さらに後述する）。そのため、本発明では、このような部分酸化物をも包含するのである。 In the present invention, the partial oxide of hydroxide is Me (II) (OH) 2 which is partly condensed to Me (II) O. For example, in a dry state, a part of Me (II) (OH) 2 is often in a state of Me (II) O. Even in this case, however, Me (II) (OH) is hydrated in water. ) 2 in the end, so that from the viewpoint of the action as an active ingredient of the radioactive Cs adsorbent, Me (II) (OH) 2 and Me ( II) It can be evaluated as equivalent to O (this point will be further described later). Therefore, in the present invention, such a partial oxide is also included.
＜複合体の組成＞
本発明の放射性Ｃｓ吸着剤は、前記ＰＢの分子及び／またはそのクラスターとＭｅ(II)(ＯＨ)2又はその部分酸化物との複合体を有効成分とするが、前記ＰＢとＭｅ(II)(ＯＨ)2又はその部分酸化物との割合は、前記ＰＢを構成するＦｅ(II)（ＣＮ）6の当量をαモルとし、Ｍｅ(II)(ＯＨ)2又はその部分酸化物を構成するＭｅ(II)の当量をβモルとするとき、αとβの比（α／β）が０．１〜１０となる割合であることが好ましい。
特に、処理液の全シアン濃度の排水基準値を考慮する場合には、α／βが０．１〜１．０であることが好ましい。
α／βが上記範囲であることが好ましい理由は、後記〔放射性Ｃｓ吸着剤の使用〕において詳述する。
<Composition composition>
The radioactive Cs adsorbent of the present invention contains, as an active ingredient, a complex of the PB molecule and / or cluster thereof and Me (II) (OH) 2 or a partial oxide thereof, but the PB and Me (II) The proportion of (OH) 2 or a partial oxide thereof is Me (II) (OH) 2 or a partial oxide thereof, with the equivalent of Fe (II) (CN) 6 constituting the PB being α mol. When the equivalent of Me (II) is β mole, the ratio of α and β (α / β) is preferably a ratio of 0.1-10.
In particular, when considering the drainage standard value of the total cyan concentration of the treatment liquid, α / β is preferably 0.1 to 1.0.
The reason why α / β is preferably in the above range will be described in detail later in [Use of radioactive Cs adsorbent].
＜放射性Ｃｓ吸着剤の性状＞
本発明の放射性Ｃｓ吸着剤の性状は、特に限定されず、分散液、含水物、乾燥物など、いずれでも良い。
<Properties of radioactive Cs adsorbent>
The property of the radioactive Cs adsorbent of the present invention is not particularly limited, and any of a dispersion, a hydrated product, a dried product, and the like may be used.
具体的には、本発明の放射性Ｃｓ吸着剤は、例えば、後述する本発明の放射性Ｃｓ吸着剤の製造方法によって製造することができるが、後述の製造方法においては、上記ＰＢの分子及び／又はそのクラスターと上記Ｍｅ(II)(ＯＨ)2との複合体を含有する分散液が得られるのであり、これを濾過すれば含水物が、また、乾燥すれば乾燥物が得られる。
なお、上記乾燥物などの性状においては、上記Ｍｅ(II)(ＯＨ)2の一部が脱水縮合してＭｅ(II)Ｏの状態（つまり、Ｍｅ(II)(ＯＨ)2の部分酸化物）となる場合もある。
Specifically, the radioactive Cs adsorbent of the present invention can be produced, for example, by the production method of the radioactive Cs adsorbent of the present invention described later. In the production method described later, the PB molecule and / or A dispersion containing the complex of the cluster and the Me (II) (OH) 2 can be obtained. A water-containing product can be obtained by filtration, and a dried product can be obtained by drying.
In addition, in the properties of the dried product and the like, a part of the Me (II) (OH) 2 is dehydrated and condensed to a state of Me (II) O (that is, a partial oxide of Me (II) (OH) 2 ) In some cases.
また、本発明の放射性Ｃｓ吸着剤は、本発明の効果を害しない範囲であれば、上記有効成分以外の成分を含有していても良い。例えば、放射性Ｃｓ吸着剤の製造過程で含有される成分や目的に応じた任意の添加剤などが含まれていても良い。 Further, the radioactive Cs adsorbent of the present invention may contain components other than the above-mentioned effective components as long as the effects of the present invention are not impaired. For example, the component contained in the manufacturing process of radioactive Cs adsorbent, the arbitrary additive according to the objective, etc. may be contained.
〔放射性Ｃｓ吸着剤の製造方法〕
次に、上記本発明の放射性Ｃｓ吸着剤を製造する好適な方法について説明する。ただし、本発明の放射性Ｃｓ吸着剤は、下記製造方法で製造されたものに限定されるものではない。
なお、下記製造方法において、各種薬剤の添加方法は、粒剤、粉末、水溶液、分散液など、いずれの形態で使用しても良く、特に限定されない。
[Method for producing radioactive Cs adsorbent]
Next, a suitable method for producing the radioactive Cs adsorbent of the present invention will be described. However, the radioactive Cs adsorbent of the present invention is not limited to those produced by the following production method.
In addition, in the following manufacturing method, the addition method of various chemical | medical agents may be used with any form, such as a granule, powder, aqueous solution, a dispersion liquid, and is not specifically limited.
＜工程（Ａ）＞
水中で、Ｍ(I)4Ｆｅ(II)（ＣＮ）6及び／又はＭ(I)3Ｆｅ(III)（ＣＮ）6で表される鉄シアノ錯体と、２価及び／又は３価の鉄塩化合物とを反応させることによりＰＢを合成する工程である。
合成されるＰＢは、Ｍ(I)3xＦｅ(III)4-x［Ｆｅ(II)（ＣＮ）6］3で表される。
<Process (A)>
An iron cyano complex represented by M (I) 4 Fe (II) (CN) 6 and / or M (I) 3 Fe (III) (CN) 6 and divalent and / or trivalent iron in water This is a step of synthesizing PB by reacting with a salt compound.
The synthesized PB is represented by M (I) 3x Fe (III) 4-x [Fe (II) (CN) 6 ] 3 .
ここで、Ｍ(I)、鉄塩化合物、ｘについては、〔放射性Ｃｓ吸着剤〕において上述した説明と重複するので説明を割愛する。 Here, since M (I), the iron salt compound, and x overlap with those described above in [Radioactive Cs adsorbent], description thereof is omitted.
工程（Ａ）におけるＰＢの合成反応は、Ｍ(I)4Ｆｅ(II)（ＣＮ）6で表される鉄シアノ錯体（フェロシアン化合物）及び／又はＭ(I)3Ｆｅ(III)（ＣＮ）6で表される鉄シアノ錯体（フェリシアン化合物）と、２価及び／又は３価の鉄塩化合物との反応によって実施されるものであり、具体的には以下に説明するとおりである。 The synthesis reaction of PB in the step (A) is carried out by using an iron cyano complex (ferrocyan compound) represented by M (I) 4 Fe (II) (CN) 6 and / or M (I) 3 Fe (III) (CN ) The reaction is carried out by a reaction of an iron cyano complex (ferricyan compound) represented by 6 and a divalent and / or trivalent iron salt compound, as specifically described below.
すなわち、まず、フェロシアン化合物からの合成は、下記反応式（１）に示すとおりである。 That is, first, synthesis from a ferrocyan compound is as shown in the following reaction formula (1).
また、フェリシアン化合物からの合成は、下記反応式（２）〜（４）に示すとおりである。 The synthesis from the ferricyan compound is as shown in the following reaction formulas (2) to (4).
ＰＢの理想的な形は不溶性の（ＰＢ２）とされているが、実際の反応では主生成物は水溶性の（ＰＢ１）であって、Ｃｓイオンの吸着には水不溶性の（ＰＢ２）よりも水溶性の（ＰＢ１）の方が重要な役割をすると考えられる。 Although the ideal form of PB is considered to be insoluble (PB2), in the actual reaction, the main product is water-soluble (PB1), and the adsorption of Cs ions is more than water-insoluble (PB2). It is thought that water-soluble (PB1) plays an important role.
工程（Ａ）において合成されたＰＢは、生成直後では分子の状態であるか及び／又は数分子が集合した微小な集合体（クラスター）の状態にある。本発明の放射性Ｃｓ吸着剤の製造方法は、これらＰＢ分子及び／又はＰＢクラスターを２価の遷移金属の水酸化物で不溶化することを特徴とする。 The PB synthesized in the step (A) is in a molecular state immediately after generation and / or in a minute aggregate (cluster) in which several molecules are aggregated. The method for producing a radioactive Cs adsorbent of the present invention is characterized in that these PB molecules and / or PB clusters are insolubilized with a divalent transition metal hydroxide.
＜工程（Ｂ）＞
工程（Ａ）で得たＰＢの水溶液にＭｅ(II)(ＯＨ)2を含有させる工程である。
Ｍｅ(II)については、〔放射性Ｃｓ吸着剤〕において上述した説明と重複するので説明を割愛する。
<Process (B)>
In this step, Me (II) (OH) 2 is added to the aqueous PB solution obtained in step (A).
About Me (II), since it overlaps with the description mentioned above in [Radioactive Cs adsorbent], explanation is omitted.
工程（Ａ）で得たＰＢ分子、及び／又はＰＢ分子クラスターをＭｅ(II)(ＯＨ)2の結晶構造中に含有させ、上記複合体を形成させる方法としては、例えば、工程（Ａ）の前及び／又は後にＭｅ(II)塩化合物を含有させ、そののち、前記ＰＢの水溶液中でＭｅ(II)塩化合物を加水分解することにより行う方法が挙げられる。好ましくは、工程（Ａ）の後にＭｅ(II)塩化合物を添加する。 Examples of the method for forming the complex by including the PB molecule and / or PB molecule cluster obtained in the step (A) in the crystal structure of Me (II) (OH) 2 include, for example, the step (A). An example is a method in which the Me (II) salt compound is contained before and / or after the hydrolysis, and then the Me (II) salt compound is hydrolyzed in the aqueous solution of PB. Preferably, the Me (II) salt compound is added after step (A).
Ｍｅ(II)塩化合物としては、例えば、前記Ｍｅ(II)の塩化物、硝酸塩、硫酸塩、炭酸塩、リン酸塩、有機酸塩などが好ましく挙げられる。
また、３価の遷移金属塩、例えば塩化鉄(III)を処理液に含有させておいてこれを還元剤で塩化鉄(II)に還元したり、あるいは、１価の遷移金属塩、例えば塩化銅(I)を処理液に含有させておいてこれを塩化銅(II)に酸化したりすることによって、Ｍｅ(II)塩化合物を含有させるようにする方法も本発明の範疇に入る。
Preferred examples of the Me (II) salt compound include the Me (II) chloride, nitrate, sulfate, carbonate, phosphate, and organic acid salt.
In addition, a trivalent transition metal salt such as iron (III) chloride is contained in the treatment liquid, and this is reduced to iron (II) chloride with a reducing agent, or a monovalent transition metal salt such as chloride. A method of adding a Me (II) salt compound by adding copper (I) to a treatment liquid and oxidizing it to copper (II) chloride also falls within the scope of the present invention.
Ｍｅ(II)塩化合物の加水分解によるＭｅ(II)(ＯＨ)2への変換は、下記反応式（５）で表される。 The conversion to Me (II) (OH) 2 by hydrolysis of the Me (II) salt compound is represented by the following reaction formula (5).
このような加水分解は、水溶液のｐＨを調整することによって容易に進行させることができる。 Such hydrolysis can easily proceed by adjusting the pH of the aqueous solution.
Ｍｅ(II)塩化合物の加水分解を行う際の水溶液のｐＨは５．０〜１０．０の範囲であることが好ましく、ｐＨ６．０〜９．０であることがより好ましい。加水分解のｐＨが高すぎたり、低すぎたりするとＰＢ分子の分解が起こり、遊離シアンが発生したり、ＰＢ分子を不溶化した構造が損なわれ、不溶化したＰＢ分子が再溶解したりするおそれがある。
更に、吸着剤を蒸発乾固して乾燥粉末にする場合は、加水分解後、水溶液のｐＨを６．０〜８．５に調整することが望ましい。
The pH of the aqueous solution when the Me (II) salt compound is hydrolyzed is preferably in the range of 5.0 to 10.0, and more preferably pH 6.0 to 9.0. If the pH of hydrolysis is too high or too low, the PB molecule may be decomposed to generate free cyanide, the structure in which the PB molecule is insolubilized may be damaged, and the insolubilized PB molecule may be redissolved. .
Furthermore, when evaporating the adsorbent to dry powder, it is desirable to adjust the pH of the aqueous solution to 6.0 to 8.5 after hydrolysis.
ＰＢ分子、及び／又はＰＢ分子クラスターをＭｅ(II)(ＯＨ)2により不溶化するための別の方法として、前記工程（Ａ）の前及び／又は後に、Ｍｅ(II)(ＯＨ)2及び／又はＭｅ(II)Ｏを添加することにより、Ｍｅ(II)(ＯＨ)2を反応液中に含有させるようにするにしてもよい。好ましくは、工程（Ａ）の後にＭｅ(II)(ＯＨ)2及び／又はＭｅ(II)Ｏを添加する。
また、鉄粉や亜鉛粉などを反応液に含有させておいて、これを空気や腐食などで酸化することによって、Ｆｅ(ＯＨ)2やＺｎ(ＯＨ)2などのＭｅ(II)(ＯＨ)2を生成させる方法も本発明の範疇に入る。
As another method for insolubilizing PB molecules and / or PB molecule clusters with Me (II) (OH) 2 , before and / or after the step (A), Me (II) (OH) 2 and / or Alternatively, Me (II) (OH) 2 may be contained in the reaction solution by adding Me (II) O. Preferably, Me (II) (OH) 2 and / or Me (II) O is added after step (A).
Further, by adding iron powder or zinc powder to the reaction solution and oxidizing it with air or corrosion, Me (II) (OH) such as Fe (OH) 2 or Zn (OH) 2 is used. method of forming a 2 also within the scope of the present invention.
以上のような放射性Ｃｓ吸着剤の製造方法において前記ＰＢ反応液にＭｅ(II)(ＯＨ)2を共存させることによってＰＢ分子及び／又はそのクラスターを不溶化し、粗大粒子化（通常、粒径１μｍ以上）した複合体が生成する機構については、詳細は定かでないが、本発明者らは以下のように考察した。 In the method for producing a radioactive Cs adsorbent as described above, Me (II) (OH) 2 is allowed to coexist in the PB reaction solution to insolubilize PB molecules and / or clusters thereof, thereby forming coarse particles (usually 1 μm in particle size). The details of the mechanism by which the above-described complex is generated are not clear, but the present inventors considered as follows.
すなわち、ＰＢ分子及び／又はそのクラスターの不溶化による放射性Ｃｓ吸着剤の合成のためにＭｅ(II)塩化合物を用いる場合、ＰＢ分子やＰＢ分子クラスターの不溶化は、Ｍｅ(II)塩化合物分子のＭｅ(II)のｄ軌道とＰＢ分子及び／又はそのクラスターのシアノ基のπ電子との相互作用により、Ｍｅ(II)塩化合物がＰＢ分子と架橋結合を形成して不溶化する。さらに、処理液のｐＨを弱酸〜弱アルカリに調整するなどしてＭｅ(II)塩化合物を加水分解するとＭｅ(II)(ＯＨ)2が生成し、結晶構造を形成する。なお、このＭｅ(II)(ＯＨ)2の溶解度積は１０-12以下と小さい。
そして、本発明のＭｅ(II)(ＯＨ)2は六方晶の結晶構造を取るので、ＰＢ分子及び／又はそのクラスターのシアノ基を介して架橋構造を形成しながら、Ｍｅ(II)(ＯＨ)2をａ軸とｂ軸が作る平面内に配置し、ｃ軸方向に層状に結晶成長して１μｍ以上の粗大粒子を形成する。
以上の結果、該粗大粒子化した複合体は、ＰＢ分子及び／又はそのクラスターを層間水と共にＭｅ(II)(ＯＨ)2の層状構造の層間にインターカレートした構造を有していると考えられる。
That is, when the Me (II) salt compound is used for the synthesis of the radioactive Cs adsorbent by insolubilizing the PB molecule and / or its cluster, the insolubilization of the PB molecule or the PB molecule cluster is caused by Me of the Me (II) salt compound molecule. Due to the interaction between the d orbitals of (II) and the π electrons of the cyano group of the PB molecule and / or its cluster, the Me (II) salt compound forms a crosslink with the PB molecule and is insolubilized. Further, when the Me (II) salt compound is hydrolyzed by adjusting the pH of the treatment liquid to a weak acid to a weak alkali, Me (II) (OH) 2 is generated to form a crystal structure. The solubility product of Me (II) (OH) 2 is as small as 10 −12 or less.
And since Me (II) (OH) 2 of the present invention has a hexagonal crystal structure, Me (II) (OH) 2 forms a cross-linked structure via the cyano group of the PB molecule and / or its cluster. 2 is arranged in a plane formed by the a-axis and the b-axis, and crystals are grown in layers in the c-axis direction to form coarse particles of 1 μm or more.
As a result of the above, it is considered that the coarse-particle composite has a structure in which PB molecules and / or clusters thereof are intercalated between layers of Me (II) (OH) 2 together with interlayer water. It is done.
一方、ＰＢ分子及び／又はそのクラスターの凝集や沈殿のためにＭｅ(II)(ＯＨ)2、Ｍｅ(II)Ｏ、Ｍｅ(II)の金属粉などを添加する場合、前記ｄ−π相互作用により、水難溶性のＭｅ(II)(ＯＨ)2の結晶表面でＰＢ分子及び／又はそのクラスターと架橋結合が形成される。Ｍｅ(II)(ＯＨ)2は六方晶で層状構造を取っているので、製造工程の攪拌によりＰＢ分子及び／又はそのクラスターと架橋結合をしたＭｅ(II)(ＯＨ)2の結晶面が剥離する。
そして、剥離した該結晶面はＰＢ分子及び／又はそのクラスターを層間にインターカレートした形で層状に結晶成長して、粒子径１μｍ以上の粗大粒子が形成されるものと考えられる。
或いは、水中では層内に水分子が浸入しＭｅ(II)(ＯＨ)2の層状構造の層間隔が広がるため、分子容の大きなＰＢ分子、及び／又はＰＢ分子クラスターでも容易に層間内に拡散し、層間にインターカレートすることにより不溶化する機構も考えられる。
On the other hand, when adding metal powder of Me (II) (OH) 2 , Me (II) O, Me (II), etc. for aggregation and precipitation of PB molecules and / or their clusters, the d-π interaction As a result, a cross-linking bond is formed with the PB molecule and / or its cluster on the crystal surface of the poorly water-soluble Me (II) (OH) 2 . Since Me (II) (OH) 2 is hexagonal and has a layered structure, the crystal plane of Me (II) (OH) 2 cross-linked with PB molecules and / or clusters thereof is peeled off by stirring in the production process. To do.
Then, it is considered that the exfoliated crystal plane grows in a layered manner by intercalating PB molecules and / or clusters thereof between layers, and coarse particles having a particle diameter of 1 μm or more are formed.
Alternatively, in water, water molecules penetrate into the layer and the layer spacing of the layered structure of Me (II) (OH) 2 widens, so even PB molecules and / or PB molecule clusters with a large molecular volume can easily diffuse into the layers. However, a mechanism of insolubilization by intercalating between layers is also conceivable.
Ｍｅ(II)(ＯＨ)2には不安定なものが多く、乾燥状態では容易に脱水縮合してＭｅ(II)Ｏに変換される。Ｍｅ(II)Ｏは水溶液では水和反応によりＭｅ(II)(ＯＨ)2に変換されるので、本発明においてはＭｅ(II)ＯとＭｅ(II)(ＯＨ)2は同等と考えることができる。 Many of Me (II) (OH) 2 are unstable, and in the dry state, they are easily dehydrated and converted to Me (II) O. Since Me (II) O is converted into Me (II) (OH) 2 by an hydration reaction in an aqueous solution, it is considered that Me (II) O and Me (II) (OH) 2 are equivalent in the present invention. it can.
＜その他の工程＞
工程（Ｂ）でＭｅ(II)(ＯＨ)2によりＰＢ分子及び／又はそのクラスターを不溶化させることで上記複合体を含む分散液が得られる。通常、この分散液を濾過により不溶化・沈殿した複合体を分離するのであるが、その場合、液のｐＨ調整を行うことが好ましい。その範囲はｐＨ５．０〜９．０であることが好ましく、ｐＨ６．０〜８．５であることがより好ましく、得られた分散液を加熱により蒸発・乾燥する場合、ｐＨ６．０〜８．５であることが特に好ましい。これより酸性側、或いはアルカリ側であると蒸発・乾燥過程でＰＢの分解やＰＢ分子を不溶化した構造が損なわれるおそれがある。
<Other processes>
In step (B), a dispersion containing the complex is obtained by insolubilizing PB molecules and / or clusters thereof with Me (II) (OH) 2 . Usually, the complex obtained by insolubilizing and precipitating the dispersion is separated, and in this case, it is preferable to adjust the pH of the liquid. The range is preferably pH 5.0 to 9.0, more preferably pH 6.0 to 8.5. When the obtained dispersion is evaporated and dried by heating, the pH is 6.0 to 8. 5 is particularly preferred. If it is on the acidic side or alkaline side, the structure in which PB is decomposed or PB molecules are insolubilized may be damaged during the evaporation / drying process.
〔放射性Ｃｓ吸着剤の使用〕
本発明の放射性Ｃｓ吸着剤の使用による放射性Ｃｓイオンの吸着除去について、実施方法の他、技術的見地からの考察も含め、以下に詳述する。
[Use of radioactive Cs adsorbent]
The adsorption removal of radioactive Cs ions by use of the radioactive Cs adsorbent of the present invention will be described in detail below, including a method and a consideration from a technical viewpoint.
ＰＢ分子がＣｓイオンを捕捉する反応を式（６）に示す。 The reaction in which the PB molecule captures Cs ions is shown in Formula (6).
上式（６）において、ｍ＝ｎ＝１のときはＰＢ分子、ｎ≧ｍ＞１のときはＰＢ分子のクラスターを表す。 In the above formula (6), when m = n = 1, a PB molecule is represented, and when n ≧ m> 1, a cluster of PB molecules is represented.
ここで、ＰＢ分子が、Ｎａイオン、Ｋイオンなどの他のアルカリ金属イオンや、Ｍｇイオン、Ｃａイオンなどのアルカリ土類金属イオンよりも、Ｃｓイオンと優先的に結合する機構は、Ｒ．Ｇ．Ｐｅａｒｓｏｎが提唱したＨＳＡＢ規則により説明することができる（Pearson, Ralph G. (1963)."Hard and Soft Acids and Bases". J. Am. Chem. Soc.85 (22): 3533-3539.を参照）。 Here, the mechanism by which PB molecules bind preferentially to Cs ions over other alkali metal ions such as Na ions and K ions, and alkaline earth metal ions such as Mg ions and Ca ions is described in R.A. G. It can be explained by the HSAB rules proposed by Pearson (see Pearson, Ralph G. (1963). "Hard and Soft Acids and Bases". J. Am. Chem. Soc. 85 (22): 3533-3539. ).
すなわち、ＨＳＡＢ規則によると、Ｃｓは主量子数６のアルカリ金属であり、Ｃｓイオンの最低空原子軌道ＬＵＡＯは６ｓ軌道となり、それぞれ３ｓ、４ｓ軌道がＬＵＡＯであるＮａイオン、Ｋイオン、Ｃａイオンに比較して、分極し易く軟らかい酸に分類される。つまり、アルカリイオンの酸としての硬さ、軟らかさの順は次のようになる。
軟らかい Ｃｓ+≫Ｋ+＞Ｎａ+〜Ｍｇ2+〜Ｃａ2+ 硬い
That is, according to the HSAB rule, Cs is an alkali metal having a principal quantum number of 6, and the lowest vacant orbital LUAO of Cs ions is 6s orbital, and the 3s and 4s orbitals are LUAO Na ions, K ions, and Ca ions, respectively. In comparison, it is classified as a soft acid that is easily polarized. That is, the order of the hardness and softness of the alkali ions as acid is as follows.
Soft Cs + >> K + > Na + to Mg 2+ to Ca 2+ hard
一方、ＰＢイオンＦｅ(III)[Ｆｅ(II)(ＣＮ)6]-は軟らかい塩基に分類される。ＨＳＡＢ規則によれば、硬い酸は硬い塩基と強く結合し、軟らかい酸は軟らかい塩基と強く結合するが、硬い酸と軟らかい塩基の間又は軟らかい酸と硬い塩基の間で形成される結合は弱い。従って、Ｃｓイオンは他のアルカリ金属イオンやアルカリ土類金属イオンよりもＰＢイオンと強く結合する。
ＨＳＡＢ規則は量子化学で説明されている（G.Klopman (1968). "Chemical Reactivity and Concept of Charge- and Frontier-Controlled Reactions" J. Am. Chem. Soc. 90(2):223-234.を参照）。
それによると、酸と塩基の結合形成による安定化エネルギー（−ΔＥ）は式（７）で表される。
On the other hand, PB ions Fe (III) [Fe (II) (CN) 6 ] − are classified as soft bases. According to the HSAB rule, hard acids bind strongly to hard bases and soft acids bind strongly to soft bases, but the bonds formed between hard and soft bases or between soft and hard bases are weak. Therefore, Cs ions are more strongly bound to PB ions than other alkali metal ions or alkaline earth metal ions.
HSAB rules are described in quantum chemistry (G. Klopman (1968). “Chemical Reactivity and Concept of Charge- and Frontier-Controlled Reactions” J. Am. Chem. Soc. 90 (2): 223-234. reference).
According to this, the stabilization energy (-ΔE) due to the bond formation between the acid and the base is expressed by the formula (7).
ｑa：Ｍ(I)イオンの電荷 ｑb：ＰＢイオンｂの電荷
ε：反応場の誘電率 ｒab：Ｍ(I)とＰＢの結合距離
Γab：クーロン反発項
Ｅm *：ＰＢイオンｂの最高占有分子軌道（ＨＯＭＯ）エネルギー
Ｅn *：陽イオンａの最低非占有原子軌道（ＬＵＡＯ）エネルギー
ｃm：ＰＢイオンのＨＯＭＯを構成する原子軌道関数の係数の最大値
ｃn：Ｍ(I)イオンのＬＵＡＯ関数の係数
β：Ｍ(I)のＬＵＡＯとＰＢイオンのＨＯＭＯの共鳴積分項
q a : charge of M (I) ion q b : charge of PB ion b ε: dielectric constant of reaction field r ab : bond distance between M (I) and PB Γ ab : Coulomb repulsion term E m * : PB ion b the highest occupied molecular orbital (HOMO) energy E n *: cation a minimum unoccupied atomic orbital (LUAO) energy c m: maximum value of the coefficient of atomic orbitals that constitute the HOMO of PB ion c n: M (I ) Coefficient of the LUAO function of ions β: Resonance integral term of LUAO of M (I) and HOMO of PB ions
式（７）の左辺−ΔＥの値が大きいほど酸と塩基の結合は安定化する。右辺の第１項と第２項はそれぞれＭ(I)イオンの正電荷とＰＢイオンの負電荷のクーロン相互作用と溶媒和によるエネルギーの安定化を意味し、硬い酸と硬い塩基の相互作用には第１項と第２項が寄与する。
電荷密度が小さいＣｓイオンとＰＢイオンの場合、第１項及び第２項の−ΔＥ値への寄与は小さい。一方、第３項は軟らかい酸と軟らかい塩基の相互作用を意味しており、軟らかい酸ＣｓイオンのＬＵＡＯと軟らかい塩基のＰＢイオンＦｅ(III)Ｆｅ(II)(ＣＮ)6 -の最高占有分子軌道（ＨＯＭＯ）間の強い相互作用が−ΔＥ値の増加に大きく寄与するのである。つまり、この場合、第３項の｜Ｅm *−Ｅn *｜が小さくβ2が大きくなるので、第３項が−ΔＥ値の増加に寄与することになる。
硬い酸であるＮａイオン，Ｋイオン，Ｍｇイオン，Ｃａイオンと軟らかい塩基であるＰＢイオンとの相互作用では式（７）の第１項〜第３項による−ΔＥ増加への寄与は小さい。つまり、これらのカチオンとＰＢイオンは強い結合を形成しない。
The larger the value of the left side -ΔE of the formula (7), the more the acid-base bond is stabilized. The first and second terms on the right-hand side mean the energy stabilization by the Coulomb interaction and solvation of the positive charge of the M (I) ion and the negative charge of the PB ion, respectively, and the interaction between the hard acid and the hard base. The first and second terms contribute.
In the case of Cs ions and PB ions having a small charge density, the contribution of the first and second terms to the -ΔE value is small. On the other hand, the third term means a interaction soft acid and a soft base, the LUAO and soft base soft acids Cs ions PB ions Fe (III) Fe (II) (CN) 6 - the highest occupied molecular orbital The strong interaction between (HOMO) greatly contributes to the increase of the -ΔE value. That is, in this case, | E m * −E n * | in the third term is small and β 2 is large, so the third term contributes to an increase in the −ΔE value.
The interaction between Na ions, K ions, Mg ions, and Ca ions, which are hard acids, and PB ions, which are soft bases, contributes little to the increase in −ΔE due to the first to third terms of Equation (7). That is, these cations and PB ions do not form a strong bond.
従って、下式（８）において、平衡反応は以下の順で右側に傾斜する。
Ｍ(I)+： Ｃｓ+≫Ｋ+＞Ｎａ+
Therefore, in the following formula (8), the equilibrium reaction is inclined to the right in the following order.
M (I) + : Cs + >> K + > Na +
ＰＢ分子、及びＰＢ分子クラスターをＭｅ(II)(ＯＨ)2の層状構造にインターカレートした複合体がＣｓイオンを迅速に吸着する機構は定かではないが、本発明者は、次のように考察した。
Ｍｅ(II)(ＯＨ)2は層状の結晶構造を形成しており、水中では水分子が層内に取込まれるが、層構造を破壊することなく粘土物質のように層間隔を拡大することができる。その結果、Ｃｓイオンが層間内に自由に拡散することができ、吸着平衡状態に短時間で達することができる。
そして、Ｍｅ(II)(ＯＨ)2の層構造は層間水の取り込みによって層間隔を拡大するのであるが、層内にインターカレートされたＰＢ分子やＰＢ分子クラスターはＭｅ(II)のｄ軌道とＰＢのシアノ基のπ電子とのｄ−π相互作用の結合により層間からのＰＢ分子の溶出が抑制されるのである。
これに対して、従来のように、成長した結晶構造を有する微粉末のＰＢを添加する場合、水中での格子定数の拡大は期待できず、Ｃｓイオンの吸着速度はＣｓイオンの結晶格子内での拡散が緩慢になるため、吸着平衡に達するまでに１日以上を要していたものと考えられる。
The mechanism by which a complex in which PB molecules and PB molecule clusters are intercalated into a layered structure of Me (II) (OH) 2 adsorbs Cs ions quickly is not clear, but the present inventor Considered.
Me (II) (OH) 2 forms a layered crystal structure, and water molecules are taken into the layer in water, but the layer spacing is expanded like a clay material without destroying the layer structure. Can do. As a result, Cs ions can freely diffuse between the layers, and an adsorption equilibrium state can be reached in a short time.
The layer structure of Me (II) (OH) 2 expands the layer spacing by taking in interlayer water, but the PB molecules and PB molecule clusters intercalated in the layer are Me's d orbitals. The elution of PB molecules from the interlayer is suppressed by the bond of d-π interaction between the cyano group and the π electron of the cyano group of PB.
On the other hand, when adding fine powder PB having a grown crystal structure as in the prior art, expansion of the lattice constant in water cannot be expected, and the adsorption rate of Cs ions is within the crystal lattice of Cs ions. It is considered that it took one day or more to reach the adsorption equilibrium because of the slow diffusion.
ここで、Ｃｓイオンを吸着するＰＢ分子及び／又はそのクラスターの実体は、主に、上式（１）〜（４）における（ＰＢ１）であることからＣｓイオンを吸着するＰＢ分子数は鉄シアノ錯体Ｆｅ(II)(ＣＮ)6 4-の分子数に関係する。
従って、本発明の放射性Ｃｓ吸着剤の有効成分となる複合体において、Ｃｓ吸着部位となる鉄シアノ錯体の当量をα（ｍｏｌ）、層状結晶構造を形成するＭｅ(II)(ＯＨ)2又はその部分酸化物の当量をβ(ｍｏｌ)とすると放射性Ｃｓ吸着剤の活物質は下式（９）又は下式（１０）であると考えられる。
Here, since the substance of the PB molecule and / or its cluster that adsorbs Cs ions is mainly (PB1) in the above formulas (1) to (4), the number of PB molecules adsorbing Cs ions is iron cyano. It relates to the number of molecules of the complex Fe (II) (CN) 6 4- .
Therefore, in the complex as the active ingredient of the radioactive Cs adsorbent of the present invention, the equivalent of the iron cyano complex that becomes the Cs adsorption site is α (mol), Me (II) (OH) 2 that forms a layered crystal structure or its When the equivalent of the partial oxide is β (mol), the active material of the radioactive Cs adsorbent is considered to be the following formula (9) or the following formula (10).
上式（９）はＭｅ(II)(ＯＨ)2、上式（１０）はＭｅ(II)(ＯＨ)2の部分酸化物に対応する。すなわち、Ｍｅ(II)(ＯＨ)2の中には不安定なものがあり、乾燥状態では脱水縮合してＭｅ(II)Ｏになるので、このような場合には、本発明の放射性Ｃｓ吸着剤の有効成分となる複合体においてＣｓイオンを吸着する活物質は上式（１０）の形で表される（なお、上式（１０）において、ｘ＋ｙ＝１である）。 The above formula (9) corresponds to Me (II) (OH) 2 and the above formula (10) corresponds to a partial oxide of Me (II) (OH) 2 . That is, some Me (II) (OH) 2 is unstable and dehydrated and condensed to Me (II) O in the dry state. In such a case, the radioactive Cs adsorption of the present invention is performed. The active material that adsorbs Cs ions in the complex as the active ingredient of the agent is represented by the above formula (10) (in the above formula (10), x + y = 1).
しかし、Ｍｅ(II)Ｏは水中では水和反応によりＭｅ(II)(ＯＨ)2を再生するので、本発明においてはＭｅ(II)ＯとＭｅ(II)(ＯＨ)2は同等、つまり上式（９）と上式（１０）とは同等と考えることができる。 However, since Me (II) O regenerates Me (II) (OH) 2 in water by a hydration reaction, in the present invention, Me (II) O and Me (II) (OH) 2 are equivalent, that is, Equation (9) and equation (10) can be considered equivalent.
そして、上述のとおり、ＰＢを構成するＦｅ(II)（ＣＮ）6の当量をαモルとし、Ｍｅ(II)(ＯＨ)2又はその部分酸化物を構成するＭｅ(II)の当量をβモルとするとき、αとβの比（α／β）が０．１〜１０となる割合であることが好ましく、０．２〜５であることがより好ましい。特に、処理液の全シアン濃度の排水基準値を考慮する場合には、α／βが０．１〜１．０であることが好ましい。その理由は以下のとおりである。
ＰＢ分子をＭｅ(II)(ＯＨ)2の層状結晶構造の層間にインターカレートして不溶化するには、α／βを小さくする方向が好ましいが、０．１より小さくしてもそれ以上の改善効果は期待できず、むしろ、過剰のＭｅ(II)(ＯＨ)2の溶出によって処理液の水質を損なうおそれがある。一方、α／βが１０を超えると、Ｍｅ(II)(ＯＨ)2によるＰＢ分子の不溶化が不十分となり、放射性Ｃｓ汚染水の吸着処理濾過工程において、Ｃｓイオンを吸着したＰＢ分子及び／又はそのクラスターがフィルターの篩目を透過するおそれがある。
As described above, the equivalent of Fe (II) (CN) 6 constituting PB is α mol, and the equivalent of Me (II) constituting Me (II) (OH) 2 or its partial oxide is β mol. , The ratio of α and β (α / β) is preferably a ratio of 0.1 to 10, more preferably 0.2 to 5. In particular, when considering the drainage standard value of the total cyan concentration of the treatment liquid, α / β is preferably 0.1 to 1.0. The reason is as follows.
In order to intercalate and insolubilize PB molecules between layers of the layered crystal structure of Me (II) (OH) 2 , the direction of decreasing α / β is preferable. The improvement effect cannot be expected, but there is a possibility that the water quality of the treatment liquid may be impaired by the elution of excess Me (II) (OH) 2 . On the other hand, when α / β exceeds 10, insolubilization of PB molecules by Me (II) (OH) 2 becomes insufficient, and in the adsorption treatment filtration step of radioactive Cs contaminated water, PB molecules adsorbed Cs ions and / or There is a possibility that the cluster may pass through the filter mesh.
なお、α／βの値は、放射性Ｃｓ吸着剤を製造する際に、αは鉄シアノ鉄(II)ヘキサシアノ基Ｆｅ(II)(ＣＮ)6の量、βはＭｅ(II)(ＯＨ)2やＭｅ(II)Ｏ、Ｍｅ(II)塩化合物の添加量などを適宜選定して調整することができる。 The α / β values are as follows: α is the amount of iron cyanoiron (II) hexacyano group Fe (II) (CN) 6 and β is Me (II) (OH) 2 when producing the radioactive Cs adsorbent. And the addition amount of Me (II) O and Me (II) salt compounds can be appropriately selected and adjusted.
ところで、一般に水処理工程では微粒子を凝集させるために硫酸バンドＡｌ2（ＳＯ4）3や塩鉄Ｆｅ(III)Ｃｌ3などを添加する方法が汎用されている。また、廃液中の重金属類の不溶化にマグネシウム塩ＭｇＳＯ4などを添加する方法が採られている。しかし、本発明ではＭｅ(II)(ＯＨ)2の代わりに前記凝集剤や不溶化剤を適用しても効果は得られない。これは加水分解で生成するこれら水酸化物のＡｌ(III)、Ｆｅ(III)、Ｍｇ(II)は硬い酸に属し、軟らかい塩基のＰＢ分子のシアノ基との相互作用による結合形成が出来ないためと考えられる。 By the way, in general, in the water treatment process, a method of adding a sulfate band Al 2 (SO 4 ) 3 , iron salt Fe (III) Cl 3 or the like to agglomerate fine particles is widely used. Further, a method of adding magnesium salt MgSO 4 or the like to insolubilize heavy metals in the waste liquid is employed. However, in the present invention, no effect is obtained even if the above-mentioned flocculant or insolubilizing agent is applied instead of Me (II) (OH) 2 . This is because Al (III), Fe (III), and Mg (II) of these hydroxides produced by hydrolysis belong to hard acid, and cannot form a bond by interaction with the cyano group of the PB molecule of the soft base. This is probably because of this.
ＰＢ分子及び／又はそのクラスターをゲストとしてインターカレートしたホストのＭｅ(II)(ＯＨ)2の一部は脱水してＭｅ(II)Ｏを形成するので、上記複合体の層状構造としては、例えば下式（１１）で示すことができる。 Since part of the host Me (II) (OH) 2 intercalated with PB molecules and / or clusters thereof as a guest is dehydrated to form Me (II) O, the layered structure of the complex is as follows: For example, it can be represented by the following formula (11).
上式（１１）において、ｘ＋ｙ＝１であり、ｍ、ｎは正数である。上式（１１）で表される構造の模式図を図１に示す。
ＰＢ分子と共にＭｅ(II)(ＯＨ)2層状結晶構造の層間に存在する層間水はＣｓイオンの吸着速度に重要な役割を果たす。
上記複合体の層間水を除去すると層構造の層間隔が縮小する。そのためＣｓイオンの結晶内への拡散が抑制され、上記複合体による効率的なＣｓイオンの吸着が阻害される。
つまり、層間水の存在によりＭｅ(II)(ＯＨ)2層状結晶構造のｃ軸方向の層間隔が拡大し、Ｃｓイオンの拡散が容易になり、層間に存在するＰＢ分子、及び又はＰＢクラスターに捕捉されるのである。
従って、本発明の放射性Ｃｓ吸着剤として乾燥物を得る場合、この乾燥は１００℃以下の低温で実施されることが好ましい。また、本発明の放射性Ｃｓ吸着剤として、上記複合体を含水した形、例えばスラリー、含水スラッジ、或いは水に分散した形で使用することもできる。
In the above equation (11), x + y = 1, and m and n are positive numbers. A schematic diagram of the structure represented by the above formula (11) is shown in FIG.
Together with PB molecule Me (II) (OH) 2 interlayer water present between layers of the layered crystal structure plays an important role in adsorption rate of Cs ions.
When the interlayer water of the composite is removed, the layer spacing of the layer structure is reduced. Therefore, diffusion of Cs ions into the crystal is suppressed, and efficient adsorption of Cs ions by the complex is inhibited.
In other words, the interlayer spacing in the c-axis direction of the Me (II) (OH) two- layered crystal structure is expanded due to the presence of interlayer water, and the diffusion of Cs ions is facilitated, so that PB molecules and / or PB clusters existing between the layers It is captured.
Therefore, when a dried product is obtained as the radioactive Cs adsorbent of the present invention, this drying is preferably performed at a low temperature of 100 ° C. or less. The radioactive Cs adsorbent of the present invention can also be used in a form containing the above composite in water, for example, slurry, water-containing sludge, or dispersed in water.
以下、実施例を用いて、本発明にかかる放射性Ｃｓ吸着剤及びその製造方法について詳しく説明するが、本発明はこれら実施例に限定されるものではない。
なお、放射性Ｃｓ汚染水の入手には制約があるため、吸着剤の性能に関する実施例の多くを入手可能な安定同位体133Ｃｓで代用して実施した。
しかし、以下で観察される化学的、物理的な事象は、133Ｃｓの放射性同位体である137Ｃｓ、134Ｃｓのそれと完全に一致する。
従って、133Ｃｓを含む模擬汚染水、模擬海水及び放射性Ｃｓ汚染水からＣｓを除去した以下の実施例は、同時に、放射性同位体である137Ｃｓ、134Ｃｓについての効果も実証するものである。
Hereinafter, although the radioactive Cs adsorbent concerning this invention and its manufacturing method are demonstrated in detail using an Example, this invention is not limited to these Examples.
Since there are restrictions on the availability of radioactive Cs-contaminated water, many of the examples relating to the performance of the adsorbent were used in place of the available stable isotope 133 Cs.
However, the chemical and physical events observed below are in complete agreement with those of 137 Cs and 134 Cs, which are radioisotopes of 133 Cs.
Accordingly, the following examples in which Cs was removed from simulated contaminated water containing 133 Cs, simulated seawater, and radioactive Cs contaminated water also demonstrate the effects on 137 Cs and 134 Cs, which are radioisotopes.
以下の実施例及び比較例で用いた薬品のうち、フェロシアン化ナトリウム１０水和物以外の薬品は全てキシダ化学社製のものを使用した。
また、ＰＢ分子数αは、ＰＢ分子をＭ(I)Ｆｅ(III)Ｆｅ(II)(ＣＮ)6として吸着剤に含まれるシアン含有量から換算した値をαとした。βはそれぞれのＭｅ(II)の測定値をβとした。
シアン定量のための前処理、及び測定は底質調査法１４．１シアン化合物に準拠して実施した。また、Ｍｅ(II)含有量についても底質調査法記載の処方に準拠した前処理により試料調製を行い、アジレント社の誘導結合型プラズマ質量分析装置（ＩＣＰ−ＭＳ）７０００ｘで測定を行った。
Of the chemicals used in the following Examples and Comparative Examples, all chemicals other than sodium ferrocyanide decahydrate were manufactured by Kishida Chemical Co., Ltd.
The number of PB molecules α was defined as α obtained by converting the PB molecule as M (I) Fe (III) Fe (II) (CN) 6 from the cyan content contained in the adsorbent. For β, the measured value of each Me (II) was β.
Pretreatment for cyan determination and measurement were carried out according to the bottom sediment survey method 14.1 cyanide compound. In addition, the Me (II) content was also prepared by pretreatment based on the prescription described in the sediment survey method, and measured with an inductively coupled plasma mass spectrometer (ICP-MS) 7000x manufactured by Agilent.
〔実施例１〕
３００ｍＬの蒸留水にフェロシアン化カリウム３水和物１５ｇ（３５．５ｍｍｏｌ）を加え、続いて、攪拌下、塩化鉄(III)６水和物９．７ｇ（３６ｍｍｏｌ）を加えてＰＢを合成した。次に、硫酸マンガン(II)１水和物１２．３ｇ（７３ｍｍｏｌ）を添加した。
５ｍｏｌ／Ｌの水酸化ナトリウム水溶液を添加してｐＨを７．０〜８．０に調整しながら攪拌下加水分解を行った。硫酸マンガン(II)１水和物の添加終了２時間後、攪拌を止めて静置した。篩目１μｍのガラスフィルターを用いて吸引濾過／洗浄した後、６０℃で５時間真空乾燥を行い、吸着剤２５．０ｇを得た。吸着剤のシアノ基、及びマンガン含有量をそれぞれ定量して、α／β＝０．５を得た。
[Example 1]
PB was synthesized by adding 15 g (35.5 mmol) of potassium ferrocyanide trihydrate to 300 mL of distilled water, and then adding 9.7 g (36 mmol) of iron (III) chloride hexahydrate with stirring. Next, 12.3 g (73 mmol) of manganese (II) sulfate monohydrate was added.
Hydrolysis was performed with stirring while adjusting the pH to 7.0 to 8.0 by adding a 5 mol / L sodium hydroxide aqueous solution. Two hours after the completion of the addition of manganese (II) sulfate monohydrate, stirring was stopped and the mixture was allowed to stand. After suction filtration / washing using a glass filter having a sieve mesh of 1 μm, vacuum drying was performed at 60 ° C. for 5 hours to obtain 25.0 g of an adsorbent. The cyano group and manganese content of the adsorbent were each quantified to obtain α / β = 0.5.
〔実施例２〕
実施例１で硫酸マンガン(II)１水和物６．３ｇ（３７．３ｍｍｏｌ）を添加したほかは実施例１と同じ方法で実施して吸着剤２０．８ｇを得た。α／β＝１．０であった。
[Example 2]
The same procedure as in Example 1 was conducted except that 6.3 g (37.3 mmol) of manganese (II) sulfate monohydrate was added in Example 1, to obtain 20.8 g of an adsorbent. α / β = 1.0.
〔実施例３〕
実施例１で硫酸マンガン(II)１水和物３．０ｇ（１７．８ｍｍｏｌ）を添加したほかは実施例１と同じ方法で実施して吸着剤１８．８ｇを得た。α／β＝１．９であった。
Example 3
The same procedure as in Example 1 was carried out except that 3.0 g (17.8 mmol) of manganese (II) sulfate monohydrate was added in Example 1 to obtain 18.8 g of an adsorbent. α / β = 1.9.
〔実施例４〕
実施例１でフェリシアン化カリウム無水物６．０ｇ（１８ｍｍｏｌ）、フェロシアン化カリウム３水和物７．６ｇ（１８ｍｍｏｌ）に、還元剤として亜硫酸ナトリウム無水物５ｇを加えた後、塩化鉄(III)６水和物９．８ｇ（３６．２ｍｍｏｌ）を加えてＰＢの合成を行ったほかは、全て実施例１と同様に実施して吸着剤２４．６ｇを得た。α／β＝０．６であった。
Example 4
In Example 1, 5 g of sodium ferrous cyanide anhydride as a reducing agent was added to 6.0 g (18 mmol) of potassium ferricyanide anhydride and 7.6 g (18 mmol) of potassium ferrocyanide trihydrate, and then iron (III) chloride hexahydrate. Except for adding 9.8 g (36.2 mmol) of the product and synthesizing PB, all was carried out in the same manner as in Example 1 to obtain 24.6 g of an adsorbent. α / β = 0.6.
〔実施例５〕
実施例１で、硫酸マンガン(II)１水和物１２．３ｇ（７３ｍｍｏｌ）の代わりに金属マンガン粉４．０ｇ(７３ｍｍｏｌ)を添加し、塩酸でｐＨを５．０に調整して５時間攪拌を行った。反応終了後、５モル／Ｌ亜硫酸ナトリウム水溶液でｐＨを８．０に調整してからは実施例１と同様に実施して、吸着剤２４．６ｇを得た。α／β＝０．５であった。
Example 5
In Example 1, 4.0 g (73 mmol) of metal manganese powder was added instead of 12.3 g (73 mmol) of manganese (II) sulfate monohydrate, and the pH was adjusted to 5.0 with hydrochloric acid, followed by stirring for 5 hours. Went. After completion of the reaction, the pH was adjusted to 8.0 with a 5 mol / L sodium sulfite aqueous solution, and then the same procedure as in Example 1 was performed to obtain 24.6 g of an adsorbent. α / β = 0.5.
〔実施例６〕
５００ｍＬの蒸留水にフェロシアン化ナトリウム１０水和物（Ａｌｆａ Ａｅｓａｒ社製）２１．０ｇ（４３．４ｍｍｏｌ）を溶解し、次に攪拌下、塩化鉄(III)６水和物１２．０ｇ（４４．４ｍｍｏｌ）を加えてＰＢを合成した。つづいて硫酸銅(II)１４．０ｇ(８７．５ｍｍｏｌ)水溶液１００ｍｌを攪拌下にＰＢ合成液に添加した。添加終了後ｐＨを８．０に調整しながら１時間攪拌を続けた。攪拌終了後、ガラスフィルターで吸引濾過を行った。蒸留水で濾物を洗浄後４０℃で１晩真空乾燥を行い、吸着剤２８．９ｇを得た。α／β＝０．５であった。
Example 6
21.0 g (43.4 mmol) of sodium ferrocyanide decahydrate (manufactured by Alfa Aesar) was dissolved in 500 mL of distilled water, and then 12.0 g (44 of iron (III) chloride hexahydrate was added under stirring. .4 mmol) was added to synthesize PB. Subsequently, 100 ml of a 14.0 g (87.5 mmol) aqueous solution of copper (II) sulfate was added to the PB synthesis solution with stirring. After completion of the addition, stirring was continued for 1 hour while adjusting the pH to 8.0. After the stirring, suction filtration was performed with a glass filter. The filtrate was washed with distilled water and vacuum dried at 40 ° C. overnight to obtain 28.9 g of an adsorbent. α / β = 0.5.
〔実施例７〕
実施例６で硫酸銅(II)の代わりに塩化ニッケル(II)１０．０ｇ（７７ｍｍｏｌ）の水溶液１００ｍＬを添加したほかは同様に実施して吸着剤２９．６ｇを得た。α／β＝０．６であった。
Example 7
In the same manner as in Example 6 except that 100 mL of an aqueous solution of 10.0 g (77 mmol) of nickel (II) chloride was added instead of copper (II) sulfate, 29.6 g of an adsorbent was obtained. α / β = 0.6.
〔実施例８〕
実施例６で硫酸銅(II)の代わりに塩化コバルト(II)１１．３ｇ（８７ｍｍｏｌ）の水溶液１００ｍＬを添加したほかは同様に実施して吸着剤２８．４ｇを得た。α／β＝０．６であった。
Example 8
In the same manner as in Example 6 except that 100 mL of an aqueous solution of 11.3 g (87 mmol) of cobalt (II) chloride was added instead of copper (II) sulfate, 28.4 g of an adsorbent was obtained. α / β = 0.6.
〔実施例９〕
実施例６で硫酸銅(II)の代わりに硫酸亜鉛(II)無水和物１４．０ｇ（８６．８ｍｍｏｌ）の水溶液１００ｍＬを添加したほかは同様に実施して吸着剤２８．６ｇを得た。α／β＝０．６であった。
Example 9
In the same manner as in Example 6 except that 100 mL of an aqueous solution of 14.0 g (86.8 mmol) of zinc sulfate (II) anhydride was added instead of copper (II) sulfate, 28.6 g of an adsorbent was obtained. α / β = 0.6.
〔実施例１０〕
実施例６で硫酸銅(II)の代わりに塩化ニッケル(II)無水和物１４．０ｇ（４４．０ｍｍｏｌ）と塩化銅(II)２水和物（４４．０ｍｍｏｌ）を溶解させた水溶液１００ｍＬを添加したほかは同様に実施して吸着剤２３．０ｇを得た。α／β＝０．５であった。βはＭｅ(II)のモル数であるが、Ｎｉ(II)とＣｕ(II)のモル数の和をβとした。
Example 10
In Example 6, instead of copper (II) sulfate, 100 mL of an aqueous solution in which 14.0 g (44.0 mmol) of nickel chloride (II) anhydride and copper (II) chloride dihydrate (44.0 mmol) were dissolved was used. Except for the addition, 23.0 g of an adsorbent was obtained in the same manner. α / β = 0.5. β is the number of moles of Me (II), and the sum of the number of moles of Ni (II) and Cu (II) is β.
〔実施例１１〕
実施例６で硫酸銅(II)１４．０ｇ(８７．５ｍｍｏｌ)の代わりに硫酸銅(II)１．３ｇ（９．４ｍｍｏｌ）を加えた他は同様に実施して吸着剤１８．３ｇを得た。α／β＝５．４であった。
Example 11
The same procedure as in Example 6 was carried out except that 1.3 g (9.4 mmol) of copper (II) sulfate was added instead of 14.0 g (87.5 mmol) of copper (II) sulfate to obtain 18.3 g of an adsorbent. It was. α / β = 5.4.
〔実施例１２〕
実施例６で硫酸銅(II)１４．０ｇ(８７．５ｍｍｏｌ)の代わりに塩化コバルト(II)１．２ｇ（９．２ｍｍｏｌ）を加えた他は同様に実施して吸着剤１７．８ｇを得た。α／β＝４．８であった。
Example 12
The same procedure as in Example 6 was carried out except that 1.2 g (9.2 mmol) of cobalt (II) chloride was added instead of 14.0 g (87.5 mmol) of copper (II) sulfate, to obtain 17.8 g of an adsorbent. It was. α / β = 4.8.
〔実施例１３〕
５００ｍＬの蒸留水にフェロシアン化ナトリウム１０水和物（Ａｌｆａ Ａｅｓａｒ社製）２１．０ｇ（４３．４ｍｍｏｌ）を溶解し、次に攪拌下、塩化鉄(III)６水和物１１．７ｇ（４３．４ｍｍｏｌ）を加えてＰＢを合成した。つづいてＰＢ水溶液に窒素ガスを吹込みながら塩化鉄(II)４水和物２０．０ｇ(１００ｍｍｏｌ)水溶液１００ｍｌを攪拌下に添加した。添加終了後ｐＨを８．０〜８．５に調整しながら１時間攪拌を続けた。攪拌終了後、ガラスフィルターで吸引濾過を行った。蒸留水で濾物を洗浄後４０℃で１晩真空乾燥を行い、吸着剤３０．９ｇを得た。濾液に含まれるシアン、及び鉄の濃度がそれぞれ０．０５ｍｇ／Ｌ未満、１０ｍｇ／Ｌ未満であったことから、添加したフェロシアンシアン化ナトリウム１０水和物と塩化鉄(II)４水和物のモル比から算出した該吸着剤のα／βは０．４であった。
Example 13
21.0 g (43.4 mmol) of sodium ferrocyanide decahydrate (Alfa Aesar) was dissolved in 500 mL of distilled water, and then 11.7 g of iron (III) chloride hexahydrate (43 g) with stirring. .4 mmol) was added to synthesize PB. Subsequently, 100 ml of an aqueous solution of 20.0 g (100 mmol) of iron (II) chloride tetrahydrate was added with nitrogen gas being blown into the aqueous PB solution. After completion of the addition, stirring was continued for 1 hour while adjusting the pH to 8.0 to 8.5. After the stirring, suction filtration was performed with a glass filter. The filtrate was washed with distilled water and vacuum dried at 40 ° C. overnight to obtain 30.9 g of an adsorbent. Since the concentrations of cyanide and iron contained in the filtrate were less than 0.05 mg / L and less than 10 mg / L, respectively, sodium ferrocyanocyanide decahydrate and iron (II) chloride tetrahydrate were added. The α / β of the adsorbent calculated from the molar ratio was 0.4.
〔実施例１４〕
実施例１と同様にＰＢ分子を不溶化した後、反応液を３０００ｒｐｍで２０分間遠心沈殿した。上澄液を除去後、蒸留水３００ｍｌで沈殿物を再分散させた。該分散液を再度３０００ｒｐｍで２０分間遠心沈殿した。上澄液を除去後、α／β＝０．５の沈殿物１３６ｇを得た。含水率は８１．５％であった。
Example 14
After insolubilizing the PB molecules in the same manner as in Example 1, the reaction solution was centrifuged for 20 minutes at 3000 rpm. After removing the supernatant, the precipitate was redispersed with 300 ml of distilled water. The dispersion was centrifuged again at 3000 rpm for 20 minutes. After removing the supernatant, 136 g of a precipitate with α / β = 0.5 was obtained. The water content was 81.5%.
〔実施例１５〕
実施例１４で得られた沈殿物を４０℃で一晩風乾して吸着剤６６．７ｇを得た。α／β＝０．５で含水率は６２．５％であった。
Example 15
The precipitate obtained in Example 14 was air-dried at 40 ° C. overnight to obtain 66.7 g of an adsorbent. α / β = 0.5 and the water content was 62.5%.
〔実施例１６〕
実施例１４で得られた沈殿物を１０５℃で２時間乾燥して、吸着剤２３．８ｇを得た。
α／β＝０．５で、含水率は０．１％であった。
Example 16
The precipitate obtained in Example 14 was dried at 105 ° C. for 2 hours to obtain 23.8 g of an adsorbent.
α / β = 0.5, and the water content was 0.1%.
〔実施例１７〜２２〕
３００ｍＬの蒸留水にフェロシアン化ナトリウム１０水和物１０．０ｇ(２０．６ｍｍｏｌ)を溶解し、続いて、攪拌下、塩化鉄(III)６水和物５．６ｇ（２０．８ｍｍｏｌ／Ｌ）を加えてＰＢを合成した後、水酸化コバルト(II)３．８ｇ（４０．９ｍｍｏｌ）を加えてｐＨを７．５〜８．０に調整して攪拌を続けた。３時間後に攪拌を止めて静置した。篩目１μｍのガラスフィルターで反応液を吸引濾過した。濾物を蒸留水で洗浄後、室温で真空乾燥を一晩行い、吸着剤１４．６ｇを得た。α／β＝０．６であった。
さらに、水酸化コバルト(II)の代わりに水酸化銅(II)、水酸化ニッケル(II)、酸化マンガン(II)、酸化亜鉛(II)、水酸化カドミウム(II)を用いて同様に実施した。表１に得られた吸着剤の量、及びα／β値を示す。
[Examples 17 to 22]
Dissolve 10.0 g (20.6 mmol) of sodium ferrocyanide decahydrate in 300 mL of distilled water, followed by 5.6 g (20.8 mmol / L) of iron (III) chloride hexahydrate with stirring. Was added to synthesize PB, and then 3.8 g (40.9 mmol) of cobalt hydroxide (II) was added to adjust the pH to 7.5 to 8.0 and stirring was continued. After 3 hours, stirring was stopped and the mixture was allowed to stand. The reaction solution was suction filtered through a glass filter having a sieve mesh of 1 μm. The residue was washed with distilled water and vacuum dried at room temperature overnight to obtain 14.6 g of an adsorbent. α / β = 0.6.
Furthermore, it was carried out in the same manner using copper hydroxide (II), nickel hydroxide (II), manganese oxide (II), zinc oxide (II), cadmium hydroxide (II) instead of cobalt hydroxide (II). . Table 1 shows the amount of adsorbent obtained and α / β values.
〔比較例１〕
蒸留水３００ｍＬに大日精化工業社製のプルシアンブルー（ＮＨ4Ｆｅ(III)Ｆｅ(II)（ＣＮ）6）１０．０ｇ(３５ｍｍｏｌ)を加え、続いて硫酸マンガン（II）１水和物１２ｇ(７１ｍｍｏｌ)を加え、ｐＨを５ｍｏｌ／Ｌ水酸化ナトリウム水溶液により８．０に調整しながら攪拌を２時間行った。つづいて反応液を篩目１μｍのガラスフィルターで吸引濾過した。濾物を蒸留水で洗浄後、５０℃で１晩真空乾燥してα／β＝０．５の吸着剤１６．３ｇを得た。
[Comparative Example 1]
10.0 g (35 mmol) of Prussian blue (NH 4 Fe (III) Fe (II) (CN) 6 ) manufactured by Dainichi Seika Kogyo Co., Ltd. was added to 300 mL of distilled water, followed by 12 g of manganese (II) sulfate monohydrate. (71 mmol) was added, and the mixture was stirred for 2 hours while adjusting the pH to 8.0 with a 5 mol / L aqueous sodium hydroxide solution. Subsequently, the reaction solution was subjected to suction filtration with a glass filter having a sieve size of 1 μm. The residue was washed with distilled water and dried in vacuo at 50 ° C. overnight to obtain 16.3 g of an adsorbent with α / β = 0.5.
〔比較例２〕
蒸留水３００ｍＬ攪拌下、フェロシアン化ナトリウム１０水和物１０ｇ（２０．７ｍｍｏｌ）、つづいて塩化鉄(III)６水和物５．７ｇ(２１ｍｍｏｌ)を加えてＰＢを合成した。１５分攪拌後、更にＰＢ分子不溶化剤として塩化鉄(III)６水和物１１．４ｇ(４２ｍｍｏｌ)を加えた。５ｍｏｌ／Ｌ水酸化ナトリウム水溶液でｐＨを８．０に調整しながら塩化鉄(III)の加水分解を行った。ＰＢ合成から１時間後に攪拌を止め静置して反応液を篩目１μｍのガラスフィルターで吸引濾過した。濾物を蒸留水で洗浄後、５０℃で１晩真空乾燥してＣｓ吸着剤１６．３ｇを得た。
[Comparative Example 2]
PB was synthesized by adding 10 g (20.7 mmol) of sodium ferrocyanide decahydrate followed by 5.7 g (21 mmol) of iron (III) chloride hexahydrate while stirring 300 mL of distilled water. After stirring for 15 minutes, 11.4 g (42 mmol) of iron (III) chloride hexahydrate was further added as a PB molecule insolubilizing agent. Iron chloride (III) was hydrolyzed while adjusting the pH to 8.0 with a 5 mol / L aqueous sodium hydroxide solution. One hour after the PB synthesis, the stirring was stopped and the mixture was allowed to stand, and the reaction solution was subjected to suction filtration with a glass filter having a mesh size of 1 μm. The residue was washed with distilled water and then vacuum dried at 50 ° C. overnight to obtain 16.3 g of Cs adsorbent.
〔比較例３〕
比較例２で不溶化剤としての塩化鉄(III)６水和物を硫酸マグネシウム(II)１０ｇ(８３ｍｍｏｌ)に代えるとともに加水分解をｐＨ９．５に調整して実施したほかは比較例２と同様に実施した。
[Comparative Example 3]
Similar to Comparative Example 2, except that iron (III) chloride hexahydrate as an insolubilizing agent was replaced with 10 g (83 mmol) of magnesium sulfate (II) and the hydrolysis was adjusted to pH 9.5. Carried out.
〔比較例４〕
比較例２で不溶化剤としての塩化鉄(III)６水和物を硫酸アルミニウム(III)７．５ｇ(５０ｍｍｏｌ)に代えるとともに加水分解をｐＨ８．５に調整して実施したほかは比較例２と同様に実施した。
[Comparative Example 4]
Comparative Example 2 was different from Comparative Example 2 except that iron (III) chloride hexahydrate as an insolubilizing agent was replaced with 7.5 g (50 mmol) of aluminum sulfate (III) and the hydrolysis was adjusted to pH 8.5. It carried out similarly.
〔性能評価試験〕
下記に従い調製した模擬Ｃｓ汚染水、模擬Ｃｓ汚染海水について、上記実施例にかかる各吸着剤、従来の吸着剤、上記比較例にかかる各吸着剤を用いて、下記実施試験及び比較試験を行い、その吸着性能を評価した。
尚、各実施試験及び比較試験で測定した処理濾液のＣｓ濃度はアジレント社の誘導結合型プラズマ質量分析装置（ＩＣＰ−ＭＳ）７０００ｘで測定を行った。また、全シアン濃度についてはＪＩＳ Ｋ０１０２ ３８．１．２及び３８．２に準拠して実施した。
[Performance evaluation test]
For the simulated Cs-contaminated water and simulated Cs-contaminated seawater prepared according to the following, using the respective adsorbents according to the above examples, conventional adsorbents, and each adsorbent according to the above comparative examples, the following implementation tests and comparative tests are performed, Its adsorption performance was evaluated.
In addition, Cs density | concentration of the process filtrate measured by each implementation test and the comparative test was measured with the inductively coupled plasma mass spectrometer (ICP-MS) 7000x of Agilent. The total cyan density was measured according to JIS K0102 38.1.2 and 38.2.
＜模擬Ｃｓ汚染水の調製＞
安定なＣｓ同位体Ｃｓ１３３の塩化セシウムＣｓＣｌ（純度９９．９％）１２．６６９ｍｇをイオン交換水に溶解して、Ｃｓイオン濃度１０ｍｇ／Ｌの模擬Ｃｓ汚染水１Ｌを調製した。
＜模擬Ｃｓ汚染海水の調製＞
安定なＣｓ同位体Ｃｓ１３３の塩化セシウムＣｓＣｌ（純度９９．９％）１２．６６９ｍｇ、塩化ナトリウム３０ｇ、塩化マグネシウム５ｇ、塩化カリウム０．５ｇをイオン交換水に溶解して、模擬Ｃｓ汚染海水１Ｌを調製した。
＜Ｃｓ汚染水の調製＞
放射性Ｃｓで汚染された焼却灰を水で洗浄して、放射能濃度５５０Ｂｑ／ｋｇの放射能Ｃｓ汚染水を調製した。
Ｃｓの放射能濃度の内訳はＣｓ１３７：３３０Ｂｑ／ｋｇ、Ｃｓ１３４：２２０Ｂｑ／ｋｇである。
Ｃｓ汚染水の各種イオン濃度は次の通り：
カチオン： Ｃａ2+：２３００ｍｇ／Ｌ Ｋ+：２．０％ Ｎａ+：９２００ｍｇ／Ｌ
アニオン： ＳＯ4 2-：２２００ｍｇ／Ｌ Ｃｌ-：３．０％
Ｃｓ汚染水のｐＨは１１．２であった。
<Preparation of simulated Cs contaminated water>
Csium chloride CsCl (purity 99.9%) 12.669 mg of stable Cs isotope Cs133 was dissolved in ion-exchanged water to prepare 1 L of simulated Cs-contaminated water having a Cs ion concentration of 10 mg / L.
<Preparation of simulated Cs-contaminated seawater>
A stable Cs isotope Cs133 of cesium chloride CsCl (purity 99.9%) 12.669 mg, sodium chloride 30 g, magnesium chloride 5 g, potassium chloride 0.5 g was dissolved in ion exchange water to prepare 1 L of simulated Cs-contaminated seawater. did.
<Preparation of Cs contaminated water>
The incinerated ash contaminated with radioactive Cs was washed with water to prepare radioactive Cs-contaminated water with a radioactive concentration of 550 Bq / kg.
The breakdown of the radioactive concentration of Cs is Cs137: 330Bq / kg and Cs134: 220Bq / kg.
The various ion concentrations of Cs contaminated water are as follows:
Cation: Ca 2+ : 2300 mg / L K + : 2.0% Na + : 9200 mg / L
Anions: SO 4 2-: 2200mg / L Cl -: 3.0%
The pH of Cs contaminated water was 11.2.
＜実施試験１＞
実施例１〜５で得られた吸着剤１．０ｇを上記模擬Ｃｓ汚染水及び上記模擬Ｃｓ汚染海水１Ｌにそれぞれ添加して３０分間攪拌処理を行った。つづいて該処理液を篩目１μｍのガラスフィルターで濾過し、濾液を得た。濾液についてＣｓイオン濃度、全シアン濃度を測定して表２に示す結果を得た。
<Execution test 1>
1.0 g of the adsorbent obtained in Examples 1 to 5 was added to the simulated Cs-contaminated water and 1 L of the simulated Cs-contaminated seawater, respectively, and stirred for 30 minutes. Subsequently, the treatment liquid was filtered through a glass filter having a sieve mesh of 1 μm to obtain a filtrate. The Cs ion concentration and total cyan concentration were measured for the filtrate, and the results shown in Table 2 were obtained.
＜実施試験２＞
実施例６〜１３で得られたＣｓ吸着剤１．０ｇを上記模擬Ｃｓ汚染海水１Ｌに添加して実施試験１と同様に処理を実施した。濾液についてＣｓイオン濃度、全シアン濃度を測定して表３に示す結果を得た。
<Execution test 2>
1.0 g of the Cs adsorbent obtained in Examples 6 to 13 was added to 1 L of the simulated Cs-contaminated seawater, and the same treatment as in Experiment 1 was performed. The Cs ion concentration and total cyan concentration were measured for the filtrate, and the results shown in Table 3 were obtained.
＜実施試験３＞
実施例１４〜１６で得られたＣｓ吸着剤０．５ｇ（乾燥重量換算）を上記模擬Ｃｓ汚染海水１Ｌに添加して実施試験１と同様に実施した。処理液のＣｓイオン濃度、全シアン濃度の測定結果を表４に示す。
<Execution test 3>
It carried out similarly to the implementation test 1 by adding 0.5 g (dry weight conversion) of Cs adsorbents obtained in Examples 14 to 16 to 1 L of the simulated Cs-contaminated seawater. Table 4 shows the measurement results of Cs ion concentration and total cyan concentration of the treatment liquid.
＜実施試験４＞
実施例１７〜２２で得られた各Ｃｓ吸着剤１．０ｇを上記模擬Ｃｓ汚染海水１Ｌに添加して実施試験１と同様に実施した。各処理液についてＣｓイオン濃度、全シアン濃度測定値を表５に示した。
<Execution test 4>
1.0 g of each Cs adsorbent obtained in Examples 17 to 22 was added to 1 L of the above simulated Cs-contaminated seawater, and the same test as in Experiment 1 was performed. Table 5 shows measured values of Cs ion concentration and total cyan concentration for each treatment solution.
＜実施試験５＞
上記Ｃｓ汚染水１ｋｇに４ｍｏｌ／Ｌの硫酸を加えてｐＨ７．０に調整した後、実施例６で調製した吸着剤０．５ｇを加えて０．５時間攪拌処理を実施した。攪拌終了後、処理液を篩目１μｍテフロン（登録商標）製フィルターで吸引濾過した。該濾液について放射能濃度を測定した。放射能濃度の測定は、日立アロカ社製放射能測定装置ＣＡＮ−ＯＳＰ−ＮＡＩで所定の時間行った。
１）放射性Ｃｓ汚染水処理前
測定時間：３０分間
放射能濃度：５５０Ｂｑ／ｋｇ（検出限界２０Ｂｑ／ｋｇ）
２）処理後濾液
測定時間：１時間
放射能濃度：ＮＤ（検出限界：137Ｃｓ、134Ｃｓともに１０Ｂｑ／ｋｇ）
また、全シアン濃度は検出されなかった（定量下限値０．０１ｍｇ／Ｌ）。
<Execution test 5>
After adjusting the pH to 7.0 by adding 4 mol / L sulfuric acid to 1 kg of the Cs-contaminated water, 0.5 g of the adsorbent prepared in Example 6 was added and the mixture was stirred for 0.5 hours. After completion of the stirring, the treatment liquid was suction filtered with a 1 μm sieve Teflon (registered trademark) filter. The radioactivity concentration of the filtrate was measured. The measurement of the radioactivity concentration was performed for a predetermined time with a radioactivity measurement apparatus CAN-OSP-NAI manufactured by Hitachi Aloka.
1) Before treatment with radioactive Cs-contaminated water Measurement time: 30 minutes Radioactivity concentration: 550 Bq / kg (detection limit 20 Bq / kg)
2) Filtrate after treatment Measurement time: 1 hour Radioactivity concentration: ND (detection limit: 10 Bq / kg for both 137 Cs and 134 Cs)
Further, the total cyan density was not detected (lower limit of quantification 0.01 mg / L).
＜比較試験１＞
上記模擬Ｃｓ汚染水１Ｌに大日精化工業社製のプルシアンブルー（ＮＨ4Ｆｅ(III)Ｆｅ(II)（ＣＮ）6）１ｇを加えて１時間攪拌を行った。硫酸バンドＡｌ2（ＳＯ4）3を１ｇ添加し、攪拌しながら５ｍｏｌ／Ｌ水酸化ナトリウム水溶液で処理液のｐＨを８．０に調整した。続いて、アニオン系高分子凝集剤（ＭＴアクアポリマー社製のアコフロックＡ１１５）の０．１％水溶液を１ｍＬ添加し、フロックを形成させた後、処理液を篩目１μｍのガラスフィルターで吸引濾過した。
濾液についてＣｓイオン濃度の測定を実施試験１と同様にして実施した。
濾液のＣｓイオン濃度は２．４ｍｇ／Ｌであり、除去率は７６．０％であった。
<Comparison test 1>
1 g of Prussian blue (NH 4 Fe (III) Fe (II) (CN) 6 ) manufactured by Dainichi Seika Kogyo Co., Ltd. was added to 1 L of the simulated Cs-contaminated water and stirred for 1 hour. 1 g of sulfuric acid band Al 2 (SO 4 ) 3 was added, and the pH of the treatment liquid was adjusted to 8.0 with a 5 mol / L aqueous sodium hydroxide solution while stirring. Subsequently, 1 mL of a 0.1% aqueous solution of an anionic polymer flocculant (Akoflock A115 manufactured by MT Aquapolymer Co., Ltd.) was added to form flocs, and the treated solution was suction filtered through a glass filter with a 1 μm sieve mesh. .
The Cs ion concentration of the filtrate was measured in the same manner as in Experiment 1.
The Cs ion concentration of the filtrate was 2.4 mg / L, and the removal rate was 76.0%.
＜比較試験２＞
上記模擬Ｃｓ汚染海水１Ｌについて、比較試験１と同様、大日精化工業製のプルシアンブルー（ＮＨ4Ｆｅ(III)Ｆｅ(II)（ＣＮ）6）１ｇを添加し、ｐＨを８．０に調整して攪拌を２４時間実施した。プルシアンブルー添加から１時間、６時間、８時間経過の処理液１００ｍＬをそれぞれ採取した。採取した処理液それぞれに比較試験１と同様のアニオン系高分子凝集剤を添加した後、５Ｃの濾紙で濾過を行い、濾液についてＣｓイオン濃度を比較試験１と同様にして測定した。２４時間経過については残処理液について、凝集剤を添加して沈殿形成後、同様に濾過を行い濾液についてＣｓイオン濃度の測定を実施した。各経過時間採取試料の濾液のＣｓイオン濃度を表６に示した。
<Comparison test 2>
For 1 L of the simulated Cs-contaminated seawater, 1 g of Prussian blue (NH 4 Fe (III) Fe (II) (CN) 6 ) manufactured by Dainichi Seika Kogyo Co., Ltd. was added to adjust the pH to 8.0. Stirring was then carried out for 24 hours. 100 mL of the treatment solution was collected after 1 hour, 6 hours, and 8 hours from the Prussian blue addition. The same anionic polymer flocculant as in Comparative Test 1 was added to each of the collected treatment liquids, followed by filtration with 5C filter paper, and the Cs ion concentration of the filtrate was measured in the same manner as in Comparative Test 1. For 24 hours, a flocculant was added to the remaining treatment liquid to form a precipitate, followed by filtration in the same manner, and the Cs ion concentration of the filtrate was measured. Table 6 shows the Cs ion concentration of the filtrate of each elapsed time sample.
＜比較試験３＞
上記模擬Ｃｓ汚染水１Ｌに大日精化工業社製のプルシアンブルー１．０ｇ（ＮＨ4Ｆｅ(III)Ｆｅ(II)（ＣＮ）6）を加えて１時間攪拌を行った。
攪拌終了後、処理液を５Ｃの濾紙で濾過したところ、プルシアンブルーも濾紙を通過してしまい、紺青の濾液が得られた。
<Comparison test 3>
To 1 L of the simulated Cs-contaminated water, 1.0 g of Prussian blue (NH 4 Fe (III) Fe (II) (CN) 6 ) manufactured by Dainichi Seika Kogyo Co., Ltd. was added and stirred for 1 hour.
After the stirring, when the treatment liquid was filtered with 5C filter paper, Prussian blue also passed through the filter paper, and a bitumen filtrate was obtained.
＜比較試験４＞
比較例１で得られたＣｓ吸着剤１ｇを上記模擬Ｃｓ汚染海水１Ｌに添加して１時間攪拌処理を実施した。攪拌後、処理液を篩目１μｍのガラスフィルターで吸引濾過した。濾液についてＣｓイオン濃度の測定を実施試験１と同様にして実施した。
濾液のＣｓイオン濃度は２．８ｍｇ／Ｌであり、除去率は７２．０％であった。
<Comparison test 4>
1 g of the Cs adsorbent obtained in Comparative Example 1 was added to 1 L of the simulated Cs-contaminated seawater and stirred for 1 hour. After stirring, the treatment liquid was suction filtered through a glass filter having a sieve mesh of 1 μm. The Cs ion concentration of the filtrate was measured in the same manner as in Experiment 1.
The Cs ion concentration of the filtrate was 2.8 mg / L, and the removal rate was 72.0%.
＜比較試験５＞
比較例２〜４で得られたＣｓ吸着剤１ｇを上記模擬Ｃｓ汚染海水１Ｌに添加して比較試験４と同様に処理を行った。
比較例２〜４の濾液のＣｓイオン濃度及び全シアン濃度を表７に示した。
<Comparative test 5>
1 g of the Cs adsorbent obtained in Comparative Examples 2 to 4 was added to 1 L of the simulated Cs-contaminated seawater, and the same treatment as in Comparative Test 4 was performed.
Table 7 shows the Cs ion concentration and the total cyan concentration of the filtrates of Comparative Examples 2 to 4.
＜比較試験６＞
Ｃｓイオン濃度１０ｍｇ／Ｌの模擬Ｃｓ汚染海水１Ｌに天然ゼオライト１０ｇを添加し１時間攪拌後５Ｃの濾紙で濾過を行った。
濾液のＣｓイオン濃度を測定した結果、Ｃｓイオン濃度は８．０ｍｇ／Ｌであり、除去率は２０％であった。
<Comparative test 6>
10 g of natural zeolite was added to 1 L of simulated Cs-contaminated seawater having a Cs ion concentration of 10 mg / L, and the mixture was stirred for 1 hour and filtered through 5C filter paper.
As a result of measuring the Cs ion concentration of the filtrate, the Cs ion concentration was 8.0 mg / L, and the removal rate was 20%.
＜考察１＞
（１）上記各実施試験から、本発明にかかる実施例１〜２２の吸着剤によって、優れた吸着性能が得られることを確認できた。具体的には以下のとおりである。
Ｍｅ(II)（ＯＨ）2の異なるいずれの吸着剤においても、模擬Ｃｓ汚染海水やＣｓ汚染水に対して優れたＣｓ吸着性を発揮しており、各種のカチオンやアニオンによってその効果が阻害されない（特に実施試験１：実施例１〜５、実施試験５参照)。
全シアン濃度を抑制する上では、α／βが０．１〜１０、特に０．１〜１．０の範囲であることが好ましい（特に実施試験２：実施例６〜１３参照）。
本発明の吸着剤は、含水物や乾燥物であっても有効に吸着性を発揮する（実施試験３：実施例１４〜１６参照）。
吸着剤としては、Ｍｅ（II）塩化合物を添加したのちに加水分解してＭｅ(II)（ＯＨ）2を生成させた場合に限らず、Ｍｅ(II)（ＯＨ）2の生成のために金属粉を用いた場合（実施例５）においても、優れた吸着剤が得られる（実施試験１参照）。
また、ＰＢ合成後に各種のＭｅ(II)（ＯＨ）2やＭｅ(II)Ｏを添加することとしても優れた吸着剤が得られる（実施試験４：実施例１７〜２２参照）。
<Discussion 1>
(1) From each said implementation test, it has confirmed that the outstanding adsorption | suction performance was obtained with the adsorbent of Examples 1-22 concerning this invention. Specifically, it is as follows.
Any adsorbent with different Me (II) (OH) 2 exhibits excellent Cs adsorptivity to simulated Cs-contaminated seawater and Cs-contaminated water, and its effect is not inhibited by various cations and anions. (See especially Implementation Test 1: Examples 1-5, Implementation Test 5.)
In order to suppress the total cyan density, α / β is preferably in the range of 0.1 to 10, particularly 0.1 to 1.0 (particularly, see Test 2: Examples 6 to 13).
The adsorbent of the present invention exhibits the adsorptivity effectively even if it is a hydrated product or a dried product (see Test 3 for Examples 14-16).
The adsorbent is not limited to the case where Me (II) (OH) 2 is produced by hydrolysis after adding the Me (II) salt compound, but for the production of Me (II) (OH) 2. Even when metal powder is used (Example 5), an excellent adsorbent can be obtained (see Test 1).
Also, excellent adsorbents can be obtained by adding various types of Me (II) (OH) 2 or Me (II) O after PB synthesis (see Test 4: Examples 17 to 22).
（２）これに対して、本発明の構成を満足しない吸着剤を用いた上記各比較試験では、優れた吸着性能は得られなかった。具体的には以下のとおりである。
従来の吸着剤では、本発明の如き優れた吸着性は得られず、迅速性の点でも劣っている（比較試験１、比較試験２参照）
本発明で用いるＰＢとは化学式の異なる大日精化工業社製のプルシアンブルーを用いた場合には、濾過による分離が困難であり、また、Ｍｅ(II)（ＯＨ）2により不溶化したとしても、本発明の如き優れた吸着剤は得られない（比較試験３、比較試験４：比較例１参照）。
本発明で用いるＰＢを用いても、３価金属の水酸化物や、遷移金属でない２価金属の水酸化物を不溶化剤として添加する場合には、優れた吸着剤は得られない（比較試験５：比較例２〜４参照）。
吸着剤として天然ゼオライトを用いても優れた吸着剤は得られない（比較試験６参照）。
(2) On the other hand, in each comparative test using an adsorbent that does not satisfy the configuration of the present invention, excellent adsorption performance was not obtained. Specifically, it is as follows.
Conventional adsorbents do not provide excellent adsorbability as in the present invention and are inferior in terms of rapidity (see Comparative Test 1 and Comparative Test 2).
When Prussian blue manufactured by Dainichi Seika Kogyo Co., Ltd., which has a different chemical formula from PB used in the present invention, is difficult to separate by filtration, and even if insolubilized with Me (II) (OH) 2 , An excellent adsorbent as in the present invention cannot be obtained (see Comparative Test 3, Comparative Test 4: Comparative Example 1).
Even when using PB used in the present invention, an excellent adsorbent cannot be obtained when a hydroxide of a trivalent metal or a hydroxide of a divalent metal that is not a transition metal is added as an insolubilizer (comparison test). 5: See Comparative Examples 2 to 4).
Even if natural zeolite is used as the adsorbent, an excellent adsorbent cannot be obtained (see Comparative Test 6).
＜実施試験６：処理液のｐＨの影響〕
模擬Ｃｓ汚染海水１Ｌに実施例１で得られた吸着剤１．０ｇを添加した。攪拌しながら５ｍｏｌ／Ｌ水酸化ナトリウム、又は５ｍｏｌ／Ｌ塩酸水溶液で処理液のｐＨを３〜１２で調整し、攪拌を１時間行った。
攪拌を止め各ｐＨに調整した処理液をそれぞれ篩目１μｍのガラスフィルターで吸引濾過した。各濾液についてＣｓイオン濃度、全シアン濃度を測定した。その結果を表８及び図２に示す。
<Execution test 6: Effect of pH of treatment solution>
1.0 g of the adsorbent obtained in Example 1 was added to 1 L of simulated Cs-contaminated seawater. While stirring, the pH of the treatment solution was adjusted to 3 to 12 with 5 mol / L sodium hydroxide or 5 mol / L hydrochloric acid aqueous solution, and stirring was performed for 1 hour.
Stirring was stopped and the treatment liquid adjusted to each pH was suction filtered through a glass filter having a sieve mesh of 1 μm. The Cs ion concentration and total cyan concentration were measured for each filtrate. The results are shown in Table 8 and FIG.
＜考察２＞
処理液のｐＨ３〜１１の範囲で優れた本発明の吸着剤によるＣｓ捕集効果が確認された。
また、処理液の全シアン濃度の排水基準を考慮する場合には処理液のｐＨは４〜８．５に調整することが望ましい（図２も参照）。
<Discussion 2>
The Cs collection effect by the adsorbent of the present invention which was excellent in the pH range of 3 to 11 of the treatment liquid was confirmed.
Further, when considering the drainage standard of the total cyan concentration of the treatment liquid, it is desirable to adjust the pH of the treatment liquid to 4 to 8.5 (see also FIG. 2).
すなわち、本発明にかかる放射性Ｃｓ吸着剤は、Ｍ(I)3xＦｅ(III)4-x［Ｆｅ(II)（ＣＮ）6］3で表されるプルシアンブルー（但し、Ｍ(I)は１価のカチオンでｘは０又は１である）の分子及び／又はそのクラスターと、Ｍｅ(II)(ＯＨ)2で表される水酸化物又はその部分酸化物（但し、Ｍｅ(II)は２価の遷移金属である）との複合体を有効成分とし、未だＣｓが吸着されていない。
また、本発明にかかる放射性Ｃｓ吸着剤の製造方法は、Ｃｓを含まない水中で、Ｍ(I)4Ｆｅ(II)（ＣＮ）6及び／又はＭ(I)3Ｆｅ(III)（ＣＮ）6で表される鉄シアノ錯体（但し、Ｍ(I)は１価のカチオンである）と、２価及び／又は３価の鉄塩化合物とを反応させることによりプルシアンブルーを合成する工程（以下、便宜上、工程（Ａ）と記すことがある）と、前記プルシアンブルーの水溶液にＭｅ(II)(ＯＨ)2で表される水酸化物（但し、Ｍｅ(II)は２価の遷移金属である）を含有させる工程（以下、便宜上、工程（Ｂ）と記すことがある）とを含む、ことを特徴とする。
なお、以下では、「Ｍ(I)3xＦｅ(III)4-x［Ｆｅ(II)（ＣＮ）6］3で表されるプルシアンブルー」を単に「ＰＢ」と略記し、「Ｍｅ(II)(ＯＨ)2で表される水酸化物」を単に「Ｍｅ(II)(ＯＨ)2」と略記し、「Ｍｅ(II)Ｏで表される酸化物」を単に「Ｍｅ(II)Ｏ」と略記することがある。
That is, the radioactive Cs adsorbent according to the present invention is Prussian blue represented by M (I) 3x Fe (III) 4-x [Fe (II) (CN) 6 ] 3 (where M (I) is 1). A valent cation and x is 0 or 1) and / or a cluster thereof, and a hydroxide represented by Me (II) (OH) 2 or a partial oxide thereof (where Me (II) is 2 Cs is not adsorbed yet . The complex is a valent transition metal).
In addition, the method for producing a radioactive Cs adsorbent according to the present invention includes M (I) 4 Fe (II) (CN) 6 and / or M (I) 3 Fe (III) (CN) in water not containing Cs. Step of synthesizing Prussian blue by reacting an iron cyano complex represented by 6 (where M (I) is a monovalent cation) and a divalent and / or trivalent iron salt compound (hereinafter referred to as “Prussian blue”) For convenience, it may be referred to as step (A)) and a hydroxide represented by Me (II) (OH) 2 in the aqueous Prussian blue solution (where Me (II) is a divalent transition metal). And a step (hereinafter, may be referred to as step (B) for convenience).
In the following, “Prussian blue represented by M (I) 3x Fe (III) 4-x [Fe (II) (CN) 6 ] 3 ” is simply abbreviated as “PB” and “Me (II) The “hydroxide represented by (OH) 2 ” is simply abbreviated as “Me (II) (OH) 2 ”, and the “oxide represented by Me (II) O” is simply “Me (II) O”. May be abbreviated.
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| KR20190131071A (en) * | 2017-03-20 | 2019-11-25 | 나트론 에너지, 인코포레이티드 | Purification and Use of Ferrocyanide Solution |
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| JP2020514246A (en) * | 2017-03-20 | 2020-05-21 | ナトロン エナジー，インコーポレイテッド | Purification and use of ferrocyanide solution |
| KR102641578B1 (en) * | 2017-03-20 | 2024-02-27 | 나트론 에너지, 인코포레이티드 | Purification and use of ferrocyanide solution |
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