JP2005095784A - Cleaning method of nitrate nitrogen-containing wastewater - Google Patents
Cleaning method of nitrate nitrogen-containing wastewater Download PDFInfo
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- JP2005095784A JP2005095784A JP2003333281A JP2003333281A JP2005095784A JP 2005095784 A JP2005095784 A JP 2005095784A JP 2003333281 A JP2003333281 A JP 2003333281A JP 2003333281 A JP2003333281 A JP 2003333281A JP 2005095784 A JP2005095784 A JP 2005095784A
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- Prior art keywords
- nitrate nitrogen
- nitrogen
- catalyst
- solid catalyst
- element selected
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- MMDJDBSEMBIJBB-UHFFFAOYSA-N [O-][N+]([O-])=O.[O-][N+]([O-])=O.[O-][N+]([O-])=O.[NH6+3] Chemical compound [O-][N+]([O-])=O.[O-][N+]([O-])=O.[O-][N+]([O-])=O.[NH6+3] MMDJDBSEMBIJBB-UHFFFAOYSA-N 0.000 title claims abstract description 79
- 239000002351 wastewater Substances 0.000 title claims abstract description 65
- 238000000034 method Methods 0.000 title claims abstract description 57
- 238000004140 cleaning Methods 0.000 title abstract 2
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 claims abstract description 67
- 239000003638 chemical reducing agent Substances 0.000 claims abstract description 61
- OKKJLVBELUTLKV-UHFFFAOYSA-N Methanol Chemical compound OC OKKJLVBELUTLKV-UHFFFAOYSA-N 0.000 claims abstract description 60
- KDLHZDBZIXYQEI-UHFFFAOYSA-N Palladium Chemical compound [Pd] KDLHZDBZIXYQEI-UHFFFAOYSA-N 0.000 claims abstract description 60
- 239000011949 solid catalyst Substances 0.000 claims abstract description 55
- BASFCYQUMIYNBI-UHFFFAOYSA-N platinum Chemical compound [Pt] BASFCYQUMIYNBI-UHFFFAOYSA-N 0.000 claims abstract description 50
- LFQSCWFLJHTTHZ-UHFFFAOYSA-N Ethanol Chemical compound CCO LFQSCWFLJHTTHZ-UHFFFAOYSA-N 0.000 claims abstract description 48
- MUBZPKHOEPUJKR-UHFFFAOYSA-N Oxalic acid Chemical compound OC(=O)C(O)=O MUBZPKHOEPUJKR-UHFFFAOYSA-N 0.000 claims abstract description 47
- BDAGIHXWWSANSR-UHFFFAOYSA-N methanoic acid Natural products OC=O BDAGIHXWWSANSR-UHFFFAOYSA-N 0.000 claims abstract description 42
- WSFSSNUMVMOOMR-UHFFFAOYSA-N Formaldehyde Chemical compound O=C WSFSSNUMVMOOMR-UHFFFAOYSA-N 0.000 claims abstract description 35
- 229910052742 iron Inorganic materials 0.000 claims abstract description 30
- 229910052763 palladium Inorganic materials 0.000 claims abstract description 30
- 229910052697 platinum Inorganic materials 0.000 claims abstract description 25
- RTAQQCXQSZGOHL-UHFFFAOYSA-N Titanium Chemical compound [Ti] RTAQQCXQSZGOHL-UHFFFAOYSA-N 0.000 claims abstract description 23
- QCWXUUIWCKQGHC-UHFFFAOYSA-N Zirconium Chemical compound [Zr] QCWXUUIWCKQGHC-UHFFFAOYSA-N 0.000 claims abstract description 23
- 229910052719 titanium Inorganic materials 0.000 claims abstract description 23
- 239000010936 titanium Substances 0.000 claims abstract description 23
- 229910052726 zirconium Inorganic materials 0.000 claims abstract description 23
- OSWFIVFLDKOXQC-UHFFFAOYSA-N 4-(3-methoxyphenyl)aniline Chemical compound COC1=CC=CC(C=2C=CC(N)=CC=2)=C1 OSWFIVFLDKOXQC-UHFFFAOYSA-N 0.000 claims abstract description 21
- 235000019253 formic acid Nutrition 0.000 claims abstract description 21
- BDAGIHXWWSANSR-UHFFFAOYSA-M Formate Chemical compound [O-]C=O BDAGIHXWWSANSR-UHFFFAOYSA-M 0.000 claims abstract description 17
- 235000006408 oxalic acid Nutrition 0.000 claims abstract description 12
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 claims description 60
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 claims description 38
- 238000006243 chemical reaction Methods 0.000 claims description 31
- 229910052757 nitrogen Inorganic materials 0.000 claims description 27
- UFHFLCQGNIYNRP-UHFFFAOYSA-N Hydrogen Chemical compound [H][H] UFHFLCQGNIYNRP-UHFFFAOYSA-N 0.000 claims description 24
- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical compound [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 claims description 15
- 229910052802 copper Inorganic materials 0.000 claims description 15
- 239000010949 copper Substances 0.000 claims description 15
- 239000001257 hydrogen Substances 0.000 claims description 14
- 229910052739 hydrogen Inorganic materials 0.000 claims description 14
- 150000001875 compounds Chemical class 0.000 claims description 13
- 239000000126 substance Substances 0.000 claims description 12
- PXHVJJICTQNCMI-UHFFFAOYSA-N Nickel Chemical compound [Ni] PXHVJJICTQNCMI-UHFFFAOYSA-N 0.000 claims description 10
- KJTLSVCANCCWHF-UHFFFAOYSA-N Ruthenium Chemical compound [Ru] KJTLSVCANCCWHF-UHFFFAOYSA-N 0.000 claims description 10
- 229910052707 ruthenium Inorganic materials 0.000 claims description 10
- 229910052741 iridium Inorganic materials 0.000 claims description 9
- GKOZUEZYRPOHIO-UHFFFAOYSA-N iridium atom Chemical compound [Ir] GKOZUEZYRPOHIO-UHFFFAOYSA-N 0.000 claims description 9
- 229910052751 metal Inorganic materials 0.000 claims description 8
- 239000002184 metal Substances 0.000 claims description 8
- GUTLYIVDDKVIGB-UHFFFAOYSA-N cobalt atom Chemical compound [Co] GUTLYIVDDKVIGB-UHFFFAOYSA-N 0.000 claims description 6
- 229910052703 rhodium Inorganic materials 0.000 claims description 6
- 239000010948 rhodium Substances 0.000 claims description 6
- MHOVAHRLVXNVSD-UHFFFAOYSA-N rhodium atom Chemical compound [Rh] MHOVAHRLVXNVSD-UHFFFAOYSA-N 0.000 claims description 6
- 229910052684 Cerium Inorganic materials 0.000 claims description 5
- ATJFFYVFTNAWJD-UHFFFAOYSA-N Tin Chemical compound [Sn] ATJFFYVFTNAWJD-UHFFFAOYSA-N 0.000 claims description 5
- HCHKCACWOHOZIP-UHFFFAOYSA-N Zinc Chemical compound [Zn] HCHKCACWOHOZIP-UHFFFAOYSA-N 0.000 claims description 5
- ZMIGMASIKSOYAM-UHFFFAOYSA-N cerium Chemical compound [Ce][Ce][Ce][Ce][Ce][Ce][Ce][Ce][Ce][Ce][Ce][Ce][Ce][Ce][Ce][Ce][Ce][Ce][Ce][Ce][Ce][Ce][Ce][Ce][Ce][Ce][Ce][Ce][Ce][Ce][Ce][Ce][Ce][Ce][Ce][Ce][Ce][Ce] ZMIGMASIKSOYAM-UHFFFAOYSA-N 0.000 claims description 5
- 229910017052 cobalt Inorganic materials 0.000 claims description 5
- 239000010941 cobalt Substances 0.000 claims description 5
- PCHJSUWPFVWCPO-UHFFFAOYSA-N gold Chemical compound [Au] PCHJSUWPFVWCPO-UHFFFAOYSA-N 0.000 claims description 5
- 229910052737 gold Inorganic materials 0.000 claims description 5
- 239000010931 gold Substances 0.000 claims description 5
- 229910052738 indium Inorganic materials 0.000 claims description 5
- APFVFJFRJDLVQX-UHFFFAOYSA-N indium atom Chemical compound [In] APFVFJFRJDLVQX-UHFFFAOYSA-N 0.000 claims description 5
- 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 5
- 229910052759 nickel Inorganic materials 0.000 claims description 5
- 150000003464 sulfur compounds Chemical class 0.000 claims description 5
- 229910052718 tin Inorganic materials 0.000 claims description 5
- 239000011135 tin Substances 0.000 claims description 5
- 229910052725 zinc Inorganic materials 0.000 claims description 5
- 239000011701 zinc Substances 0.000 claims description 5
- BQCADISMDOOEFD-UHFFFAOYSA-N Silver Chemical compound [Ag] BQCADISMDOOEFD-UHFFFAOYSA-N 0.000 claims description 4
- 229910052709 silver Inorganic materials 0.000 claims description 4
- 239000004332 silver Substances 0.000 claims description 4
- 150000001298 alcohols Chemical class 0.000 claims description 3
- 150000002576 ketones Chemical class 0.000 claims description 3
- 150000007524 organic acids Chemical class 0.000 claims description 3
- 235000005985 organic acids Nutrition 0.000 claims description 3
- 150000002989 phenols Chemical class 0.000 claims description 3
- 238000000746 purification Methods 0.000 claims description 3
- 150000003839 salts Chemical class 0.000 claims description 3
- 150000001299 aldehydes Chemical class 0.000 claims description 2
- YPFNIPKMNMDDDB-UHFFFAOYSA-K 2-[2-[bis(carboxylatomethyl)amino]ethyl-(2-hydroxyethyl)amino]acetate;iron(3+) Chemical compound [Fe+3].OCCN(CC([O-])=O)CCN(CC([O-])=O)CC([O-])=O YPFNIPKMNMDDDB-UHFFFAOYSA-K 0.000 claims 1
- 239000003054 catalyst Substances 0.000 description 76
- 238000006722 reduction reaction Methods 0.000 description 25
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 18
- 239000007788 liquid Substances 0.000 description 14
- 239000002245 particle Substances 0.000 description 14
- 239000000243 solution Substances 0.000 description 13
- QGZKDVFQNNGYKY-UHFFFAOYSA-N Ammonia Chemical compound N QGZKDVFQNNGYKY-UHFFFAOYSA-N 0.000 description 12
- OAKJQQAXSVQMHS-UHFFFAOYSA-N Hydrazine Chemical compound NN OAKJQQAXSVQMHS-UHFFFAOYSA-N 0.000 description 12
- ZNCPFRVNHGOPAG-UHFFFAOYSA-L sodium oxalate Chemical compound [Na+].[Na+].[O-]C(=O)C([O-])=O ZNCPFRVNHGOPAG-UHFFFAOYSA-L 0.000 description 12
- 229910002651 NO3 Inorganic materials 0.000 description 11
- -1 nitrate ions Chemical class 0.000 description 11
- 239000000843 powder Substances 0.000 description 11
- 239000004280 Sodium formate Substances 0.000 description 10
- 229910001873 dinitrogen Inorganic materials 0.000 description 10
- HLBBKKJFGFRGMU-UHFFFAOYSA-M sodium formate Chemical compound [Na+].[O-]C=O HLBBKKJFGFRGMU-UHFFFAOYSA-M 0.000 description 10
- 235000019254 sodium formate Nutrition 0.000 description 10
- 239000007864 aqueous solution Substances 0.000 description 9
- 239000008188 pellet Substances 0.000 description 9
- XKMRRTOUMJRJIA-UHFFFAOYSA-N ammonia nh3 Chemical compound N.N XKMRRTOUMJRJIA-UHFFFAOYSA-N 0.000 description 8
- 229940039748 oxalate Drugs 0.000 description 8
- 229940039790 sodium oxalate Drugs 0.000 description 7
- UQSXHKLRYXJYBZ-UHFFFAOYSA-N Iron oxide Chemical compound [Fe]=O UQSXHKLRYXJYBZ-UHFFFAOYSA-N 0.000 description 6
- CDBYLPFSWZWCQE-UHFFFAOYSA-L Sodium Carbonate Chemical compound [Na+].[Na+].[O-]C([O-])=O CDBYLPFSWZWCQE-UHFFFAOYSA-L 0.000 description 6
- 229910021529 ammonia Inorganic materials 0.000 description 6
- 238000001035 drying Methods 0.000 description 6
- VWDWKYIASSYTQR-UHFFFAOYSA-N sodium nitrate Chemical compound [Na+].[O-][N+]([O-])=O VWDWKYIASSYTQR-UHFFFAOYSA-N 0.000 description 6
- 238000004065 wastewater treatment Methods 0.000 description 6
- 230000003197 catalytic effect Effects 0.000 description 5
- 230000007423 decrease Effects 0.000 description 5
- WSFSSNUMVMOOMR-NJFSPNSNSA-N methanone Chemical compound O=[14CH2] WSFSSNUMVMOOMR-NJFSPNSNSA-N 0.000 description 5
- 239000012299 nitrogen atmosphere Substances 0.000 description 5
- GPNDARIEYHPYAY-UHFFFAOYSA-N palladium(ii) nitrate Chemical compound [Pd+2].[O-][N+]([O-])=O.[O-][N+]([O-])=O GPNDARIEYHPYAY-UHFFFAOYSA-N 0.000 description 5
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 description 4
- 229920002472 Starch Polymers 0.000 description 4
- 229910010413 TiO 2 Inorganic materials 0.000 description 4
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 description 4
- 238000001354 calcination Methods 0.000 description 4
- VCJMYUPGQJHHFU-UHFFFAOYSA-N iron(3+);trinitrate Chemical compound [Fe+3].[O-][N+]([O-])=O.[O-][N+]([O-])=O.[O-][N+]([O-])=O VCJMYUPGQJHHFU-UHFFFAOYSA-N 0.000 description 4
- 239000007791 liquid phase Substances 0.000 description 4
- 229910052760 oxygen Inorganic materials 0.000 description 4
- 239000001301 oxygen Substances 0.000 description 4
- 235000019698 starch Nutrition 0.000 description 4
- 239000008107 starch Substances 0.000 description 4
- ZWEHNKRNPOVVGH-UHFFFAOYSA-N 2-Butanone Chemical compound CCC(C)=O ZWEHNKRNPOVVGH-UHFFFAOYSA-N 0.000 description 3
- QTBSBXVTEAMEQO-UHFFFAOYSA-N Acetic acid Chemical compound CC(O)=O QTBSBXVTEAMEQO-UHFFFAOYSA-N 0.000 description 3
- CSCPPACGZOOCGX-UHFFFAOYSA-N Acetone Chemical compound CC(C)=O CSCPPACGZOOCGX-UHFFFAOYSA-N 0.000 description 3
- LYCAIKOWRPUZTN-UHFFFAOYSA-N Ethylene glycol Chemical compound OCCO LYCAIKOWRPUZTN-UHFFFAOYSA-N 0.000 description 3
- NHNBFGGVMKEFGY-UHFFFAOYSA-N Nitrate Chemical compound [O-][N+]([O-])=O NHNBFGGVMKEFGY-UHFFFAOYSA-N 0.000 description 3
- KWYUFKZDYYNOTN-UHFFFAOYSA-M Potassium hydroxide Chemical compound [OH-].[K+] KWYUFKZDYYNOTN-UHFFFAOYSA-M 0.000 description 3
- HEMHJVSKTPXQMS-UHFFFAOYSA-M Sodium hydroxide Chemical compound [OH-].[Na+] HEMHJVSKTPXQMS-UHFFFAOYSA-M 0.000 description 3
- IXSUHTFXKKBBJP-UHFFFAOYSA-L azanide;platinum(2+);dinitrite Chemical compound [NH2-].[NH2-].[Pt+2].[O-]N=O.[O-]N=O IXSUHTFXKKBBJP-UHFFFAOYSA-L 0.000 description 3
- 230000000052 comparative effect Effects 0.000 description 3
- 230000000694 effects Effects 0.000 description 3
- 239000007789 gas Substances 0.000 description 3
- 229910017464 nitrogen compound Inorganic materials 0.000 description 3
- 150000002830 nitrogen compounds Chemical class 0.000 description 3
- 238000011946 reduction process Methods 0.000 description 3
- 229910000029 sodium carbonate Inorganic materials 0.000 description 3
- 239000004317 sodium nitrate Substances 0.000 description 3
- 235000010344 sodium nitrate Nutrition 0.000 description 3
- 238000009279 wet oxidation reaction Methods 0.000 description 3
- IKHGUXGNUITLKF-UHFFFAOYSA-N Acetaldehyde Chemical compound CC=O IKHGUXGNUITLKF-UHFFFAOYSA-N 0.000 description 2
- PNEYBMLMFCGWSK-UHFFFAOYSA-N Alumina Chemical compound [O-2].[O-2].[O-2].[Al+3].[Al+3] PNEYBMLMFCGWSK-UHFFFAOYSA-N 0.000 description 2
- KFZMGEQAYNKOFK-UHFFFAOYSA-N Isopropanol Chemical compound CC(C)O KFZMGEQAYNKOFK-UHFFFAOYSA-N 0.000 description 2
- LRHPLDYGYMQRHN-UHFFFAOYSA-N N-Butanol Chemical compound CCCCO LRHPLDYGYMQRHN-UHFFFAOYSA-N 0.000 description 2
- UIIMBOGNXHQVGW-UHFFFAOYSA-M Sodium bicarbonate Chemical compound [Na+].OC([O-])=O UIIMBOGNXHQVGW-UHFFFAOYSA-M 0.000 description 2
- QAOWNCQODCNURD-UHFFFAOYSA-N Sulfuric acid Chemical compound OS(O)(=O)=O QAOWNCQODCNURD-UHFFFAOYSA-N 0.000 description 2
- MCMNRKCIXSYSNV-UHFFFAOYSA-N Zirconium dioxide Chemical compound O=[Zr]=O MCMNRKCIXSYSNV-UHFFFAOYSA-N 0.000 description 2
- 238000004458 analytical method Methods 0.000 description 2
- XTVVROIMIGLXTD-UHFFFAOYSA-N copper(II) nitrate Chemical compound [Cu+2].[O-][N+]([O-])=O.[O-][N+]([O-])=O XTVVROIMIGLXTD-UHFFFAOYSA-N 0.000 description 2
- XBDQKXXYIPTUBI-UHFFFAOYSA-N dimethylselenoniopropionate Natural products CCC(O)=O XBDQKXXYIPTUBI-UHFFFAOYSA-N 0.000 description 2
- 238000002848 electrochemical method Methods 0.000 description 2
- 238000000909 electrodialysis Methods 0.000 description 2
- 238000001914 filtration Methods 0.000 description 2
- 239000010842 industrial wastewater Substances 0.000 description 2
- 238000009434 installation Methods 0.000 description 2
- 238000005342 ion exchange Methods 0.000 description 2
- 238000004898 kneading Methods 0.000 description 2
- 238000002156 mixing Methods 0.000 description 2
- 238000000465 moulding Methods 0.000 description 2
- 125000004433 nitrogen atom Chemical group N* 0.000 description 2
- 230000003647 oxidation Effects 0.000 description 2
- 238000007254 oxidation reaction Methods 0.000 description 2
- 238000010248 power generation Methods 0.000 description 2
- 239000002244 precipitate Substances 0.000 description 2
- 238000002360 preparation method Methods 0.000 description 2
- GTCKPGDAPXUISX-UHFFFAOYSA-N ruthenium(3+);trinitrate Chemical compound [Ru+3].[O-][N+]([O-])=O.[O-][N+]([O-])=O.[O-][N+]([O-])=O GTCKPGDAPXUISX-UHFFFAOYSA-N 0.000 description 2
- 239000000377 silicon dioxide Substances 0.000 description 2
- 239000007787 solid Substances 0.000 description 2
- NWUYHJFMYQTDRP-UHFFFAOYSA-N 1,2-bis(ethenyl)benzene;1-ethenyl-2-ethylbenzene;styrene Chemical compound C=CC1=CC=CC=C1.CCC1=CC=CC=C1C=C.C=CC1=CC=CC=C1C=C NWUYHJFMYQTDRP-UHFFFAOYSA-N 0.000 description 1
- PAWQVTBBRAZDMG-UHFFFAOYSA-N 2-(3-bromo-2-fluorophenyl)acetic acid Chemical compound OC(=O)CC1=CC=CC(Br)=C1F PAWQVTBBRAZDMG-UHFFFAOYSA-N 0.000 description 1
- 229910017076 Fe Zr Inorganic materials 0.000 description 1
- GRYLNZFGIOXLOG-UHFFFAOYSA-N Nitric acid Chemical compound O[N+]([O-])=O GRYLNZFGIOXLOG-UHFFFAOYSA-N 0.000 description 1
- JVMRPSJZNHXORP-UHFFFAOYSA-N ON=O.ON=O.ON=O.N Chemical compound ON=O.ON=O.ON=O.N JVMRPSJZNHXORP-UHFFFAOYSA-N 0.000 description 1
- NBBJYMSMWIIQGU-UHFFFAOYSA-N Propionic aldehyde Chemical compound CCC=O NBBJYMSMWIIQGU-UHFFFAOYSA-N 0.000 description 1
- VMHLLURERBWHNL-UHFFFAOYSA-M Sodium acetate Chemical compound [Na+].CC([O-])=O VMHLLURERBWHNL-UHFFFAOYSA-M 0.000 description 1
- QAOWNCQODCNURD-UHFFFAOYSA-L Sulfate Chemical compound [O-]S([O-])(=O)=O QAOWNCQODCNURD-UHFFFAOYSA-L 0.000 description 1
- 229910011212 Ti—Fe Inorganic materials 0.000 description 1
- ZDPALFHDPFYJDY-UHFFFAOYSA-N [Na].OC=O Chemical compound [Na].OC=O ZDPALFHDPFYJDY-UHFFFAOYSA-N 0.000 description 1
- 235000011054 acetic acid Nutrition 0.000 description 1
- 239000002253 acid Substances 0.000 description 1
- 229910052783 alkali metal Inorganic materials 0.000 description 1
- 150000001412 amines Chemical class 0.000 description 1
- 238000000975 co-precipitation Methods 0.000 description 1
- 239000000306 component Substances 0.000 description 1
- 238000000354 decomposition reaction Methods 0.000 description 1
- 230000003247 decreasing effect Effects 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 238000007599 discharging Methods 0.000 description 1
- 238000004821 distillation Methods 0.000 description 1
- 238000012851 eutrophication Methods 0.000 description 1
- 239000002360 explosive Substances 0.000 description 1
- 239000000835 fiber Substances 0.000 description 1
- 150000002334 glycols Chemical class 0.000 description 1
- 238000005470 impregnation Methods 0.000 description 1
- 239000013067 intermediate product Substances 0.000 description 1
- 239000003456 ion exchange resin Substances 0.000 description 1
- 229920003303 ion-exchange polymer Polymers 0.000 description 1
- 150000002500 ions Chemical class 0.000 description 1
- 230000007774 longterm Effects 0.000 description 1
- 239000000463 material Substances 0.000 description 1
- 244000005700 microbiome Species 0.000 description 1
- 238000005065 mining Methods 0.000 description 1
- 239000000203 mixture Substances 0.000 description 1
- 229910017604 nitric acid Inorganic materials 0.000 description 1
- UJVRJBAUJYZFIX-UHFFFAOYSA-N nitric acid;oxozirconium Chemical compound [Zr]=O.O[N+]([O-])=O.O[N+]([O-])=O UJVRJBAUJYZFIX-UHFFFAOYSA-N 0.000 description 1
- 239000000618 nitrogen fertilizer Substances 0.000 description 1
- 239000005416 organic matter Substances 0.000 description 1
- 238000006864 oxidative decomposition reaction Methods 0.000 description 1
- 238000011197 physicochemical method Methods 0.000 description 1
- 235000019260 propionic acid Nutrition 0.000 description 1
- IUVKMZGDUIUOCP-BTNSXGMBSA-N quinbolone Chemical compound O([C@H]1CC[C@H]2[C@H]3[C@@H]([C@]4(C=CC(=O)C=C4CC3)C)CC[C@@]21C)C1=CCCC1 IUVKMZGDUIUOCP-BTNSXGMBSA-N 0.000 description 1
- 238000011084 recovery Methods 0.000 description 1
- 230000008929 regeneration Effects 0.000 description 1
- 238000011069 regeneration method Methods 0.000 description 1
- 239000010802 sludge Substances 0.000 description 1
- 239000001632 sodium acetate Substances 0.000 description 1
- 235000017281 sodium acetate Nutrition 0.000 description 1
- 229910000030 sodium bicarbonate Inorganic materials 0.000 description 1
- 235000017557 sodium bicarbonate Nutrition 0.000 description 1
- 229910052979 sodium sulfide Inorganic materials 0.000 description 1
- GRVFOGOEDUUMBP-UHFFFAOYSA-N sodium sulfide (anhydrous) Chemical compound [Na+].[Na+].[S-2] GRVFOGOEDUUMBP-UHFFFAOYSA-N 0.000 description 1
- AKHNMLFCWUSKQB-UHFFFAOYSA-L sodium thiosulfate Chemical compound [Na+].[Na+].[O-]S([O-])(=O)=S AKHNMLFCWUSKQB-UHFFFAOYSA-L 0.000 description 1
- 235000019345 sodium thiosulphate Nutrition 0.000 description 1
- 230000009897 systematic effect Effects 0.000 description 1
- FBEIPJNQGITEBL-UHFFFAOYSA-J tetrachloroplatinum Chemical compound Cl[Pt](Cl)(Cl)Cl FBEIPJNQGITEBL-UHFFFAOYSA-J 0.000 description 1
- 229910000349 titanium oxysulfate Inorganic materials 0.000 description 1
- 231100000765 toxin Toxicity 0.000 description 1
- DANYXEHCMQHDNX-UHFFFAOYSA-K trichloroiridium Chemical compound Cl[Ir](Cl)Cl DANYXEHCMQHDNX-UHFFFAOYSA-K 0.000 description 1
- 239000012808 vapor phase Substances 0.000 description 1
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Abstract
Description
本発明は、排水中に含まれる硝酸態窒素を窒素等に湿式還元処理する方法に関する。より詳しくは、本発明は、火力発電設備、原子力発電設備、化学プラント、金属工業設備、金属鉱業設備等で生じる産業排水等に含まれる硝酸態窒素を、還元性物質の存在下、１００℃未満の温度にて、排水を固体触媒と接触させて、硝酸態窒素を窒素等に湿式還元する方法に関するものである。 The present invention relates to a method of performing wet reduction treatment of nitrate nitrogen contained in waste water to nitrogen or the like. More specifically, the present invention relates to nitrate nitrogen contained in industrial wastewater generated in thermal power generation facilities, nuclear power generation facilities, chemical plants, metal industrial facilities, metal mining facilities, etc. in the presence of reducing substances, and less than 100 ° C. The method relates to a method of wet-reducing nitrate nitrogen to nitrogen or the like by contacting waste water with a solid catalyst at this temperature.
なお、本発明の「窒素等」とは、窒素および／またはアンモニアを意味する。 In the present invention, “nitrogen etc.” means nitrogen and / or ammonia.
海域、湖沼、河川等において、富栄養化によって赤潮の発生、かび臭の発生することが問題となって久しいが、これは、該水域に流入する生活雑排水、窒素肥料を含んだ農業排水や該水域に排出される工業排水等に含有される硝酸態窒素が原因のひとつとされている。したがって、排水を海域、湖沼、河川等へ排出する前に、硝酸態窒素を排水から削減することが重要な課題となっている。 Occurrence of red tide and musty odor due to eutrophication has long been a problem in sea areas, lakes, rivers, etc., but this may be caused by miscellaneous wastewater flowing into the water area, agricultural wastewater containing nitrogen fertilizer, One of the causes is nitrate nitrogen contained in industrial wastewater discharged into water bodies. Therefore, it is an important issue to reduce nitrate nitrogen from the wastewater before discharging the wastewater to the sea area, lakes, rivers and the like.
硝酸態窒素の除去技術としては、現在、生物処理法や、イオン交換法、電気透析法、電気化学的方法等の物理化学的方法が実用化または検討されている。 As a technique for removing nitrate nitrogen, a physicochemical method such as a biological treatment method, an ion exchange method, an electrodialysis method, and an electrochemical method has been put into practical use or studied.
生物処理法は、例えば嫌気性処理を行って硝酸態窒素を窒素ガスとする方法であるが、高濃度の排水は希釈する必要があったり、処理時間を長くとる必要があったりするために、必然的に装置規模が大きくなるという問題点がある。また、ｐＨが高すぎる排水または低すぎる排水、生物毒となる物質が存在する排水、有機物濃度が高い排水等は生物処理が困難であり、あえて処理する場合には操作性が煩雑になるという問題点もある。更に、微生物に由来して発生する汚泥の処理が別途必要になる問題も挙げられる。 The biological treatment method is, for example, a method of performing anaerobic treatment to convert nitrate nitrogen into nitrogen gas, but it is necessary to dilute high concentration wastewater or to take a long treatment time. Inevitably, there is a problem that the apparatus scale becomes large. In addition, wastewater whose pH is too high or too low, wastewater containing substances that become biotoxins, wastewater with high organic matter concentration, etc., are difficult to biologically treat, and the problem is that operability becomes complicated when treated intentionally. There is also a point. Furthermore, there is a problem that it is necessary to separately treat sludge generated from microorganisms.
イオン交換法では、イオン交換樹脂を頻繁に再生する必要があり、更には、排水中に硫酸イオン等の多価イオンが存在する場合には、硝酸イオンの選択性が低くなる問題もある。また、再生時に発生する硝酸含有水の処理が別途必要になるため根本的な処理にはならない。その他、電気透析法、電気化学的方法等が検討されているが、いずれも処理コストが高くつくなどの問題がある。 In the ion exchange method, it is necessary to regenerate the ion exchange resin frequently, and further, when multivalent ions such as sulfate ions are present in the waste water, there is a problem that the selectivity of nitrate ions is lowered. In addition, since the treatment of nitric acid-containing water generated at the time of regeneration is required separately, it is not a fundamental treatment. In addition, electrodialysis methods, electrochemical methods, and the like have been studied, but all have problems such as high processing costs.
その他の硝酸態窒素の処理方法としては、硝酸態窒素含有水に水素ガスを導入し、パラジウム触媒やロジウム触媒と接触させて亜硝酸態窒素および／または硝酸態窒素を選択的に窒素ガスに転換する方法が提案されている（例えば、特許文献１参照）。この方法は低濃度の硝酸態窒素を除去するのには適するが、高濃度の硝酸態窒素を含有する場合には処理効率は不十分である。また、触媒担体としてはγ−アルミナやシリカ等が使用されているが、γ−アルミナやシリカを担体とした触媒は耐久性が不十分なものであり、長期の運転中に触媒強度が低下し、触媒が崩壊することにより触媒層での圧力損失が上昇したり、触媒活性が低下したりするという問題点もある。 As another method of treating nitrate nitrogen, hydrogen gas is introduced into nitrate nitrogen-containing water and contacted with a palladium catalyst or rhodium catalyst to selectively convert nitrite nitrogen and / or nitrate nitrogen to nitrogen gas. A method has been proposed (see, for example, Patent Document 1). This method is suitable for removing low-concentration nitrate nitrogen, but the treatment efficiency is insufficient when high-concentration nitrate nitrogen is contained. In addition, although γ-alumina, silica, etc. are used as the catalyst carrier, the catalyst using γ-alumina or silica as the carrier is insufficient in durability, and the catalyst strength decreases during long-term operation. Further, there is a problem that the pressure loss in the catalyst layer increases or the catalyst activity decreases due to the collapse of the catalyst.
同様に、高濃度の硝酸態窒素含有排水を処理するために、排水への溶解度を超える水素ガスを添加して高濃度の硝酸態窒素を含有する排水を処理する方法が提案されている（例えば、特許文献２参照）。ただし、過剰の水素を添加するため、反応後の余剰した水素を分離するための回収装置が必要であり、装置が複雑化する。更に、爆発性のある水素ガスを１００℃以上の圧力下で液と接触させるため、安全管理上の問題もある。 Similarly, in order to treat high-concentration nitrate nitrogen-containing wastewater, a method for treating wastewater containing high-concentration nitrate nitrogen by adding hydrogen gas exceeding the solubility in wastewater has been proposed (for example, , See Patent Document 2). However, since excess hydrogen is added, a recovery device for separating the surplus hydrogen after the reaction is necessary, which complicates the device. Furthermore, since explosive hydrogen gas is brought into contact with the liquid under a pressure of 100 ° C. or higher, there is a problem in safety management.
その他、還元剤として、ヒドラジンを使用した硝酸態窒素含有排水の処理方法が提案されているが（例えば、特許文献３参照）、還元剤として窒素化合物を用いるため、水溶液中の全窒素量を低下させることが困難となる場合が多い。また、触媒成分の耐久性に問題があった。 In addition, although a method for treating nitrate nitrogen-containing wastewater using hydrazine as a reducing agent has been proposed (see, for example, Patent Document 3), since a nitrogen compound is used as the reducing agent, the total amount of nitrogen in the aqueous solution is reduced. It is often difficult to do. There was also a problem with the durability of the catalyst component.
一方、１２０〜３７０℃の温度かつ排水が液相を保持する圧力下、固体触媒の存在下にて、還元剤を添加して硝酸態窒素を還元する方法が提案されている（例えば、特許文献４参照）。この方法は、上記の反応条件下においては、処理性能に優れた方法である。しかしながら、１００℃以上の反応温度のもと、液相を保持するため圧力をかける必要があり、装置コストが高くなるなどの問題がある。 同様に、８０〜１７０℃、反応圧力が常圧〜１ＭＰａにて、還元剤と固体触媒の存在下、湿式還元する方法も提案されている（例えば、特特許文献５参照）が、１００℃未満での処理性能は十分なものではなかった。 On the other hand, a method has been proposed in which nitrate nitrogen is reduced by adding a reducing agent in the presence of a solid catalyst under a temperature of 120 to 370 ° C. and a pressure at which wastewater maintains a liquid phase (for example, Patent Documents). 4). This method is excellent in processing performance under the above reaction conditions. However, under the reaction temperature of 100 ° C. or higher, it is necessary to apply pressure to maintain the liquid phase, and there is a problem that the apparatus cost is increased. Similarly, a method of wet reduction in the presence of a reducing agent and a solid catalyst at 80 to 170 ° C. and a reaction pressure of normal pressure to 1 MPa has also been proposed (see, for example, Patent Document 5), but less than 100 ° C. The processing performance at was not sufficient.
従来、一般に用いられてきた１００℃以上、かつ液相を保持する圧力下における反応では、還元剤が熱により分解されてしまうことが多く、還元剤が硝酸態窒素の還元反応に有効に使用されていないことが多かった。また、温度、圧力が高くなると、装置のコストが高くなるだけでなく、触媒の耐久性が低下する問題があった。 Conventionally, in a reaction at a temperature of 100 ° C. or higher and a pressure that maintains a liquid phase, which is generally used, the reducing agent is often decomposed by heat, and the reducing agent is effectively used for the reduction reaction of nitrate nitrogen. There were many things that were not. Further, when the temperature and pressure are increased, there is a problem that not only the cost of the apparatus is increased, but also the durability of the catalyst is lowered.
本発明の課題は、前記のような通常の技術では、１００℃未満で十分に処理することが困難な硝酸態窒素を含有する排水を１００℃未満で処理して硝酸態窒素を高効率に除去する硝酸態窒素含有排水の浄化方法を提供することにある。 The object of the present invention is to remove nitrate nitrogen with high efficiency by treating wastewater containing nitrate nitrogen, which is difficult to sufficiently treat at less than 100 ° C., with less than 100 ° C. An object of the present invention is to provide a purification method for wastewater containing nitrate nitrogen.
本発明者らは上記課題を解決すべく鋭意研究を重ねた結果、硝酸態窒素含有排水を還元性物質の存在下、１００℃未満の温度において固体触媒と接触させて排水中の硝酸態窒素を窒素等に湿式還元するに際し、特定の固体触媒と特定の還元性物質とを組み合わせて使用すると硝酸態窒素を効率よく窒素等に湿式還元できること、またこの方法はコスト的にも優れていることを見出し、本発明を完成するに至った。本発明は、以下のとおり特定されるものである。
（１）硝酸態窒素を含有する排水を還元性物質の存在下に固体触媒と接触させて硝酸態窒素を窒素等に湿式還元して浄化する方法において、１００℃未満の温度において反応させることを特徴とする硝酸態窒素含有排水の浄化方法。
（２）固体触媒として、金、銀、白金、パラジウム、ロジウム、ルテニウム、イリジウム、マンガン、コバルト、ニッケル、銅、錫、セリウム、インジウムおよび亜鉛から選ばれる少なくとも１種の元素の金属および／または化合物を、鉄、チタンおよびジルコニウムから選ばれる少なくとも１種の元素の化合物、または活性炭に担持してなる固体触媒を、また還元性物質として、アルコール類、有機酸類、アルデヒド類、ケトン類、無機硫黄化合物類、窒素化合物、フェノール類および水素から選ばれる少なくとも１種を用いる上記（１）の硝酸態窒素含有排水の浄化方法。
（３）固体触媒として、パラジウムおよび白金から選ばれる少なくとも１種の元素を鉄、チタンおよびジルコニウムから選ばれる少なくとも１種の元素の酸化物に担持してなる固体触媒を、また還元性物質として、ギ酸、ギ酸塩、シュウ酸、シュウ酸塩、メタノール、エタノールおよびホルムアルデヒドから選ばれる少なくとも１種を用いる上記（２）の硝酸態窒素含有排水の浄化方法。
（４）固体触媒として、パラジウムおよび白金から選ばれる少なくとも１種の元素と銅および鉄から選ばれる少なくとも１種の元素とを活性炭に担持してなる固体触媒を、また還元性物質として、ギ酸、ギ酸塩、シュウ酸、シュウ酸塩、メタノール、エタノールおよびホルムアルデヒドから選ばれる少なくとも１種を用いる上記（２）の硝酸態窒素含有排水の浄化方法。
As a result of intensive studies to solve the above problems, the inventors of the present invention brought nitrate nitrogen-containing wastewater into contact with a solid catalyst at a temperature of less than 100 ° C. in the presence of a reducing substance, thereby reducing nitrate nitrogen in the wastewater. When wet-reducing to nitrogen, etc., it is possible to efficiently reduce nitrate nitrogen to nitrogen, etc. by using a combination of a specific solid catalyst and a specific reducing substance, and this method is also excellent in cost. The headline and the present invention were completed. The present invention is specified as follows.
(1) In a method in which wastewater containing nitrate nitrogen is brought into contact with a solid catalyst in the presence of a reducing substance and nitrate nitrogen is wet-reduced to nitrogen or the like to be purified, the reaction is performed at a temperature of less than 100 ° C. A method for purifying drainage containing nitrate nitrogen.
(2) Metal and / or compound of at least one element selected from gold, silver, platinum, palladium, rhodium, ruthenium, iridium, manganese, cobalt, nickel, copper, tin, cerium, indium and zinc as a solid catalyst Is a compound of at least one element selected from iron, titanium and zirconium, or a solid catalyst which is supported on activated carbon, and as a reducing substance, alcohols, organic acids, aldehydes, ketones, inorganic sulfur compounds (1) The method for purifying nitrate nitrogen-containing wastewater according to (1) above, wherein at least one selected from the group consisting of nitrogen, nitrogen compounds, phenols and hydrogen is used.
(3) As a solid catalyst, a solid catalyst obtained by supporting at least one element selected from palladium and platinum on an oxide of at least one element selected from iron, titanium and zirconium, and a reducing substance, The method for purifying nitrate nitrogen-containing wastewater according to (2) above, wherein at least one selected from formic acid, formate, oxalic acid, oxalate, methanol, ethanol and formaldehyde is used.
(4) As a solid catalyst, a solid catalyst obtained by supporting activated carbon with at least one element selected from palladium and platinum and at least one element selected from copper and iron, and as a reducing substance, formic acid, The method for purifying wastewater containing nitrate nitrogen as described in (2) above, wherein at least one selected from formate, oxalic acid, oxalate, methanol, ethanol and formaldehyde is used.
本発明の方法により、１００℃未満の反応温度にて、排水中の硝酸態窒素を高効率で窒素等に湿式還元することができる。 By the method of the present invention, nitrate nitrogen in waste water can be wet reduced to nitrogen or the like with high efficiency at a reaction temperature of less than 100 ° C.
本発明の方法は、従来技術に比べ安価、効率的、安定的かつ操作容易であり、硝酸態窒素含有排水の工業的規模での浄化に好適である。 The method of the present invention is cheaper, more efficient, stable and easier to operate than the prior art, and is suitable for purification of nitrate nitrogen-containing wastewater on an industrial scale.
本発明に係る「硝酸態窒素」（以下、「ＮＯ３ −―Ｎ」と表示する場合もある）とは、広く硝酸イオンを構成する窒素原子を意味し、硝酸イオンまたは亜硝酸イオンを構成する窒素原子を意味する。したがって、本発明の硝酸態窒素含有排水とは、硝酸イオンおよび／または亜硝酸イオンを含む排水を意味する。 “Nitrate nitrogen” according to the present invention (hereinafter sometimes referred to as “NO 3 − —N”) means a nitrogen atom that widely constitutes nitrate ions, and constitutes nitrate ions or nitrite ions. Means a nitrogen atom. Therefore, the nitrate nitrogen-containing waste water of the present invention means waste water containing nitrate ions and / or nitrite ions.
例えば、還元性物質としてメタノールを用いた場合の硝酸態窒素の窒素への還元は、以下に示す反応がおこるものと考えられる。 For example, reduction of nitrate nitrogen to nitrogen when methanol is used as the reducing substance is considered to occur by the following reaction.
ＨＮＯ３ ＋５／６ＣＨ３ＯＨ→ １／２Ｎ２ ＋ ５／６ＣＯ２＋１３／６ Ｈ２Ｏ
一方、硝酸態窒素のアンモニアへの還元は、次の反応式で表わされる。
HNO 3 + 5 / 6CH 3 OH → 1 / 2N 2 + 5 / 6CO 2 +13/6 H 2 O
On the other hand, the reduction of nitrate nitrogen to ammonia is represented by the following reaction formula.
ＨＮＯ３ ＋４／３ＣＨ３ＯＨ → ＮＨ３＋４／３ＣＯ２ ＋ ５／３Ｈ２Ｏ
本発明では、排水中の硝酸態窒素を窒素ガスまで還元するのに必要な還元性物質の量関係を規定比１と表記する。
HNO 3 + 4 / 3CH 3 OH → NH 3 + 4 / 3CO 2 + 5 / 3H 2 O
In the present invention, the quantity relationship of reducing substances necessary for reducing nitrate nitrogen in waste water to nitrogen gas is expressed as a specified ratio of 1.
本発明において対象となる排水は、上記硝酸態窒素を含有している排水であれば特に限定されない。排水中の硝酸態窒素の濃度については、排水中に硝酸態窒素を含有するものであれば特に限定されないが、好ましくは硝酸態窒素として１０〜５０，０００ｍｇ／リットル、さらに好ましくは２０〜２０，０００ｍｇ／リットル、最も好ましくは３０〜１０，０００ｍｇ／リットルである。１０ｍｇ／リットル未満の場合は、処理コストの面で本発明の優位性が得られない一方で、他の方法でも十分排水を処理することができるため、本発明の方法による必要がない。５０，０００ｍｇ／リットルを超える場合は、装置の配管等で塩が析出し、系内の閉塞を起こすことがあり好ましくない。 In the present invention, the target wastewater is not particularly limited as long as the wastewater contains nitrate nitrogen. The concentration of nitrate nitrogen in the wastewater is not particularly limited as long as it contains nitrate nitrogen in the wastewater, but is preferably 10 to 50,000 mg / liter as nitrate nitrogen, more preferably 20 to 20, 000 mg / liter, most preferably 30 to 10,000 mg / liter. When the amount is less than 10 mg / liter, the superiority of the present invention cannot be obtained in terms of treatment cost, but the wastewater can be treated sufficiently by other methods, and thus there is no need for the method of the present invention. If it exceeds 50,000 mg / liter, salt may be deposited in the piping of the apparatus, etc., causing clogging in the system, which is not preferable.
また、排水中には、硝酸態窒素のほか、通常、排水中に含まれる成分が存在していてもよく、例えば、ＣＯＤ成分を含有するものであってもよい。 Further, in addition to nitrate nitrogen, components usually contained in the wastewater may be present in the wastewater, and for example, it may contain a COD component.
本発明において排水のｐＨは特に限定されるものではないが、装置材質上の制約等から通常２〜１３であり、３〜１２であることがより好ましい。硝酸態窒素を多量に含有する場合は、ｐＨが低くなることが予想されるため、そのような場合は、適宜ｐＨを調整するために、アルカリ性物質を添加してもよい。アルカリ性物質としては、水酸化ナトリウム、炭酸ナトリウム、炭酸水素ナトリウム、水酸化カリウム等、一般にｐＨを調整することに使用する物質を適宜使用すればよい。 In the present invention, the pH of the wastewater is not particularly limited, but is usually 2 to 13 and more preferably 3 to 12 due to restrictions on the material of the apparatus. When a large amount of nitrate nitrogen is contained, the pH is expected to be low. In such a case, an alkaline substance may be added to adjust the pH appropriately. As the alkaline substance, a substance generally used for adjusting pH, such as sodium hydroxide, sodium carbonate, sodium hydrogen carbonate, potassium hydroxide, etc. may be used as appropriate.
本発明に係わる還元性物質は、湿式還元処理において硝酸態窒素を還元する能力を有する物質である。還元性物質の具体例としては、メタノール、エタノール、イソプロパノール、ブタノール等のアルコール類；エチレングリコールなどのグリコール類；ギ酸、酢酸、シュウ酸、プロピオン酸等の有機酸類（その塩も含む。）；ホルムアルデヒド、アセトアルデヒド、プロピルアルデヒド等のアルデヒド類；アセトン、メチルエチルケトン等のケトン類；チオ硫酸ナトリウム、硫化ナトリウム等の無機硫黄化合物類；ヒドラジン、アミン類、アンモニア等の窒素化合物；フェノール類；水素などを挙げることができる。上記還元性物質は、単独で用いてもよいし、複数種の物質を用いてもよい。また、上記有機酸類の塩としては、ギ酸ナトリウム、酢酸ナトリウム、シュウ酸ナトリウム等の有機酸アルカリ金属塩を挙げることができる。これらのうち、取り扱い性、経済性、後処理のしやすさなどからして、特に、メタノール、エタノール、ギ酸、ギ酸塩（例えば、ギ酸ナトリウム）、シュウ酸、シュウ酸塩（例えば、シュウ酸ナトリウム）およびホルムアルデヒドが好適に用いられる。 The reducing substance according to the present invention is a substance having an ability to reduce nitrate nitrogen in a wet reduction process. Specific examples of the reducing substance include alcohols such as methanol, ethanol, isopropanol and butanol; glycols such as ethylene glycol; organic acids such as formic acid, acetic acid, oxalic acid and propionic acid (including salts thereof); formaldehyde Aldehydes such as acetaldehyde and propylaldehyde; Ketones such as acetone and methyl ethyl ketone; Inorganic sulfur compounds such as sodium thiosulfate and sodium sulfide; Nitrogen compounds such as hydrazine, amines and ammonia; Phenols; Can do. The reducing substance may be used alone or in combination of two or more kinds. Examples of the organic acid salts include organic acid alkali metal salts such as sodium formate, sodium acetate, and sodium oxalate. Of these, methanol, ethanol, formic acid, formate (e.g., sodium formate), oxalic acid, oxalate (e.g., sodium oxalate), especially in terms of handleability, economy, and ease of post-treatment ) And formaldehyde are preferably used.
なお、鉄、チタンおよびジルコニウムから選ばれる少なくとも１種の元素の酸化物に担持してなる固体触媒を使用する場合、触媒の耐久性の面から還元性物質としてギ酸よりもギ酸塩を用いるのが好ましい。 When using a solid catalyst supported on an oxide of at least one element selected from iron, titanium and zirconium, it is preferable to use a formate rather than formic acid as a reducing substance in terms of durability of the catalyst. preferable.
還元性物質の添加方法としては、例えば、排水タンク中の排水に直接投入し、混合する方法をとることもできるが、還元性物質を排水供給ポンプの吐出部から反応塔までの入口までの任意の位置に定量ポンプを用いて供給する方法をとることもできる。また、反応塔の途中に還元性物質を供給することも可能である。本発明において、還元性物質を過剰量添加した場合、本発明に係る還元処理を行なった後、触媒湿式酸化処理により、酸化分解処理することも可能であるし、蒸留等により還元性物質を回収し、再利用することもできる。上記の還元性物質を含む排水であれば、還元性物質を添加することなく反応させることが可能である。 As a method for adding the reducing substance, for example, it can be directly put into the wastewater in the drainage tank and mixed, but the reducing substance can be added arbitrarily from the discharge part of the drainage supply pump to the inlet to the reaction tower. It is also possible to use a method in which a metering pump is used to supply the position. It is also possible to supply a reducing substance in the middle of the reaction tower. In the present invention, when an excessive amount of a reducing substance is added, after performing the reduction treatment according to the present invention, it can be subjected to oxidative decomposition treatment by catalytic wet oxidation treatment, and the reducing substance is recovered by distillation or the like. And can be reused. If it is the waste water containing said reducing substance, it is possible to make it react, without adding a reducing substance.
還元性物質は、排水中の硝酸態窒素を窒素ガスに還元するのに必要な量（規定比１）の０．９〜１０倍量を用いる。すなわち、前記のように、排水中の硝酸態窒素を窒素ガスに還元するのに必要な還元剤の量関係を規定比１と表記すると、本発明の還元性物質は、規定比が０．９〜５、好ましくは１〜４となる量で使用する。０．９より少ないと、硝酸態窒素が残留し、規定比が４を超える場合は、還元性物質が未処理のまま大量に残留するが硝酸態窒素の処理効率はあまりあがらず、薬剤コストや残留した還元性物質の処理コストが増大するだけである。
The reducing substance is used in an amount of 0.9 to 10 times the amount necessary for reducing nitrate nitrogen in the wastewater to nitrogen gas (specified ratio 1). That is, as described above, when the amount of reducing agent necessary for reducing nitrate nitrogen in waste water to nitrogen gas is expressed as a specified
本発明に係る排水の供給量は、固体触媒層に対しての液空間速度で０．１〜２０ｈｒ-1であることが好ましく、０．１〜５ｈｒ-1がより好ましい。液空間速度が０．１ｈｒ-1未満では処理コストが増大し、一方液空間速度が２０ｈｒ-1を越える場合は処理水中に硝酸態窒素が無視できない濃度で残留することが多くなる。 The supply amount of waste water according to the present invention is preferably 0.1 to 20 hr −1 , more preferably 0.1 to 5 hr −1 in terms of the liquid space velocity with respect to the solid catalyst layer. When the liquid space velocity is less than 0.1 hr −1 , the processing cost increases. On the other hand, when the liquid space velocity exceeds 20 hr −1 , nitrate nitrogen often remains in the treated water at a concentration that cannot be ignored.
本発明に係わる固体触媒は、金、銀、白金、パラジウム、ロジウム、ルテニウム、イリジウム、マンガン、コバルト、ニッケル、銅、錫、セリウム、インジウムおよび亜鉛よりなる群から選ばれた少なくとも１種の元素の金属および／または化合物と鉄、チタンおよびジルコニウムよりなる群から選ばれた少なくとも１種の元素の化合物、または活性炭とを含有するものである。鉄、チタン、およびジルコニウムよりなる群から選ばれた少なくとも１種の元素の化合物または活性炭をＡ成分、金、銀、白金、パラジウム、ロジウム、ルテニウム、イリジウム、マンガン、コバルト、ニッケル、銅、錫、セリウム、インジウムおよび亜鉛よりなる群から選ばれた少なくとも１種の元素の金属および／または化合物をＢ成分とすると、本発明の固体触媒は、Ａ成分を８０〜９９．９５質量％、Ｂ成分を０．０５〜２０質量％含有するものである。 The solid catalyst according to the present invention comprises at least one element selected from the group consisting of gold, silver, platinum, palladium, rhodium, ruthenium, iridium, manganese, cobalt, nickel, copper, tin, cerium, indium and zinc. It contains a metal and / or compound and a compound of at least one element selected from the group consisting of iron, titanium and zirconium, or activated carbon. A compound of at least one element selected from the group consisting of iron, titanium, and zirconium or activated carbon is converted to A component, gold, silver, platinum, palladium, rhodium, ruthenium, iridium, manganese, cobalt, nickel, copper, tin, When the metal and / or compound of at least one element selected from the group consisting of cerium, indium and zinc is the B component, the solid catalyst of the present invention has an A component of 80 to 99.95% by mass and a B component of It contains 0.05 to 20% by mass.
Ａ成分の含有量は、８０〜９９．９５質量％であることが、触媒の耐久性および経済性の面から好ましい。Ｂ成分の含有量は、０．０５〜２０質量％であることが効果的であるが、０．１〜１５質量％であることが好ましく、０．２〜１０質量％であることがより好ましい。Ｂ成分の含有量が０．０５質量％未満の場合は、触媒活性が不十分であり、２０質量％を超える場合は、コストに見合った触媒性能が得られない。 The content of the component A is preferably 80 to 99.95% by mass from the viewpoint of durability and economical efficiency of the catalyst. The content of component B is effectively 0.05 to 20% by mass, preferably 0.1 to 15% by mass, and more preferably 0.2 to 10% by mass. . When the content of the component B is less than 0.05% by mass, the catalyst activity is insufficient, and when it exceeds 20% by mass, the catalyst performance corresponding to the cost cannot be obtained.
Ａ成分としては、チタンと鉄および／またはジルコニウムとの酸化物（すなわち、チタンと鉄との酸化物、チタンとジルコニウムとの酸化物およびチタンと鉄とジルコニウムとの酸化物）、および鉄とジルコニウムとの酸化物を用いることが好ましい。チタンと鉄および／またはジルコニウムとの酸化物を用いる場合、Ａ成分を１００％とした場合、鉄の酸化物の含有量が１０〜９８質量％であることが好ましい。鉄の酸化物の含有量が９８質量％を超える場合、触媒の耐久性が不十分となり、一方、鉄の酸化物の含有量が１０質量％未満である場合には、触媒の耐久性が不十分となることがある。 As the component A, oxides of titanium and iron and / or zirconium (that is, oxides of titanium and iron, oxides of titanium and zirconium and oxides of titanium, iron and zirconium), and iron and zirconium It is preferable to use an oxide. When using an oxide of titanium and iron and / or zirconium, the content of the iron oxide is preferably 10 to 98% by mass when the component A is 100%. When the iron oxide content exceeds 98 mass%, the durability of the catalyst becomes insufficient. On the other hand, when the iron oxide content is less than 10 mass%, the durability of the catalyst is inadequate. May be sufficient.
Ｂ成分としては、白金、パラジウム、ロジウム、ルテニウム、イリジウム、マンガン、コバルト、ニッケル、銅、錫、セリウム、インジウムおよび亜鉛から選ばれる少なくとも１種の元素および／またはその化合物である。この中でも、白金、パラジウム、イリジウム、ルテニウムおよび銅から選ばれる少なくとも一種の元素の金属および／またはその化合物を用いることが好ましく、更に好ましくは、パラジウムの金属およびその化合物、またはパラジウムと白金および銅から選ばれる少なくとも一種の元素／またはその化合物とを組み合わせて用いることが好ましい。 The component B is at least one element selected from platinum, palladium, rhodium, ruthenium, iridium, manganese, cobalt, nickel, copper, tin, cerium, indium and zinc and / or a compound thereof. Among these, it is preferable to use a metal of at least one element selected from platinum, palladium, iridium, ruthenium and copper and / or a compound thereof, more preferably from a metal of palladium and a compound thereof, or palladium, platinum and copper. It is preferable to use a combination of at least one selected element / or a compound thereof.
本発明の方法においては、固体触媒と還元性物質とを適宜組み合わせることにより効果的に硝酸態窒素の窒素等への湿式還元を行うことができる。好適な組み合わせを以下に示す。
（１）
固体触媒：パラジウムおよび白金から選ばれる少なくとも１種の元素を鉄、チタンおよびジルコニウムから選ばれる少なくとも１種の元素の酸化物に担持してなる固体触媒
還元性物質：ギ酸、ギ酸塩（例えば、ギ酸ナトリウム）、シュウ酸、シュウ酸塩（例えば、シュウ酸ナトリウム）、メタノール、エタノールおよびホルムアルデヒドから選ばれる少なくとも１種
（２）
固体触媒：パラジウムを鉄、チタンおよびジルコニウムから選ばれる少なくとも１種の元素の酸化物に担持してなる固体触媒
還元性物質：ギ酸、ギ酸塩（例えば、ギ酸ナトリウム）、シュウ酸およびシュウ酸塩（例えば、シュウ酸ナトリウム）から選ばれる少なくと１種
（３）
固体触媒：パラジウムを鉄、チタンおよびジルコニウムから選ばれる少なくとも１種の元素の酸化物に担持してなる固体触媒
還元性物質：ギ酸およびギ酸塩（例えば、ギ酸ナトリウム）から選ばれる少なくと１種
（４）
固体触媒：パラジウムおよび白金を鉄、チタンおよびジルコニウムから選ばれる少なくとも１種の元素の酸化物に担持してなる固体触媒
還元性物質：メタノール、エタノールおよびホルムアルデヒドから選ばれる少なくと１種
（５）
固体触媒：パラジウムおよび白金から選ばれる少なくとも１種の元素を活性炭に担持してなる固体触媒
還元性物質：ギ酸、ギ酸塩（例えば、ギ酸ナトリウム）、シュウ酸、シュウ酸塩（例えば、シュウ酸ナトリウム）、メタノール、エタノールおよびホルムアルデヒドから選ばれる少なくとも１種
（６）
固体触媒：パラジウムおよび白金から選ばれる少なくとも１種の元素と銅および鉄から選ばれる少なくとも１種の元素とを活性炭に担持してなる固体触媒
還元性物質：ギ酸、ギ酸塩（例えば、ギ酸ナトリウム）、シュウ酸、シュウ酸塩（例えば、シュウ酸ナトリウム）、メタノール、エタノールおよびホルムアルデヒドから選ばれる少なくとも１種
（７）
固体触媒：パラジウムおよび白金と銅または鉄とを活性炭に担持してなる固体触媒
還元性物質：メタノール、エタノールおよびホルムアルデヒドから選ばれる少なくとも１種
（８）
固体触媒：パラジウムと銅または鉄とを活性炭に担持してなる固体触媒
還元性物質：ギ酸、ギ酸塩（例えば、ギ酸ナトリウム）、シュウ酸およびシュウ酸塩（例えば、シュウ酸ナトリウム）から選ばれる少なくとも１種
（９）
固体触媒：パラジウムと銅または鉄とを活性炭に担持してなる固体触媒
還元性物質：ギ酸およびギ酸塩（例えば、ギ酸ナトリウム）から選ばれる少なくとも１種
（１０）
固体触媒：パラジウムおよびルテニウムを鉄、チタンおよびジルコニウムから選ばれる少なくとも１種の元素の酸化物、または活性炭に担持してなる固体触媒
還元性物質：メタノール、エタノール、ギ酸、ギ酸塩、ホルムアルデヒド、ヒドラジンおよび水素ガスから選ばれる少なくとも１種
（１１）
固体触媒：パラジウムおよびイリジウムを鉄、チタンおよびジルコニウムから選ばれる少なくとも１種の元素の酸化物、または活性炭に担持してなる固体触媒
還元性物質：メタノール、エタノール、ギ酸、ギ酸塩、ホルムアルデヒド、ヒドラジンおよび水素ガスから選ばれる少なくとも１種
（１２）
固体触媒：白金およびルテニウムを鉄、チタンおよびジルコニウムから選ばれる少なくとも１種の元素の酸化物、または活性炭に担持してなる固体触媒
還元性物質：メタノール、エタノール、ギ酸、ギ酸塩、ホルムアルデヒド、ヒドラジンおよび水素ガスから選ばれる少なくとも１種
（１３）
固体触媒：白金およびイリジウムを鉄、チタンおよびジルコニウムから選ばれる少なくとも１種の元素の酸化物、または活性炭に担持してなる固体触媒
還元性物質：メタノール、エタノール、ギ酸、ギ酸塩、ホルムアルデヒド、ヒドラジンおよび水素ガスから選ばれる少なくとも１種
上記の（１）〜（１３）のなかでも、（２）、（４）、（７）および（１２）が好ましい。
In the method of the present invention, wet reduction of nitrate nitrogen to nitrogen or the like can be effectively performed by appropriately combining a solid catalyst and a reducing substance. Suitable combinations are shown below.
(1)
Solid catalyst: Solid catalyst reducing substance formed by supporting at least one element selected from palladium and platinum on an oxide of at least one element selected from iron, titanium and zirconium: formic acid, formate (for example, formic acid Sodium), oxalic acid, oxalate (eg, sodium oxalate), at least one selected from methanol, ethanol and formaldehyde (2)
Solid catalyst: Solid catalyst reducing substance formed by supporting palladium on an oxide of at least one element selected from iron, titanium and zirconium: formic acid, formate (for example, sodium formate), oxalic acid and oxalate ( For example, at least one selected from sodium oxalate (3)
Solid catalyst: Solid catalyst reducing substance formed by supporting palladium on an oxide of at least one element selected from iron, titanium and zirconium: At least one selected from formic acid and formate (for example, sodium formate) ( 4)
Solid catalyst: Palladium and platinum supported on an oxide of at least one element selected from iron, titanium and zirconium. Solid catalyst reducing substance: At least one selected from methanol, ethanol and formaldehyde (5)
Solid catalyst: Solid catalyst reducing substance formed by supporting at least one element selected from palladium and platinum on activated carbon: Formic acid, formate (for example, sodium formate), oxalic acid, oxalate (for example, sodium oxalate) ), At least one selected from methanol, ethanol and formaldehyde (6)
Solid catalyst: At least one element selected from palladium and platinum and at least one element selected from copper and iron supported on activated carbon. Solid catalyst reducing substance: formic acid, formate (for example, sodium formate) , Oxalic acid, oxalate (for example, sodium oxalate), at least one selected from methanol, ethanol and formaldehyde (7)
Solid catalyst: Palladium and platinum and copper or iron supported on activated carbon. Solid catalyst reducing substance: at least one selected from methanol, ethanol and formaldehyde (8)
Solid catalyst: a solid catalyst reducing substance comprising palladium and copper or iron supported on activated carbon: at least selected from formic acid, formate (for example, sodium formate), oxalic acid and oxalate (for example, sodium oxalate) 1 type (9)
Solid catalyst: Solid catalyst reducing substance obtained by supporting palladium and copper or iron on activated carbon: At least one selected from formic acid and formate (for example, sodium formate) (10)
Solid catalyst: Palladium and ruthenium supported on oxide of at least one element selected from iron, titanium and zirconium, or solid catalyst reducing substance: methanol, ethanol, formic acid, formate, formaldehyde, hydrazine and At least one selected from hydrogen gas (11)
Solid catalyst: Palladium and iridium supported on an oxide of at least one element selected from iron, titanium and zirconium, or a solid catalyst reducing substance: methanol, ethanol, formic acid, formate, formaldehyde, hydrazine and At least one selected from hydrogen gas (12)
Solid catalyst: Platinum and ruthenium supported on oxide of at least one element selected from iron, titanium and zirconium, or solid catalyst reducing substance: methanol, ethanol, formic acid, formate, formaldehyde, hydrazine and At least one selected from hydrogen gas (13)
Solid catalyst: Platinum and iridium on an oxide of at least one element selected from iron, titanium and zirconium, or a solid catalyst reducing substance formed by supporting activated carbon: methanol, ethanol, formic acid, formate, formaldehyde, hydrazine and At least one selected from hydrogen gas Among the above (1) to (13), (2), (4), (7) and (12) are preferable.
本発明に係る固体触媒の形状としては、球状、ペレット状、ハニカム状、繊維状、破砕状等種々のものを採用することができる。球状、ペレット状、破砕状の触媒としては、平均粒径が好ましくは０．２〜１０ｍｍ、より好ましくは０．３〜７ｍｍである。平均粒径が０．２ｍｍ未満であると圧力損失が増大する恐れがあり、一方、平均粒径が１０ｍｍよりも大きい場合には十分な幾何学的表面積をとることができず、接触効率が低下して十分な処理能力が得られなくなる恐れがある。なお、本発明における平均粒径の定義は、一定方向に測定して得られる定方向径の平均値とする。 As the shape of the solid catalyst according to the present invention, various shapes such as a spherical shape, a pellet shape, a honeycomb shape, a fiber shape, and a crushed shape can be adopted. As a spherical, pellet-shaped or crushed catalyst, the average particle size is preferably 0.2 to 10 mm, more preferably 0.3 to 7 mm. If the average particle size is less than 0.2 mm, the pressure loss may increase. On the other hand, if the average particle size is larger than 10 mm, sufficient geometric surface area cannot be obtained and the contact efficiency is lowered. As a result, sufficient processing capacity may not be obtained. In addition, the definition of the average particle diameter in this invention is taken as the average value of the fixed direction diameter obtained by measuring in a fixed direction.
ハニカム状触媒の形状としては、貫通孔の相当直径が２〜２０ｍｍ、セル肉厚が０．１〜３ｍｍおよび開孔率が５０〜９０％の範囲が好ましく、貫通孔の相当直径が２．５〜１５ｍｍ、セル肉厚が０．５〜３ｍｍおよび開孔率が５０〜９０％の範囲内にあることがより好ましい。貫通孔の相当直径が２ｍｍ未満である場合には圧力損失が大きくなり、貫通孔の相当直径が２０ｍｍを越える場合には圧力損失が小さくなるが、接触率が低下して触媒活性が低くなる恐れがある。セル肉厚が０．１ｍｍ以下の場合には圧力損失が小さくなり、触媒を軽量化できるという利点があるが、触媒の機械的強度が低下する恐れがあり、セル肉厚が３ｍｍを越える場合には機械的強度は十分であるが、触媒の有効接触面積が触媒量に対して小さくなってしまい、触媒量に応じた活性を期待することができない。開孔率についても上記と同様な理由から５０〜９０％が好ましい。 As the shape of the honeycomb-shaped catalyst, it is preferable that the equivalent diameter of the through holes is 2 to 20 mm, the cell thickness is 0.1 to 3 mm, and the open area ratio is 50 to 90%, and the equivalent diameter of the through holes is 2.5. More preferably, the thickness is ˜15 mm, the cell thickness is 0.5 to 3 mm, and the open area ratio is 50 to 90%. When the equivalent diameter of the through hole is less than 2 mm, the pressure loss increases, and when the equivalent diameter of the through hole exceeds 20 mm, the pressure loss decreases, but the contact rate may decrease and the catalytic activity may decrease. There is. When the cell thickness is 0.1 mm or less, there is an advantage that the pressure loss is reduced and the weight of the catalyst can be reduced. However, there is a possibility that the mechanical strength of the catalyst may be lowered, and when the cell thickness exceeds 3 mm. Although the mechanical strength is sufficient, the effective contact area of the catalyst becomes smaller than the amount of the catalyst, and the activity corresponding to the amount of the catalyst cannot be expected. The porosity is preferably 50 to 90% for the same reason as described above.
本発明に係る固体触媒のＢＥＴ法比表面積は、触媒成分として活性炭以外の物質を用いる場合は、好ましくは５〜２００ｍ２／ｇ、より好ましくは１０〜１００ｍ２／ｇである。５ｍ２／ｇ未満の場合には硝酸態窒素および還元剤と触媒との接触効率が低下し、触媒活性が低下する。更に、触媒成分として活性炭を用いる場合は、好ましくは１００〜５,０００ｍ２／ｇ、より好ましくは５００〜２,０００ｍ２／ｇである。１００ｍ２／ｇ未満の場合には硝酸態窒素および還元剤と触媒との接触効率が低下し、触媒活性が低下する。 The BET specific surface area of the solid catalyst according to the present invention is preferably 5 to 200 m 2 / g, more preferably 10 to 100 m 2 / g when a substance other than activated carbon is used as the catalyst component. In the case of less than 5 m 2 / g, the contact efficiency between the nitrate nitrogen and the reducing agent and the catalyst is lowered, and the catalytic activity is lowered. Furthermore, in the case of using activated carbon as a catalyst component, preferably 100~5,000m 2 / g, more preferably 500~2,000m 2 / g. When it is less than 100 m 2 / g, the contact efficiency between the nitrate nitrogen and the reducing agent and the catalyst is lowered, and the catalytic activity is lowered.
本発明に係る固体触媒は、種々の触媒調製方法により作成することができ、特に限定されるものではないが、Ｂ成分の溶液をＡ成分からなるペレットに含浸することや、Ｂ成分の溶液をＡ成分からなる粉体と混練することによっても得ることができる。Ａ成分のペレットは、各成分を共沈することにより得た粉体を成型することや、各成分を混練し、成型すること等により得ることができる。 The solid catalyst according to the present invention can be prepared by various catalyst preparation methods, and is not particularly limited. However, impregnation of the B component solution into pellets composed of the A component, It can also be obtained by kneading with a powder comprising the component A. The pellet of component A can be obtained by molding powder obtained by coprecipitation of each component, kneading and molding each component, or the like.
本発明に係る排水処理時の温度は、１０℃以上１００℃未満である。さらに好ましくは、５０℃以上９８℃未満である。排水処理時の温度が１０℃未満の場合は、処理効率が不十分となり、一方、１００℃を超えると還元性物質が熱により分解され、硝酸態窒素の還元に還元性物質が有効に使用できなくなる。 The temperature at the time of waste water treatment according to the present invention is 10 ° C. or more and less than 100 ° C. More preferably, it is 50 degreeC or more and less than 98 degreeC. When the temperature during wastewater treatment is less than 10 ° C, the treatment efficiency becomes insufficient. On the other hand, when the temperature exceeds 100 ° C, the reducing substance is decomposed by heat, and the reducing substance can be used effectively for the reduction of nitrate nitrogen. Disappear.
本発明に係わる排水処理時の圧力は、常圧下でも十分反応させることができるが、１ＭＰａＧ（ゲージ）未満で反応すればよい。また、さらに好ましくは０．５ＭＰａＧ未満、より好ましくは０．２ＭＰａＧ未満である。１ＭＰａＧ以上では還元性物質が硝酸態窒素の還元反応に有効に使用できなくなるだけではなく、装置コストも高くなるため好ましくない。 The pressure at the time of wastewater treatment according to the present invention can be sufficiently reacted even under normal pressure, but may be reacted at less than 1 MPaG (gauge). Further, it is more preferably less than 0.5 MPaG, more preferably less than 0.2 MPaG. If it is 1 MPaG or more, it is not preferable because the reducing substance cannot be effectively used for the reduction reaction of nitrate nitrogen, and the cost of the apparatus increases.
本発明における湿式還元処理は、実質的に酸素の非供給下で反応してもよいが、酸素が供給された条件で実施してもよい。これまでの１００℃以上、液相を保持する圧力下の反応では、酸素存在下にて、還元性物質が完全酸化してしまうことが多く、還元性物質が硝酸態窒素の還元に使用されないことがあった。しかしながら、本発明のような温和な反応条件下では、例えば、メタノール、ホルムアルデヒド等は、酸化により中間生成物としてギ酸が生成することがあるため、酸素供給下においても還元処理を実施することが可能である。 The wet reduction treatment in the present invention may be carried out under substantially no supply of oxygen, but may be carried out under conditions in which oxygen is supplied. In the reaction under the pressure that maintains the liquid phase at 100 ° C. or higher, the reducing substance is often completely oxidized in the presence of oxygen, and the reducing substance is not used for the reduction of nitrate nitrogen. was there. However, under mild reaction conditions as in the present invention, for example, methanol, formaldehyde, and the like may form formic acid as an intermediate product by oxidation, so that reduction treatment can be performed even under oxygen supply. It is.
本発明における液の流通形式については、触媒層に対して上向流、下向流のいずれで流しても構わないが、触媒と液との接触時間を長くするためには、上向流で反応させることが好ましい。一方、気液を触媒層に通過させる場合においては、上向流、下向流のいずれで通過させてもよい。なお、常圧下で反応させる場合、液または気液を触媒層へ供給させるためには、少なくとも触媒層での圧損以上に加圧する必要はある。ただし、排水の処理が進行する反応場全体を高度に加圧する必要はない。すなわち、従来の排水処理技術では、反応場の出口に圧力制御弁等を設けて反応場全体を加圧していた。これに対し、本発明方法では、高度な加圧装置は必要でなく、反応場（図１の例でいえば「反応塔」）の出口を開放系で排水処理することができる。つまり、本発明に係る排水の処理方法における常圧とは、液および気液を反応場へ導入される前にかけられた圧力の影響による当該圧力の僅かな上昇も、常圧の範囲に含まれるものとする。 Regarding the flow mode of the liquid in the present invention, it may flow either upward or downward with respect to the catalyst layer, but in order to increase the contact time between the catalyst and the liquid, It is preferable to react. On the other hand, when the gas and liquid are passed through the catalyst layer, they may be passed either upward or downward. In addition, when making it react under a normal pressure, in order to supply a liquid or a gas-liquid to a catalyst layer, it is necessary to pressurize more than the pressure loss in a catalyst layer at least. However, it is not necessary to highly pressurize the entire reaction field where wastewater treatment proceeds. That is, in the conventional wastewater treatment technology, a pressure control valve or the like is provided at the outlet of the reaction field to pressurize the entire reaction field. On the other hand, in the method of the present invention, an advanced pressurizing apparatus is not required, and the outlet of the reaction field (“reaction tower” in the example of FIG. 1) can be drained in an open system. That is, the normal pressure in the wastewater treatment method according to the present invention includes a slight increase in the pressure due to the pressure applied before the liquid and gas-liquid are introduced into the reaction field. Shall.
本発明において使用する反応塔は、単管式または多管式のいずれの形式であってもよく、特に限定されるものではない。また、反応塔の設置方法については、１つの反応塔のみで反応してもよいし、直列に設置して連続的に処理してもよい。直列に設置した場合、一度処理した後の液に、更に、還元性物質を添加し後段の反応塔で処理させることも可能である。 The reaction column used in the present invention may be either a single tube type or a multi-tube type, and is not particularly limited. Moreover, about the installation method of a reaction tower, you may react by only one reaction tower, may install in series and may process continuously. When installed in series, it is also possible to add a reducing substance to the liquid after the treatment once and to treat it in the reaction tower at the subsequent stage.
本発明においては、還元処理後、アンモニア等が生成する。なお、生成したアンモニアを更に処理する必要がある場合、例えばストリッピング法、触媒を用いた湿式酸化法等により適宜処理することが可能である。例えば、ストリッピング法を用いる場合には、還元処理水中のアンモニア態窒素を加熱ガス等により気化させた後、触媒を用いて接触気相酸化分解により窒素等に分解することもできるほか、気化させたアンモニア態窒素含有ガスからアンモニアのみを分離回収することもできる。また、その他のアンモニア態窒素の処理方法としては、アンモニア態窒素を湿式酸化処理により窒素、水に分解することもできる。なお、これらの方法のうち、いずれの方法を採用するかは設備の設置条件、全窒素の処理目標値、還元処理水中のアンモニア態窒素濃度等を考慮し適宜決定することができる。 In the present invention, ammonia or the like is generated after the reduction treatment. In addition, when it is necessary to further process the produced ammonia, it can be appropriately processed by, for example, a stripping method, a wet oxidation method using a catalyst, or the like. For example, when the stripping method is used, ammonia nitrogen in the reduction water can be vaporized with a heated gas, etc., and then decomposed into nitrogen etc. by catalytic vapor phase oxidation decomposition using a catalyst. In addition, only ammonia can be separated and recovered from the ammonia nitrogen-containing gas. As another method for treating ammonia nitrogen, ammonia nitrogen can be decomposed into nitrogen and water by wet oxidation. Of these methods, which method is adopted can be appropriately determined in consideration of the installation conditions of the equipment, the treatment target value of total nitrogen, the concentration of ammonia nitrogen in the reduction treated water, and the like.
以下、本発明の具体的な実施例にかかる触媒の調製例と、それらの触媒を用いた実施例を詳細に説明するが、本発明はこれらに限定されるものではない。
（触媒１）
硫酸チタニルの硫酸水溶液および硝酸第２鉄を水に溶解させ、この溶液に炭酸ナトリウムを加えてｐＨを９とし、生成した沈澱物をろ過洗浄した。得られたケーキを１５０℃で一晩乾燥させ、さらに４５０℃で焼成した。得られた固形物はチタンおよび鉄を含む粉体で、ＴｉＯ2とＦｅ2Ｏ3との質量比に換算すると、蛍光Ｘ線法による分析でＴｉＯ2：Ｆｅ2Ｏ3＝２０：８０であった。
Hereinafter, although the preparation example of the catalyst concerning the specific Example of this invention and the Example using those catalysts are demonstrated in detail, this invention is not limited to these.
(Catalyst 1)
A sulfuric acid aqueous solution of titanyl sulfate and ferric nitrate were dissolved in water, sodium carbonate was added to this solution to adjust the pH to 9, and the resulting precipitate was washed by filtration. The obtained cake was dried at 150 ° C. overnight and further baked at 450 ° C. The obtained solid was a powder containing titanium and iron. When converted to a mass ratio of TiO 2 and Fe 2 O 3 , the analysis by the fluorescent X-ray method showed TiO 2 : Fe 2 O 3 = 20: 80. It was.
かくして得られた粉体にデンプンを加え、さらに粉体１ｋｇに対しパラジウムが１質量％になるように硝酸パラジウム水溶液を加え、よく混合した後、平均粒径４ｍｍ、平均長さ５ｍｍのペレット状に成型した。その後、１２０℃で１０時間乾燥、４５０℃で３時間焼成後、４００℃で２時間水素還元を実施し、完成触媒を得た。
（触媒２）
触媒１で調整したＴｉＯ2：Ｆｅ2Ｏ3＝２０：８０からなる焼成後の粉体に、デンプンを加えた、さらに粉体１ｋｇに対し白金が１質量％になるように、ジニトロジアンミン硝酸白金水溶液を加え、よく混合した後、平均粒径４ｍｍ、平均長さ５ｍｍのペレット状に成形した。その後、１２０℃で１０時間乾燥、４５０℃で３時間焼成後、４００℃で２時間水素還元を実施し、完成触媒を得た。
（触媒３）
触媒１で調整したＴｉＯ2：Ｆｅ2Ｏ3＝２０：８０からなる焼成後の粉体に、デンプンを加えた、さらに粉体１ｋｇに対し白金が０．５質量％、パラジウムが０．７５質量％になるように、ジニトロジアンミン硝酸白金水溶液および硝酸パラジウム水溶液を加え、よく混合した後、平均粒径４ｍｍ、平均長さ５ｍｍのペレット状に成形した。その後、１２０℃で１０時間乾燥、４５０℃で３時間焼成後、４００℃で２時間水素還元を実施し、完成触媒を得た。
（触媒４）
硝酸ジルコニルおよび硝酸第２鉄を水に溶解し、この溶液に炭酸ナトリウム水溶液を加えてｐＨを９とし、生成した沈澱物をろ過洗浄した。得られたケーキを１２０℃で一晩乾燥させ、さらに５００℃で焼成した。得られた固形物はジルコニウムおよび鉄を含む粉体で、ＺｒＯ2とＦｅ2Ｏ3との質量比に換算すると、蛍光Ｘ線法による分析ではＺｒＯ2：Ｆｅ2Ｏ3＝３０：７０であった。
Starch is added to the powder thus obtained, and an aqueous palladium nitrate solution is added so that palladium is 1% by mass with respect to 1 kg of the powder. After mixing well, pellets having an average particle diameter of 4 mm and an average length of 5 mm are formed. Molded. Then, after drying at 120 ° C. for 10 hours and calcining at 450 ° C. for 3 hours, hydrogen reduction was carried out at 400 ° C. for 2 hours to obtain a finished catalyst.
(Catalyst 2)
Starch is added to the calcined powder composed of TiO 2 : Fe 2 O 3 = 20: 80 prepared with
(Catalyst 3)
Starch was added to the baked powder consisting of TiO 2 : Fe 2 O 3 = 20: 80 prepared with
(Catalyst 4)
Zirconyl nitrate and ferric nitrate were dissolved in water, an aqueous sodium carbonate solution was added to this solution to adjust the pH to 9, and the resulting precipitate was washed by filtration. The obtained cake was dried at 120 ° C. overnight and further baked at 500 ° C. The obtained solid was a powder containing zirconium and iron. When converted to a mass ratio of ZrO 2 and Fe 2 O 3 , ZrO 2 : Fe 2 O 3 = 30: 70 was found by analysis by the fluorescent X-ray method. It was.
得られた粉体にデンプンを加え、よく混合した後、平均粒径３ｍｍ、平均長さ４ｍｍのペレット状に成型し、１２０℃で１０時間乾燥後、４５０℃で４時間焼成した。 Starch was added to the obtained powder and mixed well, then formed into pellets having an average particle size of 3 mm and an average length of 4 mm, dried at 120 ° C. for 10 hours, and then fired at 450 ° C. for 4 hours.
得られたペレットに、ルテニウムが３質量％となるように硝酸ルテニウム水溶液を含浸し、１５０℃で１０時間乾燥させた。その後、３００℃で４時間焼成し、４００℃で２時間水素還元処理を実施し、完成触媒を得た。
（触媒５）
触媒４で調製したＺｒＯ2：Ｆｅ2Ｏ3からなるペレットに、イリジウムが３質量％、白金が２質量％となるように塩化イリジウム溶液およびジニトロジアンミン白金溶液を同時に含浸し、１２０℃で１０時間乾燥させた。その後、３００℃で４時間焼成し、４００℃で２時間水素還元処理を実施し、完成触媒を得た。
（触媒６）
平均粒径４ｍｍ、平均長さ６ｍｍのペレット状のジルコニアに、金が２質量％になるように塩化金酸水溶液を含浸した。１２０℃で１０時間乾燥後、３００℃で４時間焼成し、完成触媒を得た。
（触媒７）
粒度が１０〜３２メッシュの破砕状の活性炭に、パラジウムが０．５質量％になるように硝酸パラジウム水溶液を含浸した。次に、窒素雰囲気下において３００℃で４時間焼成し、その後４００℃で２時間水素還元処理を実施し、完成触媒を得た。
（触媒８）
触媒７で使用した粒度が１０〜３２メッシュの破砕状の活性炭に、ルテニウムで１．０質量％になるように硝酸ルテニウム水溶液を含浸した。次に、窒素雰囲気下において３００℃で４時間焼成し、その後４００℃で２時間水素還元処理を実施し、完成触媒を得た。
（触媒９）
粒度が１０〜３２メッシュの破砕状の活性炭に、パラジウムが０．５質量％、銅が１質量％になるように、硝酸パラジウム水溶液および硝酸銅水溶液を含浸した。次に、窒素雰囲気下において３００℃で４時間焼成し、その後４００℃で２時間水素還元処理を実施し、完成触媒を得た。
（触媒１０）
平均粒径４ｍｍ、平均長さ５ｍｍの粒状活性炭に、白金が１質量％になるように、ヘキサアンミン白金テトラクロライド水溶液を含浸した。１００℃で１晩乾燥後、窒素雰囲気下、５００℃で２時間焼成し、その後、５００℃で２時間水素還元処理を実施し、完成触媒を得た。
（触媒１１）
平均粒径４ｍｍ、平均長さ５ｍｍの粒状活性炭に、白金が０．５質量％、パラジウムが１質量％、銅が１質量％になるように、ジニトロジアンミン白金水溶液、硝酸パラジウム水溶液および硝酸銅水溶液を含浸した。１００℃で１晩乾燥後、窒素雰囲気下、５００℃で２時間焼成し、その後、５００℃で２時間水素還元処理を実施し、完成触媒を得た。
（触媒１２〜１５）
触媒１に準じた方法により下記成分を含有する触媒を調製した。
The obtained pellets were impregnated with an aqueous ruthenium nitrate solution so that the content of ruthenium was 3% by mass, and dried at 150 ° C. for 10 hours. Then, it baked at 300 degreeC for 4 hours, and implemented hydrogen reduction process at 400 degreeC for 2 hours, and obtained the completed catalyst.
(Catalyst 5)
The pellet made of ZrO 2 : Fe 2 O 3 prepared with catalyst 4 was impregnated with an iridium chloride solution and a dinitrodiammine platinum solution so that iridium was 3% by mass and platinum was 2% by mass, and the resulting mixture was 120 ° C. for 10 hours. Dried. Then, it baked at 300 degreeC for 4 hours, and implemented hydrogen reduction process at 400 degreeC for 2 hours, and obtained the completed catalyst.
(Catalyst 6)
A pelleted zirconia having an average particle diameter of 4 mm and an average length of 6 mm was impregnated with an aqueous chloroauric acid solution so that the gold content was 2 mass%. After drying at 120 ° C. for 10 hours and calcining at 300 ° C. for 4 hours, a finished catalyst was obtained.
(Catalyst 7)
A pulverized activated carbon having a particle size of 10 to 32 mesh was impregnated with an aqueous palladium nitrate solution so that the palladium content was 0.5 mass%. Next, it was calcined at 300 ° C. for 4 hours in a nitrogen atmosphere, and then subjected to hydrogen reduction treatment at 400 ° C. for 2 hours to obtain a finished catalyst.
(Catalyst 8)
Crushed activated carbon having a particle size of 10 to 32 mesh used in Catalyst 7 was impregnated with ruthenium nitrate aqueous solution so as to be 1.0% by mass with ruthenium. Next, it was calcined at 300 ° C. for 4 hours in a nitrogen atmosphere, and then subjected to hydrogen reduction treatment at 400 ° C. for 2 hours to obtain a finished catalyst.
(Catalyst 9)
A pulverized activated carbon having a particle size of 10 to 32 mesh was impregnated with an aqueous palladium nitrate solution and an aqueous copper nitrate solution so that palladium was 0.5 mass% and copper was 1 mass%. Next, it was calcined at 300 ° C. for 4 hours in a nitrogen atmosphere, and then subjected to hydrogen reduction treatment at 400 ° C. for 2 hours to obtain a finished catalyst.
(Catalyst 10)
A granular activated carbon having an average particle diameter of 4 mm and an average length of 5 mm was impregnated with an aqueous hexaammine platinum tetrachloride solution so that platinum was 1% by mass. After drying at 100 ° C. overnight, it was calcined at 500 ° C. for 2 hours in a nitrogen atmosphere, and then subjected to hydrogen reduction treatment at 500 ° C. for 2 hours to obtain a finished catalyst.
(Catalyst 11)
Dinitrodiammine platinum aqueous solution, palladium nitrate aqueous solution and copper nitrate aqueous solution so that the granular activated carbon having an average particle diameter of 4 mm and an average length of 5 mm has a platinum content of 0.5 mass%, a palladium content of 1 mass% and a copper content of 1 mass%. Impregnated. After drying at 100 ° C. overnight, it was calcined at 500 ° C. for 2 hours in a nitrogen atmosphere, and then subjected to hydrogen reduction treatment at 500 ° C. for 2 hours to obtain a finished catalyst.
(Catalysts 12-15)
A catalyst containing the following components was prepared by a method according to
実施例１〜６
図１に示す湿式還元処理装置により、硝酸態窒素を含む排水として硝酸アンモニウム１質量％の排水を以下のような方法で処理した。排水タンク１中で、還元性物質としてギ酸ソーダを表１に示す規定比になるように排水に添加した。還元性物質添加後の排水を排水用定量ポンプ２を用いて、液空間速度（触媒容積基準）０．５ｈｒ−１で装置内に供給した。排水を熱交換器３で予熱後、表２に示す触媒１０リットルを充填した反応塔４へ導入した。反応塔中の排水をヒーターによりさらに加熱し、９０℃となるように温度に保ち、反応塔を通過した処理水を熱交換器３により冷却した。系内の圧力は常圧となるようにした。
Examples 1-6
With the wet reduction treatment apparatus shown in FIG. 1, wastewater containing 1% by mass of ammonium nitrate was treated by the following method as wastewater containing nitrate nitrogen. In the
得られた処理水の硝酸態窒素（ＮＯ３ −−Ｎ）、アンモニア態窒素（ＮＨ４ ＋−Ｎ）および全窒素の濃度を求め、硝酸態窒素除去率および窒素ガスへの選択率を下記式に従って求めた。
硝酸態窒素除去率（％）＝（処理前の排水中の硝酸態窒素濃度−処理水の硝酸態窒素濃度）／（処理前の排水中の硝酸態窒素濃度）（×１００）
窒素ガスへの選択率（％）＝［１−｛（処理水の全窒素濃度−処理水の硝酸態窒素濃度）／（処理前の排水中の硝酸態窒素濃度−処理水の硝酸態窒素濃度）｝］×１００
実施例７〜９
表２に示す触媒を使用し、硝酸ナトリウム２質量％を含有する排水を処理した。実施例１に準じた方法にて、表２の条件で処理テストを実施した。
実施例１０〜１５
表２に示す触媒を使用し、還元性物質として実施例１のギ酸ソーダの代わりに、メタノールを使用した。実施例１と同様の処理装置を用いて、常圧、反応温度９０℃の条件で、表２に示すＬＨＳＶ、規定比で処理を実施した。得られた処理水の硝酸態窒素（ＮＯ３ −−Ｎ）、アンモニア態窒素（ＮＨ４ ＋−Ｎ）および全窒素の濃度を求め、硝酸態窒素除去率および窒素ガスへの選択率を求めた。結果を表２に示す。
実施例１６
硝酸ナトリウム２質量％の排水を、触媒１を使用して、還元性物質としてホルムアルデヒドを規定比２．０になる量で排水に添加し、ＬＨＳＶ ０．５ｈｒ−１で処理した以外は実施例１と同様の装置、同様の条件にて処理を行った。得られた処理水の硝酸態の除去率および窒素ガスへの選択率を表２に示す。
実施例１７、１８
硝酸ナトリウム質量％の排水を、還元性物質としてメタノールを規定比３．０になる量で排水に添加した。液の供給量がＬＨＳＶ０．５ｈｒ−１となるようにして反応塔の上部より供給し、常圧の条件下、反応温度は９０℃の条件下、触媒１（実施例１７）または触媒３（実施例１８）を使用して湿式還元を実施した。得られた処理水の硝酸態窒素（ＮＯ３ −−Ｎ）、アンモニア態窒素（ＮＨ４ ＋−Ｎ）および全窒素の濃度を求め、硝酸態窒素除去率および窒素ガスへの選択率を求めた。結果を表２に示す。
比較例１
触媒を用いなかった以外は、実施例１と同様の条件で処理を行った。硝酸態窒素の除去率は３％であり、触媒を使用したときと比較して、硝酸態窒素は除去されなかった。結果を表２に示す。
比較例２
還元性物質を添加しなかった以外は実施例１と同様の条件で処理を行った。そのときの硝酸態窒素の除去率は５％であった。結果を表２に示す。
比較例３
実施例１と同じ触媒、還元性物質を使用し２５０℃、７ＭＰａＧの条件下に表２に示すＬＨＳＶ、規定比で処理を行った。９０℃のときと比較して硝酸態窒素除去率は低下した。
The concentration of nitrate nitrogen (NO 3 − —N), ammonia nitrogen (NH 4 + —N) and total nitrogen obtained in the treated water was determined, and the nitrate nitrogen removal rate and the selectivity to nitrogen gas were expressed by the following formula: Sought according to.
Nitrate nitrogen removal rate (%) = (nitrate nitrogen concentration in waste water before treatment−nitrate nitrogen concentration in treated water) / (nitrate nitrogen concentration in waste water before treatment) (× 100)
Selectivity to nitrogen gas (%) = [1-{(total nitrogen concentration of treated water−nitrate nitrogen concentration of treated water) / (nitrate nitrogen concentration in waste water before treatment−nitrate nitrogen concentration of treated water) )}] × 100
Examples 7-9
Using the catalyst shown in Table 2, wastewater containing 2% by mass of sodium nitrate was treated. A processing test was performed under the conditions shown in Table 2 by the method according to Example 1.
Examples 10-15
The catalysts shown in Table 2 were used, and methanol was used in place of the sodium formate of Example 1 as the reducing substance. Using the same processing apparatus as in Example 1, the treatment was carried out under the conditions of normal pressure and reaction temperature of 90 ° C., with LHSV and specified ratio shown in Table 2. The obtained treated water of nitrate nitrogen (NO 3 - -N), determine the concentration of ammonia nitrogen (NH 4 + -N) and total nitrogen were determined selectivity to nitrate nitrogen removal ratio and a nitrogen gas . The results are shown in Table 2.
Example 16
Example 1 except that wastewater containing 2% by mass of sodium nitrate was added to the wastewater in an amount to give a specified ratio of 2.0 as a reducing substance using the
Examples 17 and 18
The waste water of sodium nitrate mass% was added to the waste water in an amount of methanol as the reducible substance to a specified ratio of 3.0. The liquid was supplied from the top of the reaction column so that the amount of LHSV was 0.5 hr −1, and the catalyst 1 (Example 17) or the catalyst 3 (implementation) was performed under conditions of normal pressure and reaction temperature of 90 ° C. Wet reduction was carried out using Example 18). The obtained treated water of nitrate nitrogen (NO 3 - -N), determine the concentration of ammonia nitrogen (NH 4 + -N) and total nitrogen were determined selectivity to nitrate nitrogen removal ratio and a nitrogen gas . The results are shown in Table 2.
Comparative Example 1
The treatment was performed under the same conditions as in Example 1 except that the catalyst was not used. The removal rate of nitrate nitrogen was 3%, and nitrate nitrogen was not removed as compared with the case of using a catalyst. The results are shown in Table 2.
Comparative Example 2
The treatment was performed under the same conditions as in Example 1 except that no reducing substance was added. The removal rate of nitrate nitrogen at that time was 5%. The results are shown in Table 2.
Comparative Example 3
The same catalyst and reducing substance as in Example 1 were used, and the treatment was carried out under the conditions of 250 ° C. and 7 MPaG with the LHSV and specified ratio shown in Table 2. Compared with the case of 90 ° C., the nitrate nitrogen removal rate decreased.
表２において、Ｔｉ−Ｆｅ、Ｆｅ−Ｚｒとは、それぞれ、チタンと鉄との酸化物および鉄とジルコニウムとの酸化物を意味する。 In Table 2, Ti-Fe and Fe-Zr mean an oxide of titanium and iron and an oxide of iron and zirconium, respectively.
１．排水タンク
２．排水用定量ポンプ
３．熱交換器
４．反応塔
1.
Claims (4)
As the solid catalyst, a solid catalyst obtained by supporting at least one element selected from palladium and platinum and at least one element selected from copper and iron on activated carbon, and as a reducing substance, formic acid, formate, The method for purifying nitrate nitrogen-containing wastewater according to claim 2, wherein at least one selected from oxalic acid, oxalate, methanol, ethanol and formaldehyde is used.
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Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2008023522A (en) * | 2006-06-20 | 2008-02-07 | Jgc Corp | Method and apparatus for treating aqueous solution of sodium nitrate |
| JP2009183902A (en) * | 2008-02-07 | 2009-08-20 | Sud-Chemie Catalysts Inc | Treatment method of nitrate nitrogen-containing water |
| JP2010149050A (en) * | 2008-12-25 | 2010-07-08 | Sud-Chemie Catalysts Inc | Solid catalyst for treating nitrate nitrogen-containing water and method of treating nitrate nitrogen-containing water using the catalyst |
| JP2013170983A (en) * | 2012-02-22 | 2013-09-02 | Japan Atomic Energy Agency | Nitrogen ion reduction method |
| CN118892828A (en) * | 2024-07-17 | 2024-11-05 | 华中师范大学 | A catalytic reaction filter membrane and its preparation method and application |
-
2003
- 2003-09-25 JP JP2003333281A patent/JP2005095784A/en active Pending
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2008023522A (en) * | 2006-06-20 | 2008-02-07 | Jgc Corp | Method and apparatus for treating aqueous solution of sodium nitrate |
| JP2009183902A (en) * | 2008-02-07 | 2009-08-20 | Sud-Chemie Catalysts Inc | Treatment method of nitrate nitrogen-containing water |
| JP2010149050A (en) * | 2008-12-25 | 2010-07-08 | Sud-Chemie Catalysts Inc | Solid catalyst for treating nitrate nitrogen-containing water and method of treating nitrate nitrogen-containing water using the catalyst |
| JP2013170983A (en) * | 2012-02-22 | 2013-09-02 | Japan Atomic Energy Agency | Nitrogen ion reduction method |
| CN118892828A (en) * | 2024-07-17 | 2024-11-05 | 华中师范大学 | A catalytic reaction filter membrane and its preparation method and application |
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