JP2004130268A - Iron/manganese removing filter medium and its manufacturing method - Google Patents
Iron/manganese removing filter medium and its manufacturing method Download PDFInfo
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- JP2004130268A JP2004130268A JP2002299643A JP2002299643A JP2004130268A JP 2004130268 A JP2004130268 A JP 2004130268A JP 2002299643 A JP2002299643 A JP 2002299643A JP 2002299643 A JP2002299643 A JP 2002299643A JP 2004130268 A JP2004130268 A JP 2004130268A
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- manganese
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- manganese dioxide
- iron
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- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 title claims abstract description 114
- 239000011572 manganese Substances 0.000 title claims abstract description 58
- PWHULOQIROXLJO-UHFFFAOYSA-N Manganese Chemical compound [Mn] PWHULOQIROXLJO-UHFFFAOYSA-N 0.000 title claims abstract description 55
- 229910052748 manganese Inorganic materials 0.000 title claims abstract description 55
- 229910052742 iron Inorganic materials 0.000 title claims abstract description 52
- 238000004519 manufacturing process Methods 0.000 title claims description 13
- NUJOXMJBOLGQSY-UHFFFAOYSA-N manganese dioxide Chemical compound O=[Mn]=O NUJOXMJBOLGQSY-UHFFFAOYSA-N 0.000 claims abstract description 150
- 239000011148 porous material Substances 0.000 claims abstract description 109
- 230000005484 gravity Effects 0.000 claims abstract description 14
- 239000000463 material Substances 0.000 claims abstract description 9
- MIVBAHRSNUNMPP-UHFFFAOYSA-N manganese(2+);dinitrate Chemical compound [Mn+2].[O-][N+]([O-])=O.[O-][N+]([O-])=O MIVBAHRSNUNMPP-UHFFFAOYSA-N 0.000 claims description 29
- 239000012286 potassium permanganate Substances 0.000 claims description 15
- 239000002245 particle Substances 0.000 claims description 11
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 abstract description 44
- 230000003647 oxidation Effects 0.000 abstract description 12
- 238000007254 oxidation reaction Methods 0.000 abstract description 12
- 239000003054 catalyst Substances 0.000 abstract description 8
- 229910052785 arsenic Inorganic materials 0.000 abstract description 7
- RQNWIZPPADIBDY-UHFFFAOYSA-N arsenic atom Chemical compound [As] RQNWIZPPADIBDY-UHFFFAOYSA-N 0.000 abstract description 7
- 239000002663 humin Substances 0.000 abstract description 6
- 230000003197 catalytic effect Effects 0.000 abstract description 4
- 230000002093 peripheral effect Effects 0.000 abstract 1
- 238000001914 filtration Methods 0.000 description 28
- 239000007864 aqueous solution Substances 0.000 description 18
- 238000011001 backwashing Methods 0.000 description 14
- 150000002696 manganese Chemical class 0.000 description 13
- 230000007423 decrease Effects 0.000 description 8
- 239000007800 oxidant agent Substances 0.000 description 8
- 238000004140 cleaning Methods 0.000 description 7
- 238000000034 method Methods 0.000 description 7
- ZAMOUSCENKQFHK-UHFFFAOYSA-N Chlorine atom Chemical compound [Cl] ZAMOUSCENKQFHK-UHFFFAOYSA-N 0.000 description 6
- 229910021380 Manganese Chloride Inorganic materials 0.000 description 6
- GLFNIEUTAYBVOC-UHFFFAOYSA-L Manganese chloride Chemical compound Cl[Mn]Cl GLFNIEUTAYBVOC-UHFFFAOYSA-L 0.000 description 6
- 239000005708 Sodium hypochlorite Substances 0.000 description 6
- 239000000460 chlorine Substances 0.000 description 6
- 229910052801 chlorine Inorganic materials 0.000 description 6
- 230000000052 comparative effect Effects 0.000 description 6
- 239000003621 irrigation water Substances 0.000 description 6
- 239000011565 manganese chloride Substances 0.000 description 6
- 235000002867 manganese chloride Nutrition 0.000 description 6
- 229940099607 manganese chloride Drugs 0.000 description 6
- SUKJFIGYRHOWBL-UHFFFAOYSA-N sodium hypochlorite Chemical compound [Na+].Cl[O-] SUKJFIGYRHOWBL-UHFFFAOYSA-N 0.000 description 6
- 239000000243 solution Substances 0.000 description 6
- 239000000126 substance Substances 0.000 description 6
- 239000003795 chemical substances by application Substances 0.000 description 5
- 238000011156 evaluation Methods 0.000 description 5
- 238000005470 impregnation Methods 0.000 description 5
- 238000002156 mixing Methods 0.000 description 5
- 230000000694 effects Effects 0.000 description 4
- UQSXHKLRYXJYBZ-UHFFFAOYSA-N iron oxide Inorganic materials [Fe]=O UQSXHKLRYXJYBZ-UHFFFAOYSA-N 0.000 description 4
- AMWRITDGCCNYAT-UHFFFAOYSA-L manganese oxide Inorganic materials [Mn].O[Mn]=O.O[Mn]=O AMWRITDGCCNYAT-UHFFFAOYSA-L 0.000 description 4
- PPNAOCWZXJOHFK-UHFFFAOYSA-N manganese(2+);oxygen(2-) Chemical class [O-2].[Mn+2] PPNAOCWZXJOHFK-UHFFFAOYSA-N 0.000 description 4
- SQQMAOCOWKFBNP-UHFFFAOYSA-L manganese(II) sulfate Chemical compound [Mn+2].[O-]S([O-])(=O)=O SQQMAOCOWKFBNP-UHFFFAOYSA-L 0.000 description 4
- 239000012466 permeate Substances 0.000 description 4
- 230000008569 process Effects 0.000 description 4
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 description 3
- 238000001994 activation Methods 0.000 description 3
- 238000004458 analytical method Methods 0.000 description 3
- 238000010438 heat treatment Methods 0.000 description 3
- 230000001590 oxidative effect Effects 0.000 description 3
- 239000008262 pumice Substances 0.000 description 3
- 238000005406 washing Methods 0.000 description 3
- 238000002441 X-ray diffraction Methods 0.000 description 2
- 229910021536 Zeolite Inorganic materials 0.000 description 2
- 230000004913 activation Effects 0.000 description 2
- 230000008859 change Effects 0.000 description 2
- 238000006243 chemical reaction Methods 0.000 description 2
- 230000003247 decreasing effect Effects 0.000 description 2
- 238000000151 deposition Methods 0.000 description 2
- 238000010586 diagram Methods 0.000 description 2
- HNPSIPDUKPIQMN-UHFFFAOYSA-N dioxosilane;oxo(oxoalumanyloxy)alumane Chemical compound O=[Si]=O.O=[Al]O[Al]=O HNPSIPDUKPIQMN-UHFFFAOYSA-N 0.000 description 2
- 238000001035 drying Methods 0.000 description 2
- 238000011049 filling Methods 0.000 description 2
- 238000011068 loading method Methods 0.000 description 2
- 230000007774 longterm Effects 0.000 description 2
- 229940099596 manganese sulfate Drugs 0.000 description 2
- 235000007079 manganese sulphate Nutrition 0.000 description 2
- 239000011702 manganese sulphate Substances 0.000 description 2
- YMKHJSXMVZVZNU-UHFFFAOYSA-N manganese(2+);dinitrate;hexahydrate Chemical compound O.O.O.O.O.O.[Mn+2].[O-][N+]([O-])=O.[O-][N+]([O-])=O YMKHJSXMVZVZNU-UHFFFAOYSA-N 0.000 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 description 2
- 239000000203 mixture Substances 0.000 description 2
- 238000002360 preparation method Methods 0.000 description 2
- 239000004576 sand Substances 0.000 description 2
- 238000003756 stirring Methods 0.000 description 2
- 239000010457 zeolite Substances 0.000 description 2
- MGWGWNFMUOTEHG-UHFFFAOYSA-N 4-(3,5-dimethylphenyl)-1,3-thiazol-2-amine Chemical compound CC1=CC(C)=CC(C=2N=C(N)SC=2)=C1 MGWGWNFMUOTEHG-UHFFFAOYSA-N 0.000 description 1
- CWYNVVGOOAEACU-UHFFFAOYSA-N Fe2+ Chemical compound [Fe+2] CWYNVVGOOAEACU-UHFFFAOYSA-N 0.000 description 1
- 239000005909 Kieselgur Substances 0.000 description 1
- WAEMQWOKJMHJLA-UHFFFAOYSA-N Manganese(2+) Chemical compound [Mn+2] WAEMQWOKJMHJLA-UHFFFAOYSA-N 0.000 description 1
- KVKRSMAXOZCCOG-UHFFFAOYSA-N O.[O-2].[Mn+4].[O-2] Chemical compound O.[O-2].[Mn+4].[O-2] KVKRSMAXOZCCOG-UHFFFAOYSA-N 0.000 description 1
- 240000008042 Zea mays Species 0.000 description 1
- 235000005824 Zea mays ssp. parviglumis Nutrition 0.000 description 1
- 235000002017 Zea mays subsp mays Nutrition 0.000 description 1
- 230000002411 adverse Effects 0.000 description 1
- PNEYBMLMFCGWSK-UHFFFAOYSA-N aluminium oxide Inorganic materials [O-2].[O-2].[O-2].[Al+3].[Al+3] PNEYBMLMFCGWSK-UHFFFAOYSA-N 0.000 description 1
- 238000003321 atomic absorption spectrophotometry Methods 0.000 description 1
- 238000009835 boiling Methods 0.000 description 1
- 239000000919 ceramic Substances 0.000 description 1
- 239000012320 chlorinating reagent Substances 0.000 description 1
- 238000004040 coloring Methods 0.000 description 1
- 238000007796 conventional method Methods 0.000 description 1
- 235000005822 corn Nutrition 0.000 description 1
- 239000013078 crystal Substances 0.000 description 1
- 230000008021 deposition Effects 0.000 description 1
- 238000007599 discharging Methods 0.000 description 1
- 230000035622 drinking Effects 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 239000012467 final product Substances 0.000 description 1
- 239000007789 gas Substances 0.000 description 1
- 239000008187 granular material Substances 0.000 description 1
- 239000003673 groundwater Substances 0.000 description 1
- 239000008235 industrial water Substances 0.000 description 1
- 229910010272 inorganic material Inorganic materials 0.000 description 1
- 239000011147 inorganic material Substances 0.000 description 1
- 239000007788 liquid Substances 0.000 description 1
- 229910000357 manganese(II) sulfate Inorganic materials 0.000 description 1
- JCXJVPUVTGWSNB-UHFFFAOYSA-N nitrogen dioxide Inorganic materials O=[N]=O JCXJVPUVTGWSNB-UHFFFAOYSA-N 0.000 description 1
- 239000011236 particulate material Substances 0.000 description 1
- 230000000149 penetrating effect Effects 0.000 description 1
- 230000009467 reduction Effects 0.000 description 1
- 230000004044 response Effects 0.000 description 1
- 238000005979 thermal decomposition reaction Methods 0.000 description 1
- 239000002349 well water Substances 0.000 description 1
- 235000020681 well water Nutrition 0.000 description 1
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- Removal Of Specific Substances (AREA)
- Water Treatment By Sorption (AREA)
- Catalysts (AREA)
Abstract
Description
【０００１】
【発明の属する技術分野】
本発明は、水に溶存する鉄（Ｆｅ），マンガン（Ｍｎ）のみならず色度，濁度，フミン類およびヒ素等も除去できる除鉄・除マンガン濾材およびその製造方法に関する。
【０００２】
【従来の技術】
上水，工業用水および井戸水などに利用される地下水には、鉄やマンガンなどが溶存していることが多い。このような水は、そのままでは飲用不適，用水着色・汚濁および配管詰まり等種々の弊害を生ずるおそれがあるため、鉄やマンガンを除去する必要がある。この方法として接触酸化濾過法が用いられている。
【０００３】
接触酸化濾過法とは、濾過砂として濾砂や多孔質材料の表面に二酸化マンガン（ＭｎＯ２）を付着させた除鉄・除マンガン濾材を用いる濾過法である。具体的には、次亜塩素酸ソーダなどの塩素剤で用水を処理した後、除鉄・除マンガン濾材でこれを濾過すると、濾材の二酸化マンガンの酸化触媒作用によって用水中に溶存する鉄やマンガンが酸化されて不溶化する。そして、この不溶化した鉄やマンガンの酸化物を濾材表面に沈積・付着させて用水中から除去するとともに、濾材表面に沈積・付着した鉄やマンガンの酸化物などが或る程度以上の量に達すると濾材を逆洗洗浄して濾材表面の付着物を排出し、濾材を再生する濾過方法である。
【０００４】
従来より、この接触酸化濾過法に用いられる濾材として、ゼオライトなどの多孔質材料を硫酸マンガンまたは塩化マンガンなどのマンガン塩の水溶液に浸漬・攪拌することによって多孔質材料にマンガン塩を含浸させ、次いでマンガン塩を含浸させた多孔質材料を過マンガン酸カリウム水溶液や次亜塩素酸ソーダなどの酸化剤に浸漬・攪拌することによってマンガン塩を酸化させて多孔質材料に水和二酸化マンガン（ＭｎＯ２・ｍＨ２Ｏ）を付着させたものが知られている（例えば、特許文献１，２および３参照。）。
【０００５】
しかしながら、上述した従来の濾材では、多孔質材料にマンガン塩を含浸させると、多孔質材料の細孔がマンガン塩によって充填されて閉塞されるので、過マンガン酸カリウムなどの酸化剤でマンガン塩を酸化させる際、酸化剤が多孔質材料の細孔内に浸透できず、図６に示すように多孔質材料の表面にのみ水和二酸化マンガンが付着されるようになる。したがって、水和二酸化マンガンの付着量が少ないため用水中の鉄やマンガンの酸化除去能力が低いという問題があった。また、このようにして得られる水和二酸化マンガンは、多孔質材料に対する付着強度が弱いアモルファス構造（ＭｎＯ（ＯＨ）２）のものである。したがって、濾過時の通水や逆洗洗浄などの操作によって濾材表面が摩耗を受けると、濾材の表面にのみ弱い付着強度で付着されている水和二酸化マンガンが濾材から簡単に剥がされて流失し、除鉄・除マンガン能力が短期間で低下するという問題があった。さらに、上述した従来の濾材では、未反応のマンガン塩や酸化剤を濾材から完全には除去しきれなかった。このため、濾材の初回使用時には、濾材を濾過装置に装填したのち必ず逆洗などを行ない濾材の汚れを除去する必要があり、濾過装置の運転に手間と時間がかかるという問題もあった。
【０００６】
一方、これらの問題を解決し得る技術として、マンガン鉱の粉砕化物や電解二酸化マンガン粒子など結晶質二酸化マンガンを主成分とする粒状材を濾材として用いる技術が知られている（例えば、特許文献４参照。）。
【０００７】
しかしながら、結晶質二酸化マンガンを主成分とする粒状材を濾材として用いる技術では、用水中に溶存する鉄やマンガンの酸化除去能力を向上させることはできるが、有機物および鉄・マンガンの酸化物などによって濾材が目詰まりを起こした場合、濾材の比重が大きいため逆洗によって濾材を再生することができず、高価な濾材を全量交換しなければならないため実用的ではないという問題があった。
【０００８】
【特許文献１】
特開平２−２５３８４２号公報（第１−４頁）
【特許文献２】
特開平３−１５１０９５号公報（第１−３頁）
【特許文献３】
特開２００２−３５５７６号公報（第２−４頁）
【特許文献４】
特公平１−３５７１４号公報（第１−２頁）
【０００９】
【発明が解決しようとする課題】
それゆえ、この発明の主たる課題は、軽比重で、除鉄・除マンガン能力に優れるとともに、色度，濁度，フミン類およびヒ素等も除去でき、酸化触媒能力を長期間発揮できる除鉄・除マンガン濾材を提供することである。
【００１０】
【課題を解決するための手段】
請求項１に記載した発明は、「無数の細孔を有する多孔質材料と、多孔質材料に付着させた結晶質二酸化マンガンの薄層とで構成される除鉄・除マンガン濾材」である。
【００１１】
この発明では、比表面積が大きく軽比重の多孔質材料に、アモルファス構造の水和二酸化マンガンよりも多孔質材料に対する付着強度が高い結晶質二酸化マンガンの薄層が付着される。この結晶質二酸化マンガンは、微細な結晶構造を取り、多孔質材料に対して強固に付着されるので、濾過時の通水や逆洗洗浄によって濾材が摩耗を受けても二酸化マンガンの薄層が多孔質材料の表面から剥離するのを防止できる。
【００１２】
請求項２に記載した発明は、請求項１に記載の除鉄・除マンガン濾材において、「多孔質材料が粒径０．３〜３．０ｍｍ、嵩比重０．５〜０．９である」ことを特徴とするものである。
【００１３】
多孔質材料の粒径を０．３〜３．０ｍｍの範囲とすることで、濾材による濾過装置の目詰まりを防止できるとともに、比表面積の減少による鉄やマンガンの除去効率低下を防止できる。さらに、多孔質材料の嵩比重を０．５〜０．９の範囲とすることで、二酸化マンガンの薄層を付着させて濾材として使用する際に効率よく逆洗洗浄することができる軽比重の濾材が得られるとともに、逆洗洗浄時の濾材の流失を防止することができるので、濾過装置に一度濾材を充填すると長期間使用することができる。
【００１４】
請求項３に記載した発明は、請求項１または２に記載の除鉄・除マンガン濾材において、「結晶質二酸化マンガンの薄層を多孔質材料の外部表面および細孔の内部表面に付着させた」ことを特徴とするものである。
【００１５】
この発明では、多孔質材料の外部表面および細孔の内部表面に結晶質二酸化マンガンを付着させるので、多孔質材料に付着された二酸化マンガンの付着量が増え、用水と二酸化マンガンとが接触する確率が向上するため、用水中の鉄やマンガンを高い効率で除去することができるとともに、色度，濁度，フミン類およびヒ素等も除去できる。
【００１６】
また、濾過時の通水や逆洗洗浄によって濾材が摩耗を受け二酸化マンガンの薄層が濾材表面から剥がされたとしても、濾材の細孔の内部表面に付着させた二酸化マンガンが十分に酸化触媒作用を発揮させることができる。このため、用水中の鉄やマンガンの除去効率が低下することはなく、長期間高い効率で鉄やマンガンを除去することができる。
【００１７】
請求項４に記載した発明は、「多孔質材料に二酸化マンガンを付着させる除鉄・除マンガン濾材の製造方法であって、（ａ）多孔質材料に硝酸マンガンを含浸して含浸体を調製し、（ｂ）含浸体を加熱して、多孔質材料に二酸化マンガンを生成・付着させる」ことを特徴とする除鉄・除マンガン濾材の製造方法である。
【００１８】
この発明では、多孔質材料に硝酸マンガンを含浸して加熱するだけで、硝酸マンガンが完全に分解されて、結晶質の二酸化マンガンが生成され、この二酸化マンガンが多孔質材料に対して強固に付着して薄層を形成する。このため、簡単な工程および装置で除鉄・除マンガン濾材を製造することができる。
【００１９】
また、過マンガン酸カリウムや次亜塩素酸ソーダなどの酸化剤による反応を行わないため、濾材中に未反応のマンガン塩や酸化剤が残らない。したがって、濾材の初回使用時に濾材を濾過装置に装填した際、逆洗洗浄などにより濾材の汚れを除去する必要がなく、濾材装填後、直ちに濾過装置を運転できるため、無駄なく効率的な濾過装置の運転に寄与できる。
【００２０】
請求項５に記載した発明は、請求項４に記載の発明において、「工程（ａ）の前に、多孔質材料に過マンガン酸カリウムを含浸する」ことを特徴とするものである。
【００２１】
この発明では、多孔質材料に硝酸マンガンを含浸する前に過マンガン酸カリウムを含浸する。すると、過マンガン酸カリウムが細孔を通じて多孔質材料の内部に浸透し、細孔を閉塞する。そして、その後含浸させる硝酸マンガンが多孔質材料の内部へ浸透するのを抑制する。したがって、多孔質材料に生成・付着させる二酸化マンガンの量を制御できるので、例えば、二酸化マンガンの付着量を減らした安価な濾材が欲しいというような、様々な要望に対応した濾材を提供することができる。
【００２２】
【発明の実施の形態】
以下、本発明の一実施例の除鉄・除マンガン濾材およびその製造方法について説明する。
【００２３】
図１は、本発明の一実施例の除鉄・除マンガン濾材の拡大断面写真である。本実施例の濾材は、無数の細孔を有する白色系の多孔質材料と、多孔質材料に付着させた二酸化マンガンの薄層とによって構成されており、この二酸化マンガンの薄層を多孔質材料の外部表面および細孔の内部表面に付着させるため、図１に示すように濾材全体が二酸化マンガンの色すなわち黒褐色を呈する。
【００２４】
多孔質材料は、酸化触媒である二酸化マンガンを担持させるとともに、二酸化マンガンによって酸化され不溶化された用水中の鉄やマンガンの酸化物などをその表面に沈積・付着させて用水中から除去するためのものであり、人工的な多孔質セラミック粒，天然軽石，珪藻土，ゼオライトおよびアルミナ・シャモットなど無数の細孔を有する比表面積の大きな無機材料が好適に用いられる。
【００２５】
この多孔質材料の粒径は、０．３〜３．０ｍｍの範囲であることが好ましく、より好ましくは０．５〜２．０ｍｍの範囲である。多孔質材料の粒径が０．３ｍｍ未満の場合には、濾材を濾過装置に装填した際に装填密度が高くなり過ぎるため濾材がすぐに目詰まりを起こすようになり、逆に、３．０ｍｍより大きくした場合には、比表面積が小さくなるので濾材と用水との接触面積が小さくなり、二酸化マンガンによる酸化効率が低下するとともに、酸化され不溶化された用水中の鉄やマンガンの酸化物の沈積・付着率も低下するからである。
【００２６】
また、多孔質材料の嵩比重は、０．５〜０．９の範囲であることが好ましく、より好ましくは０．６〜０．８の範囲である。多孔質材料の粒径が０．５未満の場合には、二酸化マンガンの薄層を付着させて濾材を形成した際、濾材の粒子が軽すぎて用水中で浮くようになるとともに、濾過装置に装填された濾材を逆洗洗浄する際、逆洗水とともに濾過装置の外へ流失するようになり、逆に、０．９より大きくした場合には、二酸化マンガンの薄層を付着させて濾材を形成した際、濾材の粒子が重くなり、逆洗洗浄を行なう際に、濾材を装填した濾材層の膨張率が低くなり、逆洗洗浄による洗浄効果が低下するからである。
【００２７】
二酸化マンガンは、用水中に溶存する鉄やマンガンを酸化させて水に不溶な酸化物を析出させる酸化触媒であり、本発明では、多孔質材料に対する付着強度の点から、結晶質の二酸化マンガンが好適である。このように触媒として結晶質の二酸化マンガンを使用し、これを多孔質材料に対して強固に付着させることによって、濾過時の通水や逆洗洗浄によって濾材が摩耗を受けても二酸化マンガンが多孔質材料の表面から剥離するのを防止できる。
【００２８】
本発明の除鉄・除マンガン濾材を製造する際には、図２に示すように、「硝酸マンガン含浸工程（Ｓ１）」および「二酸化マンガン生成・付着工程（Ｓ２）」がこの順に実行される。
【００２９】
「硝酸マンガン含浸工程（Ｓ１）」では、まず、上述した多孔質材料をＶ型ミキサー，ナウターミキサーおよびＷコーンミキサーなどの混合・攪拌機に投入し、これにマンガン塩である硝酸マンガン水溶液を加え、全体が均一になるまで混合する。すると多孔質材料に硝酸マンガンが含浸された含浸体が調製される。
【００３０】
ここで、多孔質材料と硝酸マンガン水溶液との混合割合は、硝酸マンガン水溶液の容積１に対して多孔質材料の容積が２〜５の範囲であることが好ましい。硝酸マンガン水溶液の容積１に対して多孔質材料の容積が２未満の場合には、多孔質材料が多くの水分を包含することによって乾燥に時間がかかるようになるため、後述する「二酸化マンガン生成・付着工程（Ｓ２）」での処理時間が長くなり、逆に、５より大きい場合には、硝酸マンガン水溶液が多孔質材料全体に十分行き渡り難くなるため、均一な含浸体を調製することが困難になるからである。
【００３１】
また、硝酸マンガン水溶液の濃度に比例して、多孔質材料に付着される二酸化マンガンの付着量は多くなるが、多孔質材料に加える硝酸マンガン水溶液の濃度は、５〜２０重量％の濃度範囲であることが好ましい。硝酸マンガン水溶液の濃度が５重量％未満の場合には、多孔質材料に対する硝酸マンガンの含浸量が少なくなる結果、最終生成である濾材における二酸化マンガンの付着量が少なくなり、逆に、２０重量％より多い場合には、多孔質材料に対する硝酸マンガンの含浸量が多くなり過ぎて、最終生成物である濾材における二酸化マンガンの付着量が飽和状態に達し細孔を塞ぐようになるため、濾材の比表面積が低下し、鉄やマンガンの除去効率が低下するようになるからである。（つまり、多孔質材料の外部表面および細孔の内部表面に二酸化マンガンの薄層が形成されるようにするのが好ましい。）
【００３２】
また、多孔質材料に含浸させるマンガン塩として硝酸マンガンを用いるのは、硝酸マンガンは、他のマンガン塩とは異なり、酸化剤を用いなくても約１３０℃という比較的低い温度の熱を加えるだけで熱分解して二酸化マンガンを生成させることができるからである。これに対し、硫酸マンガン（ＩＩ）の熱分解
温度は約８５０℃と非常に高く、また塩化マンガン（ＩＩ）においては沸点が１
１９０℃と非常に高温である。したがって、硫酸マンガン（ＩＩ）や塩化マンガ
ン（ＩＩ）を熱分解して二酸化マンガンを生成させるためには、１０００℃前後
の高温にも対応できるような大がかりな装置が必要となり、濾材を経済的に製造することが困難となる。
【００３３】
そして、調製された含浸体を次の「二酸化マンガン生成・付着工程（Ｓ２）」へ与える。
【００３４】
「二酸化マンガン生成・付着工程（Ｓ２）」では、まず「硝酸マンガン含浸工程（Ｓ１）」で得られた含浸体をロータリー式乾燥機などの乾燥装置へ投入し、１３０℃〜２００℃の温度範囲で３０〜６０分間加熱・乾燥させる。すると硝酸マンガンが二酸化窒素ガスを発生させながら分解することによって結晶質の二酸化マンガンが生成され、この結晶質二酸化マンガンの薄層が多孔質材料と強固に結合し、除鉄・除マンガン濾材が完成する。
【００３５】
なお、図２に示すように「二酸化マンガン生成・付着工程（Ｓ２）」の後に、必要に応じて「濾材活性化工程（Ｓ３）」を設けるようにしてもよい。
【００３６】
「濾材活性化工程（Ｓ３）」では、まず、「二酸化マンガン生成・付着工程（Ｓ２）」で完成させた濾材に残留塩素濃度が１〜２ｍｇ／ｌの次亜塩素酸ソーダ水溶液を加え、１〜２時間浸漬させる。すると、多孔質材料に付着させた二酸化マンガンが活性化され、酸化触媒性能を十分に発揮させることができる。したがって、このような処理を行うことにより、用水中に溶存する鉄やマンガンのほかに色度，濁度，フミン類およびヒ素等も除去できるようになる。
【００３７】
そして、活性化が終了した濾材をロータリー乾燥機に投入し、多少水分が残った状態まで濾材を乾燥させることにより、この工程が完了する。また、この活性化処理は、濾材を濾過装置に装填して当該濾過装置を使用する前に、濾過装置に前述の次亜塩素酸ソーダ水溶液を通して濾材を次亜塩素酸ソーダ水溶液に浸漬させることによっても達成できる。
【００３８】
また、「硝酸マンガン含浸工程（Ｓ１）」の前に、多孔質材料に過マンガン酸カリウム水溶液を加えて混合・攪拌することによって、多孔質材料に過マンガン酸カリウムを含浸させる工程を設けてもよい。このように、多孔質材料に過マンガン酸カリウムを含浸させることによって、過マンガン酸カリウムが細孔を通じて多孔質材料の内部に浸透し細孔を閉塞する。そして、その後に硝酸マンガンを含浸させると、硝酸マンガンが多孔質材料の内部へ浸透するのを抑制でき、これを加熱して得られる濾材は、図３に示すように、多孔質材料の内部に二酸化マンガンが浸透・付着しないものとなる。また、多孔質材料に加える過マンガン酸カリウム水溶液の濃度を変えることによって多孔質材料の内部に浸透する過マンガン酸カリウムの量が変わるので、最終生成物である濾材における二酸化マンガンの浸透・付着量を変えることができる。したがって、「硝酸マンガン含浸工程（Ｓ１）」の前に、多孔質材料に過マンガン酸カリウムを含浸する工程を設けることによって、多孔質材料に付着させる二酸化マンガンの量を制御することができる。
【００３９】
【実施例】
以下に、実施例を挙げて本発明を具体的に説明するが、本発明は実施例に限定されるものではない。
【００４０】
（実施例濾材の調製）
多孔質材料として粒径０．５〜１．０ｍｍの範囲の天然軽石を準備し、これをＷコーンミキサーに投入し、濃度２０重量％の硝酸マンガン六水和物（Ｍｎ（ＮＯ３）２・６Ｈ２Ｏ）水溶液を加え、全体が均一になるまで十分に混合・攪拌した（多孔質材料と硝酸マンガン水溶液との混合割合は、多孔質材料の容積５に対して硝酸マンガン水溶液の容積１である。）。
【００４１】
そして、多孔質材料と硝酸マンガン六水和物水溶液とを均一に混合・攪拌させた後、これを温度１５０℃に設定したロータリー式乾燥機に投入し、６０分間加熱・乾燥して除鉄・除マンガン濾材を得、後述する評価試験に供した。得られた濾材の断面拡大写真を図１に示すとともに、化学成分を表２（実施例・逆洗前のカラム）に示す。なお、Ｘ線回折による分析の結果、濾材に付着された二酸化マンガンはβ−ＭｎＯ２型の結晶質のものであった。また、得られた濾材の自然充填時における嵩比重は０．６７であった。
【００４２】
（比較例濾材の調製）
マンガン塩と酸化剤とを用いる従来の除鉄・除マンガン濾材の製造方法に基づいて比較例濾材の調製を行った。具体的には、多孔質材料として上述した実施例濾材と同じ粒径０．５〜１．０ｍｍの範囲の天然軽石を準備し、これに濃度３重量％の塩化マンガン（ＭｎＣｌ２・４Ｈ２Ｏ）水溶液を加え十分に混合・攪拌した（多孔質材料と塩化マンガン水溶液との混合割合は、多孔質材料の容積８に対して塩化マンガン水溶液の容積１である。）。
【００４３】
次に濃度３重量％の過マンガン酸カリウム（ＫＭｎＯ４）水溶液を前述の塩化マンガン水溶液添加量の半分量加え、再度十分に攪拌した。
【００４４】
そして、反応残液を抜き取り、同様の薬品処理をさらに２回繰り返した後、水洗し、薬品処理が完了した多孔質材料を温度１００℃に設定したロータリー式乾燥機に投入し、６０分間加熱・乾燥して除鉄・除マンガン濾材を得、後述する評価試験に供した。得られた濾材の断面拡大写真を図６に示すとともに、化学成分を表２（比較例・逆洗前のカラム）に示す。なお、Ｘ線回折による分析の結果、濾材に付着された二酸化マンガンはアモルファス構造のものであった。また、得られた濾材の自然充填時における嵩比重は０．６５であった。
【００４５】
（評価試験例１）除鉄・除マンガン能力の評価
実施例濾材および比較例濾材について、図４に示すような、濾過筒（１２），原水槽（１４），塩素剤槽（１６）および処理水槽（１８）を備える濾過装置（１０）を用いて濾過試験を行った。ここで、濾過筒（１０）は、内部に濾材（Ａ）を装填して用水の濾過を行なう装置であり、直胴部が外径６５ｍｍ、高さ７００ｍｍの中空部材によって構成されたものを用いた。この濾過筒の軸方向一方端面（図４における上面）は、配管（２０）を介して原水槽（１４）の原水送りポンプ（１４ａ）に接続される。なお、配管（２０）の途中には配管（２２）を介して塩素剤槽（１６）が接続され、原水送りポンプ（１４ａ）と連動する塩素剤送りポンプ（１６ａ）によって、濾過筒（１２）に供給される原水に対して一定量の塩素剤が供給される。また、濾過筒の軸方向他方端面（図４における下面）には、水抜き用の配管（２４）が接続され、この配管（２４）の途中には、濾過筒（１２）で処理した処理水を処理水槽（１８）に送るための配管（２６）と、逆洗ポンプ（１８ａ）を駆動することによって処理水を逆洗水として濾過筒（１２）へ送るための配管（２８）とが接続される。そして、これらの配管（２４）（２６）および（２８）には、それぞれ開閉弁（２４ａ）（２６ａ）および（２８ａ）が取り付けられ、濾過装置（１０）の運転目的（例えば、「用水を濾過する」事や「濾過筒（１２）を逆洗洗浄する」事など。）に応じて開閉される。また、濾過筒（１２）の上部端面には開閉弁（３０ａ）を介して逆洗水を排出するための逆洗水排水管（３０）が接続される。
【００４６】
上述した濾過装置（１０）を用いて、具体的には表１に示す条件で濾過試験を行った。
【００４７】
【表１】
表１に示した条件で濾過装置（１０）を運転するとともに、濾過された処理水を一定時間ごとサンプリングして、原子吸光光度法により鉄（Ｆｅ）およびマンガン（Ｍｎ）の濃度を定量し、次式１によって鉄およびマンガンの除去率を算出し、この鉄およびマンガンの除去率の経時変化を図５に示した。なお、図中の時間軸におけるＸの部分では５分間の逆洗洗浄を行った。
【００４９】
【式１】
図５より、実施例の濾材は、比較例のものに比べて鉄およびマンガンの除去率が高く、また、この傾向は逆洗洗浄後においても変わらないことがうかがえる。このように、本発明の濾材は、従来のものに比べて鉄およびマンガンの除去効率が高いことが分かる。
【００５１】
（試験例２）長期間の使用に対する濾材の耐久性の評価
長期間の使用に対する濾材の耐久性を確認するために、上述した濾過装置（１０）を用いて、連続逆洗洗浄試験を行った。具体的には、１日２回各５分間逆洗洗浄を行うと仮定すると、３年間の積算逆洗洗浄時間は７日間となる。そこで、実施例濾材と比較例濾材について７日間連続逆洗洗浄を行ない、各濾材における逆洗洗浄前後の化学成分を分析した。この分析結果を表２に示す。
【００５２】
【表２】
表２の結果より、実施例濾材では逆洗洗浄前後における濾材の化学成分にほとんど変化がないのに対し、比較例濾材では逆洗洗浄後に二酸化マンガン（ＭｎＯ２）の割合が劇的に減少していることがうかがえる。このことから、本発明の濾材は結晶質の二酸化マンガンが多孔質材料に対して強固に付着されており、長期間安定して使用できるのに対し、従来のものでは二酸化マンガンが多孔質材料に強固に付着されておらず、長期間使用を行うと濾材表面の二酸化マンガンが剥離して流失する結果、除鉄・除マンガン能力が低下することが予想される。
【００５４】
【発明の効果】
本発明によれば、比表面積が大きく軽比重の多孔質材料に、結晶質二酸化マンガンの薄層が強固に付着されるので、濾過時の通水や逆洗洗浄によって濾材が摩耗を受けても二酸化マンガンの薄層が多孔質材料の表面から剥離するのを防止できる。
【００５５】
また、多孔質材料の外部表面および細孔の内部表面に二酸化マンガンの薄層を付着させるので、多孔質材料に付着された二酸化マンガンの付着量が増え、用水と二酸化マンガンとが接触する確率を向上させることができ、用水中の鉄やマンガンを高い効率で除去することができるとともに、色度，濁度，フミン類およびヒ素等も除去できる。また、濾過時の通水や逆洗洗浄によって濾材が摩耗を受け二酸化マンガンの薄層が濾材表面から剥がされたとしても、鉄やマンガンの除去効率が低下することはなく、長期間高い効率で鉄やマンガンを除去することができる。
【００５６】
したがって、軽比重で、除鉄・除マンガン能力に優れるとともに、色度，濁度，フミン類およびヒ素等も除去でき、酸化触媒能力を長期間発揮できる除鉄・除マンガン濾材を提供することができる。
【図面の簡単な説明】
【図１】本発明の一実施例の除鉄・除マンガン濾材の拡大断面写真である。
【図２】本発明の一実施例の除鉄・除マンガン濾材の製造工程を示すフロー図である。
【図３】本発明の他の実施例の除鉄・除マンガン濾材の拡大断面写真である。
【図４】濾過試験を行った濾過装置を示す概略フロー図である。
【図５】濾過試験の結果を示すグラフである。
【図６】従来の除鉄・除マンガン濾材の拡大断面写真である。
【符号の説明】
（１０）…濾過装置
（１２）…濾過筒
（１４）…原水槽
（１６）…塩素剤槽
（１８）…処理水槽
（Ａ）…濾材[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an iron / manganese filter medium capable of removing not only iron (Fe) and manganese (Mn) dissolved in water but also chromaticity, turbidity, humins, arsenic and the like, and a method for producing the same.
[0002]
[Prior art]
Iron and manganese are often dissolved in groundwater used for water, industrial water and well water. Such water may cause various adverse effects such as inadequate drinking, water coloring / pollution, and clogging of piping, so it is necessary to remove iron and manganese. As this method, a catalytic oxidation filtration method is used.
[0003]
The contact oxidation filtration method is a filtration method using an iron removal / manganese filter material in which manganese dioxide (MnO 2 ) is attached to the surface of filter sand or a porous material as filter sand. Specifically, after treating the irrigation water with a chlorine agent such as sodium hypochlorite and filtering it with a filter medium for removing iron and manganese, iron and manganese dissolved in the irrigation water by the oxidation catalytic action of manganese dioxide in the filter medium. Is oxidized and insolubilized. The insolubilized iron and manganese oxides are deposited and adhered to the surface of the filter medium and removed from the working water, and the iron and manganese oxides deposited and adhered to the filter medium surface reach a certain amount. Then, it is a filtration method in which the filter medium is back-washed to discharge deposits on the filter medium surface and regenerate the filter medium.
[0004]
Conventionally, as a filter medium used in this catalytic oxidation filtration method, porous materials such as zeolite are impregnated with an aqueous solution of manganese salts such as manganese sulfate or manganese chloride so as to impregnate the porous materials with manganese salts, The porous material impregnated with the manganese salt is immersed and stirred in an oxidizing agent such as an aqueous potassium permanganate solution or sodium hypochlorite to oxidize the manganese salt to hydrate manganese dioxide (MnO 2. mH 2 O) which were deposited are known (e.g., see
[0005]
However, in the conventional filter medium described above, when the porous material is impregnated with a manganese salt, the pores of the porous material are filled with the manganese salt and closed, so that the manganese salt is removed with an oxidizing agent such as potassium permanganate. When oxidizing, the oxidizing agent cannot penetrate into the pores of the porous material, and hydrated manganese dioxide is attached only to the surface of the porous material as shown in FIG. Therefore, there is a problem that the oxidative removal ability of iron and manganese in the water for use is low because the amount of hydrated manganese dioxide attached is small. Further, the hydrated manganese dioxide obtained in this way has an amorphous structure (MnO (OH) 2 ) having a low adhesion strength to the porous material. Therefore, if the surface of the filter media is worn by operations such as water flow during filtration or backwashing, the hydrated manganese dioxide adhering only to the surface of the filter media with weak adhesion strength is easily peeled off and washed away. There was a problem that the iron removal / manganese removal ability decreased in a short period of time. Furthermore, in the conventional filter medium described above, unreacted manganese salt and oxidant cannot be completely removed from the filter medium. For this reason, when the filter medium is used for the first time, the filter medium must be back-washed after the filter medium is loaded into the filter apparatus to remove dirt from the filter medium, and there is a problem that it takes time and effort to operate the filter apparatus.
[0006]
On the other hand, as a technique that can solve these problems, a technique is known in which a granular material mainly composed of crystalline manganese dioxide such as pulverized manganese ore and electrolytic manganese dioxide particles is used as a filter medium (for example, Patent Document 4). reference.).
[0007]
However, the technology that uses a particulate material mainly composed of crystalline manganese dioxide as a filter medium can improve the ability to oxidize and remove iron and manganese dissolved in the irrigation water. When the filter medium is clogged, there is a problem that it is not practical because the filter medium cannot be regenerated by backwashing because the specific gravity of the filter medium is large and the entire expensive filter medium must be replaced.
[0008]
[Patent Document 1]
JP-A-2-253842 (page 1-4)
[Patent Document 2]
Japanese Patent Laid-Open No. 3-151095 (page 1-3)
[Patent Document 3]
JP 2002-35576 A (page 2-4)
[Patent Document 4]
Japanese Patent Publication No. 1-35714 (page 1-2)
[0009]
[Problems to be solved by the invention]
Therefore, the main problem of the present invention is that it is light specific gravity, excellent in removing iron and removing manganese, and can also remove chromaticity, turbidity, humins, arsenic, etc., and can exhibit oxidation catalyst ability for a long time. It is to provide a manganese removal filter medium.
[0010]
[Means for Solving the Problems]
The invention described in claim 1 is “iron removal / manganese removal filter medium comprising a porous material having innumerable pores and a thin layer of crystalline manganese dioxide adhered to the porous material”.
[0011]
In this invention, a thin layer of crystalline manganese dioxide having a higher adhesion strength to the porous material than the hydrated manganese dioxide having an amorphous structure is attached to the porous material having a large specific surface area and a light specific gravity. Since this crystalline manganese dioxide has a fine crystal structure and is firmly attached to the porous material, a thin layer of manganese dioxide will remain even if the filter medium is worn by water flow during filtration or backwashing. It can prevent peeling from the surface of the porous material.
[0012]
The invention described in
[0013]
By setting the particle size of the porous material in the range of 0.3 to 3.0 mm, it is possible to prevent clogging of the filtering device by the filter medium, and it is possible to prevent a reduction in iron and manganese removal efficiency due to a decrease in specific surface area. Furthermore, by setting the bulk specific gravity of the porous material in the range of 0.5 to 0.9, a light specific gravity that can be efficiently backwashed and washed when a thin layer of manganese dioxide is attached and used as a filter medium. Since the filter medium can be obtained and the filter medium can be prevented from being washed away during the backwash cleaning, the filter medium can be used for a long time once it is filled.
[0014]
The invention according to
[0015]
In this invention, since crystalline manganese dioxide is attached to the outer surface of the porous material and the inner surface of the pores, the amount of manganese dioxide attached to the porous material increases, and the probability that the water and manganese dioxide come into contact with each other Therefore, iron and manganese in the irrigation water can be removed with high efficiency, and chromaticity, turbidity, humins and arsenic can be removed.
[0016]
In addition, even if the filter medium is worn by passing water or backwashing during filtration and the thin layer of manganese dioxide is peeled off from the surface of the filter medium, the manganese dioxide adhered to the inner surface of the pores of the filter medium is sufficiently oxidized catalyst. The effect can be exhibited. For this reason, the removal efficiency of iron and manganese in irrigation water does not fall, and iron and manganese can be removed with high efficiency for a long period of time.
[0017]
The invention described in claim 4 is “a method for producing an iron / manganese filter medium in which manganese dioxide is adhered to a porous material. (A) An impregnated body is prepared by impregnating a porous material with manganese nitrate. And (b) heating the impregnated body to produce and attach manganese dioxide to the porous material ”.
[0018]
In this invention, just by impregnating and heating a porous material with manganese nitrate, the manganese nitrate is completely decomposed to produce crystalline manganese dioxide, which adheres firmly to the porous material. To form a thin layer. For this reason, the iron removal / manganese removal filter medium can be manufactured with a simple process and apparatus.
[0019]
In addition, since the reaction with an oxidizing agent such as potassium permanganate or sodium hypochlorite is not performed, no unreacted manganese salt or oxidizing agent remains in the filter medium. Therefore, when the filter medium is loaded into the filter device when the filter medium is used for the first time, it is not necessary to remove the dirt of the filter medium by backwashing or the like, and the filter device can be operated immediately after the filter medium is loaded. Can contribute to driving.
[0020]
The invention described in claim 5 is characterized in that, in the invention described in claim 4, “the porous material is impregnated with potassium permanganate before the step (a)”.
[0021]
In this invention, the porous material is impregnated with potassium permanganate before being impregnated with manganese nitrate. Then, potassium permanganate permeates into the porous material through the pores and closes the pores. And it suppresses that the manganese nitrate impregnated after that osmose | permeates the inside of a porous material. Therefore, since the amount of manganese dioxide produced and adhered to the porous material can be controlled, it is possible to provide a filter medium that can meet various demands, for example, an inexpensive filter medium with a reduced amount of manganese dioxide deposited is desired. it can.
[0022]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, an iron removal / manganese removal filter according to an embodiment of the present invention and a method for producing the same will be described.
[0023]
FIG. 1 is an enlarged cross-sectional photograph of an iron removal / manganese removal filter according to an embodiment of the present invention. The filter medium of this example is composed of a white porous material having innumerable pores and a thin layer of manganese dioxide attached to the porous material, and the thin layer of manganese dioxide is formed into a porous material. Therefore, as shown in FIG. 1, the entire filter medium has a manganese dioxide color, that is, a blackish brown color.
[0024]
The porous material supports manganese dioxide, which is an oxidation catalyst, and removes iron and manganese oxides in the working water oxidized and insolubilized by manganese dioxide from the working water by depositing and adhering to the surface. Inorganic materials having a large specific surface area having innumerable pores such as artificial porous ceramic grains, natural pumice, diatomaceous earth, zeolite, and alumina chamotte are preferably used.
[0025]
The particle size of the porous material is preferably in the range of 0.3 to 3.0 mm, more preferably in the range of 0.5 to 2.0 mm. When the particle size of the porous material is less than 0.3 mm, the loading density becomes too high when the filter medium is loaded into the filtration device, so that the filter medium immediately becomes clogged, and conversely, 3.0 mm If it is larger, the specific surface area becomes smaller, so the contact area between the filter medium and the water becomes smaller, the oxidation efficiency by manganese dioxide decreases, and the deposition of oxidized and insoluble iron and manganese oxides in the water・ The adhesion rate also decreases.
[0026]
Moreover, it is preferable that the bulk specific gravity of a porous material is the range of 0.5-0.9, More preferably, it is the range of 0.6-0.8. When the particle size of the porous material is less than 0.5, when the filter medium is formed by adhering a thin layer of manganese dioxide, the particles of the filter medium are too light to float in the water, and in the filtration device When the loaded filter medium is backwashed, it flows out of the filtration device together with the backwash water. Conversely, when it is greater than 0.9, a thin layer of manganese dioxide is adhered to the filter medium. This is because, when formed, the particles of the filter medium become heavier, and when performing the backwash cleaning, the expansion rate of the filter medium layer loaded with the filter medium decreases, and the cleaning effect by the backwash cleaning decreases.
[0027]
Manganese dioxide is an oxidation catalyst that oxidizes iron and manganese dissolved in water for use to precipitate oxides that are insoluble in water. In the present invention, crystalline manganese dioxide is used in terms of adhesion strength to porous materials. Is preferred. In this way, crystalline manganese dioxide is used as a catalyst, and it adheres firmly to the porous material, so that the manganese dioxide is porous even if the filter medium is worn due to water flow during filtration or backwashing. Peeling from the surface of the quality material can be prevented.
[0028]
When producing the iron removal / manganese removal filter medium of the present invention, as shown in FIG. 2, the “manganese nitrate impregnation step (S1)” and the “manganese dioxide production / adhesion step (S2)” are executed in this order. .
[0029]
In the “manganese nitrate impregnation step (S1)”, first, the porous material described above is put into a mixing / stirring machine such as a V-type mixer, a nauter mixer and a W corn mixer, and a manganese nitrate aqueous solution as a manganese salt is added thereto. Mix until the whole is uniform. Then, an impregnated body in which the porous material is impregnated with manganese nitrate is prepared.
[0030]
Here, the mixing ratio of the porous material and the manganese nitrate aqueous solution is preferably such that the volume of the porous material is in the range of 2 to 5 with respect to the volume 1 of the manganese nitrate aqueous solution. When the volume of the porous material is less than 2 with respect to the volume 1 of the aqueous manganese nitrate solution, it takes time to dry because the porous material contains a large amount of moisture.・ The treatment time in the “adhesion step (S2)” becomes longer, and conversely, when it is larger than 5, the aqueous manganese nitrate solution is difficult to spread over the entire porous material, so it is difficult to prepare a uniform impregnated body. Because it becomes.
[0031]
In addition, the amount of manganese dioxide attached to the porous material increases in proportion to the concentration of the aqueous manganese nitrate solution, but the concentration of the aqueous manganese nitrate solution added to the porous material ranges from 5 to 20% by weight. Preferably there is. When the concentration of the manganese nitrate aqueous solution is less than 5% by weight, the amount of manganese nitrate impregnated into the porous material is reduced. As a result, the amount of manganese dioxide attached to the final filter medium is reduced, and conversely, 20% by weight. If more, the amount of manganese nitrate impregnated into the porous material becomes too large, and the amount of manganese dioxide adhering to the filter material, which is the final product, reaches saturation and closes the pores. This is because the surface area decreases, and the removal efficiency of iron and manganese decreases. (In other words, a thin layer of manganese dioxide is preferably formed on the outer surface of the porous material and the inner surface of the pores.)
[0032]
Also, manganese nitrate is used as the manganese salt impregnated into the porous material. Unlike other manganese salts, manganese nitrate only applies heat at a relatively low temperature of about 130 ° C. without using an oxidizing agent. This is because it can be pyrolyzed to produce manganese dioxide. On the other hand, the thermal decomposition temperature of manganese (II) sulfate is very high at about 850 ° C., and the boiling point of manganese (II) is 1
It is a very high temperature of 190 ° C. Therefore, in order to pyrolyze manganese sulfate (II) and manganese chloride (II) to produce manganese dioxide, a large-scale apparatus that can handle high temperatures around 1000 ° C. is required, and the filter medium is economically used. It becomes difficult to manufacture.
[0033]
Then, the prepared impregnated body is given to the next “manganese dioxide production / attachment step (S2)”.
[0034]
In the “manganese dioxide production / attachment step (S2)”, first, the impregnated body obtained in the “manganese nitrate impregnation step (S1)” is put into a drying apparatus such as a rotary dryer, and a temperature range of 130 ° C. to 200 ° C. Heat and dry for 30-60 minutes. Then, manganese nitrate is decomposed while generating nitrogen dioxide gas to produce crystalline manganese dioxide. This thin layer of crystalline manganese dioxide is firmly bonded to the porous material, and the iron removal / manganese removal filter medium is completed. To do.
[0035]
In addition, as shown in FIG. 2, you may make it provide a "filter medium activation process (S3)" as needed after a "manganese dioxide production | generation / adhesion process (S2)".
[0036]
In the “filter medium activation step (S3)”, first, a sodium hypochlorite aqueous solution having a residual chlorine concentration of 1 to 2 mg / l is added to the filter medium completed in the “manganese dioxide production and adhesion step (S2)”. Soak for ~ 2 hours. Then, the manganese dioxide adhered to the porous material is activated, and the oxidation catalyst performance can be sufficiently exhibited. Therefore, by performing such treatment, it becomes possible to remove chromaticity, turbidity, humic substances, arsenic and the like in addition to iron and manganese dissolved in the water.
[0037]
Then, the activated filter medium is put into a rotary dryer, and this process is completed by drying the filter medium until some moisture remains. In addition, this activation treatment is performed by immersing the filter medium in the sodium hypochlorite aqueous solution by passing the sodium hypochlorite aqueous solution through the filter apparatus before using the filter apparatus after the filter medium is loaded into the filter apparatus. Can also be achieved.
[0038]
Further, before the “manganese nitrate impregnation step (S1)”, a step of impregnating the porous material with potassium permanganate by adding a potassium permanganate aqueous solution to the porous material and mixing and stirring may be provided. Good. Thus, by impregnating the porous material with potassium permanganate, potassium permanganate permeates into the porous material through the pores and closes the pores. And if it impregnates manganese nitrate after that, it can suppress that manganese nitrate permeates into the inside of a porous material, and the filter medium obtained by heating this will have the inside of a porous material as shown in FIG. Manganese dioxide will not penetrate and adhere. In addition, the amount of potassium permanganate penetrating into the porous material changes by changing the concentration of the potassium permanganate aqueous solution added to the porous material. Can be changed. Therefore, by providing a step of impregnating the porous material with potassium permanganate before the “manganese nitrate impregnation step (S1)”, the amount of manganese dioxide attached to the porous material can be controlled.
[0039]
【Example】
EXAMPLES The present invention will be specifically described below with reference to examples, but the present invention is not limited to the examples.
[0040]
(Preparation of Example Filter Material)
Prepare the natural pumice particle size range of 0.5~1.0mm as the porous material, which was poured into W cone mixer, a concentration of 20 wt% of manganese nitrate hexahydrate (Mn (NO 3) 2 ·
[0041]
Then, after the porous material and the manganese nitrate hexahydrate aqueous solution were uniformly mixed and stirred, this was put into a rotary dryer set at a temperature of 150 ° C. and heated and dried for 60 minutes to remove iron. A manganese removal filter medium was obtained and subjected to an evaluation test described later. While the cross-sectional enlarged photograph of the obtained filter medium is shown in FIG. 1, a chemical component is shown in Table 2 (Example and the column before backwashing). As a result of analysis by X-ray diffraction, manganese dioxide, which is attached to the filter media were of beta-MnO 2 type crystalline. Moreover, the bulk specific gravity at the time of natural filling of the obtained filter medium was 0.67.
[0042]
(Preparation of Comparative Example Filter Material)
A comparative filter medium was prepared based on a conventional method for producing a ferrous / manganese filter medium using a manganese salt and an oxidizing agent. Specifically, natural pumice having the same particle size in the range of 0.5 to 1.0 mm as the above-described Example filter medium is prepared as a porous material, and manganese chloride (MnCl 2 .4H 2 O with a concentration of 3% by weight is prepared. ) Aqueous solution was added and sufficiently mixed and stirred (the mixing ratio of the porous material and the manganese chloride aqueous solution was the volume 1 of the manganese chloride aqueous solution to the
[0043]
Next, a potassium permanganate (KMnO 4 ) aqueous solution having a concentration of 3% by weight was added in an amount half the amount of the above-mentioned manganese chloride aqueous solution added, and sufficiently stirred again.
[0044]
Then, the reaction residual liquid is extracted, and the same chemical treatment is repeated twice, followed by washing with water. The porous material after the chemical treatment is put into a rotary dryer set at a temperature of 100 ° C. and heated for 60 minutes. It dried and obtained the iron removal and manganese removal filter material, and used for the evaluation test mentioned later. A cross-sectional enlarged photograph of the obtained filter medium is shown in FIG. As a result of analysis by X-ray diffraction, manganese dioxide adhering to the filter medium had an amorphous structure. Moreover, the bulk specific gravity at the time of natural filling of the obtained filter medium was 0.65.
[0045]
(Evaluation Test Example 1) Evaluation of iron removal / manganese removal ability Example filter medium and comparative example filter medium, as shown in FIG. 4, filter cylinder (12), raw water tank (14), chlorine agent tank (16) and treatment A filtration test was performed using a filtration device (10) equipped with a water bath (18). Here, the filter cylinder (10) is a device for filtering the water by loading the filter medium (A) therein, and uses a straight body portion constituted by a hollow member having an outer diameter of 65 mm and a height of 700 mm. It was. One end surface (the upper surface in FIG. 4) of the filter cylinder in the axial direction is connected to the raw water feed pump (14a) of the raw water tank (14) through the pipe (20). In addition, a chlorine agent tank (16) is connected to the middle of the pipe (20) via the pipe (22), and the filter cylinder (12) is connected by the chlorine agent feed pump (16a) interlocked with the raw water feed pump (14a). A certain amount of chlorinating agent is supplied to the raw water supplied to. Further, a draining pipe (24) is connected to the other axial end face (the lower face in FIG. 4) of the filter cylinder, and the treated water treated by the filter cylinder (12) is in the middle of the pipe (24). Is connected to the pipe (26) for sending the treated water to the treated water tank (18) and the pipe (28) for sending the treated water as backwash water to the filter cylinder (12) by driving the backwash pump (18a). Is done. These pipes (24), (26) and (28) are fitted with on-off valves (24a), (26a) and (28a), respectively, and the operation purpose of the filter device (10) (for example, “filter water” Open or close in response to "doing" or "washing the filter cylinder (12) backwashing". Further, a backwash water drain pipe (30) for discharging backwash water is connected to the upper end face of the filter cylinder (12) through an on-off valve (30a).
[0046]
Using the above-described filtration device (10), a filtration test was specifically performed under the conditions shown in Table 1.
[0047]
[Table 1]
While operating the filtration device (10) under the conditions shown in Table 1, the filtered treated water was sampled at regular intervals, and the concentrations of iron (Fe) and manganese (Mn) were quantified by atomic absorption spectrophotometry, The removal rate of iron and manganese was calculated by the following formula 1, and the change with time of the removal rate of iron and manganese is shown in FIG. In the portion of X on the time axis in the figure, backwash cleaning was performed for 5 minutes.
[0049]
[Formula 1]
From FIG. 5, it can be seen that the filter medium of the example has a higher removal rate of iron and manganese than that of the comparative example, and that this tendency does not change even after the backwash cleaning. Thus, it can be seen that the filter medium of the present invention has higher iron and manganese removal efficiency than the conventional filter medium.
[0051]
(Test Example 2) Evaluation of durability of filter medium for long-term use In order to confirm the durability of the filter medium for long-term use, a continuous backwash washing test was performed using the above-described filtration device (10). . Specifically, assuming that backwashing is performed twice a day for 5 minutes each, the total backwashing time for 3 years is 7 days. Thus, the back filtration was continuously performed for 7 days on the Example filter medium and the Comparative Example filter medium, and the chemical components before and after the backwash cleaning in each filter medium were analyzed. The analysis results are shown in Table 2.
[0052]
[Table 2]
From the results shown in Table 2, the chemical composition of the filter medium before and after backwashing was almost unchanged in the example filter medium, whereas the ratio of manganese dioxide (MnO 2 ) decreased dramatically after backwashing in the comparative filter medium. You can see that Therefore, in the filter medium of the present invention, crystalline manganese dioxide is firmly attached to the porous material and can be used stably for a long time, whereas in the conventional filter, manganese dioxide is used as the porous material. It is not firmly attached, and if it is used for a long period of time, manganese dioxide on the surface of the filter medium is peeled off and washed away.
[0054]
【The invention's effect】
According to the present invention, since a thin layer of crystalline manganese dioxide is firmly attached to a porous material having a large specific surface area and a light specific gravity, even if the filter medium is subjected to wear due to water flow or backwashing during filtration. The thin layer of manganese dioxide can be prevented from peeling off from the surface of the porous material.
[0055]
In addition, since a thin layer of manganese dioxide is attached to the outer surface of the porous material and the inner surface of the pores, the amount of manganese dioxide attached to the porous material increases, and the probability of contact between water and manganese dioxide increases. In addition to being able to remove iron and manganese in the irrigation water with high efficiency, chromaticity, turbidity, humins and arsenic can also be removed. In addition, even if the filter medium is worn due to water flow or backwashing during filtration and the thin layer of manganese dioxide is peeled off from the surface of the filter medium, the removal efficiency of iron and manganese does not decrease, and the efficiency is high for a long time. Iron and manganese can be removed.
[0056]
Therefore, it is possible to provide an iron / manganese filter medium that is light specific gravity and excellent in iron removal / manganese removal ability, can remove chromaticity, turbidity, humins, arsenic, etc., and can exhibit oxidation catalyst ability for a long period of time. it can.
[Brief description of the drawings]
FIG. 1 is an enlarged cross-sectional photograph of an iron removal / manganese removal filter according to an embodiment of the present invention.
FIG. 2 is a flow diagram showing a process for producing an iron removal / manganese removal filter medium according to an embodiment of the present invention.
FIG. 3 is an enlarged cross-sectional photograph of an iron removal / manganese removal filter according to another embodiment of the present invention.
FIG. 4 is a schematic flow diagram showing a filtration device that has undergone a filtration test.
FIG. 5 is a graph showing the results of a filtration test.
FIG. 6 is an enlarged cross-sectional photograph of a conventional iron removal / manganese removal filter medium.
[Explanation of symbols]
(10) ... Filtration device (12) ... Filter cylinder (14) ... Raw water tank (16) ... Chlorine agent tank (18) ... Treated water tank (A) ... Filter medium
Claims (5)
（ａ）多孔質材料に硝酸マンガンを含浸して含浸体を調製し、
（ｂ）前記含浸体を加熱して、前記多孔質材料に二酸化マンガンを生成・付着させることを特徴とする除鉄・除マンガン濾材の製造方法。A method for producing an iron removal / manganese removal filter material in which manganese dioxide is adhered to a porous material,
(A) impregnating a porous material with manganese nitrate to prepare an impregnated body,
(B) A method for producing an iron removal / manganese removal filter, wherein the impregnated body is heated to produce and attach manganese dioxide to the porous material.
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Cited By (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2010109838A1 (en) * | 2009-03-24 | 2010-09-30 | 株式会社アサカ理研 | Water treatment method and water treatment system |
| WO2015092798A1 (en) * | 2013-12-19 | 2015-06-25 | Mekorot Water Company, Ltd | Process, device and system for treatment of water |
| CN105439276A (en) * | 2015-12-28 | 2016-03-30 | 徐州市城区水资源管理处 | Device and processing method for removing high-concentration ferro-manganese in mine water with oxidation and catalysis column |
| EP3194340A1 (en) * | 2014-09-17 | 2017-07-26 | University of Copenhagen | Metal oxide coated diatomite aggregate and use thereof as adsorbent and fertilizer |
| WO2019159917A1 (en) * | 2018-02-14 | 2019-08-22 | パナソニックＩｐマネジメント株式会社 | Water treatment apparatus |
| EP3507005B1 (en) * | 2016-08-30 | 2021-07-21 | LightOre SA | Use of a volume body as filtration means and/or sorption means for regeneration by backwashing |
| CN116272841A (en) * | 2023-05-11 | 2023-06-23 | 中南大学 | Manganese dioxide/ferric hydroxide porous adsorption material and preparation method and application thereof |
-
2002
- 2002-10-11 JP JP2002299643A patent/JP4072039B2/en not_active Expired - Lifetime
Cited By (11)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2010109838A1 (en) * | 2009-03-24 | 2010-09-30 | 株式会社アサカ理研 | Water treatment method and water treatment system |
| JP4786771B2 (en) * | 2009-03-24 | 2011-10-05 | 株式会社アサカ理研 | Water treatment method and water treatment system |
| WO2015092798A1 (en) * | 2013-12-19 | 2015-06-25 | Mekorot Water Company, Ltd | Process, device and system for treatment of water |
| US10421671B2 (en) | 2013-12-19 | 2019-09-24 | Mekorot Water Company, Ltd. | Process, device and system for treatment of water |
| US11078094B2 (en) | 2013-12-19 | 2021-08-03 | Mekorot Water Company Ltd. | Process, device and system for treatment of water |
| EP3194340A1 (en) * | 2014-09-17 | 2017-07-26 | University of Copenhagen | Metal oxide coated diatomite aggregate and use thereof as adsorbent and fertilizer |
| CN105439276A (en) * | 2015-12-28 | 2016-03-30 | 徐州市城区水资源管理处 | Device and processing method for removing high-concentration ferro-manganese in mine water with oxidation and catalysis column |
| EP3507005B1 (en) * | 2016-08-30 | 2021-07-21 | LightOre SA | Use of a volume body as filtration means and/or sorption means for regeneration by backwashing |
| WO2019159917A1 (en) * | 2018-02-14 | 2019-08-22 | パナソニックＩｐマネジメント株式会社 | Water treatment apparatus |
| CN116272841A (en) * | 2023-05-11 | 2023-06-23 | 中南大学 | Manganese dioxide/ferric hydroxide porous adsorption material and preparation method and application thereof |
| CN116272841B (en) * | 2023-05-11 | 2024-04-19 | 中南大学 | Manganese dioxide/ferric hydroxide porous adsorption material and preparation method and application thereof |
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