JP3876124B2 - Method for producing hydrated iron-containing aluminum oxide - Google Patents

Description

【００１５】
本発明の含鉄アルミニウム酸化物は、下記式（２）
ＩＲ＝（Ｉ_０／Ｉ_１）×１００ …（２）
式中、Ｉ_０は水和含鉄アルミニウム酸化物の赤外線吸収スペクトルにおいて３価の水和鉄酸化物に基づく特性吸収の吸光度であり、
Ｉ_１は水和含鉄酸化物と水和アルミニウム酸化物との同一組成比のブレンド物の赤外線吸収スペクトルにおいて３価の水和鉄酸化物に基づく特性吸収の吸光度である、
で定義される吸光度比（ＩＲ）が波数８９０〜８８０ｃｍ^−１において２５％以下であることが特徴である。
添付図面の図２は、本発明（実施例４）の含鉄アルミニウム酸化物の赤外線吸収スペクトルであり、図３は、硫酸第二鉄溶液にアルカリを添加してｐＨが１０．０になるまで中和し、生成する３価の水和鉄酸化物の赤外線吸収スペクトルであり、図４は、硫酸アルミニウム溶液にアルカリを添加してｐＨが９．５になるまで中和し、生成する水和アルミニウム酸化物の赤外線吸収スペクトルであり、図５は、３価の水和鉄酸化物及び水和アルミニウム酸化物を本発明（実施例４）と同じ量比で乾式混合したものの赤外線吸収スペクトルである。
即ち、図３から水和鉄酸化物では波数８９０〜８８０ｃｍ^−１にＦｅ−Ｏに基づく強い吸収ピークが認められ、また実施例と４同じ比率で水酸化アルミニウムと水酸化第二鉄を混合した図５にも強い吸収ピークが認められる。これに対して、本発明の水和含鉄アルミニウム酸化物では、図２に示すとおり、前記特性吸収域ピークがほとんど認められないのであって、これは、本発明の水和含鉄アルミニウム酸化物では、鉄分とアルミニウム分とが緊密複合体になっているためと認められる。
【００１６】
本発明の水和含鉄アルミニウム酸化物は、種々の有臭成分に対する吸着性に優れている。例えば、この水和含鉄アルミニウム酸化物では硫化水素吸着量が自重の７５重量％以上であるという特徴を有している。
後述する表７に示すとおり、本発明の水和含鉄アルミニウム酸化物は、含水鉄酸化物と含水アルミニウム酸化物との単なる混合物に比べて、硫化水素の吸着容量においても、吸着速度においても格段に優れている。このことは、３価の鉄酸化物とアルミニウム酸化物とが均一に分散した複合体を形成しているためと思われる。
更に後述する表９に示すとおり、本発明の水和含鉄アルミニウム酸化物は、アルデヒドに対しても優れた吸着性能を示すことが分かる。
【００１７】
本発明によれば、酸化鉄の含有量を変化させることにより、水和含鉄アルミニウム酸化物の酸強度分布をコントロールできるという利点がある。表１２に本発明の水和含鉄アルミニウム酸化物の固体酸量を示す。鉄分の含有量の少ない実施例１の水和含鉄アルミニウム酸化物では、酸強度函数（Ｈ_０）が＋４．８迄の酸量が０．５０８であるのに対して、鉄分の含有量の多い実施例４の水和含鉄アルミニウム酸化物では、酸強度函数（Ｈ_０）が＋４．８迄の酸量が０．２１３で、酸強度函数（Ｈ_０）−５．６〜−３．０の酸量がゼロである。
【００１８】
［製法］
本発明の水和含鉄アルミニウム酸化物は、三価の鉄塩及びアルミニウム塩を含む原料溶液を、複分解により生成する塩が水溶性であるアルカリ土類金属水酸化物によりｐＨが４．０〜４．５になるまで中和し、生成する沈殿を上記ｐＨ範囲で濾過洗浄し、ケーキを再分散させて更にｐＨが７〜１０になるまで酸根を除去することにより製造される。
【００１９】
上記で得られた水和含鉄アルミニウム酸化物は、１１０℃乾燥後、２００乃至１２００℃で焼成して使用することができる。
【００２０】
本発明の代表的な例として、三価の鉄塩及びアルミニウム塩を含む原料溶液（Ｆｅ_２Ｏ_３／Ａｌ_２Ｏ_３モル比０．１乃至０．９）と５乃至４０％の水酸化マグネシウムスラリーをｐＨが４．２〜４．５になる範囲で同時注加する。この時の反応温度は室温〜９０℃で行う。反応後濾過・水洗し、濾過ケーキを更に水に分散させ、アルカリを添加しｐＨが７〜１０になるように調整を行う。その後４０〜１００℃で熟成を行った後、酸根が４％、好ましくは２％以下になるまで濾過水洗し、本発明の水和含鉄アルミニウム酸化物を得ることができる。
反応は同時注加以外に、三価の鉄塩及びアルミニウム塩を含む原料溶液にアルカリを添加しｐＨ２．０〜２．５で水和鉄酸化物粒子を一旦沈殿させた後、更にｐＨが４．２〜４．５になるようにアルカリを添加して本発明の水和含鉄アルミニウム酸化物を得ることもできる。
【００２１】
特に、原料の三価の鉄塩及びアルミニウム塩を含む溶液としては、酸性白土を酸処理した際に生成する廃酸が適している。その廃酸の代表的な組成を示すと、
Ａｌ_２Ｏ_３ ０．１〜８％
Ｆｅ_２Ｏ_３ ０．０５〜６％
ＳＯ_３ ０．５〜３０％
の組成を有する。具体的には、この廃酸に水酸化マグネシウムを添加しｐＨが４．０〜４．５になるまで中和し、生成する沈殿を上記ｐＨ範囲で濾過洗浄し、ケーキを再分散させて更にｐＨが７〜１０になるまで酸根を除去する
【００２２】
本発明の方法によれば、鉄塩がｐＨ２．０付近でアルミニウム塩より先に水和含鉄酸化物粒子の沈殿が生成する。次にｐＨが４．０付近で沈殿した水和アルミニウム酸化物がベーマイトゲルに成長するが、鉄分が増加してくると非晶質になりやすくなる。このことから３価の水和鉄酸化物及び水和アルミニウム酸化物が緊密な複合体を形成していると思われる。
【００２３】
本発明で三価の鉄塩としては、硫酸塩、硝酸塩、塩酸塩等使用できる。具体的には、硫酸第二鉄、硝酸第二鉄、塩化第二鉄溶液が挙げられ、好ましくは硫酸第二鉄が使用される。
【００２４】
本発明でアルミニウム塩としては、硫酸塩、硝酸塩、塩酸塩等使用できる。具体的には、硫酸アルミニウム、塩基性硫酸アルミニウム、塩化アルミニウム、塩基性塩化アルミニウム、硝酸アルミニウム等が挙げられる。好ましくは、硫酸アルミニウム、塩基性硫酸アルミニウムが使用される。
【００２５】
また、ｐＨ調整剤として用いられるアルカリ土類金属水酸化物としては、水酸化マグネシウム、水酸化カルシウム、水酸化亜鉛、水酸化バリウム等が挙げられる。好ましくは水酸化マグネシウム、水酸化カルシウムが使用される他、必要に応じて苛性ソーダ、苛性カリ、アルミン酸ソーダ、ケイ酸ソーダ等を用いても良い。
また、硫酸、硝酸及び塩酸塩として溶解するものであれが酸化マグネシウム、酸化カルシウム、亜鉛華、炭酸カルシウム、炭酸マグネシウム、塩基性炭酸マグネシウム等を用いることもできる。
【００２６】
［用途］
本発明の水和含鉄アルミニウム酸化物は、消臭剤、調湿剤、壁材、成型助剤、触媒、触媒担体及び水中のリン除去剤等の吸着剤として有用であり、必要によりその性能を損なわない限り、有機酸、無機吸着剤、II族の金属水酸化物及びIV族の金属のリン酸塩或いは光反応性半導体と組み合わせて用いることが出来る。有機酸は、従来消臭剤の用途に使用されているものは全て使用できる。
【００２７】
（有機酸）
有機酸としては、スルホン酸、モノカルボン酸、ジカルボン酸、トリカルボン酸等を挙げることができる。アミノスルホン酸の例としてはスルファニル酸が挙げられ、モノカルボン酸の例としては、ギ酸、酢酸、安息香酸等が代表的に挙げられる。ジカルボン酸としては、脂肪族不飽和ジカルボン酸、脂肪族飽和ジカルボン酸、芳香族ジカルボン酸、脂環式ジカルボン酸が挙げられる。該脂肪族不飽和ジカルボン酸は、好ましくは炭素数４〜６のものである。具体的にはフマル酸、マレイン酸、イタコン酸、シトラコン酸等が挙げられる。該脂肪族飽和ジカルボン酸は、好ましくは炭素数２〜６のものである。具体的には、コハク酸、マロン酸、酒石酸、リンゴ酸、グルタル酸、アジピン酸等が挙げられる。芳香族ジカルボン酸は、ベンゼン環を有することが好ましく、具体的にはフタル酸、イソフタル酸、テレフタル酸が挙げられる。該脂環式ジカルボン酸は、シクロヘキシル環を有する酸が好ましい。具体的にはシクロヘキサンジカルボン酸等が挙げられる。トリカルボン酸としてはクエン酸が代表的に挙げられる。
【００２８】
用いる有機酸は、実質上無臭で且つ常温において固体であるものが好適であり、酒石酸、リンゴ酸、クエン酸、フマル酸が好適である。これらの酸は、用途に応じて、水に可溶性の酸でも、或いは水に難溶性の酸でもよい。水に可溶性の酸、例えば酒石酸や、リンゴ酸は、本発明の消臭剤の細孔内に添着するのが容易であり、しかもこれを添着してなる該消臭剤は、Ｘ線回折的にピークを示さなくなるように微細化されている。一方、水に難溶性の酸、例えばフマル酸は水との接触を避け得ないような用途や、水系で該消臭剤を施工する用途に適しており、この場合にも後述する手段により、該消臭剤の細孔内に組み込むことが可能となる。
【００２９】
本発明の水和含鉄アルミニウム酸化物と有機酸は、９９：１乃至５０：５０の重量比、特に９９：１乃至８０：２０の重量比で組み合わせて使用するのがよい。
【００３０】
有機酸の少なくとも一部を水和含鉄アルミニウム酸化物の表面或いは細孔内に添着させるには、種々の手段を採用することができ、有機酸溶液の本発明の水和含鉄アルミニウム酸化物への含浸法や、有機酸と該酸化物との共粉砕法等が用いられる。中でも、メカノケミカル処理による添着が特に好ましい。
【００３１】
含浸法では、有機酸を水或いは有機極性溶媒、例えば、メタノール、エタノール等のアルコール類、アセトン、メチルエチルケトン等のケトン類、メチルエーテル、テトラヒドロフラン等のエーテル類、セロソルブ系溶媒、ジエチレングリコールエーテル系溶媒等に溶解した溶液を、本発明の水和含鉄アルミニウム酸化物に含浸させ、これを乾燥して製品とする。
有機酸の溶液としては、一般に有機酸の濃度が５乃至２０重量％の溶液を用いるのが好ましい。
【００３２】
一方、共粉砕法では、固体の有機酸と本発明の水和含鉄アルミニウム酸化物とを、粉砕機中で共粉砕する。粉砕機としては、ボールミル、ジェットミル、振動ミル、コロイドミル等が使用されるが、特にジェットミルが好適に使用される。
この粉砕に対して、少量の水分、一般に組成物当たり５乃至２５重量％の水分を加えると、細孔内への有機酸の取り込みが有効に行われる。
【００３３】
（無機吸着剤）
無機吸着剤としては、例えば、結晶性ケイ酸亜鉛化合物、含アルミニウムフィロケイ酸亜鉛乃至そのケイ酸質複合体、フィロケイ酸マグネシウム、含アルミニウムフィロケイ酸マグネシウム、メソポーラスシリカ、セピオライト、パリゴルスカイト、活性炭、竹炭、木炭、天然ゼオライト、合成ゼオライト、抗菌ゼオライト、活性炭素繊維、シリカゲル、活性白土、アルミナ、バーミキュライト、ケイソウ土などが挙げられ、更にパルプ、繊維、布、高分子多孔体など併用することができる。
これらの無機吸着剤は、前記の有機酸と組み合わせて用いることももちろんできる。無機吸着剤と有機酸は、９９：１乃至５０：５０の重量比、特に９５：５乃至６０：４０の重量比で組み合わせて使用するのがよい。
【００３４】
（II族の金属水酸化物及びIV族の金属のリン酸塩）
II族の金属水酸化物は、鉄、コバルト、ニッケル、亜鉛、銅から選ばれる１種又は２種以上の金属からなり、IV族の金属のリン酸塩はチタン、ジルコニウム、スズから選ばれる１種又は２種以上の金属からなる。好ましくは水酸化亜鉛とリン酸チタンを含有する沈殿生成物が好ましい。特に光触媒機能を持つチタン、リン酸チタンを含むものがよい。
【００３５】
上記沈殿生成物のII族の金属とIV族の金属の含有比率は、金属原子比（II族金属／IV族金属）で約０．０１乃至１００、好ましくは０．１乃至１０、更に好ましくは０．２乃至５である。
【００３６】
上記沈殿生成物のII族の金属水酸化物及びIV族の金属のリン酸塩以外に性能を損なわない程度に非晶質シリカ、ゼオライト、珪藻土、スメクタイト等の無機多孔質物質を含有させてもよく、特に好ましくは非晶質シリカを含有させるのがよい。
【００３７】
II族の金属水酸化物及びIV族の金属のリン酸塩を含有する沈殿生成物の製造方法としては次のような製造方法が挙げられるが、これに制限されるものではない。例えば、IV族金属の水不溶性リン酸塩とII族金属イオン共存下にII族金属の水酸化物を生成してもよいし、先にIV族金属の水不溶性リン酸塩を生成した後、II族金属イオンを加え、その水酸化物を生成してもよい、このとき残留しているリン酸分とII族金属が反応しないように水不溶性リン酸塩が生成した後、アルカリ金属水酸化物を用いて余剰のリン酸を除去しておくのが望ましい。
【００３８】
（光反応性半導体）
本発明では、性能を損なわない量で光反応性半導体との併用も可能である。光反応性半導体は、主に波長が４００ｎｍ以下の紫外線の照射により電子・正孔対が生成し、接触している臭気物質などを酸化還元反応で分解することができる物質であり、例えば、酸化チタン、酸化タングステン、酸化亜鉛、酸化セリウム、チタン酸ストロンチウム、及びニオブ酸カリウム等が挙げられる。これらの内でも、特に酸化チタン、更にアナターゼ型の酸化チタンが好ましく、この場合正孔のもつ強い酸化力が脱臭能力に関係すると思われる。
【００３９】
更に、酸化力をより一層高めるために、酸化チタン、酸化タングステン、酸化亜鉛などの粒子の表面又は内部に銅、銀、金、亜鉛、バナジウム、鉄、コバルト、ニッケル、ルテニウム、ロジウム、パラジウム、白金などの金属や金属酸化物を存在させても良い。
【００４０】
これらの光半導体は粉末またはゾルの形態で用いられ、その一次粒径は５乃至５０ｎｍの範囲にあることが好ましい。これらの光反応性半導体は、分散性、非溶解性の改良のため、脱臭能力をあまり低下させない程度に無機または有機物質で表面処理を行うことも可能である。
【００４１】
表面を覆う無機物としては、シリカゾル、エアロジル、疎水処理エアロジル等の微粒子シリカ、ケイ酸カルシウム、ケイ酸マグネシウム等のケイ酸塩、カルシア、マグネシア、チタニア等の金属酸化物、水酸化マグネシウム、水酸化アルミニウム等の金属水酸化物、炭酸カルシウム等の金属炭酸塩、ハイドロタルサイト、Ａ型、Ｘ型、Ｙ型、Ｐ型等の合成ゼオライト及びその酸処理物又はその金属イオン交換物から成る定形粒子等があり、有機物としてはシラン系、アルミニウム系、チタン系或いはジルコニウム系のカップリング剤、高級脂肪酸、金属石鹸或いは樹脂酸石鹸、または界面活性剤等が目的に応じて使用される。
【００４２】
アルデヒド類等の有害物質を除去するためには、本発明の水和含鉄アルミニウム酸化物や光触媒担持体とを、光反応性半導体が活性化される光の照射下に、処理すべき気体或いは液体と接触させればよく、その方法は特に限定されない。
照射する光としては、一般に波長が２００乃至４００ｎｍの紫外線が使用しやすく、光源としては、ブラックランプ、低圧水銀灯、高圧水銀灯等が使用される。
【００４３】
また、本発明の水和含鉄アルミニウム酸化物または上記有機酸、無機吸着剤、II族の金属水酸化物及びIV族の金属のリン酸塩或いは光反応性半導体と組み合わせたものは粉末、顆粒状或いは棒状、ペレット状、ハニカム状に押し出し成形し用途に応じた適宜の形状に容易に成形することができる。
更に本発明の水和含鉄アルミニウム酸化物をシート状基材に担持させ、シート状消臭剤とすることが可能である。このようなシート状消臭剤としては、本水和含鉄アルミニウム酸化物を梳き込んだ抄紙や被覆したコート紙等の消臭紙（この場合、シート状基材は紙またはパルプである）、不織布等の薄いシート状基材とシート状物などが挙げられる。シート基材とシート基材との間に本発明水和含鉄アルミニウム酸化物を保持せしめたシート状物やコルゲート加工したシート状物に用いられるシート状基材としては、少なくとも通気性のあるもので、更には、液中の臭気成分を除去するためから濾布のような通液性のあるものであればよい。用いるシートの基材としては、天然繊維や合成繊維のいずれでもよく、例えば、不織布として一般に知られているものが好ましく、これらの素材としては、ナイロン−６、ナイロン６、６、ポリエチレンテレフタレート等のポリエステル、ビニロン、ポリプロピレン、ポリビニルアルコールなどの合成繊維、麻、綿、製紙用パルプなどの天然繊維が挙げられる。
また本水和含鉄アルミニウム酸化物の使用条件によっては該シートに対し、親水性、撥水性、透水性などの材質を用いて、使用条件に適したものとすることができる。
【００４４】
本発明の水和含鉄アルミニウム酸化物をシートの間に保持せしめる方法としては、特に限定されるものではない。
例えば、２枚のシートの間に本発明の水和含鉄アルミニウム酸化物を均等に挟み込み、両シートを接着または接合することによって、該水和含鉄アルミニウム酸化物を保持することができる。
また１枚のシートを折り曲げて、その間に本発明の水和含鉄アルミニウム酸化物を挟み、上下シートを接合することによって、該水和含鉄アルミニウム酸化物を保持する。
保持させる本発明の水和含鉄アルミニウム酸化物の目付け量は、１０００ｇ／ｍ^２以下、好ましくは１０〜８５０ｇ／ｍ^２、より好ましくは１５〜６００ｇ／ｍ^２である。
【００４５】
更に本発明の水和含鉄アルミニウム酸化物を天然繊維や合成繊維と水に分散し、これを混抄して抄紙を得ることができる。また、本発明の水和含鉄アルミニウム酸化物を水に分散しシート基材に含浸させてシート状消臭剤を得ることもできる。また、上記の繊維類を原料としてそれ自体公知の方法により不織布の形態にすることもできる。例えば紡糸の過程で予め繊維と該水和含鉄アルミニウム酸化物とを混ぜた後、不織布にすることもできる（化学便覧［応用化学編］改訂３版、第６６０頁）。ここで用いられる原料繊維としては、綿、麻、パルプ等の天然繊維、セルロース系（レーヨン等）、ポリアミド系（ナイロン等）、ポリエステル系、ポリ塩化ビニル系、ポリ塩化ビニリデン系、ポリアクリロニトリル系（アクリル等）、ポリオレフィン系（ポリプロピレン、ポリエチレン等）、ポリウレタン系、ポリビニルアルコール系（ビニロン等）等の化学繊維が挙げられる。
【００４６】
かくして本発明の水和含鉄アルミニウム酸化物を混抄して抄紙したり、シート基材に担持させる際には、通常の抄造法などにおいて用いられる分散剤、凝集剤、結合剤、湿潤剤、可塑剤、接着剤等を適宜必要に応じて添加してもよい。
【００４７】
該凝集剤や分散剤としては、一般に抄紙に用いられるものであればよい。例えば、アニオン系有機高分子やカチオン系有機高分子などの高分子凝集剤が用いられる。該アニオン系有機高分子としてはアクリルアミド重合体の部分加水分解物等が挙げられる。更にこれらは、アクリルアミドと共重合可能な不飽和酸との共重合体、アクリル酸の単独または共重合体、アニオン変性でんぷん（酸化でんぷん等）、その他のアニオン性糊剤も併用可能である。該カチオン系有機高分子としては、カチオン変性ポリアクリルアミド樹脂、マンニッヒ反応物、ホフマン分解物、４級アミン含有モノマーとの共重合体、カチオン化でんぷんなどが挙げられる。
【００４８】
該結合剤としては、スチレン、アクリロニトリル、イソプレン等とブタジエンの共重合体やアクリル酸エステル、酢酸ビニル、塩化ビニル等の単独または共重合体、或いは天然ガム類、アルギン酸ナトリウム、ＣＭＣ、フェノールホルムアルデヒド樹脂、メラミンホルムアルデヒド樹脂、尿素ホルムアルデヒド樹脂、アルキッド樹脂などが挙げられる。
【００４９】
該可塑剤としては、フタル酸エステル系可塑剤等が、オレイン酸アンモニウム石鹸で乳化、分散した後、使用することができる。
該接着剤としては、カゼイン、ラテックス、でんぷん、ポリビニルアルコールなどが用いられる。
【００５０】
その他の分散剤や湿潤剤等もそれ自体公知のものを用いることが可能である。
前記の各種添加剤は、適宜必要に応じて適量が配合される。
混合抄紙消臭剤やシート状消臭剤における消臭素材の割合は、全体重量に対して、１〜７０重量％、好ましくは５〜５０重量％である。消臭剤の含有量が少ないと消臭能力が劣り、また多すぎると紙やシートの強度が十分でなくなったり、また消臭剤の保持が困難となる。
【００５１】
このようにして得られた混合抄紙消臭剤は、各種の用途に応用可能である。例えば、そのまま使用して部屋やトイレの消臭壁紙やオムツの材料として使用して消臭紙オムツ、箱や蓋の内貼り用として使用して消臭ごみ箱、押し入れやタンス等の中敷き、水槽の濾過材、多孔性プラスチックや布の間に挟み込んだトイレの消臭床敷き、小さくカットしたものを布袋等に入れたハンドバックやカバンの消臭袋、袋状に加工した消臭ゴミ袋等が挙げられる。特にトイレの床敷き用には、吸湿剤の使用やエンボス加工をすると効果的である。
以上のことは、本発明の水和含鉄アルミニウム酸化物単独品だけでなく、有機酸、無機吸着剤、II族の金属水酸化物及びIV族の金属のリン酸塩或いは光反応性半導体と組み合わせたものでも、用いることができる。
【００５２】
また、本発明の水和含鉄アルミニウム酸化物は、前述した固体酸量をコントロールできることにより有害ガス例えば、ＮＯｘ、ＳＯｘ等の分解触媒兼担体として有用である。更に、本発明の水和含鉄アルミニウム酸化物は、酸化アルミニウム、酸化鉄を主成分としていることから、水中のリン除去剤の吸着剤としても有効であり、リン酸分を含有する任意の水、例えば都市下水、化学工場排水、食品工業排水に適用できる。その場合当該吸着剤を粉末或いは粒状物等任意の形で用いることができ、特に０．５乃至５mmの粒状物の形で用いることが望ましい。
【００５３】
【実施例】
本発明を次の例で説明するが、本発明は以下の例に限定されるものではない。
尚、各試験方法は下記の方法に従って行った。
【００５４】
（１）Ｘ線回折測定試験
理学電機（株）製のＲＡＤ−ＩＢシステムを用いて、Ｃｕ−Ｋαにて測定した。
ターゲット Ｃｕ
フィルター 湾曲結晶グラファイトモノクロメーター
検出器 ＳＣ
電圧 ４０ＫＶＰ
電流 ２０ｍＡ
カウントフルスケール ８０００ｃ／ｓ
スムージングポイント ２５
走査速度 １°／ｍｉｎ
ステップサンプリング ０．０２°
スリット ＤＳ１° ＲＳ０．１５ｍｍ ＳＳ１°
照角 ６°
【００５５】
（２）化学分析
強熱減量(Ig-loss )、二酸化ケイ素(SiO_２)、酸化アルミニウム(Al_２O_３) 、酸化ナトリウム(Na_２O)の分析はＪＩＳ．Ｍ．８８５５に準拠して測定した。なお、Fe_２O_３、CaO、MgO、K_２Oは原子吸光法を用いた。なお、測定試料は110℃乾燥物を基準とする。
【００５６】
（３）ＢＥＴ比表面積、細孔容積
カルロエルバ社製Ｓｏｒｐｔｏｍａｔｉｃ Ｓｅｒｉｅｓ １９００を使用し、ＢＥＴ法により測定した。
【００５７】
（４）ｐＨ測定
ＪＩＳ Ｋ ５１０１−２６（３）３．１に依った。
【００５８】
（５）赤外吸収スペクトル
日本分光（株）社製ＦＴ／ＩＲ−６１０を用いて，ＫＢｒ錠剤法で測定した。
【００５９】
（６）水分吸着量
試料を１１０℃の乾燥機で２時間乾燥し、その前後の重量変化を測定して求めた。
【００６０】
（７）濾過試験
試料液３００ｍｌを径１２.５ｃｍのブフナーロートでＮｏ２の濾紙を用いて真空度１０Ｔｏｒｒで吸引濾過し液を切らさないようにさらに水洗液６００ｍｌを加え、完全に濾過するまでの時間を濾過時間とした。
【００６１】
（８）消臭性能試験
１．８Ｌ密閉容器に試料を０．２５ｇまたは０．５０ｇ入れ、各種悪臭ガスを所定量注入した後、残存するガス濃度を測定した。なお、測定対象としたガスは、硫化水素（Ｈ_２Ｓ）、アンモニア（ＮＨ_３）、エチルメルカプタン、ホルムアルデヒドである。
尚硫化水素（Ｈ_２Ｓ）の吸着平衡量は同容器にＨ_２Ｓガス２５ｍｌづつ注入し、一定時間経過してもさらに吸着しない点を平衡吸着量とし吸着容積からガス重量を換算して求めた。
【００６２】
（９）吸湿量
試料約１ｇをあらかじめ重量を測定した４０×４０ｃｍの秤量瓶に入れ、１５０℃の電気乾燥機で３時間乾燥後デシケーター中で放冷する。
次いで試料の重さを精秤し、硫酸で関係湿度を調節したデシケーター中に入れ７２時間後の重量増を測定して吸湿量とした。
【００６３】
（１０）固体酸測定
n-ブチルアミン測定法[参考文献：「触媒」Vol.11,No6,P210-216（1969）]にて測定した。結果は、表１２に示した。
【００６４】
（鉄アルミニウム含有抽出液の調製−１）
表２に示すジオクタヘドラル型スメクタイト粘土鉱物原料１を用いて、粉砕、混練し５ｍｍ径に造粒し、この造粒物１００Ｋｇを処理槽に充填した。
そこに２８重量％硫酸水溶液を１５０Ｋｇ注加し循環させながら９０℃に昇温し、その温度で５時間処理した。
処理終了後母液を抜き取り、抽出液１を得た。この抽出液の組成を表２に示した。
【００６５】
（鉄アルミニウム含有抽出液の調製−２）
表２に示すジオクタヘドラル型スメクタイト粘土鉱物原料２を用いて硫酸濃度を３０重量％にした以外は参考例１と同様に処理して抽出液２を得た。この液の組成を表２に示した。
【００６６】
（鉄アルミニウム含有抽出液の調製−３）
表２に示すジオクタヘドラル型スメクタイト粘土鉱物原料３を用いて硫酸濃度を３２重量％にした以外は参考例１と同様に処理して抽出液３を得た。この液の組成を表２に示した。
【００６７】
（実施例１）
３００Ｌのステンレス製反応容器に参考例１で得られた抽出液（Ａｌ_２Ｏ_３濃度を１．０％に調整）を２００Ｌ入れ３５℃に加熱調整後、ｐＨが４．３で一定するまで約３時間かけて３５％水酸化マグネシウムスラリーを加えた。
その後１時間熟成後吸引濾過・洗浄し一次中和した鉄アルミニウム水和物ケーキ（試料１−Ａ）を約７Ｋｇ（固形分濃度３０％）得た。このケーキ及び１１０℃で乾燥した粉末のＸ線回折図を図１に、粉末性状を表２に示した。
次いで２０Ｌのステンレス製容器に水８．０Ｋｇを入れ、攪拌下上記ケーキ（試料１−Ａ）５．０Ｋｇを加え十分分散後６０℃まで昇温する。
６０℃に達した事を確認してから希アルミン酸ソーダ（Ｎａ_２Ｏ １６．０％、Ａｌ_２Ｏ_３ １１．５％）をｐＨが１０を越えないようにゆっくり注加し（二次中和・脱硫処理）最終的にｐＨが８．５で安定したところで注加を止め、そのまま４時間攪拌・熟成後吸引濾過・洗浄し水和含鉄アルミニウム酸化物のケーキ（試料１−Ｂ）を得た。このケーキ及び１１０℃で乾燥した粉末のＸ線回折図を図１に、粉末性状を表２に、固体酸量を表１２に示した。
【００６８】
（実施例２）
実施例１で一次中和に水酸化マグネシウムスラリーと１５％苛性ソーダを１：１で混合して使用した以外は実施例１同様に調製した。その時のケーキ組成及び１１０℃で乾燥した粉末の性状を表２に示した。
【００６９】
（実施例３）
抽出液１中のＦｅ_２Ｏ_３分が３倍になるように試薬硫酸第二鉄（和光純薬製試薬特級）を所定量添加し５時間かけて十分溶解する。次いで実施例１と同様に調製し水和含鉄アルミニウム酸化物を得た。このケーキ及び１１０℃で乾燥した粉末の性状を表２に示した。
【００７０】
（実施例４）
抽出液２を用いて実施例１と同様に調製して水和含鉄アルミニウム酸化物を得た。このケーキ及び１１０℃で乾燥した粉末の性状を表２に、ＩＲスペクトルを図２に、固体酸量を表１２に示した。
この乾燥粉末を４００℃、６００℃焼成したものの比表面積は各々３１４、３０２ｍ^２／ｇで、Ｘ線回折上は非晶質であった。（図１に６００℃焼成品のＸ線回折図を示した。）
【００７１】
（実施例５）
抽出液３を用いてＡｌ_２Ｏ_３濃度を０．７％にした以外は実施例１と同様に調製して水和含鉄アルミニウム酸化物を得た。このケーキ及び１１０℃で乾燥した粉末の性状を表２に示した。
【００７２】
（比較例１）
実施例１で一次中和用として１５％苛性ソーダを用いて中和し試料１−Ａ−２を調製した。この場合の濾過速度は２２分と非常に悪かった。ケーキの性状について表２に示した。
【００７３】
【表２】

【００７４】
（実施例６）
抽出液３を用いて二次中和に１５％苛性ソーダを用いた以外は実施例５と同様に調製して水和含鉄アルミニウム酸化物を得た。この水和含鉄アルミニウム酸化物を １１０℃で乾燥した粉末の性状を表３に示した。
【００７５】
（実施例７）
実施例１で二次処理（脱硫処理）温度を８５℃にした以外は実施例１と同様に調製して水和含鉄アルミニウム酸化物を得た。この水和含鉄アルミニウム酸化物を １１０℃で乾燥した粉末の性状を表３に示した。
【００７６】
（実施例８）
実施例４で二次処理（脱硫処理）温度を３０℃にし、攪拌・熟成時間を２４時間にした以外は実施例４と同様に調製して水和含鉄アルミニウム酸化物を得た。
この水和含鉄アルミニウム酸化物を １１０℃で乾燥した粉末の性状を表３に示した。
【００７７】
（比較例２）
実施例８で二時中和時の最終中和ｐＨを６．０にした以外は実施例８と同様に調製して水和含鉄アルミニウム酸化物を得た。この水和含鉄アルミニウム酸化物を １１０℃で乾燥した粉末の性状を表３に示した。
【００７８】
【表３】

【００７９】
（実施例９〜１８）
実施例１（試料１−Ｂ）及び実施例４（試料２−Ｂ）と表４に示した吸着剤等を粉末換算で所定割合に混合し自動肉挽機を用いて径５ｍｍの柱状に成型後１１０℃乾燥または３００℃で焼成して表４に示す成型品を得た。
【００８０】
【表４】

【００８１】
（実施例１９〜２８）
実施例１、４と表５に示した吸着剤等を混合後、小型回転式乾燥機で一部脱水し卓上パワーミルで破砕造粒した後、フルイで所定粒度に分篩して表５に示す成型品を得た。
【００８２】
【表５】

【００８３】
（実施例２９〜３４）
実施例１、４及び表６に示した吸着剤等を所定割合で混合し回転式の転動造粒機を用いて水をバインダーにして球状に成型し、篩別後所定温度で乾燥して表６に示す成型品を得た。
【００８４】
【表６】

【００８５】
（応用例１）
硫化水素吸着試験法を用いて表７に示したサンプルの吸着（消臭）速度及び硫化水素の平衡吸着量（消臭量）を測定した。結果を表７に示した。
【００８６】
【表７】

【００８７】
（応用例２）
実施例１４，３４の成型品を径約１ｍの下水導管の上部にステンレス製の金網で作った籠の中に５０Ｌ入れ、使用前後の硫化水素量を測定した結果を表８に示したが、大きく減少した。
【００８８】
【表８】

【００８９】
（応用例３）
表９に示した実施例のアンモニア吸着速度、ホルマリン吸着速度、エチルメルカプタン吸着速度を示した。
【００９０】
【表９】

【００９１】
（応用例４）
５００ｍｌのビーカーに純水３００ｍｌと表面の紙を取り除いたタバコ（ハイライト）６本を入れ、一夜攪拌分散させた後メンブランフィルターで濾過して抽出原液を得た。次いでこの原液３０ｍｌに試料０．３ｇを加えマグネッチックスターラー（５００ｒｐｍ）で２０分間攪拌後原液同様メンブランフィルターで濾過した液の透過率を測定して評価した。結果を表１０に示したが、透過率の高いものほど着色が少ない事を示す。
尚測定器はＨＩＲＡＭＡ ＲＩＫＡ ＫＥＮＫＹＵＪＯ製ＰＨＯＴＯ−ＥＬＥＣＴＲＩＣＦＩＬＴＥＲ ＰＨＯＴＯＭＥＴＥＲ ＭＯＤＥＬ２Ｃに依った。
【００９２】
【表１０】

【００９３】
（応用例５）
濃度３％に希釈したパルプ（ＬＢＫＰ）４０Ｌを６０Ｌのステンレス製容器に入れ攪拌下、表１１に示した実施例のケーキを入れ（乾燥時パルプ：試料＝１５：８５）十分分散した。次いで径２０ｃｍのロートで濾過しプレス脱水後、１１０℃で２４時間乾燥し１２×１２×１ｃｍにカッティングした。
さらにこのサンプルをＲＨ５０％２５℃の恒温恒湿室に２４時間入れてエージングし調湿板サンプルを作成後その重量を測定する（ａ）。
次に恒温恒湿室（２５℃、ＲＨ５０％）内でＲＨ９０％のデシケーター中に２４時間入れた後のサンプル重量を測定し（ｂ）次式から吸湿量を求めた。
吸湿量（ｇ／ｍ^２）＝（ｂ−ａ）×１００×｛１０,０００／（１２×１２）｝
次にＲＨ４０％のデシケーターに入れ２４時間後同様に重量を測定し（ｃ）次式から放湿量を求めた。
放湿量（ｇ／ｍ^２）＝（ｂ−ｃ）×１００×｛１０,０００／（１２×１２）｝
測定結果について表１１に示した。
【００９４】
【表１１】

【００９５】
【表１２】

【００９６】
（応用例６）
一般住宅用の壁剤として実施例１、４のケーキを乾燥物換算で６５％混合し土壁として塗った。２ヶ月経過しても粉落ち、脱落等が見られなかった。
【００９７】
【発明の効果】
特定の量比の３価鉄分を含有し、ＢＥＴ比表面積が２００ｍ^２ ／ｇ以上で、且つＲＨ７５％における平衡水分吸着量が２０％以上である水和含鉄アルミニウム酸化物を低廉なコストで製造することができた。この含鉄アルミニウム酸化物は悪臭に対する消臭性能、調湿性能、壁材、触媒及び触媒担体等の用途に優れている。
【図面の簡単な説明】
【図１】図１−１は市販ベーマイトゲルのＸ線回折像、図１−２は実施例１の第一段中和物（試料１−Ａ）のＸ線回折像、図１−３は実施例１の第二段中和物（試料１−Ｂ）のＸ線回折像、図１−４は実施例４の含鉄アルミニウム酸化物（６００℃焼成品）のＸ線回折像をそれぞれ示す図である。
【図２】実施例４の水和含鉄アルミニウム酸化物（試料２−Ｂ）の赤外吸収スペクトルを示す図である。
【図３】水酸化第二鉄の赤外吸収スペクトルを示す図である。
【図４】水酸化アルミニウム（ベーマイトゲル）の赤外吸収スペクトルを示す図である。
【図５】実施例４（試料２−Ｂ）と同一組成になるように水酸化第二鉄、水酸化アルミニウム（ベーマイトゲル）を乾式混合した試料の赤外吸収スペクトルを示す図である。[0001]
BACKGROUND OF THE INVENTION
  The present invention relates to a hydrated iron-containing aluminum oxide.Related to the manufacturing methodMore specifically, hydrated iron-containing aluminum oxide with extremely high adsorptivity to hydrogen sulfide and the likeManufacturing methodAbout.
[0002]
[Prior art]
Inorganic compositions containing alumina and iron are widely used in the fields of deodorants, adsorbents, catalysts and the like.
Japanese Patent Publication No. 56-6337 discloses Fe.₂O₃And Al₂O₃And the weight ratio is Al₂O₃/ Fe₂O₃0.01 to 0.1, and 0.5 to 5% by weight of one or more of alkali metal oxides or alkaline earth metal oxides is included with respect to the total amount of the oxides, A carbon monoxide conversion catalyst is described.
[0003]
Japanese Patent Laid-Open No. 63-154178 discloses that activated alumina contains at least one compound selected from the group consisting of copper sulfate, iron sulfate, zinc sulfate and magnesium sulfate in an amount of 1 to 20% by weight based on the activated alumina. A deodorant characterized by being carried is described.
[0004]
JP-A-6-339630 discloses a step of adding a basic aluminum salt and an alkali to a divalent iron salt solution to produce a neutral boehmite alumina hydrate sol, and a neutral region sol. Forming a mixed sol in which the divalent and trivalent iron salt is uniformly dispersed in the boehmite alumina hydrate sol by forcibly oxidizing to form a divalent and trivalent iron salt; And a method for producing an alumina-iron salt composite including a step of dehydrating and powdering.
[0005]
Japanese Patent No. 3068518 describes a deodorizing agent for odorous gas in which a trivalent aluminum salt, a trivalent iron salt and an alumina potassium salt adhere to a porous inorganic substance having open pores.
[0006]
[Problems to be solved by the invention]
Boehmite gel (pseudo boehmite), activated alumina, and amorphous alumina hydrate are adsorbents with excellent adsorptive properties, while iron is a well-known component with an excellent deodorizing action against hydrogen sulfide and the like. However, the conventionally known deodorant composition has a high production cost, and its performance is still not fully satisfactory.
[0007]
  The present inventors have succeeded in producing a hydrated iron-containing aluminum oxide by coprecipitation of iron and aluminum, and this iron-containing aluminum oxide has excellent deodorizing performance against bad odor and excellent humidity control performance. I found out.
  That is, an object of the present invention is to provide a novel hydrated iron-containing aluminum oxide that has excellent deodorizing performance against bad odor, humidity control performance, etc.Manufacturing methodTo provide.
  Another object of the present invention is to provide a method for producing the hydrated iron-containing aluminum oxide with a relatively small number of steps and at a low cost.
[0008]
[Means for Solving the Problems]
  According to the present invention, a raw material solution containing a trivalent iron salt and an aluminum salt is subjected to pH 4.0 to 4.5 with an alkaline earth metal hydroxide in which a salt produced by metathesis is water-soluble. The hydrated iron-containing iron is characterized by neutralizing and filtering and washing the resulting precipitate in the above pH range, redispersing the cake to remove acid radicals until the pH reaches 7 to 10, and drying or baking as necessary. A method for producing aluminum oxide is provided.
  In the production method of the present invention, the raw material solution is preferably a waste acid generated when acid clay is acid-treated, and the trivalent iron salt and aluminum salt are sulfates, and alkaline earth metal hydroxide Preferably, the product is magnesium hydroxide.
  The hydrated iron-containing aluminum oxide obtained by the above production method is formed by coprecipitation of iron and aluminum.
  Following formula (1)
    xFe₂O₃・ Al₂O₃・ NH₂O (1)
    In the formula, x is a number in a molar ratio of 0.01 to 1.0,
    n is a number in a molar ratio of 0 <n ≦ 4Is,
The BET specific surface area is 200 m.²/ G or more and the equilibrium water adsorption amount at RH75% is 20% or moreIt is. TakeIn iron-containing aluminum oxide,
1. Following formula (2)
      IR = (I₀/ I₁) × 100
      Where I₀Is the infrared absorption spectrum of hydrated iron-containing aluminum oxide
          Is the absorbance of the characteristic absorption based on trivalent hydrated iron oxide,
            I₁Is the same composition ratio of hydrated iron oxide and hydrated aluminum oxide.
          Based on trivalent hydrated iron oxide in the infrared absorption spectrum of the blend
          Is the absorbance of the characteristic absorption,
Absorbance ratio (IR) defined by the wave number 890-880 cm^-125% or less in,
2. In the above formula (1), n is a number satisfying 0 <n ≦ 4 and has an X-ray diffraction image peculiar to boehmite gel or is amorphous.
3. The hydrogen sulfide adsorption amount is 75% by weight or more of its own weight,
4). The acid radical content is 4% by weight or less,
Is preferred.
  The above iron-containing aluminum oxide isDeodorant, humidity control agent, wall material, catalyst, catalyst carrier and adsorbentIt is suitably used for
[0009]
DETAILED DESCRIPTION OF THE INVENTION
[Action]
In the present invention, a raw material solution containing a trivalent iron salt and an aluminum salt is neutralized with an alkaline earth metal hydroxide having a water-soluble salt produced by metathesis until the pH becomes 4.0 to 4.5. The first characteristic is that the produced precipitate is filtered and washed in the above pH range.
In the present invention, the acid radicals contained in the trivalent iron salt and aluminum salt react with the alkaline earth metal hydroxide, and the iron content and aluminum content precipitate as hydroxide. As a result of this reaction, the alkaline earth metal component becomes a salt of the acid radical. At this time, the alkaline earth metal component is neutralized until the pH becomes 4.0 to 4.5, and the resulting precipitate is filtered and washed in the above pH range. It is important for preventing precipitation of alkaline earth metal components and preventing contamination of the hydrated iron-containing aluminum oxide with alkaline earth metal components.
[0010]
The iron and aluminum coprecipitate cake obtained by separation and washing in this way is redispersed, and the acid radicals are further removed until the pH is 7 to 10, and drying or baking is performed as necessary. Thus, a hydrated iron-containing aluminum oxide is obtained.
According to the present invention, by applying the above-described two-stage neutralization method and using an alkaline earth metal hydroxide for the first stage neutralization, an acid radical is prevented while preventing an alkaline earth metal component from being mixed. This makes it possible to produce hydrated iron-containing aluminum oxide having excellent adsorption activity.
[0011]
The hydrated iron-containing aluminum oxide of the present invention is formed by coprecipitation of iron and aluminum, and has the following formula (1)
xFe₂O₃・ Al₂O₃・ NH₂O (1)
In which x is a number in the molar ratio of 0.01 to 1.0, in particular 0.03 to 0.4,
n is a number in a molar ratio of 0 <n ≦ 4.
The BET specific surface area is 200 m.²/ G or more, preferably 250 m²/ G or more and the equilibrium water adsorption amount at RH 75% is 20% or more, preferably 25% or more.
When the iron content is less than the above range, it is not preferable because the adsorption activity for hydrogen sulfide and the like is reduced compared to the case where the iron content is within the above range. This is not preferable because it decreases and the equilibrium moisture adsorption amount also decreases.
[0012]
The hydrated iron-containing aluminum oxide of the present invention is different from a simple mixture of trivalent hydrated iron oxide and hydrated aluminum oxide components, or a coating or adsorbate, and exists in a unique form, for example, in the form of a complex. It seems to have done.
This is confirmed from an X-ray diffraction image and an infrared absorption spectrum.
[0013]
First, although the hydrated iron-containing aluminum oxide of the present invention varies depending on the iron content, it has an X-ray diffraction image peculiar to boehmite gel in a state where the iron content is low, but it becomes amorphous as the iron content increases. I found out that
Table 1 shows the X-ray diffraction (Cu-α) diffraction angle, face spacing, and relative intensity of the boehmite gel. FIG. 1-1 shows an X-ray diffraction image of a commercially available boehmite gel, FIG. 1-2 shows an X-ray diffraction image of the first-stage neutralized product of Example 1 (Sample 1-A), and FIG. Is an X-ray diffraction image of the second-stage neutralized product of Example 1 (Sample 1-B), and FIG. 1-4 shows an X-ray diffraction image of the iron-containing aluminum oxide (fired product at 600 ° C.) of Example 4. It is shown.
According to these results, the hydrated iron-containing aluminum oxide having a low iron content is amorphous in the state of the first stage neutralization, whereas the X-ray characteristic of the boehmite gel is obtained by the second stage neutralization. It can be seen that the diffraction image is shown and that the hydrated iron-containing aluminum oxide having a high iron content has an amorphous structure.
[0014]
[Table 1]

[0015]
The iron-containing aluminum oxide of the present invention has the following formula (2)
IR = (I₀/ I₁) × 100 (2)
Where I₀Is the absorbance of the characteristic absorption based on trivalent hydrated iron oxide in the infrared absorption spectrum of hydrated iron-containing aluminum oxide,
I₁Is the absorbance of the characteristic absorption based on trivalent hydrated iron oxide in the infrared absorption spectrum of the blend of hydrated iron oxide and hydrated aluminum oxide in the same composition ratio.
Absorbance ratio (IR) defined by the wave number 890-880 cm^-1Is 25% or less.
FIG. 2 of the accompanying drawings is an infrared absorption spectrum of the iron-containing aluminum oxide of the present invention (Example 4), and FIG. 3 shows that the pH is 10.0 by adding alkali to the ferric sulfate solution. FIG. 4 is an infrared absorption spectrum of a trivalent hydrated iron oxide that is summed and produced, and FIG. 4 shows the hydrated aluminum produced by adding an alkali to an aluminum sulfate solution and neutralizing it until the pH reaches 9.5. FIG. 5 is an infrared absorption spectrum of the oxide obtained by dry-mixing trivalent hydrated iron oxide and hydrated aluminum oxide in the same amount ratio as in the present invention (Example 4).
That is, from FIG. 3, the hydrated iron oxide has a wave number of 890 to 880 cm.^-1A strong absorption peak based on Fe-O is observed in Fig. 5, and a strong absorption peak is also observed in Fig. 5 in which aluminum hydroxide and ferric hydroxide are mixed in the same ratio as in Example 4. On the other hand, in the hydrated iron-containing aluminum oxide of the present invention, as shown in FIG. 2, the characteristic absorption range peak is hardly observed, and this is the case with the hydrated iron-containing aluminum oxide of the present invention. This is because the iron and aluminum components are in a close composite.
[0016]
The hydrated iron-containing aluminum oxide of the present invention is excellent in adsorptivity to various odorous components. For example, this hydrated iron-containing aluminum oxide has a feature that the hydrogen sulfide adsorption amount is 75% by weight or more of its own weight.
As shown in Table 7 to be described later, the hydrated iron-containing aluminum oxide of the present invention is remarkably improved in both the hydrogen sulfide adsorption capacity and the adsorption speed as compared with a simple mixture of hydrous iron oxide and hydrous aluminum oxide. Are better. This seems to be because a complex in which trivalent iron oxide and aluminum oxide are uniformly dispersed is formed.
Furthermore, as shown in Table 9 described later, it can be seen that the hydrated iron-containing aluminum oxide of the present invention exhibits excellent adsorption performance for aldehydes.
[0017]
According to the present invention, there is an advantage that the acid strength distribution of the hydrated iron-containing aluminum oxide can be controlled by changing the iron oxide content. Table 12 shows the solid acid amount of the hydrated iron-containing aluminum oxide of the present invention. In the hydrated iron-containing aluminum oxide of Example 1 having a low iron content, the acid strength function (H₀) Is up to +4.8, the acid content is 0.508, whereas in the hydrated iron-containing aluminum oxide of Example 4 having a high iron content, the acid strength function (H₀) Is 0.213, and the acid strength function (H₀) The acid amount of -5.6 to -3.0 is zero.
[0018]
[Production method]
In the hydrated iron-containing aluminum oxide of the present invention, the pH of the raw material solution containing a trivalent iron salt and an aluminum salt is 4.0 to 4 with an alkaline earth metal hydroxide in which a salt produced by metathesis is water-soluble. It is produced by neutralizing to 0.5 and filtering and washing the resulting precipitate in the above pH range, redispersing the cake and further removing acid radicals until the pH is 7-10.
[0019]
The hydrated iron-containing aluminum oxide obtained above can be used after being dried at 110 ° C. and calcined at 200 to 1200 ° C.
[0020]
As a typical example of the present invention, a raw material solution containing a trivalent iron salt and an aluminum salt (Fe₂O₃/ Al₂O₃A magnesium hydroxide slurry having a molar ratio of 0.1 to 0.9) and 5 to 40% is simultaneously added so that the pH becomes 4.2 to 4.5. The reaction temperature at this time is from room temperature to 90 ° C. After the reaction, it is filtered and washed, and the filter cake is further dispersed in water, and an alkali is added to adjust the pH to 7-10. Thereafter, after aging at 40 to 100 ° C., the hydrated iron-containing aluminum oxide of the present invention can be obtained by washing with filtered water until the acid radical becomes 4%, preferably 2% or less.
In addition to simultaneous addition of the reaction, alkali was added to the raw material solution containing the trivalent iron salt and aluminum salt to precipitate the hydrated iron oxide particles at pH 2.0 to 2.5, and then the pH was further increased to 4 The hydrated iron-containing aluminum oxide of the present invention can also be obtained by adding an alkali so as to be 2 to 4.5.
[0021]
In particular, as a solution containing a trivalent iron salt and an aluminum salt as raw materials, a waste acid produced when acid clay is acid-treated is suitable. The typical composition of the waste acid is
Al₂O₃0.1-8%
Fe₂O₃0.05-6%
SO₃0.5-30%
Having a composition of Specifically, magnesium hydroxide is added to this waste acid and neutralized until the pH becomes 4.0 to 4.5, and the resulting precipitate is filtered and washed in the above pH range, and the cake is redispersed to further reduce the pH. Remove acid radicals until pH is 7-10
[0022]
According to the method of the present invention, a precipitate of hydrated iron-containing oxide particles is formed prior to the aluminum salt when the iron salt has a pH of around 2.0. Next, although the hydrated aluminum oxide precipitated at pH around 4.0 grows into boehmite gel, it becomes amorphous easily as the iron content increases. From this, it is considered that trivalent hydrated iron oxide and hydrated aluminum oxide form a close complex.
[0023]
As the trivalent iron salt in the present invention, sulfate, nitrate, hydrochloride and the like can be used. Specific examples include ferric sulfate, ferric nitrate, and ferric chloride solutions, and ferric sulfate is preferably used.
[0024]
In the present invention, as the aluminum salt, sulfate, nitrate, hydrochloride and the like can be used. Specific examples include aluminum sulfate, basic aluminum sulfate, aluminum chloride, basic aluminum chloride, and aluminum nitrate. Preferably, aluminum sulfate or basic aluminum sulfate is used.
[0025]
Examples of the alkaline earth metal hydroxide used as a pH adjuster include magnesium hydroxide, calcium hydroxide, zinc hydroxide, and barium hydroxide. Preferably, magnesium hydroxide and calcium hydroxide are used, and if necessary, caustic soda, caustic potash, sodium aluminate, sodium silicate, and the like may be used.
In addition, magnesium oxide, calcium oxide, zinc white, calcium carbonate, magnesium carbonate, basic magnesium carbonate and the like can be used as long as they dissolve as sulfuric acid, nitric acid and hydrochloride.
[0026]
[Usage]
The hydrated iron-containing aluminum oxide of the present invention is useful as an adsorbent such as a deodorant, a humidity control agent, a wall material, a molding aid, a catalyst, a catalyst carrier, and a phosphorus removal agent in water. As long as they are not impaired, they can be used in combination with organic acids, inorganic adsorbents, Group II metal hydroxides and Group IV metal phosphates or photoreactive semiconductors. Any organic acid that has been conventionally used for deodorants can be used.
[0027]
(Organic acid)
Examples of the organic acid include sulfonic acid, monocarboxylic acid, dicarboxylic acid, and tricarboxylic acid. Examples of aminosulfonic acid include sulfanilic acid, and examples of monocarboxylic acid typically include formic acid, acetic acid, benzoic acid and the like. Examples of the dicarboxylic acid include aliphatic unsaturated dicarboxylic acid, aliphatic saturated dicarboxylic acid, aromatic dicarboxylic acid, and alicyclic dicarboxylic acid. The aliphatic unsaturated dicarboxylic acid is preferably one having 4 to 6 carbon atoms. Specific examples include fumaric acid, maleic acid, itaconic acid, citraconic acid and the like. The aliphatic saturated dicarboxylic acid is preferably one having 2 to 6 carbon atoms. Specific examples include succinic acid, malonic acid, tartaric acid, malic acid, glutaric acid, and adipic acid. The aromatic dicarboxylic acid preferably has a benzene ring, and specifically includes phthalic acid, isophthalic acid, and terephthalic acid. The alicyclic dicarboxylic acid is preferably an acid having a cyclohexyl ring. Specific examples include cyclohexanedicarboxylic acid. A typical example of the tricarboxylic acid is citric acid.
[0028]
The organic acid to be used is preferably substantially odorless and solid at room temperature, and tartaric acid, malic acid, citric acid, and fumaric acid are preferable. These acids may be water-soluble acids or poorly water-soluble acids, depending on the application. Acids soluble in water, such as tartaric acid and malic acid, can be easily added to the pores of the deodorant of the present invention, and the deodorant formed by adding the acid is X-ray diffractive. Are refined so that no peak is shown. On the other hand, acids that are sparingly soluble in water, such as fumaric acid, are suitable for applications where contact with water is unavoidable, and for applications where the deodorant is applied in an aqueous system. It can be incorporated into the pores of the deodorant.
[0029]
The hydrated iron-containing aluminum oxide and the organic acid of the present invention are preferably used in combination at a weight ratio of 99: 1 to 50:50, particularly 99: 1 to 80:20.
[0030]
In order to attach at least a part of the organic acid to the surface or pores of the hydrated iron-containing aluminum oxide, various means can be adopted, and the organic acid solution can be added to the hydrated iron-containing aluminum oxide of the present invention. An impregnation method, a co-grinding method of an organic acid and the oxide, or the like is used. Of these, attachment by mechanochemical treatment is particularly preferred.
[0031]
In the impregnation method, an organic acid is added to water or an organic polar solvent, for example, alcohols such as methanol and ethanol, ketones such as acetone and methyl ethyl ketone, ethers such as methyl ether and tetrahydrofuran, cellosolve solvent, diethylene glycol ether solvent and the like. The dissolved solution is impregnated with the hydrated iron-containing aluminum oxide of the present invention and dried to obtain a product.
As the organic acid solution, it is generally preferable to use a solution having an organic acid concentration of 5 to 20% by weight.
[0032]
On the other hand, in the co-grinding method, the solid organic acid and the hydrated iron-containing aluminum oxide of the present invention are co-ground in a pulverizer. As the pulverizer, a ball mill, a jet mill, a vibration mill, a colloid mill or the like is used, and a jet mill is particularly preferably used.
When a small amount of water, generally 5 to 25% by weight of water per composition, is added to the pulverization, the organic acid is effectively taken into the pores.
[0033]
(Inorganic adsorbent)
Examples of inorganic adsorbents include crystalline zinc silicate compounds, aluminum-containing zinc phyllosilicates or siliceous composites thereof, magnesium phyllosilicates, aluminum-containing magnesium phyllosilicates, mesoporous silica, sepiolite, palygorskite, activated carbon, bamboo charcoal. , Charcoal, natural zeolite, synthetic zeolite, antibacterial zeolite, activated carbon fiber, silica gel, activated clay, alumina, vermiculite, diatomaceous earth and the like, and pulp, fiber, cloth, polymer porous material and the like can be used in combination.
Of course, these inorganic adsorbents can also be used in combination with the above organic acids. The inorganic adsorbent and the organic acid may be used in combination at a weight ratio of 99: 1 to 50:50, particularly 95: 5 to 60:40.
[0034]
(Group II metal hydroxides and Group IV metal phosphates)
Group II metal hydroxides are composed of one or more metals selected from iron, cobalt, nickel, zinc and copper, and Group IV metal phosphates are selected from titanium, zirconium and tin. It consists of seeds or two or more metals. A precipitation product containing zinc hydroxide and titanium phosphate is preferred. In particular, one containing titanium or titanium phosphate having a photocatalytic function is preferable.
[0035]
The content ratio of the Group II metal and the Group IV metal in the precipitation product is about 0.01 to 100, preferably 0.1 to 10, more preferably a metal atomic ratio (Group II metal / Group IV metal). 0.2 to 5.
[0036]
In addition to the Group II metal hydroxides and Group IV metal phosphates of the precipitation product, inorganic porous materials such as amorphous silica, zeolite, diatomaceous earth, smectite, etc. may be contained to the extent that performance is not impaired. In particular, it is particularly preferable to contain amorphous silica.
[0037]
Examples of the method for producing a precipitation product containing a Group II metal hydroxide and a Group IV metal phosphate include, but are not limited to, the following production methods. For example, a Group II metal hydroxide may be produced in the presence of a Group IV metal water-insoluble phosphate and a Group II metal ion, or a Group IV metal water-insoluble phosphate may be produced first, A group II metal ion may be added to form a hydroxide. At this time, after forming a water-insoluble phosphate so that the remaining phosphoric acid content does not react with the group II metal, alkali metal hydroxide is generated. It is desirable to remove excess phosphoric acid using a material.
[0038]
(Photoreactive semiconductor)
In the present invention, the photoreactive semiconductor can be used in an amount that does not impair the performance. A photoreactive semiconductor is a substance that can generate electron-hole pairs mainly by irradiation with ultraviolet rays having a wavelength of 400 nm or less, and can decompose a contacted odorous substance by an oxidation-reduction reaction. Examples thereof include titanium, tungsten oxide, zinc oxide, cerium oxide, strontium titanate, and potassium niobate. Of these, titanium oxide and, more particularly, anatase type titanium oxide are preferable. In this case, the strong oxidizing power of holes is considered to be related to the deodorizing ability.
[0039]
Furthermore, in order to further enhance the oxidizing power, particles of titanium oxide, tungsten oxide, zinc oxide, etc. are coated on the surface or inside of copper, silver, gold, zinc, vanadium, iron, cobalt, nickel, ruthenium, rhodium, palladium, platinum. A metal such as a metal oxide or a metal oxide may be present.
[0040]
These optical semiconductors are used in the form of powder or sol, and their primary particle size is preferably in the range of 5 to 50 nm. These photoreactive semiconductors can be surface-treated with an inorganic or organic material to such an extent that the deodorizing ability is not lowered so much in order to improve dispersibility and insolubility.
[0041]
Examples of inorganic substances covering the surface include silica sol, aerosil, hydrophobized aerosil and other fine particle silica, silicates such as calcium silicate and magnesium silicate, metal oxides such as calcia, magnesia and titania, magnesium hydroxide, aluminum hydroxide Metal hydroxides such as calcium carbonate, metal carbonates such as calcium carbonate, hydrotalcite, synthetic zeolite such as A-type, X-type, Y-type, P-type, etc. As organic substances, silane-based, aluminum-based, titanium-based or zirconium-based coupling agents, higher fatty acids, metal soaps, resin acid soaps, surfactants, or the like are used depending on the purpose.
[0042]
In order to remove harmful substances such as aldehydes, the hydrated iron-containing aluminum oxide or photocatalyst carrier of the present invention is treated with a gas or liquid to be treated under irradiation of light that activates the photoreactive semiconductor. The method is not particularly limited.
In general, UV light having a wavelength of 200 to 400 nm is easily used as the light to be irradiated, and a black lamp, a low-pressure mercury lamp, a high-pressure mercury lamp, or the like is used as the light source.
[0043]
Further, the hydrated iron-containing aluminum oxide of the present invention or the above-mentioned organic acid, inorganic adsorbent, Group II metal hydroxide and Group IV metal phosphate or photoreactive semiconductor are combined in powder, granular form Alternatively, it can be extruded into a rod shape, a pellet shape, or a honeycomb shape, and easily formed into an appropriate shape according to the application.
Furthermore, the hydrated iron-containing aluminum oxide of the present invention can be supported on a sheet-like substrate to form a sheet-like deodorant. Such sheet-like deodorants include deodorized paper (in this case, the sheet-like base material is paper or pulp), non-woven fabric, such as papermaking and coated paper coated with the hydrated iron-containing aluminum oxide And a thin sheet-like substrate and sheet-like material. As a sheet-like substrate used for a sheet-like material in which the hydrated iron-containing aluminum oxide of the present invention is held between a sheet substrate and a sheet substrate or a corrugated sheet-like material, it is at least breathable. Furthermore, any liquid-permeable material such as a filter cloth may be used to remove odor components in the liquid. The base material of the sheet to be used may be either natural fiber or synthetic fiber, for example, those generally known as non-woven fabrics are preferable. Examples of these materials include nylon-6, nylon 6, 6, polyethylene terephthalate, and the like. Examples thereof include synthetic fibers such as polyester, vinylon, polypropylene, and polyvinyl alcohol, and natural fibers such as hemp, cotton, and paper pulp.
Further, depending on the use conditions of the hydrated iron-containing aluminum oxide, the sheet can be made suitable for use conditions by using materials such as hydrophilicity, water repellency, and water permeability.
[0044]
The method for holding the hydrated iron-containing aluminum oxide of the present invention between the sheets is not particularly limited.
For example, the hydrated iron-containing aluminum oxide of the present invention is evenly sandwiched between two sheets, and the two sheets can be bonded or joined together to hold the hydrated iron-containing aluminum oxide.
Further, the hydrated iron-containing aluminum oxide is held by bending one sheet, sandwiching the hydrated iron-containing aluminum oxide of the present invention between them and joining the upper and lower sheets.
The basis weight of the hydrated iron-containing aluminum oxide of the present invention to be retained is 1000 g / m.²Or less, preferably 10 to 850 g / m², More preferably 15 to 600 g / m²It is.
[0045]
Further, the hydrated iron-containing aluminum oxide of the present invention can be dispersed in natural fibers or synthetic fibers and water, and mixed to obtain paper. Further, the sheet-like deodorant can be obtained by dispersing the hydrated iron-containing aluminum oxide of the present invention in water and impregnating the sheet base material. Moreover, it can also be made into the form of a nonwoven fabric by the method known per se using said fibers as a raw material. For example, the fiber and the hydrated iron-containing aluminum oxide can be mixed in advance in the spinning process, and then made into a non-woven fabric (Chemical Handbook [Applied Chemistry], 3rd revised edition, page 660). The raw fibers used here include natural fibers such as cotton, hemp and pulp, cellulose (such as rayon), polyamide (such as nylon), polyester, polyvinyl chloride, polyvinylidene chloride, and polyacrylonitrile ( Acrylic), polyolefin (polypropylene, polyethylene, etc.), polyurethane, polyvinyl alcohol (vinylon, etc.) and the like.
[0046]
Thus, when paper is made by mixing the hydrated iron-containing aluminum oxide of the present invention or supported on a sheet substrate, a dispersant, a flocculant, a binder, a wetting agent, a plasticizer used in a normal paper making method and the like. Adhesives or the like may be added as necessary.
[0047]
Any flocculant or dispersant may be used as long as it is generally used for papermaking. For example, a polymer flocculant such as an anionic organic polymer or a cationic organic polymer is used. Examples of the anionic organic polymer include partial hydrolysates of acrylamide polymers. Further, these can be used in combination with a copolymer of an unsaturated acid copolymerizable with acrylamide, a homopolymer or copolymer of acrylic acid, an anion-modified starch (such as oxidized starch), and other anionic pastes. Examples of the cationic organic polymer include a cation-modified polyacrylamide resin, a Mannich reaction product, a Hoffmann decomposition product, a copolymer with a quaternary amine-containing monomer, and a cationized starch.
[0048]
Examples of the binder include copolymers of styrene, acrylonitrile, isoprene, and the like and butadiene, acrylic acid esters, vinyl acetate, vinyl chloride and the like alone or copolymers, or natural gums, sodium alginate, CMC, phenol formaldehyde resin, Examples include melamine formaldehyde resin, urea formaldehyde resin, alkyd resin and the like.
[0049]
As the plasticizer, a phthalate ester plasticizer or the like can be used after being emulsified and dispersed with an ammonium oleate soap.
As the adhesive, casein, latex, starch, polyvinyl alcohol and the like are used.
[0050]
Other dispersants, wetting agents, and the like that are known per se can be used.
Appropriate amounts of the various additives are appropriately blended as necessary.
The ratio of the deodorizing material in the mixed paper making deodorant and the sheet-like deodorant is 1 to 70% by weight, preferably 5 to 50% by weight, based on the total weight. If the content of the deodorant is small, the deodorizing ability is inferior, and if it is too large, the strength of the paper or sheet becomes insufficient, and it becomes difficult to hold the deodorant.
[0051]
The mixed paper making deodorant thus obtained can be applied to various uses. For example, it can be used as it is as a deodorant wallpaper or diaper material in rooms and toilets, as a deodorant paper diaper, as a box or lid for internal use, a deodorized trash can, an insole or insole for insoles, a tank Examples include filter media, toilet deodorant flooring sandwiched between porous plastic and cloth, handbags with small cuts in cloth bags, bag deodorization bags, deodorized garbage bags processed into bags, etc. It is done. Especially for toilet flooring, it is effective to use a moisture absorbent or emboss.
The above is not only the hydrated iron-containing aluminum oxide of the present invention alone, but also a combination with an organic acid, an inorganic adsorbent, a group II metal hydroxide and a group IV metal phosphate or a photoreactive semiconductor. Can also be used.
[0052]
Further, the hydrated iron-containing aluminum oxide of the present invention is useful as a decomposition catalyst and carrier for harmful gases such as NOx and SOx because it can control the amount of solid acid described above. Furthermore, since the hydrated iron-containing aluminum oxide of the present invention is mainly composed of aluminum oxide and iron oxide, it is also effective as an adsorbent for a phosphorus removing agent in water, and any water containing a phosphoric acid component, For example, it can be applied to municipal sewage, chemical factory effluent, and food industry effluent. In that case, the adsorbent can be used in any form such as powder or granules, and it is particularly desirable to use it in the form of granules of 0.5 to 5 mm.
[0053]
【Example】
The present invention will be described with reference to the following examples, but the present invention is not limited to the following examples.
Each test method was performed according to the following method.
[0054]
(1) X-ray diffraction measurement test
Using a RAD-IB system manufactured by Rigaku Corporation, the measurement was performed with Cu-Kα.
Target Cu
Filter Curved crystal graphite monochromator
Detector SC
Voltage 40KVP
Current 20mA
Count full scale 8000c / s
Smoothing point 25
Scanning speed 1 ° / min
Step sampling 0.02 °
Slit DS1 ° RS0.15mm SS1 °
Lighting angle 6 °
[0055]
(2) Chemical analysis
Ignition loss (Ig-loss), silicon dioxide (SiO₂), Aluminum oxide (Al₂O₃), Sodium oxide (Na₂The analysis of O) is JIS. M.M. Measurement was performed according to 8855. Fe₂O₃, CaO, MgO, K₂O used the atomic absorption method. The measurement sample is based on a dried product at 110 ° C.
[0056]
(3) BET specific surface area, pore volume
Measurement was performed by BET method using Sorptomatic Series 1900 manufactured by Carlo Elba.
[0057]
(4) pH measurement
It was based on JIS K 5101-26 (3) 3.1.
[0058]
(5) Infrared absorption spectrum
Measurement was performed by KBr tablet method using FT / IR-610 manufactured by JASCO Corporation.
[0059]
(6) Moisture adsorption
The sample was dried for 2 hours with a dryer at 110 ° C., and the weight change before and after the drying was measured.
[0060]
(7) Filtration test
300 ml of the sample solution was suction filtered with a Buchner funnel having a diameter of 12.5 cm using a No. 2 filter paper at a vacuum degree of 10 Torr, and 600 ml of the water washing solution was further added so as not to cut the solution. .
[0061]
(8) Deodorizing performance test
0.25 g or 0.50 g of the sample was put in a 1.8 L sealed container, and after a predetermined amount of various malodorous gases were injected, the residual gas concentration was measured. The gas to be measured is hydrogen sulfide (H₂S), ammonia (NH₃), Ethyl mercaptan and formaldehyde.
Hydrogen sulfide (H₂The adsorption equilibrium amount of S) is H in the same container.₂S gas was injected in an amount of 25 ml, and the point at which no further adsorption occurred even after a certain period of time was taken as the equilibrium adsorption amount, and the gas weight was converted from the adsorption volume.
[0062]
(9) Moisture absorption
About 1 g of a sample is put in a 40 × 40 cm weighing bottle previously weighed, dried in an electric dryer at 150 ° C. for 3 hours, and then allowed to cool in a desiccator.
Next, the weight of the sample was precisely weighed, placed in a desiccator whose relative humidity was adjusted with sulfuric acid, and the weight increase after 72 hours was measured to obtain a moisture absorption amount.
[0063]
(10) Solid acid measurement
n-Butylamine measurement [Reference: “Catalyst” Vol. 11, No. 6, P210-216 (1969)]. The results are shown in Table 12.
[0064]
(Preparation of iron-aluminum-containing extract-1)
Using the dioctahedral smectite clay mineral raw material 1 shown in Table 2, it was pulverized, kneaded and granulated to a diameter of 5 mm, and 100 kg of this granulated product was filled into a treatment tank.
Thereto, 150 kg of a 28 wt% sulfuric acid aqueous solution was poured, and the temperature was raised to 90 ° C. while being circulated.
After the treatment was completed, the mother liquor was extracted to obtain Extract 1. The composition of this extract is shown in Table 2.
[0065]
(Preparation of iron-aluminum-containing extract-2)
Extract 2 was obtained in the same manner as in Reference Example 1 except that the dioctahedral smectite clay mineral raw material 2 shown in Table 2 was used and the sulfuric acid concentration was changed to 30% by weight. The composition of this solution is shown in Table 2.
[0066]
(Preparation of iron-aluminum-containing extract-3)
Extract 3 was obtained in the same manner as in Reference Example 1 except that the dioctahedral smectite clay mineral raw material 3 shown in Table 2 was used and the sulfuric acid concentration was changed to 32% by weight. The composition of this solution is shown in Table 2.
[0067]
Example 1
Extract liquid (Al) obtained in Reference Example 1 in a 300 L stainless steel reaction vessel₂O₃After adjusting the concentration to 200% and heating to 35 ° C., 35% magnesium hydroxide slurry was added over about 3 hours until the pH was constant at 4.3.
Thereafter, about 7 kg (solid content concentration 30%) of an iron aluminum hydrate cake (sample 1-A) which was aged for 1 hour and then subjected to suction filtration, washing and primary neutralization was obtained. The X-ray diffraction pattern of this cake and the powder dried at 110 ° C. is shown in FIG.
Next, 8.0 kg of water is put into a 20 L stainless steel container, 5.0 kg of the cake (sample 1-A) is added with stirring, and the mixture is sufficiently dispersed and heated to 60 ° C.
After confirming that the temperature reached 60 ° C, dilute sodium aluminate (Na₂O 16.0%, Al₂O₃ 11.5%) is slowly added so that the pH does not exceed 10 (secondary neutralization / desulfurization treatment). When the pH is finally stabilized at 8.5, the addition is stopped and the mixture is stirred and aged for 4 hours. Thereafter, suction filtration and washing were performed to obtain a cake of hydrated iron-containing aluminum oxide (Sample 1-B). The X-ray diffraction pattern of this cake and the powder dried at 110 ° C. is shown in FIG. 1, the powder properties are shown in Table 2, and the solid acid amount is shown in Table 12.
[0068]
(Example 2)
Example 1 was prepared in the same manner as in Example 1 except that magnesium hydroxide slurry and 15% sodium hydroxide were mixed at a ratio of 1: 1 for primary neutralization. The cake composition at that time and the properties of the powder dried at 110 ° C. are shown in Table 2.
[0069]
(Example 3)
Fe in extract 1₂O₃A predetermined amount of a reagent ferric sulfate (reagent grade manufactured by Wako Pure Chemical Industries, Ltd.) is added so that the amount becomes 3 times, and sufficiently dissolved over 5 hours. Subsequently, it prepared similarly to Example 1 and obtained the hydrated iron-containing aluminum oxide. The properties of this cake and the powder dried at 110 ° C. are shown in Table 2.
[0070]
(Example 4)
The extract 2 was used in the same manner as in Example 1 to obtain a hydrated iron-containing aluminum oxide. The properties of the cake and the powder dried at 110 ° C. are shown in Table 2, the IR spectrum is shown in FIG. 2, and the solid acid amount is shown in Table 12.
The specific surface areas of these dried powders calcined at 400 ° C and 600 ° C are 314 and 302 m, respectively.²/ G, it was amorphous on X-ray diffraction. (The X-ray diffraction pattern of the 600 ° C. fired product is shown in FIG. 1.)
[0071]
(Example 5)
Extract 3 is used for Al₂O₃A hydrated iron-containing aluminum oxide was obtained in the same manner as in Example 1 except that the concentration was 0.7%. The properties of this cake and the powder dried at 110 ° C. are shown in Table 2.
[0072]
(Comparative Example 1)
In Example 1, sample 1-A-2 was prepared by neutralizing with 15% sodium hydroxide for primary neutralization. The filtration rate in this case was very poor at 22 minutes. The properties of the cake are shown in Table 2.
[0073]
[Table 2]

[0074]
(Example 6)
A hydrated iron-containing aluminum oxide was obtained in the same manner as in Example 5 except that 15% caustic soda was used for secondary neutralization using Extract 3. Table 3 shows the properties of the powder obtained by drying this hydrated iron-containing aluminum oxide at 110 ° C.
[0075]
(Example 7)
A hydrated iron-containing aluminum oxide was obtained in the same manner as in Example 1 except that the secondary treatment (desulfurization treatment) temperature was 85 ° C. in Example 1. Table 3 shows the properties of the powder obtained by drying this hydrated iron-containing aluminum oxide at 110 ° C.
[0076]
(Example 8)
A hydrated iron-containing aluminum oxide was obtained in the same manner as in Example 4 except that the secondary treatment (desulfurization treatment) temperature was 30 ° C. and the stirring and aging time was 24 hours in Example 4.
Table 3 shows the properties of the powder obtained by drying this hydrated iron-containing aluminum oxide at 110 ° C.
[0077]
(Comparative Example 2)
A hydrated iron-containing aluminum oxide was obtained in the same manner as in Example 8 except that the final neutralization pH at the time of neutralization in Example 8 was 6.0. Table 3 shows the properties of the powder obtained by drying this hydrated iron-containing aluminum oxide at 110 ° C.
[0078]
[Table 3]

[0079]
(Examples 9 to 18)
Example 1 (Sample 1-B) and Example 4 (Sample 2-B) and the adsorbents shown in Table 4 are mixed at a predetermined ratio in terms of powder and molded into a columnar shape with a diameter of 5 mm using an automatic meat grinder. Thereafter, the molded article shown in Table 4 was obtained by drying at 110 ° C. or baking at 300 ° C.
[0080]
[Table 4]

[0081]
(Examples 19 to 28)
Examples 1, 4 and the adsorbents shown in Table 5 were mixed, then partially dehydrated with a small rotary dryer, crushed and granulated with a tabletop power mill, and then sieved to a predetermined particle size with a sieve and shown in Table 5. A molded product was obtained.
[0082]
[Table 5]

[0083]
(Examples 29 to 34)
The adsorbents shown in Examples 1 and 4 and Table 6 were mixed at a predetermined ratio, formed into a spherical shape with water as a binder using a rotary rolling granulator, dried at a predetermined temperature after sieving. Molded products shown in Table 6 were obtained.
[0084]
[Table 6]

[0085]
(Application 1)
Using the hydrogen sulfide adsorption test method, the adsorption (deodorization) rate of the sample shown in Table 7 and the equilibrium adsorption amount (deodorization amount) of hydrogen sulfide were measured. The results are shown in Table 7.
[0086]
[Table 7]

[0087]
(Application example 2)
Table 8 shows the results of measuring the amount of hydrogen sulfide before and after use by putting 50 L of the molded products of Examples 14 and 34 into a cage made of a stainless steel wire mesh on the upper part of a sewage conduit having a diameter of about 1 m. It decreased greatly.
[0088]
[Table 8]

[0089]
(Application 3)
The ammonia adsorption rate, formalin adsorption rate, and ethyl mercaptan adsorption rate of the examples shown in Table 9 were shown.
[0090]
[Table 9]

[0091]
(Application 4)
A 500 ml beaker was charged with 300 ml of pure water and 6 cigarettes (highlights) from which the paper on the surface was removed, and the mixture was stirred and dispersed overnight and then filtered through a membrane filter to obtain an extraction stock solution. Next, 0.3 g of the sample was added to 30 ml of this stock solution, stirred for 20 minutes with a magnetic stirrer (500 rpm), and then evaluated by measuring the transmittance of the solution filtered through a membrane filter in the same manner as the stock solution. The results are shown in Table 10. The higher the transmittance, the less the coloring.
The measuring device was based on PHOTO-ELECTRIC FILTER PHOTOMETER MODEL 2C manufactured by HIRAMA RIKA KENKYYUJO.
[0092]
[Table 10]

[0093]
(Application example 5)
40 L of pulp (LBKP) diluted to a concentration of 3% was placed in a 60 L stainless steel container, and the cakes of the examples shown in Table 11 were placed under stirring (pulp during drying: sample = 15: 85) and sufficiently dispersed. Next, it was filtered through a funnel having a diameter of 20 cm, press dehydrated, dried at 110 ° C. for 24 hours, and cut to 12 × 12 × 1 cm.
Further, this sample is placed in a constant temperature and humidity chamber of RH 50% and 25 ° C. for 24 hours to prepare a humidity control plate sample, and the weight is measured (a).
Next, the sample weight after being placed in a desiccator of RH 90% in a constant temperature and humidity chamber (25 ° C., RH 50%) for 24 hours was measured. (B) The moisture absorption amount was obtained from the following equation.
Moisture absorption (g / m²) = (B−a) × 100 × {10,000 / (12 × 12)}
Next, the sample was put in a desiccator of 40% RH and the weight was measured in the same manner 24 hours later. (C) The moisture release amount was obtained from the following formula.
Moisture release (g / m²) = (B−c) × 100 × {10,000 / (12 × 12)}
The measurement results are shown in Table 11.
[0094]
[Table 11]

[0095]
[Table 12]

[0096]
(Application example 6)
65% of the cakes of Examples 1 and 4 were mixed as a wall material for a general house in terms of dry matter and applied as a soil wall. Even after 2 months, neither powder falling nor dropping off was observed.
[0097]
【The invention's effect】
Contains a specific amount of trivalent iron and has a BET specific surface area of 200m²/ G and hydrated iron-containing aluminum oxide having an equilibrium water adsorption amount of 20% or more at 75% RH could be produced at low cost. This iron-containing aluminum oxide is excellent in deodorizing performance against bad odor, humidity control performance, wall material, catalyst, catalyst support and the like.
[Brief description of the drawings]
FIG. 1-1 is an X-ray diffraction image of a commercially available boehmite gel, FIG. 1-2 is an X-ray diffraction image of a first-stage neutralized product (Sample 1-A) of Example 1, and FIG. The X-ray diffraction image of the second-stage neutralized product (Sample 1-B) of Example 1 and FIGS. 1-4 show the X-ray diffraction images of the iron-containing aluminum oxide (fired at 600 ° C.) of Example 4, respectively. It is.
2 is a graph showing an infrared absorption spectrum of a hydrated iron-containing aluminum oxide (Sample 2-B) in Example 4. FIG.
FIG. 3 is a diagram showing an infrared absorption spectrum of ferric hydroxide.
FIG. 4 is an infrared absorption spectrum of aluminum hydroxide (boehmite gel).
FIG. 5 is an infrared absorption spectrum of a sample obtained by dry-mixing ferric hydroxide and aluminum hydroxide (boehmite gel) so as to have the same composition as in Example 4 (Sample 2-B).

Claims (3)

  A raw material solution containing a trivalent iron salt and an aluminum salt is neutralized with an alkaline earth metal hydroxide having a water-soluble salt produced by metathesis until a pH of 4.0 to 4.5 is obtained. A method for producing a hydrated iron-containing aluminum oxide comprising filtering and washing the precipitate in the above pH range, redispersing the cake, further removing the acid radical until the pH reaches 7 to 10, and drying or firing as necessary. .   The manufacturing method according to claim 1, wherein the raw material solution is a waste acid produced when acid clay is acid-treated.   The method according to claim 1 or 2, wherein the trivalent iron salt and aluminum salt are sulfates, and the alkaline earth metal hydroxide is magnesium hydroxide.

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