JP3975557B2 - Ethylene adsorption removal method - Google Patents

Description

【００１７】
本発明のガス中のエチレン吸着除去方法に使用される吸着剤を構成するフェリエライトのＳｉＯ₂／Ａｌ₂Ｏ₃モル比は、１５以上である。ＳｉＯ₂／Ａｌ₂Ｏ₃モル比が１５未満ではゼオライト自身の耐熱性が低くなり、吸着剤が高温に晒される場合には、吸着特性が低下する。フェリエライトのＳｉＯ₂／Ａｌ₂Ｏ₃モル比は、より好ましくは２１〜１０００であり、更に好ましくは４０〜２００である。
【００１８】
フェリエライトの製造方法については特に限定はないが、例えば特開昭５９−７３４２３号公報及び特開昭６０−１４１６１７号公報等で開示されている有機硬化剤を使用しない方法で調製することができる。これらの製造方法は、シリカ源、アルミナ源をアルカリ溶液中に分散させ、水熱合成により得る手法である。更に、ピリジン、Ｎ−メチルピリジンヒドロキシド、ピペリジン、アルキル置換ピペリジン、ブタンジアミン等の有機硬化剤を合成原料中に存在せしめて製造することもできる。有機硬化剤の添加量は、有機硬化剤／ＳｉＯ₂モル比で０．０１〜１０であり、好ましくは０．０５〜５である。より耐熱性、耐久性の高い炭化水素吸着剤とするには、特開平８−１８８４１４号公報に記載されているピリジンとフッ素化合物を用いた方法で製造することがより好ましい。
【００１９】
フェリエライトを製造する際のフッ素化合物としては、フッ化水素、フッ化ナトリウム、ケイフッ化ナトリウム、クリオライト等の可溶性フッ素化合物を用いることができる。その添加量はフッ素化合物／ＳｉＯ₂モル比で０．０１〜１０であり、好ましくは０．０５〜５が良い。ピリジンの添加量はピリジン／ＳｉＯ₂モル比で０．０〜１０であり、好ましくは０．１〜５が良い。
【００２０】
また、シリカ源としては、ケイ酸ナトリウム、無定型シリカ、シリカゾル、シリカゲル、カオリナイト、珪藻土等を、アルミナ源としてはアルミン酸ナトリウム、水酸化アルミニウム、塩化アルミニウム、硝酸アルミニウム、硫酸アルミニウム等を用いることができる。特公昭６３−４６００７号公報に開示されている珪酸アルカリ水溶液と含アルミニウム水溶液とを同時に且つ連続的に反応させることによって得られる粒状無定型アルミノ珪酸塩均一相化合物も、シリカ源、アルミナ源の好適な材料として使用することができる。
【００２１】
反応系にピリジン及びフッ素化合物を添加してフェリエライトを製造する場合、フェリエライト中にフッ素及び／またはフッ素化合物が残存する場合がある。フッ素及び／またはフッ素化合物は残存していてもよいが、耐熱性、耐久性を更に高めるためにはフッ素及び／またはフッ素化合物を除去することが好ましい。フッ素及び／又はフッ素化合物の除去方法としては、例えば８０℃の大量の熱水で濾過洗浄する方法、希薄な塩酸または塩化アルミニウム水溶液等を用いて洗浄する方法等が挙げられる。
【００２２】
フェリエライトは、合成品あるいはそのか焼品等が用いられるが、フェリエライト中のＮａ等のイオンをアンモニウム塩あるいは鉱酸等で処理し、Ｈ型あるいはアンモニウム型として用いることもできる。か焼は３００〜１２００℃で行うことができる。
【００２３】
本発明のガス中のエチレン吸着除去方法に使用されるエチレン吸着剤は、上記のフェリエライトにＡｇが含有されている。Ａｇの含有量は、エチレンの吸着性能を十分に発揮させるためには、フェリエライト及び活性金属成分の合計量に対して０．１〜２０重量％の範囲であることが好ましい。より好ましくは０．２〜１０重量％であり、更に好ましくは０．２〜７重量％である。
【００２４】
Ａｇを含有させる方法としては、特に限定されず、公知の方法を適宜採用することができる。例えば、イオン交換法、含浸担持法、蒸発乾固法、浸漬法、固相交換法等を採用することができる。Ａｇの含有に用いる塩としては、特に限定されるものではなく、硝酸塩、硫酸塩、酢酸塩、蓚酸塩あるいはアンミン錯塩等の塩で良い。
【００２５】
本発明のガス中のエチレン吸着除去方法に使用されるエチレン吸着剤は、更にＰｄが含有されていても良い。Ｐｄの含有量は、特に限定されないが、フェリエライト及び活性金属成分の合計量に対して０．０１〜１０重量％の範囲であることが好ましい。より好ましくは０．０５〜５重量％であり、更に好ましくは０．１〜３重量％である。Ｐｄを含有させる方法としては特に限定はなく、上述のＡｇと同様の方法、同様の塩を用いることができる。またＡｇとＰｄはどちらを先にフェリエライトに含有させてもよく、また同時に含有させてもよい。
【００２６】
本発明のガス中のエチレン吸着除去方法に使用される吸着剤は、Ａｇ，Ｐｄだけでなく、他の遷移金属をフェリエライトに含有させてもよい。遷移金属としては特に限定はなく、周期表のＩＩＩＡ，ＩＶＡ，ＶＡ，ＶＩＡ，ＶＩＩＡ，ＶＩＩＩ，ＩＢ，ＩＩＢ族の元素があげられ、これらも上述のＡｇと同様の方法、同様の塩を用いて含有させることができる。
【００２７】
以上のようにして、本発明のガス中のエチレン吸着除去方法に使用されるエチレン吸着剤を調製することができる。
【００２８】
本発明のガス中のエチレン吸着除去方法に使用される吸着剤は、シリカ、アルミナ及び粘土鉱物等のバインダ−と混合し成形して使用することもできる。粘土鉱物としては、カオリン、アタパルガイト、モンモリロナイト、ベントナイト、アロフェン、セピオライト等を挙げることができる。また、コ−ジェライト製あるいは金属製のハニカム状基材に本発明の吸着材をウォッシュコ−トして使用することもできる。
【００２９】
本発明のガス中のエチレン吸着除去方法により、エチレンの吸着除去を行うことが出来る。このガスには特に制限はなく、具体的には大気、排気ガス、農作物の保管室内ガスなどエチレンを含んでいるガスが例示される。またエチレン以外に、一酸化炭素、二酸化炭素、水素、酸素、窒素、窒素酸化物、硫黄酸化物、水、エチレン以外の炭化水素が含まれている場合にも有効である。
【００３０】
ガス中のエチレンの濃度は特に限定されないが、メタン換算で０．００１〜５ｖｏｌ％が好ましく、より好ましくは０．００５〜３ｖｏｌ％である。エチレン以外の各成分の濃度についても特に限定されず、例えばＣＯ＝０〜１ｖｏｌ％、ＣＯ₂＝０〜１０ｖｏｌ％、Ｏ₂＝０〜２０ｖｏｌ％、窒素酸化物＝０〜１ｖｏｌ％、硫黄酸化物＝０〜０．０５ｖｏｌ％、Ｈ₂Ｏ＝０〜１５ｖｏｌ％でよい。
【００３１】
エチレンを吸着除去する際の空間速度、温度は特に限定されないが、空間速度：１００〜５０００００ｈｒ^-1、温度：−３０〜２５０℃であることが好ましい。
【００３２】
本発明において、Ａｇを含有したＳｉＯ₂／Ａｌ₂Ｏ₃モル比が１５以上のフェリエライトが高いエチレン吸着特性を示す理由は不明であるが、フェリエライトの細孔構造に起因すると考えられる。フェリエライトの細孔は長径５．５オングストロ−ム（Ａ）短径４．３Ａの酸素１０員環細孔と長径４．８Ａ短径３．４Ａの酸素８員環細孔が２次元的に連結した構造である。一方、ＺＳＭ−５、ゼオライトβ等の細孔のサイズは、フェリエライトより大きいことが知られている。エチレンの有効分子径は３．９Ａであり、フェリエライト細孔内への拡散は可能である。更にエチレンの分子径とフェリエライト細孔の大きさが近似しており、吸着したエチレンとフェリエライトの相互作用が強くなる。即ち、吸着したエチレンの脱離が容易でなくなり、保持力が大きくなると考えられる。
【００４５】
したがって本発明で処理される排ガスに含まれる炭化水素の種類は特に限定されないが、エチレンが含まれいる場合は窒素酸化物の除去率が大きく向上するため好ましく、その他にパラフィン、オレフィン、芳香族化合物及びそれらの混合物が含まれていてもよい。具体的には、パラフィン及びオレフィンとして炭素数が１〜２０の炭化水素を例示することができ、芳香族化合物としてベンゼン、ナフタレン、アントラセン及びこれらの誘導体を例示することができる。また、軽油、灯油、ガソリンなどを例示することもできる。
【００４６】
また本発明で処理される排ガス中に一酸化炭素、二酸化炭素、水素、窒素、硫黄酸化物、水が含まれている場合にも有効である。
【００４７】
排ガス中の各成分ガスの濃度は特に限定されないが、通常、窒素酸化物が５０〜２０００ｐｐｍ、炭化水素がメタン換算で０．００１〜５ｖｏｌ％、酸素が０．１〜２０％が好ましい。上記成分ガス以外の各成分の濃度についても特に限定されず、一酸化炭素が０〜１ｖｏｌ％、二酸化炭素が０〜１０ｖｏｌ％、硫黄酸化物が０〜０．０５ｖｏｌ％、水が０〜１５ｖｏｌ％が好ましい。また排ガス中の炭化水素の濃度が低い場合には、上記の適当な炭化水素を排ガス中に添加しても良い。
【００４８】
処理される排ガスの空間速度及び温度は特に限定されないが、空間速度（体積基準）が１００〜５０００００ｈｒ^-1、温度が−３０〜９００℃であることが好ましい。更に好ましくは空間速度が２０００〜２０００００ｈｒ^-1、温度が−３０〜８５０℃である。
【００４９】
【実施例】
以下、本発明を実施例により更に詳細に説明するが、本発明は、これらの実施例に何ら限定されるものではない。
【００５０】
＜実施例１＞吸着剤１の調製
ＳｉＯ₂／Ａｌ₂Ｏ₃モル比が１７の東ソ−製フェリエライト（商品名：ＨＳＺ−７２０ＫＯＡ）４０ｇを、ＮＨ₄Ｃｌ：１８．０ｇを純水４００ｇに溶解した塩化アンモニウム水溶液中に添加し、６０で２０時間のイオン交換操作を行った。このイオン交換操作を２回繰り返した後、固液分離し、Ｃｌイオンが検出できなくなるまで純水で洗浄し、１１０℃で２０時間乾燥して、アンモニウム型フェリエライト（ＮＨ₄−ＦＥＲ−１）を得た。
【００５１】
ＮＨ₄−ＦＥＲ−１：２０ｇ（無水換算）を、硝酸銀：０．６２ｇを純水１００ｇに溶解させた硝酸銀水溶液中に添加し、６０℃減圧条件下で蒸発乾固し、Ａｇ担持を行った。その後、１１０℃で２０時間乾燥して、吸着剤１を得た。吸着剤１のＡｇ担持量をＩＣＰ発光分析により分析したところ、２重量％であった。
【００５２】
＜実施例２＞吸着剤２の調製
用いた硝酸銀が１．５５ｇであること以外は、実施例１と同様の条件でＡｇ担持を行って、吸着剤２を調製した。吸着剤２のＡｇ担持量をＩＣＰ発光分析により分析したところ、５重量％であった。
【００５３】
＜実施例３＞吸着剤３の調製
フェリエライトとして、水熱合成法により合成したＳｉＯ₂／Ａｌ₂Ｏ₃モル比が２１のフェリエライトを用いたこと以外は、実施例１と同様にして吸着剤３を得た。吸着剤３のＡｇ担持量をＩＣＰ発光分析により分析したところ、２重量％であった。
【００５４】
＜実施例４＞吸着剤４の調製
塩化アルミニウム・６水和物（ＡｌＣｌ₃・６Ｈ₂Ｏ：９８．０重量％）８．２ｇと塩化アルミニウムから生成するＨＣｌを中和するだけの水酸化ナトリウム（ＮａＯＨ：９９重量％）６．５ｇとフッ素源としてフッ化ナトリウム（ＮａＦ：９９重量％）４０．３ｇとピリジン（Ｃ₅Ｈ₅Ｎ）９５．６ｍｌを、純水６２８ｍｌに溶解し、均一な溶液とした。
【００５５】
この均一溶液にホワイトカ−ボン（日本シリカ工業製、商品名：ニップシ−ルＶＮ−３、ＳｉＯ₂：８８重量％）８１．１ｇを加えて、次のモル組成比の原料混合物スラリ−を調製した。
【００５６】
ＳｉＯ₂／Ａｌ₂Ｏ₃＝５７
Ｆ／ＳｉＯ₂＝０．８
Ｃ₅Ｈ₅Ｎ／ＳｉＯ₂＝１
Ｈ₂Ｏ／ＳｉＯ₂＝３０
この混合物を容積１Ｌのオ−トクレ−ブに入れ、回転速度５０ｒｐｍで攪拌しながら１８０℃で７２時間の水熱合成を行った。結晶化後のゼオライトスラリ−のｐＨは１０．７であった。冷却後、固形分を分離し、十分水洗した後、１１０℃で一晩乾燥した。
【００５７】
フッ素及び／またはフッ素化合物を除去するために、得られた生成物を８０℃の純水で十分に洗浄した。蛍光Ｘ線分析の結果、洗浄後のゼオライト中のフッ素及び／またはフッ素化合物は検出限界（０．１％）以下であった。また洗浄後の生成物の組成をＩＣＰ発光分析により分析したところ、無水換算で
０．９６Ｎａ₂Ｏ・Ａｌ₂Ｏ₃・７４ＳｉＯ₂
であった。
【００５８】
洗浄後の生成物の結晶構造をＸＲＤ分析により分析したところ、表１に示したものと同等のＸ線回折図が得られ、フェリエライトであることを確認した。
【００５９】
この得られたフェリエライト型ゼオライトを、空気流通下で６００℃で４時間焼成することによりピリジンを除去した。その後、フェリエライト：４０ｇをＮＨ₄Ｃｌ：３．３６ｇを純水４００ｇに溶解した塩化アンモニウム水溶液中に添加し、６０℃で２０時間のイオン交換操作を行った。このイオン交換操作を２回繰り返した後、固液分離し、Ｃｌイオンが検出できなくなるまで純水で洗浄し、１１０℃で２０時間乾燥して、アンモニウム型フェリエライト（ＮＨ₄−ＦＥＲ−２）を得た。
【００６０】
ＮＨ₄−ＦＥＲ−２：２０ｇ（無水換算）を、硝酸銀：０．６２ｇを純水１００ｇに溶解させた硝酸銀水溶液中に添加し、６０℃減圧条件下で蒸発乾固し、Ａｇ担持を行った。その後、１１０℃で２０時間乾燥して、吸着剤４を得た。吸着剤４のＡｇ担持量をＩＣＰ発光分析により分析したところ、２重量％であった。
【００６１】
＜実施例５＞吸着剤５の調製
フェリエライト合成の原料混合スラリーの組成比を
ＳｉＯ₂／Ａｌ₂Ｏ₃＝３５
Ｆ／ＳｉＯ₂＝０．８
Ｃ₅Ｈ₅Ｎ／ＳｉＯ₂＝１
Ｈ₂Ｏ／ＳｉＯ₂＝３０
にしたこと以外は、実施例４と同様にして、フェリエライトの合成を行った。実施例４と同様な水洗、乾燥、フッ素及びフッ素化合物の除去操作を行った後の生成物の組成は無水換算で
１．０２Ｎａ₂Ｏ・Ａｌ₂Ｏ₃・４８ＳｉＯ₂
であった。
【００６２】
洗浄後の生成物の結晶構造をＸＲＤ分析により分析したところ、表１に示したものと同等のＸ線回折図が得られ、フェリエライトであることを確認した。
【００６３】
この得られたフェリエライト型ゼオライトを、空気流通下で６００℃で４時間焼成することによりピリジンを除去した。その後、フェリエライト：４０ｇをＮＨ₄Ｃｌ：３．３６ｇを純水４００ｇに溶解した塩化アンモニウム水溶液中に添加し、６０℃で２０時間のイオン交換操作を行った。このイオン交換操作を２回繰り返した後、固液分離し、Ｃｌイオンが検出できなくなるまで純水で洗浄し、１１０℃で２０時間乾燥して、アンモニウム型フェリエライト（ＮＨ₄−ＦＥＲ−３）を得た。
【００６４】
ＮＨ₄−ＦＥＲ−３：２０ｇ（無水換算）を、硝酸銀：０．６２ｇを純水１００ｇに溶解させた硝酸銀水溶液中に添加し、６０℃減圧条件下で蒸発乾固し、Ａｇ担持を行った。その後、１１０℃で２０時間乾燥して、吸着剤５を得た。吸着剤５のＡｇ担持量をＩＣＰ発光分析により分析したところ、２重量％であった。
【００６５】
＜実施例６＞吸着剤６の調製
フェリエライト合成の原料混合物スラリ−の組成比を
ＳｉＯ₂／Ａｌ₂Ｏ₃＝８０
Ｆ／ＳｉＯ₂＝０．８
Ｃ₅Ｈ₅Ｎ／ＳｉＯ₂＝１．５
Ｈ₂Ｏ／ＳｉＯ₂＝３０
にしたこと以外は、実施例４と同様にして、フェリエライトの合成を行った。実施例４と同様な水洗、乾燥、フッ素及びフッ素化合物の除去操作を行った後の生成物の組成は無水換算で
１．０９Ｎａ₂Ｏ・Ａｌ₂Ｏ₃・８６ＳｉＯ₂
であった。
【００６６】
洗浄後の生成物の結晶構造をＸＲＤ分析により分析したところ、表１に示したものと同等のＸ線回折図が得られ、フェリエライトであることを確認した。
【００６７】
この得られたフェリエライト型ゼオライトを、空気流通下で６００℃で４時間焼成することによりピリジンを除去した。その後、フェリエライト：４０ｇをＮＨ₄Ｃｌ：３．３６ｇを純水４００ｇに溶解した塩化アンモニウム水溶液中に添加し、６０℃で２０時間のイオン交換操作を行った。このイオン交換操作を２回繰り返した後、固液分離し、Ｃｌイオンが検出できなくなるまで純水で洗浄し、１１０℃で２０時間乾燥して、アンモニウム型フェリエライト（ＮＨ₄−ＦＥＲ−４）を得た。
【００６８】
ＮＨ₄−ＦＥＲ−４：２０ｇ（無水換算）を、硝酸銀：０．６２ｇを純水１００ｇに溶解させた硝酸銀水溶液中に添加し、６０℃減圧条件下で蒸発乾固し、Ａｇ担持を行った。その後、１１０℃で２０時間乾燥して、吸着剤６を得た。吸着剤６のＡｇ担持量をＩＣＰ発光分析により分析したところ、２重量％であった。
【００６９】
＜実施例７＞吸着剤７の調製
フェリエライト合成の原料混合物スラリ−の組成比を
ＳｉＯ₂／Ａｌ₂Ｏ₃＝１００
Ｆ／ＳｉＯ₂＝０．８
Ｃ₅Ｈ₅Ｎ／ＳｉＯ₂＝１．５
Ｈ₂Ｏ／ＳｉＯ₂＝３０
にしたこと以外は、実施例４と同様にして、フェリエライトの合成を行った。実施例４と同様な水洗、乾燥、フッ素及びフッ素化合物の除去操作を行った後の生成物の組成は無水換算で
１．０９Ｎａ₂Ｏ・Ａｌ₂Ｏ₃・１１３ＳｉＯ₂
であった。
【００７０】
洗浄後の生成物の結晶構造をＸＲＤ分析により分析したところ、表１に示したものと同等のＸ線回折図が得られ、フェリエライトであることを確認した。
【００７１】
この得られたフェリエライト型ゼオライトを、空気流通下で６００℃で４時間焼成することによりピリジンを除去した。その後、フェリエライト：４０ｇをＮＨ₄Ｃｌ：３．３６ｇを純水４００ｇに溶解した塩化アンモニウム水溶液中に添加し、６０℃で２０時間のイオン交換操作を行った。このイオン交換操作を２回繰り返した後、固液分離し、Ｃｌイオンが検出できなくなるまで純水で洗浄し、１１０℃で２０時間乾燥して、アンモニウム型フェリエライト（ＮＨ₄−ＦＥＲ−５）を得た。
【００７２】
ＮＨ₄−ＦＥＲ−５：２０ｇ（無水換算）を、硝酸銀：０．６２ｇを純水１００ｇに溶解させた硝酸銀水溶液中に添加し、６０℃減圧条件下で蒸発乾固し、Ａｇ担持を行った。その後、１１０℃で２０時間乾燥して、吸着剤７を得た。吸着剤７のＡｇ担持量をＩＣＰ発光分析により分析したところ、２重量％であった。
【００７３】
＜実施例８＞
実施例１で得られたＮＨ₄−ＦＥＲ−１：１０ｇ（無水換算）を、硝酸銀：０．３１ｇを純水１００ｇに溶解させた硝酸銀水溶液中に添加し、６０℃減圧条件下で蒸発乾固し、Ａｇ担持を行った。そのＡｇ担持フェリエライトを酢酸パラジウム：０．０８ｇをアセトン５０ｇに溶解させたパラジウム水溶液に添加し、７０℃で蒸発乾固し、Ｐｄ担持を行った。その後、１１０℃で２０時間乾燥して、吸着剤７を得た。吸着剤７のＡｇ及びＰｄ担持量をＩＣＰ発光分析により分析したところ、Ａｇが２重量％、Ｐｄが０．４重量％であった。
【００７４】
＜実施例９＞
実施例４で得られたＮＨ₄−ＦＥＲ−２を用いたこと以外は実施例８と同様にして、吸着剤９を得た。吸着剤９のＡｇ及びＰｄ担持量をＩＣＰ発光分析により分析したところ、Ａｇが２重量％、Ｐｄが０．４重量％であった。
【００７５】
＜比較例１＞比較吸着剤１の調製
フェリエライトとして、水熱合成法により合成したＳｉＯ₂／Ａｌ₂Ｏ₃モル比が１３のフェリエライトを用いたこと以外は、実施例１と同様にして、比較吸着剤１を得た。比較吸着剤１のＡｇ担持量をＩＣＰ発光分析により分析したところ、２重量％であった。
【００７６】
＜比較例２＞比較吸着剤２の調製
ＳｉＯ₂／Ａｌ₂Ｏ₃モル比が２４の東ソ−製のＺＳＭ−５構造のゼオライト（商品名：ＨＳＺ−８２０ＮＡＡ）４０ｇを用いたこと以外は実施例１と同様にして、比較吸着剤２を得た。比較吸着剤１のＡｇ担持量をＩＣＰ発光分析により分析したところ、２重量％であった。
【００７７】
＜比較例３＞比較吸着剤３の調製
ＳｉＯ₂／Ａｌ₂Ｏ₃モル比が７２の東ソ−製のＺＳＭ−５構造のゼオライト（商品名：ＨＳＺ−８６０ＨＯＡ）を用いたこと以外は実施例１と同様にして、比較吸着剤３を得た。比較吸着剤３のＡｇ担持量をＩＣＰ発光分析により分析したところ、２重量％であった。
【００７８】
＜比較例４＞比較吸着剤４の調製
ＳｉＯ₂／Ａｌ₂Ｏ₃モル比が２１００の東ソ−製のＺＳＭ−５構造のゼオライト（商品名：ＨＳＺ−８９０ＨＯＡ）を用いたこと以外は実施例１と同様にして、比較吸着剤４を得た。比較吸着剤４のＡｇ担持量をＩＣＰ発光分析により分析したところ、２重量％であった。
【００７９】
＜比較例５＞比較吸着剤５の調製
ＳｉＯ₂／Ａｌ₂Ｏ₃モル比が２６の東ソ−製のモルデナイト構造のゼオライト（商品名：ＨＳＺ−６６０ＨＯＡ）を用いたこと以外は実施例１と同様にして、比較吸着剤５を得た。比較吸着剤５のＡｇ担持量をＩＣＰ発光分析により分析したところ、２重量％であった。
【００８０】
＜比較例６＞比較吸着剤６の調製
ＳｉＯ₂／Ａｌ₂Ｏ₃モル比が２２４の東ソ−製のモルデナイト構造のゼオライト（商品名：ＨＳＺ−６９０ＨＯＡ）を用いたこと以外は実施例１と同様にして、比較吸着剤６を得た。比較吸着剤６のＡｇ担持量をＩＣＰ発光分析により分析したところ、２重量％であった。
【００８１】
＜比較例７＞比較吸着剤７の調製
ＳｉＯ₂／Ａｌ₂Ｏ₃モル比が６の東ソ−製のＬ型構造のゼオライト（商品名：ＨＳＺ−５００ＫＯＡ）を用いたこと以外は実施例１と同様にして、比較吸着剤７を得た。比較吸着剤７のＡｇ担持量をＩＣＰ発光分析により分析したところ、２重量％であった。
【００８２】
＜比較例８＞比較吸着剤８の調製
ＳｉＯ₂／Ａｌ₂Ｏ₃モル比が２９の東ソ−製のＹ型ゼオライト（商品名：ＨＳＺ−５００ＫＯＡ）を用いたこと以外は実施例１と同様にして、比較吸着剤８を得た。比較吸着剤８のＡｇ担持量をＩＣＰ発光分析により分析したところ、２重量％であった。
【００８３】
＜比較例９＞比較吸着剤９の調製
ＳｉＯ₂／Ａｌ₂Ｏ₃モル比が２７の東ソ−製のベータ型ゼオライト（商品名：ＨＳＺ−９３０ＮＨＡ）を用いたこと以外は実施例１と同様にして、比較吸着剤９を得た。比較吸着剤９のＡｇ担持量をＩＣＰ発光分析により分析したところ、２重量％であった。
【００８４】
＜比較例１０＞比較吸着剤１０の調製
実施例１で得られたＮＨ₄−ＦＥＲ−１をそのまま比較吸着剤１０とした。
【００８５】
＜比較例１１＞比較吸着剤１１の調製
実施例１で得られたＮＨ₄−ＦＥＲ−１：２０ｇ（無水換算）を、硝酸銅３水和物：１．５２ｇを純水１００ｇに溶解させた硝酸銅水溶液中に添加し、６０℃減圧条件下で蒸発乾固し、Ｃｕ担持を行った。その後、１１０℃で２０時間乾燥して、比較吸着剤１１を得た。比較吸着剤１１のＣｕ担持量をＩＣＰ発光分析により分析したところ、２重量％であった。
【００８６】
＜比較例１２＞比較吸着剤１２の調製
実施例１で得られたＮＨ₄−ＦＥＲ−１：２０ｇ（無水換算）を、硝酸鉄９水和物：２．９ｇを純水１００ｇに溶解させた硝酸鉄水溶液中に添加し、６０℃減圧条件下で蒸発乾固し、Ｆｅ担持を行った。その後、１１０℃で２０時間乾燥して、比較吸着剤１２を得た。比較吸着剤１２のＦｅ担持量をＩＣＰ発光分析により分析したところ、２重量％であった。
【００８７】
＜比較例１３＞比較吸着剤１３の調製
実施例１で得られたＮＨ₄−ＦＥＲ−１：２０ｇ（無水換算）を、硝酸バリウム：０．７６ｇを純水１００ｇに溶解させた硝酸バリウム水溶液中に添加し、６０℃減圧条件下で蒸発乾固し、Ｂａ担持を行った。その後、１１０℃で２０時間乾燥して、比較吸着剤１３を得た。比較吸着剤１３のＢａ担持量をＩＣＰ発光分析により分析したところ、２重量％であった。
【００８８】
＜比較例１４＞比較吸着剤１４の調製
実施例１で得られたＮＨ₄−ＦＥＲ−１：２０ｇ（無水換算）を、硝酸亜鉛：１．８２ｇを純水１００ｇに溶解させた硝酸亜鉛水溶液中に添加し、６０℃減圧条件下で蒸発乾固し、Ｚｎ担持を行った。その後、１１０℃で２０時間乾燥して、比較吸着剤１４を得た。比較吸着剤１４のＺｎ担持量をＩＣＰ発光分析により分析したところ、２重量％であった。
【００８９】
＜比較例１５＞比較吸着剤１５の調製
実施例１で得られたＮＨ₄−ＦＥＲ−１：２０ｇ（無水換算）を、硝酸マグネシウム：４．２２ｇを純水１００ｇに溶解させた硝酸マグネシウム水溶液中に添加し、６０℃減圧条件下で蒸発乾固し、Ｍｇ担持を行った。その後、１１０℃で２０時間乾燥して、比較吸着剤１５を得た。比較吸着剤１５のＭｇ担持量をＩＣＰ発光分析により分析したところ、２重量％であった。
【００９０】
＜比較例１６＞比較吸着剤１６の調製
実施例１で得られたＮＨ₄−ＦＥＲ−１：２０ｇ（無水換算）を、パラタングステン酸アンモニウム：０．５７ｇを純水１００ｇに溶解させたタングステン水溶液中に添加し、６０℃減圧条件下で蒸発乾固し、Ｗ担持を行った。その後、１１０℃で２０時間乾燥して、比較吸着剤１６を得た。比較吸着剤１６のＷ担持量をＩＣＰ発光分析により分析したところ、２重量％であった。
【００９１】
＜比較例１７＞比較吸着剤１７の調製
実施例１で得られたＮＨ₄−ＦＥＲ−１：２０ｇ（無水換算）を、モリブデン酸アンモニウム：５．１５ｇを純水１００ｇに溶解させたモリブデン水溶液中に添加し、６０℃減圧条件下で蒸発乾固し、Ｍｏ担持を行った。その後、１１０℃で２０時間乾燥して、比較吸着剤１７を得た。比較吸着剤１７のＭｏ担持量をＩＣＰ発光分析により分析したところ、２重量％であった。
【００９２】
＜比較例１８＞比較吸着剤１８の調製
実施例１で得られたＮＨ₄−ＦＥＲ−１：２０ｇ（無水換算）を、０．４ｇのＩｒを含有するヘキサアンミンイリジウム水溶液中に添加し、６０℃減圧条件下で蒸発乾固し、Ｉｒ担持を行った。その後、１１０℃で２０時間乾燥して、比較吸着剤１８を得た。比較吸着剤１８のＩｒ担持量をＩＣＰ発光分析により分析したところ、２重量％であった。
【００９３】
＜比較例１９＞比較吸着剤１９の調製
実施例１で得られたＮＨ₄−ＦＥＲ−１：２０ｇ（無水換算）を、硝酸ランタン水和物：１．２５ｇを純水１００ｇに溶解させた硝酸ランタン水溶液中に添加し、６０℃減圧条件下で蒸発乾固し、Ｌａ担持を行った。その後、１１０℃で２０時間乾燥して、比較吸着剤１９を得た。比較吸着剤１９のＬａ担持量をＩＣＰ発光分析により分析したところ、２重量％であった。
【００９４】
＜比較例２０＞比較吸着剤２０の調製
実施例１で得られたＮＨ₄−ＦＥＲ−１：２０ｇ（無水換算）を、硝酸ニッケル６水和物：１．９８ｇを純水１００ｇに溶解させた硝酸ニッケル水溶液中に添加し、６０℃減圧条件下で蒸発乾固し、Ｎｉ担持を行った。その後、１１０℃で２０時間乾燥して、比較吸着剤２０を得た。比較吸着剤２０のＮｉ担持量をＩＣＰ発光分析により分析したところ、２重量％であった。
【００９５】
＜エチレンの吸着除去試験＞
吸着剤１〜９及び比較吸着剤１〜１０について、各々０．１ｇを石英ガラス製の常圧固定床流通式反応管に充填し、エチレンの吸着実験に供した。前処理として、空気を５０ｃｃ／ｍｉｎ流通させながら、２０℃／ｍｉｎの昇温速度で５００℃まで加熱し、５００℃で１時間保持した。室温まで冷却し、Ｈｅガスで完全に置換した後に、表２の組成のモデル排ガスを室温下、ガス流速１００ｃｃ／ｍｉｎで吸着剤に１時間接触させた。このときの空間速度（体積基準）は３００００ｈｒ^-1であった。モデル排ガス中のエチレンの吸着剤への吸着が飽和に達したのを確認し、再度Ｈｅガスを吸着剤に導入し、気相に残存するエチレンを完全に除去した。続いて、Ｈｅガスを５０ｃｃ／ｍｉｎで流通させながら、吸着剤を１０℃／ｍｉｎで昇温しながら、吸着剤から脱離する炭化水素を水素炎イオン化検出器（ＦＩＤ）を備えたガスクロマトグラフにより、連続的に定量分析し、エチレンの吸着特性を評価した。表３にエチレンの吸着量及び脱離ピ−ク温度の吸着特性を示す。
【００９６】
【表２】

【００９７】
【表３】

【００９８】
＜吸着剤の耐久試験＞
吸着剤１〜９、比較吸着剤１〜２０を各々加圧成形後、粉砕して１２〜２０メッシュに整粒した。整粒した各吸着剤３ｃｃを石英ガラス製の常圧固定床流通反応管に充填し、耐久試験に供した。耐久試験は、ＡｉｒガスにＨ₂Ｏを体積換算で１０ｖｏｌ％となるように含有させた混合ガスを流速３００ｃｃ／ｍｉｎで吸着剤に流通しながら、８５０℃で５時間処理した。これら耐久処理を施した吸着剤を＜炭化水素の吸着除去試験＞と同様な前処理、評価条件で炭化水素の吸着特性を評価した。耐久試験後の炭化水素の吸着特性をそれぞれ表４に示す。
【００９９】
【表４】

【０１００】
表３および表４からも分かるように、本発明の吸着剤はエチレンの吸着量が大きく、これまでに提案されている吸着剤に比して、吸着特性が優れている。また、本発明の吸着剤は耐久処理による吸着量の低下がみられず、吸着剤が高温に晒された後でもエチレンの吸着除去性能が維持される。
【０１２１】
本発明に係るエチレン吸着剤は、炭化水素、特にエチレンの吸着量が大きく、吸着特性が優れており、更には本発明に係る吸着剤は、耐久処理よる吸着量の低下がみられず、吸着剤が高温にさらされた後でもエチレンの吸着除去性能が維持される。しかし表６，７より、吸着剤だけでは窒素酸化物及び炭化水素を含む酸素過剰の排ガスから窒素酸化物を除去する活性が低く、その触媒性能は低い。一方、従来提案されている窒素酸化物除去触媒は酸素過剰の排ガスより窒素酸化物の除去活性を示すが、窒素酸化物の除去性能は十分に満足されるものではない。
【０１２３】
【発明の効果】
本発明のエチレン吸着剤は、気相中のエチレンを効率よく吸着除去でき、かつ吸着剤が高温に晒された後でも炭化水素の吸着性能は低下しない。更に本発明の吸着剤はエチレンを吸着保持する性能が高い。従って、本発明の吸着剤をエチレンを含む気相に接触させることでエチレンを効率よく除去できる。この性質を利用して、本発明の吸着剤により自動車などのエンジン始動時に排出されるエチレンを効率よく吸着除去し、排ガス浄化触媒が作動する温度まで吸着保持することができる。
【０１２４】
また、本発明の吸着剤は農作物から発生するエチレンの吸着除去等にも適用できる。[0001]
[Industrial application fields]
The present invention relates to hydrocarbons contained in gas, for example, exhaust gas discharged from the atmosphere or an internal combustion engine.Adsorption removal methodFor example, the present invention can be applied to purification of hydrocarbons in exhaust gas discharged from an internal combustion engine such as an automobile, particularly ethylene, and adsorption / removal of ethylene, which is a mature / aging hormone generated from agricultural products.
[0002]
[Prior art]
In purification of exhaust gas containing hydrocarbons discharged from an internal combustion engine such as an automobile, a method of bringing the exhaust gas into contact with exhaust gas using a three-way catalyst has been put into practical use. It is known that the exhaust gas purification ability of the three-way catalyst is manifested at 300 ° C. or higher. For this reason, when the exhaust gas temperature at the time of starting the engine is low, in addition to the high hydrocarbon concentration in the exhaust gas, the temperature does not reach the temperature at which the three-way catalyst operates, so the hydrocarbons are discharged without being purified.
[0003]
In contrast to the purification of hydrocarbons from exhaust gas at low temperatures, JP-A-2-135126 discloses that a part of a monolith support coated with Y-type zeolite and mordenite zeolite is used for the purpose of adsorbing and purifying hydrocarbons. An exhaust gas purification apparatus using a hydrocarbon adsorbent carrying one or more metals has been proposed. In addition, many hydrocarbon adsorbents containing zeolite as a constituent component have been proposed. For example, JP-A-6-126165 discloses a molecular sieve supporting Ag, and JP-A-6-312132 discloses Ag and Ag and Co, Ni, Cr, Fe, Mn, Ag, Au, Pt, Pd, Ru, Rh, Zeolite containing at least one metal selected from the group consisting of V, Zeolite ion-exchanged with Ag and Group IIIB metal of the Periodic Table in JP-A-8-99033, JP-A-6-210165 In this publication, the adsorbent is composed of Pd and zeolite, and in JP-A-6-210163, it is composed of Cu and Cu and Co, Ni, Cr, Fe, Mn, Ag, Au, Pt, Pd, Ru, Rh, V. Zeolite containing at least one metal selected from the group, in Japanese Patent Application Laid-Open No. 6-170234, at least one metal of Cu and Pd is ionized Conversion was ZSM-5 zeolite, SiO in JP-A 5-31359 Patent Publication₂/ Al₂O_ThreeZeolite having a molar ratio of 40 or more has been proposed.
[0004]
It is also known that hydrocarbons can be adsorbed by an adsorbent from exhaust gas at a low temperature and the removal performance of nitrogen oxides can be improved by using hydrocarbons desorbed from the adsorbent when the exhaust gas temperature rises. . The following catalysts have been proposed so far as exhaust gas purification catalysts that combine hydrocarbon adsorbents and nitrogen oxide removal catalysts.
[0005]
In Japanese Patent Laid-Open No. 2-56247, hydrocarbons are selectively adsorbed on zeolite in a cold state and in a rich air-fuel ratio, and hydrocarbons desorbed from the zeolite due to an increase in exhaust gas temperature and nitrogen oxidation in the exhaust gas. As a catalyst for purifying substances, carbon monoxide, and hydrocarbons, a first catalyst layer mainly composed of zeolite on a support, and a second catalyst layer mainly composed of a noble metal catalyst having oxidation-reduction ability thereon. In JP-A-5-293380, an exhaust gas purification catalyst characterized in that a catalyst component containing at least Pt is supported on a porous carrier, and an alumino having solid acidity and molecular sieving properties are disclosed. It is characterized by comprising a hydrocarbon adsorbent composed mainly of silicate and carrying at least one metal selected from alkali metals and alkaline earth metals. Exhaust gas purifying catalyst has been proposed that.
[0006]
In JP-A-8-24655, hydrocarbons in exhaust gas are adsorbed to a NOx catalyst that purifies nitrogen oxides in exhaust gas in which a catalytic metal is supported on a crystalline metal-containing silicate in the presence of hydrocarbons. An exhaust gas purification catalyst characterized by mixing a hydrocarbon adsorbent that desorbs hydrocarbons adsorbed at a temperature above a certain temperature, or by laminating a NOx catalyst layer and a hydrocarbon adsorbent layer, Japanese Patent Application Laid-Open No. 8-164338 In the publication, a hydrocarbon adsorbent composed of an inorganic crystalline molecular sieve is supported on a carrier, a first catalyst layer having Pd as a catalyst metal is formed on the surface of the hydrocarbon adsorbent particles, and further, A rare earth oxide layer mainly composed of a rare earth oxide is formed thereon, and a second catalyst layer using at least one of Pt and Rh as a catalyst is formed on the rare earth oxide layer. Exhaust gas purifying catalyst has been proposed.
[0007]
Further, the exhaust pipe of an internal combustion engine described in JP-A-9-872 has a low-temperature ignitable catalyst composition containing a substance having an electron donating and / or nitrogen dioxide absorption and release action and a noble metal, and a hydrocarbon adsorption ability. An exhaust gas purification system in which an adsorbent is arranged has also been proposed.
[0008]
The hydrocarbon adsorption removal method and the exhaust gas purification method using these adsorbents both adsorb the hydrocarbons contained in the exhaust gas once on the adsorbent in the low temperature range when starting the engine, and the exhaust gas purification catalyst. The hydrocarbon is desorbed from the adsorbent at a temperature range higher than that at which the gas is activated, and the exhaust gas purifying catalyst is used to purify the hydrocarbon. That is, the adsorption removal of hydrocarbons by the adsorbent functions effectively by combining the selective adsorption of hydrocarbons at low temperatures and the adsorption holding power.
[0009]
[Problems to be solved by the invention]
In recent years, attention has been paid to the problem of environmental pollution caused by the discharge of hydrocarbons, and improvements in hydrocarbon removal technology are desired. For example, since many types of hydrocarbons are mixed in exhaust gas discharged from an internal combustion engine such as an automobile, an adsorbent corresponding to the type of hydrocarbon is necessary. In particular, the study on the adsorption characteristics of ethylene is insufficient, and the adsorbents disclosed in the prior art have not been sufficient in ethylene adsorption characteristics.
[0010]
In general, the adsorption characteristics of hydrocarbons when zeolite is used as an adsorbent are greatly affected by the type of hydrocarbon and the pore structure of the zeolite. As for the adsorption characteristics of hydrocarbons having a small number of carbon atoms, the molecular diameter thereof is small, so that diffusion and movement into zeolite pores are likely to occur, and adsorption is also easy. However, due to the ease of hydrocarbon migration, desorption is also easy, and when purifying exhaust gas, the hydrocarbons at a temperature lower than the temperature at which the hydrocarbon purification catalyst represented by the three-way catalyst operates as a result. Desorbs and purification becomes insufficient. In addition, in the exhaust gas purification with excess oxygen, the utilization rate of adsorbed hydrocarbons is lowered. On the other hand, as for the adsorption characteristics of hydrocarbons having a large number of carbon atoms, the amount of adsorption decreases because hydrocarbons having a molecular diameter larger than the pore diameter of zeolite cannot diffuse and move into the pores. Therefore, the amount of adsorbed hydrocarbons is reduced, and the hydrocarbons are discharged as they are without being sufficiently purified.
[0011]
Further, since the exhaust gas temperature of the internal combustion engine reaches 600 ° C. or higher, the adsorption performance of hydrocarbons does not deteriorate even after the adsorbent is exposed to high temperature exhaust gas, that is, the adsorbent has high heat resistance. There is a need. Furthermore, an exhaust gas purification system that combines a hydrocarbon adsorbent and a nitrogen oxide removal catalyst must function effectively by matching the desorption temperature of the adsorbed hydrocarbon with the operating temperature of the nitrogen oxide removal catalyst.
[0012]
It is an object of the present invention to have an adsorption capability for adsorbing and holding hydrocarbons up to a temperature at which an exhaust gas purification catalyst operates even when it has a high ethylene adsorption capacity and is used for exhaust gas purification. An adsorbent having heat resistance, a method for adsorbing and removing hydrocarbons contained in gas using the adsorbent, and an exhaust gas purification method using the adsorbent of the present invention and a nitrogen oxide removing catalyst are provided. By the way.
[0013]
[Means for Solving the Problems]
In view of these circumstances, the present inventors have intensively studied the adsorption characteristics of lower hydrocarbons, particularly ethylene, and as a result, compared with the hydrocarbon adsorbents disclosed so far, SiO 2₂/ Al₂O_ThreeThe adsorbent composed of zeolite having a ferrierite type structure with a molar ratio of 15 or more has a particularly large amount of adsorption of ethylene, a strong retention of adsorbed hydrocarbons, and even after exposure to high temperatures. The inventors have found that there is no decrease in adsorption characteristics, that is, excellent heat resistance, and have completed the present invention.
[0014]
That is, the present invention relates to SiO containing Ag.₂/ Al₂O_ThreeEthylene adsorbent comprising a zeolite having a ferrierite structure having a molar ratio of 15 or moreOf adsorbing and removing ethylene in a gas, characterized by contacting the gas with a gasIt is. Hereinafter, the present invention will be described in detail.
[0015]
Of the present inventionUsed in ethylene adsorption removal method in gasIt is essential that the adsorbent is composed of zeolite having a ferrierite structure (hereinafter referred to as ferrierite). The ferrierite according to the present invention is xM_{n / 2}O ・ Al₂O_Three・ YSiO₂・ ZH₂Having a composition of 0 (where n is the valence of the cation M, x is a number in the range of 0 to 2.5, y is a number of 15 or more, and z is a number of 0 or more), Obtained as a synthetic product. Regarding the structure, for example, COLLECTION OF SIMULATED XRD POWDER PATTERNS FOR ZEOLITES, M.C. M.M. J. et al. Treacy, J. et al. B. Higgins and R.M. von Ballmoos, ZEOLITES, vol. 16, p. 456-459 (1996) and is defined as a structure having an X-ray diffraction pattern as shown in Table 1.
[0016]
[Table 1]

[0017]
Of the present inventionUsed in ethylene adsorption removal method in gasSiO of ferrierite constituting adsorbent₂/ Al₂O_ThreeThe molar ratio is 15 or more. SiO₂/ Al₂O_ThreeIf the molar ratio is less than 15, the heat resistance of the zeolite itself becomes low, and if the adsorbent is exposed to a high temperature, the adsorption characteristics deteriorate. Ferrierite SiO₂/ Al₂O_ThreeThe molar ratio is more preferably 21 to 1000, still more preferably 40 to 200.
[0018]
The method for producing ferrierite is not particularly limited, but it can be prepared by a method that does not use an organic curing agent disclosed in, for example, JP-A-59-73423 and JP-A-60-141617. . These production methods are methods in which a silica source and an alumina source are dispersed in an alkaline solution and obtained by hydrothermal synthesis. Furthermore, it can also be produced in the presence of an organic curing agent such as pyridine, N-methylpyridine hydroxide, piperidine, alkyl-substituted piperidine, butanediamine in the synthetic raw material. The amount of organic curing agent added is organic curing agent / SiO₂The molar ratio is 0.01 to 10, preferably 0.05 to 5. In order to obtain a hydrocarbon adsorbent having higher heat resistance and durability, it is more preferable to produce by a method using pyridine and a fluorine compound described in JP-A-8-188414.
[0019]
Soluble fluorine compounds such as hydrogen fluoride, sodium fluoride, sodium silicofluoride, and cryolite can be used as the fluorine compound for producing ferrierite. The amount added is fluorine compound / SiO₂The molar ratio is 0.01 to 10, preferably 0.05 to 5. The amount of pyridine added is pyridine / SiO₂The molar ratio is 0.0 to 10, preferably 0.1 to 5.
[0020]
Also, sodium silicate, amorphous silica, silica sol, silica gel, kaolinite, diatomaceous earth, etc. are used as the silica source, and sodium aluminate, aluminum hydroxide, aluminum chloride, aluminum nitrate, aluminum sulfate, etc. are used as the alumina source. Can do. A granular amorphous aluminosilicate homogeneous phase compound obtained by reacting an alkali silicate aqueous solution and an aluminum-containing aqueous solution simultaneously and continuously as disclosed in JP-B 63-46007 is also suitable for a silica source and an alumina source. Can be used as a new material.
[0021]
When ferrierite is produced by adding pyridine and a fluorine compound to the reaction system, fluorine and / or a fluorine compound may remain in the ferrierite. Fluorine and / or fluorine compounds may remain, but it is preferable to remove fluorine and / or fluorine compounds in order to further improve heat resistance and durability. As a method for removing fluorine and / or fluorine compounds, for example, a method of filtering and washing with a large amount of hot water at 80 ° C., a method of washing using dilute hydrochloric acid or an aluminum chloride aqueous solution, and the like can be mentioned.
[0022]
A synthetic product or a calcined product thereof is used as the ferrierite, but it can also be used as an H type or an ammonium type by treating ions such as Na in the ferrierite with an ammonium salt or a mineral acid. Calcination can be performed at 300-1200 degreeC.
[0023]
Of the present inventionUsed in ethylene adsorption removal method in gasThe ethylene adsorbent contains Ag in the above ferrierite. The Ag content is preferably in the range of 0.1 to 20% by weight with respect to the total amount of ferrierite and active metal component in order to sufficiently exhibit ethylene adsorption performance. More preferably, it is 0.2-10 weight%, More preferably, it is 0.2-7 weight%.
[0024]
The method for containing Ag is not particularly limited, and a known method can be appropriately employed. For example, an ion exchange method, an impregnation support method, an evaporation to dryness method, an immersion method, a solid phase exchange method, or the like can be employed. The salt used for containing Ag is not particularly limited, and may be a salt such as nitrate, sulfate, acetate, oxalate, or ammine complex.
[0025]
Of the present inventionUsed in ethylene adsorption removal method in gasThe ethylene adsorbent may further contain Pd. Although content of Pd is not specifically limited, It is preferable that it is the range of 0.01 to 10 weight% with respect to the total amount of a ferrierite and an active metal component. More preferably, it is 0.05-5 weight%, More preferably, it is 0.1-3 weight%. The method for containing Pd is not particularly limited, and the same method and the same salt as Ag described above can be used. Further, either Ag or Pd may be contained in the ferrierite first, or may be contained simultaneously.
[0026]
Of the present inventionUsed in ethylene adsorption removal method in gasThe adsorbent may contain not only Ag and Pd but also other transition metals in ferrierite. The transition metal is not particularly limited, and includes elements of groups IIIA, IVA, VA, VIA, VIIA, VIII, IB, and IIB in the periodic table, and these are also used in the same method and the same salt as Ag described above. It can be included.
[0027]
As described above, the present inventionUsed in ethylene adsorption removal method in gasAn ethylene adsorbent can be prepared.
[0028]
Of the present inventionUsed in ethylene adsorption removal method in gasThe adsorbent can also be used after being mixed with a binder such as silica, alumina and clay mineral. Examples of clay minerals include kaolin, attapulgite, montmorillonite, bentonite, allophane, and sepiolite. Also, the adsorbent of the present invention can be washed and used on a cordierite or metal honeycomb substrate.
[0029]
Of the present inventionDepending on the adsorption and removal method of ethylene in gasThe adsorption and removal of ethylene can be performed. There are no particular limitations on this gas, and specific examples include gas containing ethylene, such as the atmosphere, exhaust gas, and storage room gas for agricultural products. In addition to ethylene, it is also effective when carbon monoxide, carbon dioxide, hydrogen, oxygen, nitrogen, nitrogen oxides, sulfur oxides, water, and hydrocarbons other than ethylene are included.
[0030]
Although the density | concentration of ethylene in gas is not specifically limited, 0.001-5 vol% is preferable in conversion of methane, More preferably, it is 0.005-3 vol%. The concentration of each component other than ethylene is not particularly limited. For example, CO = 0 to 1 vol%, CO₂= 0 to 10 vol%, O₂= 0 to 20 vol%, nitrogen oxide = 0 to 1 vol%, sulfur oxide = 0 to 0.05 vol%, H₂O = 0 to 15 vol% may be sufficient.
[0031]
The space velocity and temperature when ethylene is adsorbed and removed are not particularly limited, but the space velocity is 100 to 500,000 hr.^-1The temperature is preferably -30 to 250 ° C.
[0032]
In the present invention, Ag containing SiO₂/ Al₂O_ThreeThe reason why ferrierite having a molar ratio of 15 or more exhibits high ethylene adsorption characteristics is unclear, but is thought to be due to the pore structure of ferrierite. Ferrierite pores are two-dimensionally composed of a major axis 5.5 angstrom (A) a minor axis 4.3A oxygen 10-membered ring pore and a major axis 4.8A minor axis 3.4A oxygen 8-membered ring pore. It is a connected structure. On the other hand, it is known that the pore size of ZSM-5, zeolite β, etc. is larger than that of ferrierite. The effective molecular diameter of ethylene is 3.9 A, and diffusion into the ferrierite pores is possible. Furthermore, the molecular diameter of ethylene and the size of the ferrierite pore are close, and the interaction between adsorbed ethylene and ferrierite becomes stronger. That is, it is considered that the adsorbed ethylene is not easily desorbed and the holding force is increased.
[0045]
Therefore, the type of hydrocarbons contained in the exhaust gas treated in the present invention is not particularly limited, but when ethylene is contained, the removal rate of nitrogen oxides is greatly improved, and in addition, paraffin, olefin, aromatic compounds are preferable. And mixtures thereof. Specifically, hydrocarbons having 1 to 20 carbon atoms can be exemplified as paraffin and olefin, and benzene, naphthalene, anthracene and derivatives thereof can be exemplified as aromatic compounds. Moreover, light oil, kerosene, gasoline, etc. can also be illustrated.
[0046]
It is also effective when the exhaust gas treated in the present invention contains carbon monoxide, carbon dioxide, hydrogen, nitrogen, sulfur oxide, and water.
[0047]
The concentration of each component gas in the exhaust gas is not particularly limited, but normally, nitrogen oxide is preferably 50 to 2000 ppm, hydrocarbon is preferably 0.001 to 5 vol% in terms of methane, and oxygen is preferably 0.1 to 20%. The concentration of each component other than the above component gas is not particularly limited, and carbon monoxide is 0 to 1 vol%, carbon dioxide is 0 to 10 vol%, sulfur oxide is 0 to 0.05 vol%, and water is 0 to 15 vol%. Is preferred. In addition, when the concentration of hydrocarbons in the exhaust gas is low, the above-mentioned appropriate hydrocarbons may be added to the exhaust gas.
[0048]
The space velocity and temperature of the exhaust gas to be treated are not particularly limited, but the space velocity (volume basis) is 100 to 500,000 hr.^-1The temperature is preferably -30 to 900 ° C. More preferably, the space velocity is 2000 to 200000 hr.^-1The temperature is -30 to 850 ° C.
[0049]
【Example】
EXAMPLES Hereinafter, although an Example demonstrates this invention still in detail, this invention is not limited to these Examples at all.
[0050]
<Example 1> Preparation of adsorbent 1
SiO₂/ Al₂O_Three40 g of Tosoh ferrierite (trade name: HSZ-720KOA) having a molar ratio of 17_FourCl: 18.0 g was added to an ammonium chloride aqueous solution dissolved in 400 g of pure water, and an ion exchange operation was performed at 60 for 20 hours. This ion exchange operation was repeated twice, followed by solid-liquid separation, washing with pure water until Cl ions could no longer be detected, drying at 110 ° C. for 20 hours, and ammonium-type ferrierite (NH_Four-FER-1) was obtained.
[0051]
NH_Four-FER-1: 20 g (anhydrous conversion) was added to a silver nitrate aqueous solution in which 0.62 g of silver nitrate was dissolved in 100 g of pure water, and evaporated to dryness under reduced pressure at 60 ° C. to carry Ag. Then, it dried at 110 degreeC for 20 hours, and the adsorption agent 1 was obtained. When the amount of Ag supported on the adsorbent 1 was analyzed by ICP emission analysis, it was 2% by weight.
[0052]
<Example 2> Preparation of adsorbent 2
Adsorbent 2 was prepared by carrying Ag under the same conditions as in Example 1 except that the silver nitrate used was 1.55 g. The amount of Ag supported on the adsorbent 2 was analyzed by ICP emission analysis, and found to be 5% by weight.
[0053]
<Example 3> Preparation of adsorbent 3
SiO synthesized by hydrothermal synthesis as ferrierite₂/ Al₂O_ThreeAdsorbent 3 was obtained in the same manner as in Example 1 except that ferrierite having a molar ratio of 21 was used. When the amount of Ag supported on the adsorbent 3 was analyzed by ICP emission analysis, it was 2% by weight.
[0054]
<Example 4> Preparation of adsorbent 4
Aluminum chloride hexahydrate (AlCl_Three・ 6H₂O: 98.0 wt%) 8.2 g and 6.5 g of sodium hydroxide (NaOH: 99 wt%) to neutralize HCl produced from aluminum chloride and sodium fluoride (NaF: 99 wt%) as a fluorine source ) 40.3 g and pyridine (C_FiveH_FiveN) 95.6 ml was dissolved in 628 ml of pure water to obtain a uniform solution.
[0055]
To this homogeneous solution, white carbon (manufactured by Nippon Silica Kogyo, trade name: nip seal VN-3, SiO₂: 88 wt%) 81.1 g was added to prepare a raw material mixture slurry having the following molar composition ratio.
[0056]
SiO₂/ Al₂O_Three= 57
F / SiO₂= 0.8
C_FiveH_FiveN / SiO₂= 1
H₂O / SiO₂= 30
This mixture was put into an autoclave having a volume of 1 L, and hydrothermal synthesis was performed at 180 ° C. for 72 hours while stirring at a rotation speed of 50 rpm. The pH of the zeolite slurry after crystallization was 10.7. After cooling, the solid content was separated, washed thoroughly with water, and dried at 110 ° C. overnight.
[0057]
In order to remove fluorine and / or fluorine compounds, the obtained product was sufficiently washed with pure water at 80 ° C. As a result of fluorescent X-ray analysis, the fluorine and / or fluorine compound in the zeolite after washing was below the detection limit (0.1%). The composition of the product after washing was analyzed by ICP emission analysis.
0.96Na₂O ・ Al₂O_Three・ 74SiO₂
Met.
[0058]
When the crystal structure of the product after washing was analyzed by XRD analysis, an X-ray diffraction pattern equivalent to that shown in Table 1 was obtained, and it was confirmed to be ferrierite.
[0059]
The obtained ferrierite-type zeolite was calcined at 600 ° C. for 4 hours under air flow to remove pyridine. Then ferrierite: 40g NH_FourCl: 3.36 g was added to an ammonium chloride aqueous solution dissolved in 400 g of pure water, and an ion exchange operation was performed at 60 ° C. for 20 hours. This ion exchange operation was repeated twice, followed by solid-liquid separation, washing with pure water until Cl ions could no longer be detected, drying at 110 ° C. for 20 hours, and ammonium-type ferrierite (NH_Four-FER-2) was obtained.
[0060]
NH_Four-FER-2: 20 g (anhydrous conversion) was added to a silver nitrate aqueous solution in which 0.62 g of silver nitrate was dissolved in 100 g of pure water, and evaporated to dryness under reduced pressure at 60 ° C. to carry Ag. Then, it dried at 110 degreeC for 20 hours, and the adsorption agent 4 was obtained. The amount of Ag supported on the adsorbent 4 was analyzed by ICP emission analysis and found to be 2% by weight.
[0061]
<Example 5> Preparation of adsorbent 5
The composition ratio of the raw slurry for ferrierite synthesis
SiO₂/ Al₂O_Three= 35
F / SiO₂= 0.8
C_FiveH_FiveN / SiO₂= 1
H₂O / SiO₂= 30
The ferrierite was synthesized in the same manner as in Example 4 except for the above. The composition of the product after performing the same water washing, drying, and fluorine and fluorine compound removal operation as in Example 4 was calculated as anhydrous.
1.02Na₂O ・ Al₂O_Three・ 48SiO₂
Met.
[0062]
When the crystal structure of the product after washing was analyzed by XRD analysis, an X-ray diffraction pattern equivalent to that shown in Table 1 was obtained, and it was confirmed to be ferrierite.
[0063]
The obtained ferrierite-type zeolite was calcined at 600 ° C. for 4 hours under air flow to remove pyridine. Then ferrierite: 40g NH_FourCl: 3.36 g was added to an ammonium chloride aqueous solution dissolved in 400 g of pure water, and an ion exchange operation was performed at 60 ° C. for 20 hours. This ion exchange operation was repeated twice, followed by solid-liquid separation, washing with pure water until Cl ions could no longer be detected, drying at 110 ° C. for 20 hours, and ammonium-type ferrierite (NH_Four-FER-3) was obtained.
[0064]
NH_Four-FER-3: 20 g (anhydrous conversion) was added to a silver nitrate aqueous solution in which 0.62 g of silver nitrate was dissolved in 100 g of pure water, and evaporated to dryness under reduced pressure conditions at 60 ° C. to carry Ag. Then, it dried at 110 degreeC for 20 hours, and the adsorption agent 5 was obtained. When the amount of Ag supported on the adsorbent 5 was analyzed by ICP emission analysis, it was 2% by weight.
[0065]
<Example 6> Preparation of adsorbent 6
The composition ratio of the raw material mixture slurry for ferrierite synthesis
SiO₂/ Al₂O_Three= 80
F / SiO₂= 0.8
C_FiveH_FiveN / SiO₂= 1.5
H₂O / SiO₂= 30
The ferrierite was synthesized in the same manner as in Example 4 except for the above. The composition of the product after performing the same water washing, drying, and fluorine and fluorine compound removal operation as in Example 4 was calculated as anhydrous.
1.09Na₂O ・ Al₂O_Three・ 86SiO₂
Met.
[0066]
When the crystal structure of the product after washing was analyzed by XRD analysis, an X-ray diffraction pattern equivalent to that shown in Table 1 was obtained, and it was confirmed to be ferrierite.
[0067]
The obtained ferrierite-type zeolite was calcined at 600 ° C. for 4 hours under air flow to remove pyridine. Then ferrierite: 40g NH_FourCl: 3.36 g was added to an ammonium chloride aqueous solution dissolved in 400 g of pure water, and an ion exchange operation was performed at 60 ° C. for 20 hours. This ion exchange operation was repeated twice, followed by solid-liquid separation, washing with pure water until Cl ions could no longer be detected, drying at 110 ° C. for 20 hours, and ammonium-type ferrierite (NH_Four-FER-4) was obtained.
[0068]
NH_Four-FER-4: 20 g (anhydrous conversion) was added to a silver nitrate aqueous solution in which 0.62 g of silver nitrate was dissolved in 100 g of pure water, and evaporated to dryness under reduced pressure conditions at 60 ° C. to carry Ag. Then, it dried at 110 degreeC for 20 hours, and the adsorption agent 6 was obtained. The amount of Ag supported on the adsorbent 6 was analyzed by ICP emission analysis and found to be 2% by weight.
[0069]
<Example 7> Preparation of adsorbent 7
The composition ratio of the raw material mixture slurry for ferrierite synthesis
SiO₂/ Al₂O_Three= 100
F / SiO₂= 0.8
C_FiveH_FiveN / SiO₂= 1.5
H₂O / SiO₂= 30
The ferrierite was synthesized in the same manner as in Example 4 except for the above. The composition of the product after performing the same water washing, drying, and fluorine and fluorine compound removal operation as in Example 4 was calculated as anhydrous.
1.09Na₂O ・ Al₂O_Three・ 113SiO₂
Met.
[0070]
When the crystal structure of the product after washing was analyzed by XRD analysis, an X-ray diffraction pattern equivalent to that shown in Table 1 was obtained, and it was confirmed to be ferrierite.
[0071]
The obtained ferrierite-type zeolite was calcined at 600 ° C. for 4 hours under air flow to remove pyridine. Then ferrierite: 40g NH_FourCl: 3.36 g was added to an ammonium chloride aqueous solution dissolved in 400 g of pure water, and an ion exchange operation was performed at 60 ° C. for 20 hours. This ion exchange operation was repeated twice, followed by solid-liquid separation, washing with pure water until Cl ions could no longer be detected, drying at 110 ° C. for 20 hours, and ammonium-type ferrierite (NH_Four-FER-5) was obtained.
[0072]
NH_Four-FER-5: 20 g (anhydrous conversion) was added to a silver nitrate aqueous solution in which 0.62 g of silver nitrate was dissolved in 100 g of pure water, and evaporated to dryness under reduced pressure at 60 ° C. to carry Ag. Then, it dried at 110 degreeC for 20 hours, and the adsorption agent 7 was obtained. When the amount of Ag supported on the adsorbent 7 was analyzed by ICP emission analysis, it was 2 wt%.
[0073]
<Example 8>
NH obtained in Example 1_Four-FER-1: 10 g (anhydrous conversion) was added to an aqueous silver nitrate solution in which 0.31 g of silver nitrate was dissolved in 100 g of pure water, and evaporated to dryness under reduced pressure at 60 ° C. to carry Ag. The Ag-carrying ferrierite was added to an aqueous palladium solution in which 0.08 g of palladium acetate was dissolved in 50 g of acetone and evaporated to dryness at 70 ° C. to carry Pd. Then, it dried at 110 degreeC for 20 hours, and the adsorption agent 7 was obtained. The amount of Ag and Pd supported on the adsorbent 7 was analyzed by ICP emission analysis. As a result, Ag was 2% by weight and Pd was 0.4% by weight.
[0074]
<Example 9>
NH obtained in Example 4_FourAdsorbent 9 was obtained in the same manner as in Example 8, except that -FER-2 was used. The amount of Ag and Pd supported on the adsorbent 9 was analyzed by ICP emission analysis. As a result, Ag was 2% by weight and Pd was 0.4% by weight.
[0075]
<Comparative Example 1> Preparation of Comparative Adsorbent 1
SiO synthesized by hydrothermal synthesis as ferrierite₂/ Al₂O_ThreeA comparative adsorbent 1 was obtained in the same manner as in Example 1 except that ferrierite having a molar ratio of 13 was used. The amount of Ag supported in Comparative Adsorbent 1 was analyzed by ICP emission analysis and found to be 2% by weight.
[0076]
<Comparative Example 2> Preparation of Comparative Adsorbent 2
SiO₂/ Al₂O_ThreeComparative adsorbent 2 was obtained in the same manner as in Example 1 except that 40 g of a ZSM-5 structure zeolite (trade name: HSZ-820NAA) manufactured by Tosoh Corporation having a molar ratio of 24 was used. The amount of Ag supported in Comparative Adsorbent 1 was analyzed by ICP emission analysis and found to be 2% by weight.
[0077]
<Comparative Example 3> Preparation of Comparative Adsorbent 3
SiO₂/ Al₂O_ThreeComparative adsorbent 3 was obtained in the same manner as in Example 1 except that a ZSM-5 structure zeolite (trade name: HSZ-860HOA) manufactured by Tosoh Corporation having a molar ratio of 72 was used. The amount of Ag supported in Comparative Adsorbent 3 was analyzed by ICP emission analysis and found to be 2% by weight.
[0078]
<Comparative Example 4> Preparation of Comparative Adsorbent 4
SiO₂/ Al₂O_ThreeComparative adsorbent 4 was obtained in the same manner as in Example 1 except that a ZSM-5 structure zeolite (trade name: HSZ-890HOA) manufactured by Tosoh Corporation having a molar ratio of 2100 was used. The amount of Ag supported in Comparative Adsorbent 4 was analyzed by ICP emission analysis and found to be 2% by weight.
[0079]
<Comparative Example 5> Preparation of Comparative Adsorbent 5
SiO₂/ Al₂O_ThreeComparative adsorbent 5 was obtained in the same manner as in Example 1, except that a mordenite structure zeolite (trade name: HSZ-660HOA) manufactured by Tosoh Corporation having a molar ratio of 26 was used. The amount of Ag supported in Comparative Adsorbent 5 was analyzed by ICP emission analysis and found to be 2% by weight.
[0080]
<Comparative Example 6> Preparation of comparative adsorbent 6
SiO₂/ Al₂O_ThreeComparative adsorbent 6 was obtained in the same manner as in Example 1, except that a mordenite structure zeolite (trade name: HSZ-690HOA) manufactured by Tosoh Corporation having a molar ratio of 224 was used. The amount of Ag supported on the comparative adsorbent 6 was analyzed by ICP emission analysis and found to be 2% by weight.
[0081]
<Comparative Example 7> Preparation of Comparative Adsorbent 7
SiO₂/ Al₂O_ThreeComparative adsorbent 7 was obtained in the same manner as in Example 1 except that a zeolite having an L-type structure (trade name: HSZ-500KOA) manufactured by Tosoh Corporation having a molar ratio of 6 was used. The amount of Ag supported on the comparative adsorbent 7 was analyzed by ICP emission analysis and found to be 2% by weight.
[0082]
<Comparative Example 8> Preparation of comparative adsorbent 8
SiO₂/ Al₂O_ThreeComparative adsorbent 8 was obtained in the same manner as in Example 1 except that Y type zeolite made by Tosoh (trade name: HSZ-500KOA) having a molar ratio of 29 was used. The amount of Ag supported on the comparative adsorbent 8 was analyzed by ICP emission analysis and found to be 2% by weight.
[0083]
<Comparative Example 9> Preparation of comparative adsorbent 9
SiO₂/ Al₂O_ThreeComparative adsorbent 9 was obtained in the same manner as in Example 1 except that a beta zeolite made by Tosoh (trade name: HSZ-930NHA) having a molar ratio of 27 was used. The amount of Ag supported on the comparative adsorbent 9 was analyzed by ICP emission analysis and found to be 2% by weight.
[0084]
<Comparative Example 10> Preparation of Comparative Adsorbent 10
NH obtained in Example 1_Four-FER-1 was used as the comparative adsorbent 10 as it was.
[0085]
<Comparative Example 11> Preparation of Comparative Adsorbent 11
NH obtained in Example 1_Four-FER-1: 20 g (anhydrous conversion) is added to a copper nitrate aqueous solution in which copper nitrate trihydrate: 1.52 g is dissolved in 100 g of pure water, evaporated to dryness under reduced pressure at 60 ° C., Cu Loading was performed. Then, it dried at 110 degreeC for 20 hours, and the comparative adsorption agent 11 was obtained. When the amount of Cu supported on the comparative adsorbent 11 was analyzed by ICP emission analysis, it was 2% by weight.
[0086]
<Comparative Example 12> Preparation of Comparative Adsorbent 12
NH obtained in Example 1_Four-FER-1: 20 g (anhydrous equivalent) was added to an iron nitrate aqueous solution in which iron nitrate nonahydrate: 2.9 g was dissolved in 100 g of pure water, evaporated to dryness under reduced pressure at 60 ° C., Fe Loading was performed. Then, it dried at 110 degreeC for 20 hours, and the comparative adsorption agent 12 was obtained. The amount of Fe supported on the comparative adsorbent 12 was analyzed by ICP emission analysis and found to be 2% by weight.
[0087]
<Comparative Example 13> Preparation of Comparative Adsorbent 13
NH obtained in Example 1_Four-FER-1: 20 g (anhydrous conversion) was added to a barium nitrate aqueous solution in which 0.76 g of barium nitrate was dissolved in 100 g of pure water, and evaporated to dryness under reduced pressure at 60 ° C. to carry Ba. . Then, it dried at 110 degreeC for 20 hours, and the comparative adsorption agent 13 was obtained. The amount of Ba supported on the comparative adsorbent 13 was analyzed by ICP emission analysis and found to be 2% by weight.
[0088]
<Comparative Example 14> Preparation of Comparative Adsorbent 14
NH obtained in Example 1_Four-FER-1: 20 g (anhydrous conversion) was added to a zinc nitrate aqueous solution in which 1.82 g of zinc nitrate was dissolved in 100 g of pure water, and evaporated to dryness under reduced pressure at 60 ° C. to carry Zn. . Then, it dried at 110 degreeC for 20 hours, and the comparative adsorption agent 14 was obtained. The amount of Zn supported on the comparative adsorbent 14 was analyzed by ICP emission analysis and found to be 2% by weight.
[0089]
<Comparative Example 15> Preparation of Comparative Adsorbent 15
NH obtained in Example 1_Four-FER-1: 20 g (anhydrous conversion) was added to a magnesium nitrate aqueous solution in which 4.22 g of magnesium nitrate was dissolved in 100 g of pure water, and evaporated to dryness under reduced pressure at 60 ° C. to carry Mg. . Then, it dried at 110 degreeC for 20 hours, and the comparative adsorption agent 15 was obtained. The amount of Mg supported on the comparative adsorbent 15 was analyzed by ICP emission analysis and found to be 2% by weight.
[0090]
<Comparative Example 16> Preparation of Comparative Adsorbent 16
NH obtained in Example 1_Four-FER-1: 20 g (anhydrous conversion) is added to a tungsten aqueous solution in which 0.57 g of ammonium paratungstate is dissolved in 100 g of pure water, evaporated to dryness under reduced pressure at 60 ° C., and W is supported. It was. Then, it dried at 110 degreeC for 20 hours, and the comparative adsorption agent 16 was obtained. When the W carrying amount of the comparative adsorbent 16 was analyzed by ICP emission analysis, it was 2% by weight.
[0091]
<Comparative Example 17> Preparation of Comparative Adsorbent 17
NH obtained in Example 1_Four-FER-1: 20 g (anhydrous conversion) was added to an aqueous molybdenum solution in which 5.15 g of ammonium molybdate was dissolved in 100 g of pure water, and evaporated to dryness under reduced pressure at 60 ° C. to carry Mo. . Then, it dried at 110 degreeC for 20 hours, and the comparative adsorption agent 17 was obtained. The amount of Mo supported on the comparative adsorbent 17 was analyzed by ICP emission analysis and found to be 2% by weight.
[0092]
<Comparative Example 18> Preparation of comparative adsorbent 18
NH obtained in Example 1_Four-FER-1: 20 g (anhydrous conversion) was added to a hexaammineiridium aqueous solution containing 0.4 g of Ir and evaporated to dryness under reduced pressure at 60 ° C. to carry Ir. Then, it dried at 110 degreeC for 20 hours, and the comparative adsorption agent 18 was obtained. The amount of Ir supported on the comparative adsorbent 18 was analyzed by ICP emission analysis and found to be 2% by weight.
[0093]
<Comparative Example 19> Preparation of Comparative Adsorbent 19
NH obtained in Example 1_Four-FER-1: 20 g (anhydrous conversion) was added to a lanthanum nitrate aqueous solution in which 1.25 g of lanthanum nitrate hydrate was dissolved in 100 g of pure water, evaporated to dryness under reduced pressure at 60 ° C., and La-supported Went. Then, it dried at 110 degreeC for 20 hours, and the comparative adsorption agent 19 was obtained. When the amount of La supported on the comparative adsorbent 19 was analyzed by ICP emission analysis, it was 2% by weight.
[0094]
<Comparative Example 20> Preparation of Comparative Adsorbent 20
NH obtained in Example 1_Four-FER-1: 20 g (anhydrous conversion) was added to a nickel nitrate aqueous solution in which nickel nitrate hexahydrate: 1.98 g was dissolved in 100 g of pure water, evaporated to dryness under reduced pressure at 60 ° C., Ni Loading was performed. Then, it dried at 110 degreeC for 20 hours, and the comparative adsorption agent 20 was obtained. The amount of Ni supported on the comparative adsorbent 20 was analyzed by ICP emission analysis and found to be 2% by weight.
[0095]
<Ethylene adsorption removal test>
About each of the adsorbents 1 to 9 and the comparative adsorbents 1 to 10, 0.1 g was filled in an atmospheric pressure fixed bed flow type reaction tube made of quartz glass and subjected to an ethylene adsorption experiment. As a pretreatment, the air was heated to 500 ° C. at a rate of temperature increase of 20 ° C./min while flowing air at 50 cc / min, and held at 500 ° C. for 1 hour. After cooling to room temperature and completely replacing with He gas, a model exhaust gas having the composition shown in Table 2 was brought into contact with the adsorbent at a gas flow rate of 100 cc / min for 1 hour at room temperature. The space velocity (volume basis) at this time is 30000 hr.^-1Met. After confirming that the adsorption of ethylene in the model exhaust gas to the adsorbent reached saturation, He gas was again introduced into the adsorbent, and the ethylene remaining in the gas phase was completely removed. Subsequently, hydrocarbon gas desorbed from the adsorbent was heated by a gas chromatograph equipped with a flame ionization detector (FID) while the He gas was circulated at 50 cc / min and the adsorbent was heated at 10 ° C./min. Then, quantitative analysis was continuously performed to evaluate the adsorption characteristics of ethylene. Table 3 shows the adsorption characteristics of ethylene adsorption amount and desorption peak temperature.
[0096]
[Table 2]

[0097]
[Table 3]

[0098]
<Durability test of adsorbent>
The adsorbents 1 to 9 and the comparative adsorbents 1 to 20 were respectively pressure-molded and then pulverized and sized to 12 to 20 mesh. Each sized adsorbent 3 cc was filled in a quartz glass normal pressure fixed bed flow reaction tube and subjected to an endurance test. The endurance test was performed using Air gas with H₂The mixed gas containing O at 10 vol% in terms of volume was treated at 850 ° C. for 5 hours while flowing through the adsorbent at a flow rate of 300 cc / min. The adsorbents subjected to these endurance treatments were evaluated for hydrocarbon adsorption characteristics under the same pretreatment and evaluation conditions as in the <Hydrocarbon adsorption removal test>. Table 4 shows the hydrocarbon adsorption characteristics after the durability test.
[0099]
[Table 4]

[0100]
As can be seen from Tables 3 and 4, the adsorbent of the present invention has a large ethylene adsorption amount and is superior in adsorption characteristics as compared with the adsorbents proposed so far. Further, the adsorbent of the present invention does not show a decrease in the amount of adsorption due to endurance treatment, and maintains the adsorption / removal performance of ethylene even after the adsorbent is exposed to a high temperature.
[0121]
The ethylene adsorbent according to the present invention has a large amount of adsorption of hydrocarbons, particularly ethylene, and has excellent adsorption characteristics. Further, the adsorbent according to the present invention does not show a decrease in the amount of adsorption due to endurance treatment, and is adsorbed. Even after the agent is exposed to a high temperature, the adsorption and removal performance of ethylene is maintained. However, from Tables 6 and 7, the adsorbent alone has a low activity for removing nitrogen oxides from exhaust gas containing excess oxygen containing nitrogen oxides and hydrocarbons, and its catalytic performance is low. On the other hand, conventionally proposed nitrogen oxide removal catalysts exhibit nitrogen oxide removal activity from exhaust gas containing excess oxygen, but the nitrogen oxide removal performance is not fully satisfactory.
[0123]
【The invention's effect】
The ethylene adsorbent of the present invention can efficiently adsorb and remove ethylene in the gas phase, and the adsorption performance of hydrocarbons does not deteriorate even after the adsorbent is exposed to a high temperature. Furthermore, the adsorbent of the present invention has high performance for adsorbing and holding ethylene. Therefore, ethylene can be efficiently removed by bringing the adsorbent of the present invention into contact with a gas phase containing ethylene. Utilizing this property, it is possible to efficiently adsorb and remove ethylene discharged when starting an engine of an automobile or the like with the adsorbent of the present invention, and to adsorb and hold it up to a temperature at which the exhaust gas purification catalyst operates.
[0124]
The adsorbent of the present invention can also be applied to adsorption removal of ethylene generated from agricultural crops.

Claims (4)

Characterized in that an ethylene adsorbent composed of a zeolite having a ferrierite structure having a SiO ₂ / Al ₂ O ₃ molar ratio of 15 or more containing Ag is brought into contact with the gas. Of ethylene adsorption removal . The method for adsorbing and removing ethylene in a gas according to claim 1, wherein a zeolite having a ferrierite structure synthesized by adding pyridine and a fluorine compound to the reaction system is used. The ethylene in the gas according to claim 1 or 2, wherein the content of Ag is 0.1 to 20% by weight based on the total amount of the zeolite having a ferrierite structure and the active metal component. Adsorption removal method . The method for adsorbing and removing ethylene in a gas according to any one of claims 1 to 3, wherein the zeolite having a ferrierite structure further contains Pd.