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1、2005年2月中文摘要本文用高溫?zé)峤飧呔畚锏姆椒ㄖ苽浼{米孔碳膜,用來(lái)分離小分子氣體,如:H2,He,CH4,C02和N2。利用單質(zhì)氣體的滲透率來(lái)計(jì)算納米孔碳膜對(duì)各氣體的理想分離系數(shù)。碳膜的制各我們主要用以下兩種方法:以鋁溶膠修飾過(guò)的pAl203管或不銹鋼管為支撐體,以聚酰亞胺的吡咯烷酮溶膠為前驅(qū)體,在惰性氣體氮?dú)獾谋Wo(hù)下,于600~7000C下直接碳化前驅(qū)體制備碳膜,并通過(guò)改變碳化的條件,來(lái)考察其氣體分離的效果。結(jié)果表明所制得的膜主要以努森擴(kuò)散的機(jī)理進(jìn)行氣體傳質(zhì)。將含鎳的化合物溶解于聚酰亞胺溶膠中,形成含鎳的前驅(qū)體,以修飾過(guò)的多孔a—A1203管為支撐體,通過(guò)高溫碳化
2、高聚物和鎳催化C1-14裂解進(jìn)行氣相沉積相結(jié)合的方法制備納米孔分子篩膜,運(yùn)用測(cè)定單氣體的滲透率來(lái)表征膜的分離性能,并與不加鎳情況下制得的碳膜相比較。此種方法下H2/N2和H2/CH4的理想分離系數(shù)分別為8.4和14,遠(yuǎn)大于按努森擴(kuò)散下的理論分離系數(shù),表明是按分子篩分的機(jī)理進(jìn)行氣體分離。試驗(yàn)結(jié)果表明加鎳制碳膜法一次炭化過(guò)程就可以獲得結(jié)構(gòu)完整,分離性能較好的納米孔碳膜,大大降低制膜成本和時(shí)間。此外,對(duì)支撐體,前驅(qū)體和碳膜進(jìn)行了一系列的表征,如空隙率,孔徑分布的測(cè)定,F(xiàn)T-IR,XRD,SEM.EDX的分析,氣體滲透率與溫度壓強(qiáng)的關(guān)系。關(guān)鍵詞:納米孔碳膜;氣相沉積;鎳催化裂
3、解;一次碳化ABSTRACTNanoporouscarbonmembraneswerepreparedbycarbonizingpolymersathightemperaturethroughtwodifferentmethodsanditsseparationperformancewasinvestigatedforsmallmoleculesgases,suchasH2,He,C02,N2,CH4.Meanwhile,idealseparationfactorwerecalculated,baseonthepermeanceofpuregases.Stainles
4、ssteeltubeand¨A1203tubemodifiedandcleanedbymeansofsol—geltechniquewerechosenassupports.Nanoporouscarbonmembraneswerepreparedthroughpyrolyzingprecursor(polyimidewithN—methyl-pyrrolidoneassolvents)at6000C-7000Cundertheconditionofflowingnitrogengasfflowrate:45ml/min).Theinfluenceofcarbonat
5、ionconditiononseparationperformancewereinvestigated,theresultsshowedthatthediffusionofgasthroughthemembranewasmainlycontrolledbythemechanismofKnudsendiffusion.DissolvingNim03)2‘6H20inpolyimideandN—methyl—pyrrolidone,withmodifiedc【一A1203tubeassupport,nanoporouscarbonmembraneswereprepared
6、bymeansofthecombinationofthecarbonizingathightemperaturewithcatalyticdecompositionofmethaneusingtheNi/polyimideastemplate.Thedifferencebetweennanoporouscarbonmembraneswithnickelandwithoutnickelshowedthattheintroductionofnickelimprovesthestructureofmembraneandlowerthetimeandcosts.Meanwhi
7、le,idealseparationfactorofH2/N2,H2/CH4were8.4and14,largerthantheoreticalvalueofKnudsendiffusion.Diffusionofgasthroughthemembranewasmainlycontrolledbythemechanismofmolecularsieving.Support,precursorandnanoporouscarbonmembraneswerecharacterizedbyFT-IR,XRDandSEM—EDX.Theeffectofthe