金属有机骨架化合物的二氧化碳吸附性能的研究进展

2019,Vol.33,No.2

www.mater-rep.com

slf@chd.edu.cnDOI:10.11896/cldb.201903022 基金项目:国家自然科学基金(51502021);陕西自然科学基金(2017JQ2025);广西信息材料重点实验室开放基金(151001-K) ThisworkwasfinanciallysupportedbytheNationalNaturalScienceFoundationofChina(51502021),NaturalScienceBasicResearchPlaninShaanxiProv-inceofChina(2017JQ2025),theGuangxiKeyLaboratoryofInformationLaboratoryFoundation(151001-K).金属有机骨架化合物的二氧化碳吸附性能的研究进展

孙增智1,薛 程1,宋莉芳

1,,邱树君2,褚海亮2,夏永鹏2,孙立贤2

1 长安大学材料科学与工程学院,西安7100642 桂林电子科技大学材料科学与工程学院,桂林541004

能源与环境是人类生存和发展的必要条件,两者协调发展是社会实现可持续发展的重要保证三近几年来,人类赖以生存的化石燃料所带来的负面影响逐渐受到社会的关注,而化石燃料燃烧所释放出的CO2是造成温室效应的主要原因三因此在低碳经济环境下开发出高效环保的碳捕获和封存技术,对能源循环利用及环境保护起到至关重要的作用三

使用胺溶液进行洗涤及吸收CO2是工业上捕获和存储(CCS)最常用的技术之一(例如从电厂烟气中分离CO2),该法可以大幅减少CO2的排放量,但同时也会增大工厂的能源消耗(25%~40%),从而大幅增加额外成本三胺洗涤的其他缺点包括碱溶液对设备的腐蚀二溶剂的损失二大量产热引起的胺降解以及捕获之后不易被分离出来三另一种捕获CO2的方法是采用高温下吸收(化学吸附)的固体材料如碱金属陶瓷二固体胺二层状双氢氧化物或钙基吸附剂,但此类方法的能量消耗和对水分子及其他组分的敏感性限制了其应用范围三此外,采用聚合物或无机膜,在不同的机制下选择性分离混合气体也是一种可行的方法,但很难获得具有高稳定性二高选择性和高通量的薄膜,并且提高膜的吸附分离作用和选择性非常必要三对于固体吸附剂而言,高压下多孔材料对CO2的捕获是以吸附剂与被吸附物相互作用为主,而在低压或低CO2浓度下的选择性捕获主要受吸附剂与被吸附物相互作用以及吸附剂对CO2的化学亲和力两者共同影响三

金属有机骨架化合物(MOFs)具有高结晶度二高比表面积和可调的孔隙结构,在气体吸附尤其是CO2捕获方面展示出巨大的潜力三相对于活性炭二沸石等固体吸附剂来说,MOFs具有更高的吸附选择性三将其应用于碳捕获和封存技术中,可以大幅拓宽CO2吸附剂的可选择范围,在提高吸附选择性的同时,也可以有效地降低成本三目前,有望采用MOFs材料捕获CO2的场合包括发电厂的碳捕集二天然气中CH4/CO2的分离二交通工具排放的CO2的收集甚至直接从空气中捕获三因此,研发能够高效吸附分离CO2的MOFs材料对于缓解环境压力意义重大三

本文概括了CO2吸附模型的建立方法,提出了几种提高MOFs对CO2捕获量的策略三如提高开放金属位点的密度二掺杂金属或氮原子二调节孔径或进行氨基功能化以及合成MOFs复合材料等,并比较了不同方法对于改善低压条件下CO2吸附量的影响,有望将其应用于捕获燃烧后烟道气二汽车尾气以及其他小型排放源中的CO2三

关键词 金属有机骨架化合物(MOFs) 二氧化碳捕获 吸附分离

中图分类号:O611.4 文献标识码:A

ResearchProgressonImprovingtheCaptureofCarbonDioxidebyMetal-Organic Frameworks

SUNZengzhi1,XUECheng1,SONGLifang

1,,QIUShujun2,CHUHailiang2,XIAYongpeng2,SUNLixian21 SchoolofMaterialsScienceandEngineering,Chang anUniversity,Xi an7100642 SchoolofMaterialsScienceandEngineering,GuilinUniversityofElectronicTechnology,Guilin541004E

nergyandenvironmentaretheessential conditionsforhumansurvival anddevelopment,furthermore,themutual coordinationbetweenthemisavital guaranteeforsocial sustainabledevelopment.Inrecentyears,thenegativeimpactoffossil fuelsonhumansurvival hasgra-duallyattractedwidespreadattentionfromsociety.ThegreenhouseeffectismainlyattributedtothereleaseofCO2fromtheburningoffossil fuel.There-fore,thedevelopmentofefficientandenvironmental-friendlycarboncaptureandstoragetechnologiesinalow-carboneconomyenvironmentplayacrucial roleinenergyrecyclingandenvironmental protection. UtilizingtheaminesolutionsforscrubbingandabsorbingCO2isoneofthemostcommonlytechnologiesforindustrial captureandstorage(CCS)(e.g.,separatingCO2fromfluegasofpowerplantfluegas),whichcansignificantlyreducetheCO2emissions,butalsoincreasestheplantenergyconsumptionby25%~40%,henceleadingtoanincreaseinadditional coststoalargeextent.Inaddition,otherdisadvantagesofaminescrubbingincludecorrosionoftheequipmentbythealkalinesolution,lossofsolvent,degradationoftheaminecausedbyheatproduction,anddifficultyofseparationaftercapturing.Solidmaterialssuchasalkalimetal ceramics,solidamines,layereddoublehydroxidesorcalcium-basedadsorbentsforhightemperatureabsorption(chemisorption)areanothermethodofcapturingCO2,whiletheenergyconsumptionandthesensitivityofwatermoleculesandothercomponentslimittheirscopeofapplication.Inaddition,itisalsoafeasiblemethodtoselectivelyseparatethemixedgaseswithdifferentmechanismsbyutilizingpolymersorinorganicmembranes,yetthemembraneswithhighstability,highselectivity,andhighthroughputarehardtoobtain,anditisnecessarytoamelioratethemembranes adsorptionandseparationandtheirselectivity.Forsolidadsorbents,thecaptureofCO2byporousmaterialsathighpressureisdominatedbyadsorptiveinteractions,whileselectivecaptureatlowpres-sureorlowCO2concentrationsisprimarilyinfluencedbytheinteractionofadsorbentsandachemical affinitytoCO2. Metal organicframeworks(MOFs)exhibittremendouspotential forgasadsorption,especiallyforCO2capture,duetotheirhighcrystallinity,highspecificsurfaceareaandtunableporestructure.Comparedwithothersolidadsorbents,suchasactivatedcarbon,zeolites,MOFshavehigheradsorptionselectivity.ApplyingittothecarboncaptureandstoragetechnologycandramaticallybroadentherangeofCO2adsorbents,increasetheadsorptionselectivity,meanwhile,effectivelyreducethecosts.Currently,MOFsareexpectedtocaptureCO2inpowerplants,sepa-rationofCH4/CO2innatural gas,CO2collectionfromvehicles,andevendirectcapturefromtheair.Therefore,thedevelopmentofMOFsmate-rialscapableofefficientlyadsorbingandseparatingCO2isofgreatsignificanceforrelievingenvironmental stress. ThispapersummarizestheestablishmentofCO2adsorptionmodel andproposesseveral methodstoimprovetheadsorptioncapacityofCO2,suchasincreasingthedensityofopenmetal sites,dopingmetal ornitrogenatoms,adjustingtheirporesizeoramino-functionalization,andsyn-thesizingMOFscompositematerials,andcomparedtheeffectsofdifferentmethodsontheadsorptioncapacityofCO2underlowpressure.Inad-dition,theyareexpectedtobeappliedtothecaptureofCO2inpost-combustionfluegas,vehicleexhaustandothersmall emissionsources.145万方数据

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