MaterialsChemistryandPhysics101(2007)87–92
TheroleofMg2+andMg2+/aminoacidincontrollingpolymorph
andmorphologyofcalciumcarbonatecrystal
An-jianXiea,b,?,Yu-huaShena,b,?,Xiao-yanLia,Zong-weiYuana,
Ling-guangQiua,Chun-yanZhanga,Yuan-fengYanga
b
SchoolofChemistryandChemicalEngineering,AnhuiUniversity,Hefei230039,PRChinaStateKeyLaboratoryofCoordinationChemistry,NanjingUniversity,Nanjing210093,PRChina
a
Received21August2005;receivedinrevisedform31December2005;accepted14February2006
Abstract
Mg2+andthemixtureofMg2+/dl-asparticorl-tyrosinewereusedaseffectivecrystalnucleationandgrowthmodi?erstocontrolthecrystallizationofCaCO3.Thepolymorphandmorphologyofcrystalswerecharacterizedusingscanningelectronmicroscopy(SEM),Fouriertransforminfraredspectroscopy(FT-IR)andX-raydiffraction(XRD).Theresultsdemonstratedthatvariousmorphologiessuchasrod-shapedparticles,spinosesphereparticles,cauli?ower-likecrystals,andthespindlyparticlesproducedinaboveaqueoussolutions.WhenthemolarratioofMg2+toCa2+waslessthan8,theproductswereallthemixturesofcalciteandaragonite.TheabilityofMg2+toinducetheformationofaragonitewasenhancedasthemolarratioofMg2+toCa2+increased.Whenthemolarratioreached8,thecrystalsobtainedwereallaragonite.InthemixedsystemsofMg2+/aminoacids,thepresenceofaminoacidswashelpfulfortheformationofaragonite.ThepossibleformationmechanismsofCaCO3indifferentsystemswerediscussedinthepaper.?2006ElsevierB.V.Allrightsreserved.
Keywords:Calciumcarbonate;Crystalgrowth;Mg2+;Aminoacids
1.Introduction
Biomineralizationistheprocessofinorganiccrystalgrowthatinorganic–organicinterface[1–3],whichexertsasigni?cantin?uenceonthegrowthoflife.Therefore,theresearchesaboutthebiomineralizationhavearousedmanyinterests[4–9].Fromthenumberofcarbonateminerals,CaCO3isthemostimpor-tantbiomineralsinvariousindustrial?elds,suchasadditivesinmedicine,foods,plastics,printingink,etc.Its?nalapplica-tionisdeterminedbyitspurity,particlesizeanddistribution,crystalstructureandmorphology[10].Somestudiesindicatedthathigh-densityMg2+wasfoundinbioenvironmentandittookanimportantpartinthebiomineralizationofcalciumcarbonate[11,12].EvaLosteetal.havestudiedtheroleofmagnesiuminstabilizingamorphouscalciumcarbonateandcontrollingcal-citemorphologies[13].Yong-JinHanetal.haveinvestigatedeffectofMg2+onorientedgrowthofcalciteoncarboxylic
Correspondingauthors.Tel.:+865515108090;fax:+865515107342.E-mailaddresses:anjx@163.com(A.-j.Xie),s(Y.-h.Shen).
0254-0584/$–seefrontmatter?2006ElsevierB.V.Allrightsreserved.doi:10.1016/j.matchemphys.2006.02.019
?
acidfunctionalizedself-assembledmonolayer[14].Davisetal.haveindicatedthattheroleofMg2+asanimpurityincalcitegrowth[15].NorioWadaetal.havedemonstratedtheeffectsofdivalentcationsuponnucleation,growthandtransformationofcalciumcarbonatepolymorphsunderconditionsofdoubledif-fusion[16].However,theeffectofdifferentconcentrationMg2+onthepolymorphandmorphologyofCaCO3crystalusingdirectprecipitationmethodwasnotdescribedsystemicallysofar.Further,proteinasanorganicmatrixalsoplaysacriticalroleinthebiomineralizationoftheCaCO3[2,17],itexistsatinorganic–organicinterfaceofalmostallthebiomineralssuchasteeth,bones,pearls,molluskshells[2,18].Aminoacidsaremaincomponentsofproteins,theymaybeimportantfactorsincontrollingofCaCO3polymorphsandmorphologies.ThenucleationandgrowthofCaCO3crystalintheMg2+/aminoacidmixedsystemwasnotreportedbynow.
Inthisstudy,thein?uenceofthedifferentMg2+/Ca2+molarratiosystemandtheMg2+/aminoacidmixedsystemonthenucleationandgrowthofCaCO3crystalswereinvestigated.Simultaneously,thepossibleformationmechanismofCaCO3crystalsonthebasisoftheprincipleofbiomineralizationwasdiscussed.Itissigni?canttounderstandthemechanismof
久久建筑网m.kkreddy.com提供大量：建筑图纸、施工方案、工程书籍、建筑论文、合同表格、标准规范、CAD图纸等内容。