شكل گيري در جاي تيتانيوم دي اكسيد در نانو الياف كربن فعال با استفاده از تيتانيوم ايزوپروپكسيد

چكيده انگليسي :

In Situ TiO2 Formation in Activated Carbon Nanofibers through Titanium Isopropoxide Fahimeh Mehrpouya f mehrpouya@tx iut ac ir Date of Submission 12 03 2011 Department of Textile Engineering Isfahan University of Technology Isfahan 8415683111 Iran Degree M Sc Language FarsiSupervisor Prof H Tavanai tavanai@cc iut ac ir Prof M Morshed morshed@cc iut ac irAbstract Titanium dioxide TiO2 has fascinating properties such as chemical stability corrosion resistanceand non toxicity Tiatanium dioxide which exists in four crystal forms namely anatase rutile brookite andtitanium dioxide B is one of the most frequently used photocatalysts Activated carbon is an importantcarrier and support for the titanium dioxide Using activated carbon as a catalyst support will improve thephotocatalytic properties of titanium dioxide nanoparticles by increasing their degree of exposure toneighboring materials High surface area and porous structure of activated carbon nanofibers make them anideal photocatalyst carrier The preparation of the titanium dioxide nanoparticles in the nanometer range can be conducted through thehydrolysis and condensation of titanium alkoxides Titanium isopropoxide TIPP is one of the most widelyused titanium alkoxides as a titanium source In the present work titanium dioxide nanoparticles weregenerated in situ in activated carbon nanofibers In an in situ formation process the metal oxide particlesare generated from the precursors already embedded in the matrix polymer In situ process has advantagessuch as high content of titanium dioxide nanoparticles in activated carbon titanium dioxide nano compositenanofibers as well as low aggregation of titanium dioxide nanoparticles The general characteristics ofactivated carbon titanium dioxide composite nanofibers i e surface morphology crystallinity crystal size ratio of anatase to rutile structure nanoparticle size and distribution of the generated titanium dioxidenanoparticles can be observed by scanning electron microscopy field emission scanning microscopy atomicforce microscopy X ray diffractometer and electron diffraction scanning EDS or EDX and also the effectsof pH and ratio of titanium isoperpoxide to ethanol were investigated In this research the electrospinning solution was prepared by dissolving polyacrylonitrile PAN Mw 70000 in N N dimethylformamide DMF to form a transparent solution Three levels of titaniumisopropoxide TIPP 99 99 Aldrich namely 5 7 and 9 w w dissolved in ethanol were added to thePAN solution drop by drop producing 1g of brilliant yellow solution DMF was used directly used asreceived but ethanol Merck was dehydrated first This solution was transferred into a syringe connected toa needle which was connected to a high voltage supply The distance between the tip of the needle and thecollector was fixed at 15 cm An electrical field of 17 kV was employed for electrospinning The feed ratewas 0 2 mlh 1 The electrospun nanofibrous webs were placed into quatrz boats and transferred to a tubefurnace The samples were first stabilized thermally in the tube furnace at 280 C under oxygen for 1h andthen carbonized by increasing the temperature from 280 C to 600 C under nitrogen Activation undernitrogen followed next by increasing the temperature from 600 C to 800 C and ageing the sample at thistemperature for 1h The results of this study showed that Titanium dioxide nanoparticles with high anatase structure content havebeen synthesized in the in situ process The titanium dioxide nanoparticles showed an excellent dispersion inthe activated carbon nanofibers The titanium dioxide content in the nano composite nanofibers wasestimated by ash content analysis Keywords Titanium isopropoxide Titanium dioxide Activated carbon Nanofiber Nanoparticle

مهرپويا، فهيمه

شكل گيري در جاي تيتانيوم دي اكسيد در نانو الياف كربن فعال با استفاده از تيتانيوم ايزوپروپكسيد