سنتز بلور زئوليت نوع A به روش هاي هيدروژل و نانوامولسيون و بررسي سينتيك تبلور آن

چكيده انگليسي :

101Synthensis of A Zeolite Crystal Via Hydrogel and Nanoemulsion Methods and Investigation of Kinetics of it s Crystallization Seyyed Masoud Rahnamaei Yahyaabadi m rahnamaie@gmail com Data of submission 2014 15 12 Department of Chemical Engineering Isfahan University of Technology Isfahan 84156 83111 Iran Degree Msc Language FarsiSupervisor s Name and Email address K Shams K shams@cc iut ac irAbstract Zeolite are Aluminasilicate porous materials which used chiefly as catalytic ion exchange and molecularsieve agents to achieve numerous purposes in chemical and petrochemical industries Over recent years synthesis of zeolites in nano scale attracted researchers due to their improved properties Short crystallizationtime lower energy consumption and more conversion percent conducted decrease in production cost soknowledge about the kinetic of zeolite s crystallization is very important factor todesign the crystallizer andoptimize production process Two important kinetic s parameters which impact on crystal size and time ofcrystallization are nucleation and crystal growth rates Increasing the nucleation rate perform decreasingcrystal size and faster crystallization but enlarge crystal growth rate increase crystal size and crystallizationrate Population balance equation connect the crystal size distribution to crystallization parameters In thisstudy 4A zeolite was synthesized via hydrogel and micro emulsion methods and effect of temperature oncrystallization rates and it s kinetic is investigated XRD analysis showed A type zeolite synthesis fromsodium hydroxide via hydrogel and microemulsion methods was successful Result showed the maximumcrystallization time in hydrogel method is more than microemulsion method also at higher crystallizationtemperature the crystallization rate is faster in both method minimum crystallization time is 164 and 260minutes in microemulsion and hydrogel method at 90 C increase in crystallization temperature caused lessamount of zeolite was synthesized at the end of crystallization process through hydrogel method but thecrystallization temperature has humble effect on this amount Image analysis on final sample showed thatzeolite crystal size which is synthesized via microemulsion method are smaller than hydrogel method also athigher temperature the average crystal size is larger but the impact of crystallization temperature on hydrogelmethod is more than microemulsion method At the end of crystallization the minimum average crystal sizeis 0 716 micrometer by microemulsion method and 1 75 micrometer by hydrogel method which reported at70 C At continue nucleation profile and crystal growth rate calculated after fitting simulation data toexperimental results and effect of crystallization temperature on kinetic s parameters was investigated thenArrhenius equation used for understanding crystal growth rate relation with crystallization temperature Theresults showed at higher temperatures crystal growth occurred faster also mean crystal growth rate is more inhydrogel method High value of activation crystal growth energy confirm this reality that reaction on zeolitesurface control the growth of zeolite s crystal also the activation crystal growth energy in microemulsionmethod is lower than hydrogel method The nucleation rate profile showed that the average nucleation rate islarger in microemulsion method Surfactant which parcipitated in microemulsion caused lower interfacialtension in nano reactor which made from microemulsion and consequently caused increase in nucleation rateby heterogeneous nucleation Keywords Zeolite Crystallization Nucleation rate Crystal growth rate Microemulsion

رهنمايي يحيي آبادي، مسعود

سنتز بلور زئوليت نوع A به روش هاي هيدروژل و نانوامولسيون و بررسي سينتيك تبلور آن

زئوليت , هسته زايي , نرخ رشد بلور , ميكروامولسيون