بررسي تجربي كاربرد فرايند الكترودياليز ناپيوسته در جداسازي سديم سولفات از دوغابه منيزيم استئارات

چكيده انگليسي :

98 Experimental Study of Batch Electrodialysis Process in Separation of Sodium Sulfate from Magnesium Stearate Aqueous Slurry Mohammad Ali Masigol m masigol@ce iut ac ir March 3 2012 Department of Chemical Engineering Isfahan University of Technology Isfahan 84156 83111 Iran Degree M Sc Language FarsiSupervisors Ahmad Moheb ahmad@cc iut ac ir Arjomand Mehrabani Zeinabad arjomand@cc iut ac irAbstractMagnesium stearate MgSt is widely used as an effective lubricant in the pharmaceutical industry for tabletformulation This widespread application is due to its low price and very high lubricating ability It isnonsoluble in water because of its highly apolar molecular structure and hydrophobic nature and its goodchemical and physical properties make it a good candidate for being used as an emulsifier and anti stickingagent The aim of this work was to separate sodium sulfate from MgSt aqueous slurry which exists as animpurity at the final stage of industrial production of MgSt By separating sodium sulfate it was possible torecover some of excess sodium hydroxide used at the first stage of MgSt production and also avoid using alarge amount of water used in the common process used in industry for sodium sulfate removal For thispurpose an electrodialysis cell was designed and built and batch mode of electrodialysis process wasimplemented At the first step some preliminary experiments were done to investigate the influences of someparameters including applied voltage MgSt concentration middle compartment stirrer speed and NaOHinitial concentration in cathodic chamber on sodium ions recovery energy consumption and sodium ionstransport flux High sodium recovery about 90 was obtained at 15 wt MgSt voltage of 20 volt andstirrer speed of 250 rpm which proved that implemented method can be considered as proper candidate forsalt recovery from MgSt slurry The results indicated that increasing voltage in ED cell enhanced theseparation of sodium ions Also using higher MgSt concentration led to decrease of sodium recovery whichshowed that this system is more suitable for low feed concentrations By increasing feed compartment stirrerspeed from 250 to 500 rpm formation of very high turbulence regime in feed chamber prevented ions frommigrating from diluate to concentrate compartment which led to lower ion transport flux and decreasingsodium ions recovery Response surface method RSM was used to investigate the effects of operatingparameters on sodium ions recovery and specific power consumption Five levels were selected for theoperaing parameters including voltage in range of 5 25 volts MgSt concentration in range of 10 60 wt stirrer speed in range of 200 600 rpm and time in range of 20 180 min to design the experiments In thispart of the work initial concentration of NaOH and H2SO4 in cathodic and anodic chambers were adjusted at0 5 M The quadratic models established for sodium recovery and energy consumption in terms of operatingparameters with determination coefficient R2 of 0 9276 and 0 9243 respectively indicated that offeredresponse surface models are helpful to describe the sodium ions recovery and specific power consumption Analysis of variance ANOVA showed that voltage and time were the most influent parameters on thesodium ions recovey with Prob F less than 0 0001 whereas stirrer speed had no significiant effect withProb F of 0 3595 Also voltage and middle compartment stirrer speed were the most influent variables on thespecific power consumption with F value of 132 9 and 23 37 and Prob F of less than 0 0001 and 0 0002respectively Keywords Magnesium stearate Electrodialysis Separation Response surface method

مسيگل، محمدعلي

بررسي تجربي كاربرد فرايند الكترودياليز ناپيوسته در جداسازي سديم سولفات از دوغابه منيزيم استئارات

استئارات منيزيم , روش رويه پاسخ