10072

9302

كارشناسي ارشد

علوم خاك

اصفهان: دانشگاه صنعتي اصفهان، دانشكده كشاورزي

1393

سيزده، 74ص.: مصور، جدول، نمودار

ص.ع. به فارسي و انگليسي

مهران شيرواني

حسين خادمي

94/2/29

شمس الله ايوبي، جهانگير عابدي كوپايي

1396/09/27

كتابنامه

كشاورزي

مهندسي كشاورزي

ID9302

Sorption of Lead by Sepiolite Nanofibers and Zeolite Free and Entrapped in Alginate Beads Nasim Zough nasimzough@yahoo com January 17 2015 Department of Soil Science Isfahan University of Technology Isfahan 84156 83111 IranDegree M Sc Language FarsiSupervisor Mehran Shirvani Shirvani@cc iut ac irAbstractIndustrial development population growth and application of new technologies have causedcontamination of soil and water resources by heavy metals Industrial production of metal alloys plastics paints and resins mining activities vehicular traffic and application of chemical fertilizers and biosolidsare the main sources of heavy metals in contaminated water bodies Adsorption is an effective andeconomic process for removal of heavy metals from polluted waters In this study zeolites and sepioliteclay minerals and alginate biopolymer were used for adsorptive removal of Pb from aqueous solutions Several hybrid adsorbent with different ratios of clay to alginate 1 2 1 4 and 1 8 were also prepared andtheir abilities to adsorb Pb were compared with those of the clays and alginate The sorption experimentswere carried out in different Pb concentrations 25 to 2000 mg L 1 and temperatures 15 25 35 and 45C to determine the isothermal and thermodynamic constants for Pb sorption The results showed that theLangmuir and Freundlich models described Pb sorption on all sorbents very well Based on the Langmuirmodel alginate showed the highest and clays showed the lowest sorption capacities for Pb and the hybridsorbents were intermediate in Pb sorption The capacities of all sorbents for Pb retention increased withincreasing temperature from 15 to 45 C Negative values were calculated for the Gibbs free energychanges indicating that Pb sorption on the sorbents was spontaneous Positive values were calculated forthe enthalpy change suggesting that Pb sorption reaction was endothermic in nature Positive values werealso obtained for the entropy changes which indicates the increased randomness at the solid solutioninterface with some structural changes in the sorbate and sorbents Based on the values of the obtainedthermodynamic parameters it can be concluded that chemisorption was the main mechanism for Pbsorption by the studied sorbents At all temperatures by increasing the proportion of zeolite in clay alginate hybrids an increasing trend in Pb sorption was observed But in the case of sepiolite alginatehybrids no significant differences in Pb sorption were detected among the hybrids Keywords Hybrid sorbent isotherm thermodynamics adsorption

مهران شيرواني

حسين خادمي

شمس الله ايوبي، جهانگير عابدي كوپايي