حذف كروم از محلول هاي آبي با استفاده از زيتوده جلبك سبز سند سموس كوادريكوادا

چكيده انگليسي :

Chromium Removal From Aqueous Solutions Using Biomass of Green Microalgae Scenedesmus quadricauda Roghayeh Shokri Khoubestani R shokri89@yahoo com January 16 2013 Department of Natural Resources Isfahan University of Technology Isfahan 84156 83 111 IranLanguage Farsi Degree M Sc Supervisors Noorolla Mirghaffari mnorolah@cc iut ac ir Omidvar Farhadian omfarhad@cc iut ac irAbstractRapid increases in world population and industrialization have seriously contributed to heavymetals pollution in aquatic terrestrial ecosystems Among heavy metals chromium pollution hastaken more attention in recent years due to its harmful effects to living organisms and ecosystems The two common stable species of chromium are trivalent Cr III and hexavalent Cr VI thatfound mostly in wastewater from electroplating industries leather tanning wood preservation anddyes steel alloy glass textile industries film and photography Different technologies such aschemical precipitation ion exchange membrane technologies reverse osmosis and adsorptionwere used to remove heavy metals from aqueous solution In recent years more interests have beenfocused on biosorption as an economic and efficient method to remove metals ions Biosorption isa method which natural materials with different biological origin including bacteria fungi yeast algae agricultural and industrial wastes were used as biosorbent In this study dry biomass ofgreen microalgae Scenedesmus quadricauda Chlorophyta was used to remove Cr III and Cr VI from aqueous solutions and industrial wastewater by batch and column experiments Some ofphysical chemical and morphological properties of microalgae biosorbent were determined by theelemental analysis Fourier transform infrared spectroscopy FTIR and scanning electronmicroscopy SEM In addition the parameters influencing on biosorption including equilibriumtime pH metal solution initial concentration amount of adsorbent were investigated Resultsshowed that equilibrium time for removal of Cr III VI is 120 min The adsorption kinetics hadbetter fit by the pseudo second order kinetics for both species of Cr III VI The maximumadsorption of Cr III and Cr VI were occurred at pH 6 and pH 1 respectively The comparisonof results illustrated that Cr III adsorption was fitted better by Redlich Peterson and Langmuirisotherm models than that the Freundlich model The adsorption of Cr IV was fitted better byRedlich Peterson and Freundlich isotherm models The highest adsorption of Cr III and Cr VI were predicted 58 47 and 46 51 mg g according to Langmuir equation respectively When theamount of microalgae biosorbent increased from 0 2 to 10 g L at 100 mg L of Cr III VI theadsorption percentage were increased from 30 03 to 96 40 for Cr III and 7 67 to 64 12 for Cr IV In the column experiments sorption performance was 30 for Cr III ions 63 3 mg g and13 for Cr VI ions 25 5 mg g Chromium desorption was possible using HNO3 and NaOH Thehigher ability for desorption were obtained by 0 1 M of HNO3 for Cr III 85 and 0 1 M ofNaOH for Cr VI 60 Keywords Chromium Biosorption Microalgae Scenedesmus quadricauda Adsorption isotherms

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حذف كروم از محلول هاي آبي با استفاده از زيتوده جلبك سبز سند سموس كوادريكوادا

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