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چكيده انگليسي :

Removal of Mercury From Industrial Wastewaters Using Carbon Nanostructures Fatemeh Mohamadi Landi mohamadi iut@yahoo com April 9 2011 Department of Natural Resource Isfahan University of Technology Isfahan 84156 83111 Iran Degree M Sc Language Farsi B Rezaei rezaei@cc iut ac ir and A M Rashidi rashidiam@ripi ir AbstractOne of the most important and dangerous environmental pollutants is the presence of heavy metal ions inindustrial units effluent Among the heavy metals mercury deriving from industrial wastewater discharges ofchlor alkali paper and pulp oil re nery paint pharmaceutical and battery manufacturing has particularimportance due to toxicity bioaccumulation and environmental effects on living organisms Various physicaland chemical methods including coagulation and sedimentation reverse osmosis chemical reduction adsorption and ion exchange are used to remove mercury from wastewater and contaminated waters Inrecent years adsorption process has taken more attention due to high efficiency and approximately low cost The necessity to reduce the amount of mercury ions in industrial wastewater stream has led to an increasinginterest to find selective adsorbent Different adsorbents are used for removal of mercury from industrialwastewater But considerable attention has been devoted to use nano adsorbent such as nanoparticle andnanostructure in removing metal contaminants from industrial wastewater because of their high specificsurface high area to volume ratio and consequently the high efficiency In this study two carbonnanostructures MWNT COOH and CNFs were applied for mercury adsorption from synthetic solutions andindustrial wastewater using batch and column techniques The parameters affecting the sorption includingequilibrium time pH initial mercury concentration adsorbent amount the effect of disturbing cations andionic strength were investigated Some physical chemical and morphological properties of adsorbents weredetermined by Brunauer Emmett Teller BET X ray diffraction fourier transform infrared spectroscopy FT IR scanning electron microscopy SEM and transmission electron microscopy TEM Adsorptionkinetics studies showed that the adsorption of mercury by MWNT COOH and CNFs is rapid The kineticdata for mercury sorption by CNFs were precisely described by Pseudo First order and pseudo second ordermodels The optimum pH for mercury sorption by MWNT COOH was between 3 0 7 0 and by CNFsbetween 4 0 7 0 The suitability of the Langmuir Freundlich and Redlich Peterson adsorption models to theequilibrium data was investigated for mercury sorbent system Mercury adsorbed on MWNT COOH wasfitted well to Redlich Peterson model and on CNFs to Redlich Peterson and Freundlich model Maximumcapacity of mercury adsorption was 500 mg g for both adsorbents The presence of metal cations includingcadmium chromium copper nickel lead and zinc with two concentrations 50 and 100 mg L did notaffect significantly the mercury adsorption The increase of ionic strength decreased the mercury sorptionpercentage so that the competitive effect of the electrolytes on mercury adsorption by MWNT COOH was inorder NaCl KCl Na2SO4 and by CNFs was Na2SO4 NaCl KCl Mercury desorption byhydrochloric acid was higher than nitric acid for both sorbents Maximum mercury desorption 100 and83 3 was occurred using hydrochloric acid for MWNT COOH and CNFs respectively Mercury adsorptionfrom an industrial wastewater indicated that both carbon nanostructures have an acceptable efficiency andcould be used for wastewater treatment Also the result showed mercury adsorption on MWNT COOH ishigher and faster than CNFs The enhanced mercury ions sorption by MWNT COOH might be duo tofunctional group COOH on the carbon nanostructure surface Key wordsMercury Adsorption MWNT COOH CNFs Adsorption kinetic Adsorption isotherms

محمدي لندي، فاطمه

حذف جيوه از پساب هاي صنعتي با استفاده از نانو ساختارهاي كربني

جذب سطحي , MWNT-COOH , سينتيك جذب , CNFS , هم دماي جذب