Sharif Digital Repository

In this work bioleaching of vanadium has been done from Saghand Ore (Anomaly II). Leaching of vanadium was done in several stages. First, Acidithiobacillus ferrooxidans and Acidithiobacillus thiooxxidans were used for dissolution of pure vanadium pentoxide and it was observed that these bacteria are able to dissolve and reduce vanadium with high efficiency. After that these bacteria were employed to leaching of vanadium from ore; however there were no results by those experiments and no vanadium dissolved in liquor although bacterial activity was visible. In the second stage, oxalic acid 0.1 M as an organic acid and three inorganic acids, namely sulfuric, hydrochloridric and nitric acids, in... 

To synthesizeFe3O4@SiO2 core-shellnanoparticles,at first,Fe3O4 magnetic nanoparticle synthesisedby usingcoprecipitation method.Then tetraethyl orthosilicate (TEOS) was used to coverthe surface of this nanoparticle with layer of silica. In the next step, the surface of Fe3O4@SiO2 core-shellnanoparticlesfunctionalized by NO-bidentate and ONO-tridentate ligands. Finally the functionalized nanoparticle coordinated to oxovanadium(IV) to achieve Fe3O4@SiO2@NO-VO2+ and Fe3O4@SiO2@ONO-VO2+nanocatalysts for selective oxidation of sulfides to corresponding sulfoxide and oxidation of alkene. FT-IR, 1HNMR, 13CNMR, SEM, VSM and ICP analysis were used for characterization of this nanocatalysts. This... 

Because of limitation of titania coating that can act as self-cleaning surface under UV light irradiation, introduction of transition metal ions into titania lattice can decrease band gap energy of titania in order to activate the coating under visible light irradiation. In this research, by using vanadium element and silica prelayer, a titania coating was deposited on the soda-lime glass substarte to produce self-cleaning surface. The scope of coating was to increase the photocatalytic activity and hydrophilicity of vanadium doped titania coating on the soda-lime glass and silica coated glass by sol-gel dip coating method. XRD and FTIR analysis were done on the powders with different... 

In this study, the photocatalytic activity and hydrophilicity of coat improved using Nitrogen and Vanadium elements as dopant in TiO2 coating. By using vanadium and nitrogen elements and silica prelayer, a titania coating was deposited on the soda-lime glass substrate by sol-gel dip coating method to produce self-cleaning surface. XRD and FTIR analyses were done on the powders after heat treating at in 450˚C for 30 min. XPS analysis was done for investigation of N replacement in titania structure. The band-gap energy of formed anatase was derived using UV-Vis analysis. The coating morphology and thickness were also investigated by SEM. Hydrophilicity of coatings was determined by measuring... 

Solvent extraction of vanadium (V) from sulfated leaching solution of the converter slag of the Isfahan steel company followed by stripping of this element from the organic solvent were examined in this study. In the experimental section, 2-ethyl-1-hexanol extractor was utilized for selective separation of V(V) from the acidic medium containing Si, Na, Fe, Al, Ca, and P ions. Ammonium chloride solution was also used for stripping V from the organic phase. Under optimal condition (pH=1.9, T=65℃, extractor concentration of 68% and organic phase volume fraction of 0.66), 91% was extracted in solvent extraction stage. Under optimal stripping conditions (pH=7.5, T=25℃, organic phase volume...