Attachment of Acidithiobacillus ferrooxidans onto different solid substrates and fitting through Langmuir and Freundlich equations

Artículo de publicación ISIAttachments of Acidithiobacillus ferrooxidans ATCC 23270 onto elemental sulfur, quartz and complex chalcopyrite were investigated by analysis of its extracellular polymeric substances as well as applying Langmuir and Freundlich equations. The two equations fitted the adsorption equilibrium data with significant correlation coefficient over 0.9. This indicated that bacterial attachment is complicated and involves Langmuir and Freundlich characterizations. Sulfur-grown cells showed the highest affinity for the three solid substrates. The investigated complex chalcopyrite possessed a higher maximum adsorption capacity for A. ferrooxidans than elemental sulfur or quartz. The Freundlich fitting parameters suggested that quartz had a weaker adsorption capacity and smaller adsorption areas than elemental sulfur or the complex chalcopyrite. It is not the content of total carbohydrates or proteins in EPS but their ratios that determine the affinity differences between cells and substrates

Kinetic study on leaching of nickel from Turkish lateritic ore in nitric acid solution

Dissolution kinetics of nickel from lateritic ore in nitric acid solution was investigated. Experimental parameters used were stirring speed (100-600 r/min), temperature (40-96 A degrees C), nitric acid concentration (0.1-2 mol/L) and particle size (< 106 A mu m). The shrinking core model was applied to the results of experiments investigating the effects of leaching temperature in the range of 40-90 A degrees C and nitric acid concentration in range of 0.1-2 mol/L on nickel dissolution rate. The kinetic analysis shows that the nickel dissolution from lateritic ore could be described by diffusion model. The activation energy (E (a)) for the dissolution reaction is calculated as 79.52 kJ/mol.Research Foundation of the Selcuk UniversitySelcuk University [06101021]This study was produced from the PhD thesis of Tevfik Agacayak and supported by The Research Foundation of the Selcuk University under the Project No: 06101021