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Modeling of platinum extraction from used reforming catalyst in iodine solutions

Moghaddam, H. R ; Sharif University of Technology

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  1. Type of Document: Article
  2. DOI: 10.1149/1.3684791
  3. Abstract:
  4. Platinum extraction from spent reforming catalysts in iodine solutions under atmospheric pressure and at temperatures up to 95°C was previously investigated in our group. In this system, platinum is oxidized from the spent catalyst with tri-iodide. In some of the experiments, it was observed that platinum extraction peaked and then decreased. This indicates that a precipitation reaction slowly occurs that removes the dissolved Pt ions from the solution. Power-law rate equation for the Pt extraction to PtI6 2- and the precipitation of the dissolved platinum to PtI 4(s) was implemented to model the experimental Pt extraction data. The activation energies for the platinum dissolution reaction and the precipitation reaction were calculated as 49 and 48 kJ/mol, respectively. The large values of activation energies indicate that both processes are controlled by surface chemical/electrochemical reactions. The reaction order for Pt extraction was identified as 2.82 for the Pt mass fraction in the solid catalyst and 0.43 for the hydrogen ion concentration in solution
  5. Keywords:
  6. Iodine solutions ; Platinum dissolution ; Precipitation reaction ; Reaction orders ; Reforming catalyst ; Solid catalysts ; Spent catalyst ; Surface chemicals ; Activation energy ; Atmospheric pressure ; Catalysts ; Electrochemistry ; Extraction ; Iodine ; Surface reactions ; Platinum
  7. Source: ECS Transactions ; Volume 41, Issue 17 , 2012 , Pages 45-51 ; 19385862 (ISSN) ; 9781607683070 (ISBN)
  8. URL: http://ecst.ecsdl.org/content/41/17/45.abstract