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Comparative study on adsorption of iodine vapor by silica-supported Cu nanoparticles and micronized copper

Outokesh, M ; Sharif University of Technology | 2012

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  1. Type of Document: Article
  2. DOI: 10.1021/ie301263j
  3. Publisher: 2012
  4. Abstract:
  5. The current study is aimed at comparison of adsorption behaviors of silica-supported Cu nanoparticles (Si-N-Cu) and micrometric copper powder (Mi-Cu) for uptake of iodine vapor. The Si-N-Cu was synthesized by the decomposition of aqueous Cu(NO3)2 solution at supercritical condition, followed by reduction of the sample by H 2-N2 mixture. The Si-N-Cu sample with 29.4 nm Cu particles adsorbed 95% of I2 at partial pressure 10-5 bar in 1 h, while the 1 μm Mi-Cu adsorbed 51% of iodine in 6 h, indicating higher yield and faster kinetics of the nanometric sample. Theoretical analysis revealed the existence of a strong thermodynamic size effect in the Cu-I2 reaction system, so that molar |ΔG| for 2 nm Cu particles was 2.5 times larger than |ΔG| for 1 μm particles. For the Mi-Cu, kinetics obeyed a three-dimensional diffusion model, while in the case of Si-N-Cu, diffusion did not play any role in the kinetics. Apparently, no passivation mechanism was operative in the iodination
  6. Keywords:
  7. Adsorption behavior ; Comparative studies ; Cu nanoparticles ; Diffusion model ; Higher yield ; Iodine vapor ; Nanometrics ; Reaction system ; Size effects ; Supercritical condition ; Adsorption ; Copper powder ; Iodine ; Kinetics ; Nanoparticles ; Silica ; Vapors ; Silicon
  8. Source: Industrial and Engineering Chemistry Research ; Volume 51, Issue 47 , 2012 , Pages 15315-15323 ; 08885885 (ISSN)
  9. URL: http://pubs.acs.org/doi/abs/10.1021/ie301263j