Nanostructured sorbents for capture of cadmium species in combustion environments

Myong Hwa Lee, Kuk Cho, Apoorva P. Shah, Pratim Biswas

Research output: Contribution to journalArticlepeer-review

39 Scopus citations

Abstract

The pathways of cadmium species to form a submicrometer-sized aerosol in a combustion system exhaust were established. Cadmium oxide was the predominant species formed in the experiments and resulted in particles of a mean size of 26-63 nm with number concentrations in the range of 2-8 × 106 cm-3. Two different nanostructured sorbents, a solid montmorillonite (MMT) and an in situ generated agglomerated silica, were used for capture of the cadmium species. The MMT sorbent was not stable at 1000 °C, and structural changes resulted. MMT did not suppress nucleation of cadmium species and partially captured it by weak physisorption as established by the leachability tests. In contrast, the in situ generated silica nanostructured agglomerates had a high surface area, suppressed nucleation of cadmium species vapors, and chemisorbed them effectively resulting in a firm binding, as compared to the MMT sorbent. There is an optimal temperature-time relationship at which the capture process is expected to be most effective. The leaching efficiency under these conditions was less than 3.2%. The nanostructured silica agglomerate size can be tuned for effective capture in existing particle control devices.

Original languageEnglish (US)
Pages (from-to)8481-8489
Number of pages9
JournalEnvironmental Science and Technology
Volume39
Issue number21
DOIs
StatePublished - Nov 1 2005
Externally publishedYes

ASJC Scopus subject areas

  • Chemistry(all)
  • Environmental Chemistry

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