On the crystal growth of nanoscale schwertmannite
Schwertmannite (Fe16O16(OH)12(SO4)2), commonly found in acidic aqueous systems, forms rapidly into a “hedge-hog” morphology, where nano-dimension whiskers project outwards from an electron-dense interior. Schwertmannite whiskers were recently found to contain the highly disordered and maghemite-like...
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| Format: | Journal Article |
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Elsevier Science BV
2005
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| Online Access: | http://hdl.handle.net/20.500.11937/40448 |
| _version_ | 1848755874040905728 |
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| author | Loan, Mitch Richmond, William Parkinson, Gordon |
| author_facet | Loan, Mitch Richmond, William Parkinson, Gordon |
| author_sort | Loan, Mitch |
| building | Curtin Institutional Repository |
| collection | Online Access |
| description | Schwertmannite (Fe16O16(OH)12(SO4)2), commonly found in acidic aqueous systems, forms rapidly into a “hedge-hog” morphology, where nano-dimension whiskers project outwards from an electron-dense interior. Schwertmannite whiskers were recently found to contain the highly disordered and maghemite-like structural components present in ferrihydrite, and on this basis, schwertmannite was postulated to be an intermediate phase (in terms of crystallinity and kinetics of formation) to the least and most crystalline forms of ferrihydrite, 2- and 6-line, respectively. To test this hypothesis and help elucidate the schwertmannite growth mechanism, we reduced supersaturation (a function of pH and ferric concentration) during the crystallization of 2-line ferrihydrite from ferric sulphate liquors. Lower supersaturations resulted in schwertmannite formation, often in an admixture or possibly nucleated on 2-line ferrihydrite aggregates. Alternate experiments performed in the presence of arsenic (as a crystal growth modifier) produced X-ray diffraction (XRD) patterns consistent with admixed ferrihydrite and schwertmannite, but with a morphology where aligned ferrihydrite nanoparticles appeared to approximate the structure of schwertmannite whiskers. We postulate that as similar structural components constitute 2-line ferrihydrite and schwertmannite, but are only minor components in 6-line ferrihydrite, the proportion of each component (with the maghemite-like phase dominating) permits the specific alignment and growth of the intriguing schwertmannite morphology. |
| first_indexed | 2025-11-14T09:03:14Z |
| format | Journal Article |
| id | curtin-20.500.11937-40448 |
| institution | Curtin University Malaysia |
| institution_category | Local University |
| last_indexed | 2025-11-14T09:03:14Z |
| publishDate | 2005 |
| publisher | Elsevier Science BV |
| recordtype | eprints |
| repository_type | Digital Repository |
| spelling | curtin-20.500.11937-404482019-02-19T05:35:06Z On the crystal growth of nanoscale schwertmannite Loan, Mitch Richmond, William Parkinson, Gordon A1.Nucleation B1.Nanomaterial A1.Crystal structure A1.Crystal morphology A1.Nanostructures Schwertmannite (Fe16O16(OH)12(SO4)2), commonly found in acidic aqueous systems, forms rapidly into a “hedge-hog” morphology, where nano-dimension whiskers project outwards from an electron-dense interior. Schwertmannite whiskers were recently found to contain the highly disordered and maghemite-like structural components present in ferrihydrite, and on this basis, schwertmannite was postulated to be an intermediate phase (in terms of crystallinity and kinetics of formation) to the least and most crystalline forms of ferrihydrite, 2- and 6-line, respectively. To test this hypothesis and help elucidate the schwertmannite growth mechanism, we reduced supersaturation (a function of pH and ferric concentration) during the crystallization of 2-line ferrihydrite from ferric sulphate liquors. Lower supersaturations resulted in schwertmannite formation, often in an admixture or possibly nucleated on 2-line ferrihydrite aggregates. Alternate experiments performed in the presence of arsenic (as a crystal growth modifier) produced X-ray diffraction (XRD) patterns consistent with admixed ferrihydrite and schwertmannite, but with a morphology where aligned ferrihydrite nanoparticles appeared to approximate the structure of schwertmannite whiskers. We postulate that as similar structural components constitute 2-line ferrihydrite and schwertmannite, but are only minor components in 6-line ferrihydrite, the proportion of each component (with the maghemite-like phase dominating) permits the specific alignment and growth of the intriguing schwertmannite morphology. 2005 Journal Article http://hdl.handle.net/20.500.11937/40448 10.1016/j.jcrysgro.2004.11.276 Elsevier Science BV fulltext |
| spellingShingle | A1.Nucleation B1.Nanomaterial A1.Crystal structure A1.Crystal morphology A1.Nanostructures Loan, Mitch Richmond, William Parkinson, Gordon On the crystal growth of nanoscale schwertmannite |
| title | On the crystal growth of nanoscale schwertmannite |
| title_full | On the crystal growth of nanoscale schwertmannite |
| title_fullStr | On the crystal growth of nanoscale schwertmannite |
| title_full_unstemmed | On the crystal growth of nanoscale schwertmannite |
| title_short | On the crystal growth of nanoscale schwertmannite |
| title_sort | on the crystal growth of nanoscale schwertmannite |
| topic | A1.Nucleation B1.Nanomaterial A1.Crystal structure A1.Crystal morphology A1.Nanostructures |
| url | http://hdl.handle.net/20.500.11937/40448 |