Synthesis and characterisation of ferrihydrite/silica co-precipitates
The effect of the presence of soluble silicates on ferrihydrite precipitation and some properties of the products formed in co-precipitation of ferrihydrite and silica have been investigated. The co-precipitates were formed using a continuous crystallisation process in which a combined iron/silicon...
| Main Authors: | , , , |
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| Format: | Journal Article |
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Elsevier
2010
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| Online Access: | http://hdl.handle.net/20.500.11937/36767 |
| _version_ | 1848754862125219840 |
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| author | Dyer, Laurence Fawell, P. Newman, O. Richmond, William |
| author_facet | Dyer, Laurence Fawell, P. Newman, O. Richmond, William |
| author_sort | Dyer, Laurence |
| building | Curtin Institutional Repository |
| collection | Online Access |
| description | The effect of the presence of soluble silicates on ferrihydrite precipitation and some properties of the products formed in co-precipitation of ferrihydrite and silica have been investigated. The co-precipitates were formed using a continuous crystallisation process in which a combined iron/silicon feed solution was reacted with sodium hydroxide at a constant rate, while maintaining pH at 2.65 and temperature at 85 °C. The products of co-precipitation and the supernatant solutions were characterised using a variety of analytical techniques including X-ray diffraction (XRD), transmission electron microscopy (TEM) and surface charge measurements. The addition of silicates was shown to have a significant impact on the crystallinity and surface charge of the precipitates formed. For products collected after five residence times in the continuous crystalliser, co-precipitates formed from ferric sulfate solution were found to contain considerably less silica than those formed from ferric nitrate. We conclude that adsorption of silicate species on ferrihydrite surfaces speeds up the polymerisation process, and that sulfate ion competes with silicate for surface adsorption sites. Thus, the precipitation of silica proceeds much more rapidly in ferric nitrate media, than in ferric sulfate. |
| first_indexed | 2025-11-14T08:47:09Z |
| format | Journal Article |
| id | curtin-20.500.11937-36767 |
| institution | Curtin University Malaysia |
| institution_category | Local University |
| last_indexed | 2025-11-14T08:47:09Z |
| publishDate | 2010 |
| publisher | Elsevier |
| recordtype | eprints |
| repository_type | Digital Repository |
| spelling | curtin-20.500.11937-367672017-09-13T15:20:00Z Synthesis and characterisation of ferrihydrite/silica co-precipitates Dyer, Laurence Fawell, P. Newman, O. Richmond, William The effect of the presence of soluble silicates on ferrihydrite precipitation and some properties of the products formed in co-precipitation of ferrihydrite and silica have been investigated. The co-precipitates were formed using a continuous crystallisation process in which a combined iron/silicon feed solution was reacted with sodium hydroxide at a constant rate, while maintaining pH at 2.65 and temperature at 85 °C. The products of co-precipitation and the supernatant solutions were characterised using a variety of analytical techniques including X-ray diffraction (XRD), transmission electron microscopy (TEM) and surface charge measurements. The addition of silicates was shown to have a significant impact on the crystallinity and surface charge of the precipitates formed. For products collected after five residence times in the continuous crystalliser, co-precipitates formed from ferric sulfate solution were found to contain considerably less silica than those formed from ferric nitrate. We conclude that adsorption of silicate species on ferrihydrite surfaces speeds up the polymerisation process, and that sulfate ion competes with silicate for surface adsorption sites. Thus, the precipitation of silica proceeds much more rapidly in ferric nitrate media, than in ferric sulfate. 2010 Journal Article http://hdl.handle.net/20.500.11937/36767 10.1016/j.jcis.2010.03.056 Elsevier restricted |
| spellingShingle | Dyer, Laurence Fawell, P. Newman, O. Richmond, William Synthesis and characterisation of ferrihydrite/silica co-precipitates |
| title | Synthesis and characterisation of ferrihydrite/silica co-precipitates |
| title_full | Synthesis and characterisation of ferrihydrite/silica co-precipitates |
| title_fullStr | Synthesis and characterisation of ferrihydrite/silica co-precipitates |
| title_full_unstemmed | Synthesis and characterisation of ferrihydrite/silica co-precipitates |
| title_short | Synthesis and characterisation of ferrihydrite/silica co-precipitates |
| title_sort | synthesis and characterisation of ferrihydrite/silica co-precipitates |
| url | http://hdl.handle.net/20.500.11937/36767 |