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Nanoscavengers - a simple approach to metal extraction
20 October 2005
Silica nanoparticles could be the answer to the simplification of many analyses. Alan Howard and Nezar Khdary from the University of Southampton, UK, have developed a nano-sized particle for extracting metals from aqueous solutions.
This method, termed the nanoscavenger concept, is based on silica particles and is an easy, green approach to the collection and concentration of metals for analysis. The technique is expected to yield both environmental and cost benefits.
Analytical chemists regularly need to remove metals from aqueous solutions so they can be analysed. Extraction into organic solvents is currently the most popular procedure for doing this.
Howard and Khdary's approach uses chelating organic ligands to modify the surface of silica spheres with an approximate diameter of 250 nm. These particles are able to bind to metals temporarily, and can be collected easily from solutions.
The concept behind this research is beautifully simple. The nanoscavenger moves naturally through the solution under examination, binding any metal with which it comes into contact. This movement, using Brownian motion, means that no physical agitation is required. Simple filtration removes the metal-bound nanoscavenger from the solution. Finally, separation of the metal and nanoscavenger allows analysis of the metal using standard detection methods.
When considering the future for this research area, Howard said 'the nanoscavenger concept is more widely applicable and can potentially be employed in the extraction of a much broader range of both inorganic and organic analytes. Pesticides and drugs are just two such examples.'