ISSN:
1662-0356
Source:
Scientific.Net: Materials Science & Technology / Trans Tech Publications Archiv 1984-2008
Topics:
Natural Sciences in General
,
Technology
Notes:
The removal of cadmium from water by fixation into a calcium phosphate apatiteCa10(PO4)6(OH)2 (CaHA) was investigated in batch experiments. These ones were carriedout using a wide range of initial Cd2+ concentration, three different temperatures, andseveral CaHA surface areas. The amount of immobilized cadmium was proportional to thesurface area of CaHA, whatever the experimental parameters might be. It could reach 7.1mol of Cd per mol of starting CaHA. Thermal and XPS analyses on the exchangedpowders proved that a part of cadmium was quickly adsorbed at the grains surface in theform of hydrated complexes [Cd(OH2)n]2+. The latter were formed by an ionic exchangebetween adsorbed calcium and cadmium of the solution. Adsorption reaction was mainlylimited by the number of specific sites available on the grains surface.Structural analyses showed that another part of Cd was slowly incorporated into a solidsolution Ca10-xCdx(PO4)6(OH)2 (CaCdHA) onto the CaHA crystals surface. Resultsdemonstrated unambiguously that the incorporation process was a surface precipitation andnot an intracrystalline diffusion
Type of Medium:
Electronic Resource
URL:
http://www.tib-hannover.de/fulltexts/2011/0528/01/42/transtech_doi~10.4028%252Fwww.scientific.net%252FAST.45.2055.pdf
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