Phosphate effects on cadmium(II) sorption to ferrihydrite
| العنوان: | Phosphate effects on cadmium(II) sorption to ferrihydrite |
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| المؤلفون: | Tiberg, Charlotta, Gustafsson, Jon Petter |
| المصدر: | Journal of Colloid and Interface Science. 471:103-111 |
| مصطلحات موضوعية: | Adsorption, Cadmium (Cd), Charge distribution multisite complexation (CD-MUSIC), Extended X-ray absorption spectroscopy (EXAFS), Iron hydroxide, Iron oxide, Phosphate, Surface complex, Cadmium, Charge distribution, Coordination reactions, Electrostatics, Extended X ray absorption fine structure spectroscopy, Hydraulic servomechanisms, Iron, Iron oxides, Phosphates, Sorption, X ray absorption spectroscopy, Cadmiums (Cd), Extended x-ray absorption spectroscopies, Iron hydroxides, Multi-site, Iron compounds, Land and Water Resources Engineering, Mark- och vattenteknik |
| الوصف: | Hypothesis: Phosphate influences the sorption of metals to iron (hydr)oxides. An enhanced formation of inner-sphere complexes on the (hydr)oxide surface can be attributed to electrostatic interactions and/or to changes in metal coordination on the iron (hydr)oxide surface. Phosphate was expected to increase cadmium(II) sorption on ferrihydrite. It should be possible to identify changes in cadmium(II) coordination upon phosphate addition by Extended X-ray absorption fine structure (EXAFS) spectroscopy and implement the identified complexes in a surface complexation model (SCM). Experiments: The effect of phosphate addition on cadmium(II) sorption to ferrihydrite was studied by a series of batch experiments covering the pH range from 4 to 8. EXAFS spectroscopy was performed on ferrihydrite from the batch experiments at the cadmium K edge. The identified surface complexes were incorporated in the Charge distribution multisite complexation (CD-MUSIC) model, and new surface complexation constants were optimized. Findings: Without phosphate addition cadmium(II) formed inner-sphere bidentate complexes on the ferrihydrite surface. With phosphate there was an increased cadmium(II) sorption that could not be explained by electrostatic interactions alone. The enhancement was best explained by the formation of a ternary complex including cadmium(II), phosphate and ferrihydrite surface groups. |
| وصف الملف: | electronic |
| الوصول الحر: | https://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-186957Test https://kth.diva-portal.org/smash/get/diva2:930566/FULLTEXT01.pdfTest |
| قاعدة البيانات: | SwePub |
| تدمد: | 00219797 10957103 |
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| DOI: | 10.1016/j.jcis.2016.03.016 |