کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
6437700 | 1637985 | 2016 | 18 صفحه PDF | دانلود رایگان |
عنوان انگلیسی مقاله ISI
Precipitation pathways for ferrihydrite formation in acidic solutions
ترجمه فارسی عنوان
مسیرهای بارش برای تشکیل فرای هیدریت در محلول های اسیدی
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موضوعات مرتبط
مهندسی و علوم پایه
علوم زمین و سیارات
ژئوشیمی و پترولوژی
چکیده انگلیسی
Iron oxides and oxyhydroxides form via Fe3+ hydrolysis and polymerization in many aqueous environments, but the pathway from Fe3+ monomers to oligomers and then to solid phase nuclei is unknown. In this work, using combined X-ray, UV-vis, and Mössbauer spectroscopic approaches, we were able to identify and quantify the long-time sought ferric speciation over time during ferric oxyhydroxide formation in partially-neutralized ferric nitrate solutions ([Fe3+] = 0.2 M, 1.8 < pH < 3). Results demonstrate that Fe exists mainly as Fe(H2O)63+, μ-oxo aquo dimers and ferrihydrite, and that with time, the μ-oxo dimer decreases while the other two species increase in their concentrations. No larger Fe oligomers were detected. Given that the structure of the μ-oxo dimer is incompatible with those of all Fe oxides and oxyhydroxides, our results suggest that reconfiguration of the μ-oxo dimer structure occurs prior to further condensation leading up to the nucleation of ferrihydrite. The structural reconfiguration is likely the rate-limiting step involved in the nucleation process.
ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Geochimica et Cosmochimica Acta - Volume 172, 1 January 2016, Pages 247-264
Journal: Geochimica et Cosmochimica Acta - Volume 172, 1 January 2016, Pages 247-264
نویسندگان
Mengqiang Zhu, Cathrine Frandsen, Adam F. Wallace, Benjamin Legg, Syed Khalid, Hengzhong Zhang, Steen Mørup, Jillian F. Banfield, Glenn A. Waychunas,