کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
9675663 | 1454103 | 2005 | 5 صفحه PDF | دانلود رایگان |
عنوان انگلیسی مقاله ISI
Transformation of γ-FeOOH to α-FeOOH in acidic solutions containing metal ions
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موضوعات مرتبط
مهندسی و علوم پایه
مهندسی شیمی
شیمی کلوئیدی و سطحی
پیش نمایش صفحه اول مقاله
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چکیده انگلیسی
The transformation reaction of γ-FeOOH to α-FeOOH in FeSO4 solutions dissolving Ti(IV), Cr(III), Cu(II) and Ni(II) at pH < 3 was examined by FT-IR. The TEM observation demonstrated that the transformation proceeds by dissolution of γ-FeOOH particles and recrystallization of γ-FeOOH particles. The transformation occurred in FeSO4 solutions but not in both FeCl2 and Na2SO4 solutions, indicating that the transformation needs the coexistence of Fe(II) and SO42â. This can be explained by a strong adsorption of SO42â promoting the reductive dissolution of γ-FeOOH particles by Fe(II). All the metal ions added in FeSO4 solutions before the reaction markedly interfered with the transformation in the order of Ti(IV), Cu(II) > Cr(III) > Ni(II), though the difference was not pronounced. The incorporation of the metal ions into the formed α-FeOOH particles was in the order of Ti(IV) > Cr(III) > Cu(II) > Ni(II) well according to the order of their hydrolysis constants. Ti(IV) and Cr(III) with a high hydrolysis constant lowered the solution pH after the reaction from 2.7 to 1.7, that is unfavorable to α-FeOOH formation. Taking every factor into consideration, the marked inhibitory effect of the metal ions is ascribed mainly to interruption of the reductive dissolution of γ-FeOOH particles.
ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Colloids and Surfaces A: Physicochemical and Engineering Aspects - Volume 266, Issues 1â3, 15 September 2005, Pages 155-159
Journal: Colloids and Surfaces A: Physicochemical and Engineering Aspects - Volume 266, Issues 1â3, 15 September 2005, Pages 155-159
نویسندگان
T. Ishikawa, K. Takeuchi, K. Kandori, T. Nakayama,