کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
1458166 | 989308 | 2006 | 8 صفحه PDF | دانلود رایگان |
عنوان انگلیسی مقاله ISI
Uptake of Se(IV/VI) oxyanions by hardened cement paste and cement minerals: An X-ray absorption spectroscopy study
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کلمات کلیدی
موضوعات مرتبط
مهندسی و علوم پایه
سایر رشته های مهندسی
مهندسی صنعتی و تولید
پیش نمایش صفحه اول مقاله
چکیده انگلیسی
The uptake of selenate (SeVIO42â) or selenite (SeIVO32â) by hardened cement paste (HCP) and important constituents of the cement matrix such as calcium silicate hydrate (C-S-H), portlandite (CH), ettringite (AFt) and monosulfate (AFm) was investigated using X-ray absorption spectroscopy (XAS). The XAS measurements were conducted on samples with Se loadings ranging between 1200 and 8800 ppm. X-ray absorption near edge structure (XANES) spectroscopy shows that redox reactions do not influence uptake processes in the cementitious systems. The EXAFS (extended X-ray absorption fine structure) spectra of Se(IV) and Se(VI) bound to CH, AFt, AFm and C-S-H are similar to those of SeO42â and SeO32â in solution, indicating a “solution-like” coordination environment upon uptake by the cement minerals. Similarly, the spectra of Se(IV)- and Se(VI)-treated HCP samples reveal the absence of backscattering atoms at short distances. These results suggest that the coordination sphere of the SeO42â and SeO32â entities is maintained upon immobilization by HCP and cement minerals and non-specific interactions dominate at the given Se loadings.
ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Cement and Concrete Research - Volume 36, Issue 1, January 2006, Pages 91-98
Journal: Cement and Concrete Research - Volume 36, Issue 1, January 2006, Pages 91-98
نویسندگان
Isabelle Bonhoure, Isabel Baur, Erich Wieland, C. Annette Johnson, André M. Scheidegger,