Eine Plattform für die Wissenschaft: Bauingenieurwesen, Architektur und Urbanistik
Eine Plattform für die Wissenschaft: Bauingenieurwesen, Architektur und Urbanistik
Speciation of cadmium in cement - Part I. Cd2+ uptake by C-S-H
Hazardous cadmium can be trapped in C-S-H, the main 'phase' in Portland cement. Two kinds of Cd-containing calcium silicates were synthesized: Cd/Ca silicate hydrates prepared by coprecipitation and Cd-exchanged C-S-H. In Cd-exchanged C-S-H, chemical and structural studies (ICP-AES, XRD, extended X-ray absorption fine structure (EXAFS), and nuclear magnetic resonance (NMR)) show that up to 30 wt.% Cd uptake is possible, with little structural change. XRD patterns and 29Si magic angle spinning (MAS) NMR spectra are similar in Cd-free and Cd-containing C-S-H. Cd-EXAFS shows that the majority of Cd2+ atoms are homogeneously distributed within the C-S-H structure, although 113Cd cross-polarization (CP) MAS NMR cannot discriminate between Cd atoms in main layer location and Cd atoms in interlayer location. In Cd/Ca silicate coprecipitates, the structure is nearly amorphous and the silicate species do not polymerize to a C-S-H-like structure.
Speciation of cadmium in cement - Part I. Cd2+ uptake by C-S-H
Hazardous cadmium can be trapped in C-S-H, the main 'phase' in Portland cement. Two kinds of Cd-containing calcium silicates were synthesized: Cd/Ca silicate hydrates prepared by coprecipitation and Cd-exchanged C-S-H. In Cd-exchanged C-S-H, chemical and structural studies (ICP-AES, XRD, extended X-ray absorption fine structure (EXAFS), and nuclear magnetic resonance (NMR)) show that up to 30 wt.% Cd uptake is possible, with little structural change. XRD patterns and 29Si magic angle spinning (MAS) NMR spectra are similar in Cd-free and Cd-containing C-S-H. Cd-EXAFS shows that the majority of Cd2+ atoms are homogeneously distributed within the C-S-H structure, although 113Cd cross-polarization (CP) MAS NMR cannot discriminate between Cd atoms in main layer location and Cd atoms in interlayer location. In Cd/Ca silicate coprecipitates, the structure is nearly amorphous and the silicate species do not polymerize to a C-S-H-like structure.
Speciation of cadmium in cement - Part I. Cd2+ uptake by C-S-H
Pomies, M.P. (Autor:in) / Lequeux, N. (Autor:in) / Boch, P. (Autor:in)
Cement and Concrete Research ; 31 ; 563-569
2001
7 Seiten, 28 Quellen
Aufsatz (Zeitschrift)
Englisch
Speciation of cadmium in cement - Part I. Cd2+ uptake by C-S-H
| Online Contents | 2001
Speciation of cadmium in cement
| British Library Online Contents | 2001
Speciation of cadmium in cement
| British Library Online Contents | 2001
Speciation of cadmium in cement - Part II. C3S hydration with Cd2+ solution
| Online Contents | 2001
Speciation of cadmium in cement - Part II. C3S hydration with Cd 2+ solution
| Tema Archiv | 2001