title: Spectroscopy study of Zn, Cd, Pb and Cr ions immobilization on C-S-H phase.
abstract: Calcium silicate hydrates (C-S-H) have a large number of structural sites available for cations and anions to bind. The C-S-H phases are materials which have ability to toxic ions immobilization. Immobilization mechanisms for C-S-H include sorption, phase mixing, substitution and precipitation of insoluble compounds. This study presents the C-S-H (prepared with C/S ratios 1.0) phase as absorbent for immobilization of Zn, Cd, Pb and Cr ions. The C-S-H spectra before and after incorporation of heavy metals ions into the C-S-H structure were obtained. The effect of added heavy metals ions on the hydration phenomena was studied by means of X-ray diffractions analysis. FTIR spectra was measured. The microstructure and phase composition of C-S-H indicate that they can play an essential role in the immobilization of heavy metals. The properties of C-S-H in the presence of Zn, Cd, Pb and Cr cations were studied. The leaching ML test was used to evaluate the level of immobilization of heavy metals in C-S-H. The leached solutions are diluted and analyzed using atomic absorption spectrometry (AAS) and the activated solid particles are separated, washed, desiccated and analyzed by Fourier transform infrared (FTIR) spectroscopy. It was found that the degree of Cd, Zn, Pb and Cr cations immobilization was very high (exceeding 99.96%).
authors.affiliation: AGH - University of Science and Technology, Faculty of Materials Science and Ceramics, Department of Building Materials Technology, Al. Mickiewicza 30, 30-059 Cracow, Poland. Electronic address: zakr@agh.edu.pl.
authors.forename: Renata
authors.initials: R
authors.lastname: Żak
authors.affiliation: AGH - University of Science and Technology, Faculty of Materials Science and Ceramics, Department of Building Materials Technology, Al. Mickiewicza 30, 30-059 Cracow, Poland.
authors.forename: Jan
authors.initials: J
authors.lastname: Deja
mesh_terms: D017610:Calcium Compounds / Q000737:chemistry*; D007477:Ions / Q000737:chemistry; D019216:Metals, Heavy / Q000737:chemistry*; D017640:Silicates / Q000737:chemistry*; D017550:Spectroscopy, Fourier Transform Infrared; D014961:X-Ray Diffraction
chemical_list: D017610:Calcium Compounds; D007477:Ions; D019216:Metals, Heavy; D017640:Silicates; C031293:calcium silicate
keywords: AAS; Calcium silicate hydrate (C–S–H); Heavy metals immobilization; IR spectra; Ions exchange reactions; Leaching