This study will discuss how layer charge can affect chemical speciation and topology of heavy metals adsorbed to 2:1 layer silicates, by providing: i) an overview of literature data; ii) experimental data on Cd complexes adsorbed by 2:1 layer silicates with different layer charge (montmorillonite and vermiculite); iii) a comparison between our results and literature data. This study will also be supported by several different experimental techniques such as chemical and thermal analyses, X-ray powder diffraction and X-ray absorption spectroscopy.Based on our data Cd atoms were found to complex water molecules in both clay minerals and to show four-fold coordination in montmorillonite (CdO distances of 2.24 Å) and six-fold coordination in vermiculite (CdO distances of 2.16 and 2.28 Å). Furthermore our models clearly suggest that Cd mainly bonds to interlayer water, without neglecting the more limited, but still significant, Cd multinuclear surface complexes at the octahedral broken edges. Both clay minerals show H2O/Cd ratio, as evidenced by thermal analyses, drastically higher than expected from X-ray adsorption spectroscopy data, thus implying that most of the water molecules are only loosely coordinated to interlayer cations.

Layer charge and heavy metals structures in hydrated 2 : 1 silicates:state of the art and new advances on cadmium / Malferrari, Daniele; Brigatti, Maria Franca; Elmi, Chiara; Laurora, Angela; G., Valdre. - In: ZEITSCHRIFT FUR KRISTALLOGRAPHIE. - ISSN 0044-2968. - STAMPA. - 224:5-6(2009), pp. 311-315. [10.1524/zkri.2009.1139]

Layer charge and heavy metals structures in hydrated 2 : 1 silicates:state of the art and new advances on cadmium

MALFERRARI, Daniele;BRIGATTI, Maria Franca;ELMI, Chiara;LAURORA, Angela;
2009

Abstract

This study will discuss how layer charge can affect chemical speciation and topology of heavy metals adsorbed to 2:1 layer silicates, by providing: i) an overview of literature data; ii) experimental data on Cd complexes adsorbed by 2:1 layer silicates with different layer charge (montmorillonite and vermiculite); iii) a comparison between our results and literature data. This study will also be supported by several different experimental techniques such as chemical and thermal analyses, X-ray powder diffraction and X-ray absorption spectroscopy.Based on our data Cd atoms were found to complex water molecules in both clay minerals and to show four-fold coordination in montmorillonite (CdO distances of 2.24 Å) and six-fold coordination in vermiculite (CdO distances of 2.16 and 2.28 Å). Furthermore our models clearly suggest that Cd mainly bonds to interlayer water, without neglecting the more limited, but still significant, Cd multinuclear surface complexes at the octahedral broken edges. Both clay minerals show H2O/Cd ratio, as evidenced by thermal analyses, drastically higher than expected from X-ray adsorption spectroscopy data, thus implying that most of the water molecules are only loosely coordinated to interlayer cations.
2009
224
5-6
311
315
Layer charge and heavy metals structures in hydrated 2 : 1 silicates:state of the art and new advances on cadmium / Malferrari, Daniele; Brigatti, Maria Franca; Elmi, Chiara; Laurora, Angela; G., Valdre. - In: ZEITSCHRIFT FUR KRISTALLOGRAPHIE. - ISSN 0044-2968. - STAMPA. - 224:5-6(2009), pp. 311-315. [10.1524/zkri.2009.1139]
Malferrari, Daniele; Brigatti, Maria Franca; Elmi, Chiara; Laurora, Angela; G., Valdre
File in questo prodotto:
File Dimensione Formato  
Layer charge and heavy metals structures in hydrated.pdf

Accesso riservato

Tipologia: Versione pubblicata dall'editore
Dimensione 207.41 kB
Formato Adobe PDF
207.41 kB Adobe PDF   Visualizza/Apri   Richiedi una copia
Pubblicazioni consigliate

Licenza Creative Commons
I metadati presenti in IRIS UNIMORE sono rilasciati con licenza Creative Commons CC0 1.0 Universal, mentre i file delle pubblicazioni sono rilasciati con licenza Attribuzione 4.0 Internazionale (CC BY 4.0), salvo diversa indicazione.
In caso di violazione di copyright, contattare Supporto Iris

Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11380/622557
Citazioni
  • ???jsp.display-item.citation.pmc??? ND
  • Scopus 1
  • ???jsp.display-item.citation.isi??? 1
social impact