Chromium speciation in hazardous, cement-based waste forms

✍ Scribed by J.F. Lee; S. Bajt; S.B. Clark; G.M. Lamble; C.A. Langton; L. Oji

• Book ID: 103939543
• Publisher: Elsevier Science
• Year: 1995
• Tongue: English
• Weight: 125 KB
• Volume: 208-209
• Category: Article
• ISSN: 0921-4526
• DOI: 10.1016/0921-4526(94)00758-n

✦ Synopsis

XANES and EXAFS techniques were used to determine the oxidation states and local structural environment of Cr in cement-based waste forms. Results show that Cr in untreated Portland cement formulations remains as toxic Cr 6 +, while slag additives to the cement reduce Cr 6 + to the less toxic, less mobile Cr a + species. EXAFS analysis suggests that the Cr 6 + species is surrounded by four nearest oxygen atoms, while the reduced Cr 3 + species issurrounded by six oxygen atoms. The fitted Cr-O bond lengths for Cr 6 + and Cr 3 + species are around 1.66 and 1.98 A, respectively.