TY - JOUR
T1 - Immobilization Mechanisms of Arsenate in Iron Hydroxide Sludge Stabilized with Cement
AU - Jing, Chuanyong
AU - Korfiatis, George P.
AU - Meng, Xiaoguang
PY - 2003/11/1
Y1 - 2003/11/1
N2 - Leaching tests, Fourier transform infrared spectroscopy (FTIR), extended X-ray absorption fine structure (EXAFS) spectroscopy, and thermodynamic modeling were performed to investigate arsenate [As(V)] immobilization mechanisms in iron hydroxide sludge stabilized with cement. The sludge from a groundwater remediation site in Tacoma, WA was mixed and immobilized with premixed cement to reach cement-to-sludge ratios of 2.5, 3.3, 5, 10, and 20 (wt premixed cement/wt dry sludge). The EXAFS analysis determined that As(V) formed bidentate mononuclear complexes on the iron hydroxide surface in the sludge. The adsorbed As(V) had a characteristic FTIR band at 830 cm-1. Cement treatment converted the adsorbed As(V) to calcium arsenate precipitate with a FTIR peak at 860 cm-1. The chemical forms of the As(V) were incorporated in an adsorption triple layer model (TLM) to describe the leaching behavior of As(V) in a pH range between 3 and 12. Cement treatment significantly reduced arsenic mobility because of the formation of the sparingly soluble calcium arsenate.
AB - Leaching tests, Fourier transform infrared spectroscopy (FTIR), extended X-ray absorption fine structure (EXAFS) spectroscopy, and thermodynamic modeling were performed to investigate arsenate [As(V)] immobilization mechanisms in iron hydroxide sludge stabilized with cement. The sludge from a groundwater remediation site in Tacoma, WA was mixed and immobilized with premixed cement to reach cement-to-sludge ratios of 2.5, 3.3, 5, 10, and 20 (wt premixed cement/wt dry sludge). The EXAFS analysis determined that As(V) formed bidentate mononuclear complexes on the iron hydroxide surface in the sludge. The adsorbed As(V) had a characteristic FTIR band at 830 cm-1. Cement treatment converted the adsorbed As(V) to calcium arsenate precipitate with a FTIR peak at 860 cm-1. The chemical forms of the As(V) were incorporated in an adsorption triple layer model (TLM) to describe the leaching behavior of As(V) in a pH range between 3 and 12. Cement treatment significantly reduced arsenic mobility because of the formation of the sparingly soluble calcium arsenate.
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U2 - 10.1021/es021027g
DO - 10.1021/es021027g
M3 - Article
C2 - 14620837
AN - SCOPUS:0242459834
SN - 0013-936X
VL - 37
SP - 5050
EP - 5056
JO - Environmental Science and Technology
JF - Environmental Science and Technology
IS - 21
ER -