TY - JOUR
T1 - Chemical stability and extent of isomorphous substitution in ferrites precipitated under ambient temperatures
AU - Klas, Sivan
AU - Dubowski, Yael
AU - Lahav, Ori
N1 - Funding Information:
This work was supported by Research Grant No. 2007934 from BMBF/MOST, the Joint German-Israeli Water Technology Research Program .
PY - 2011/10/15
Y1 - 2011/10/15
N2 - The ferrite process is an established method for treating wastewaters containing dissolved toxic metals, using precipitation at temperatures above 65°C. Various ambient-temperature operation methodologies have also been proposed, but the effects of temperature reduction on product stability, and on the extent of isomorphous substitution (in terms of x in Me xFe 3-xO 4, Me representing a non-iron metal), have not been adequately quantified. At ambient temperature precipitation, maximal x of Zn 2+, Co 2+, Ni 2+ and Cd 2+ was found in the current study to be approximately 0.73, 0.67, 0.39 and 0.17, respectively. These values are 73% to 50% of the corresponding values attained by precipitation at 90°C. The chemical stability of the ferrites produced under ambient temperatures was found to deteriorate upon high Me 2+ incorporation levels, in stark contrast with the trend observed in ferrites precipitated at 90°C. Both observations were ascribed to the increased importance of Fe 2+-Fe 3+ interaction under ambient conditions in driving spinel ordering. In the presence of high Me to Fe ratio in the initial solution, this interaction is weaker, resulting in impeded dehydration.
AB - The ferrite process is an established method for treating wastewaters containing dissolved toxic metals, using precipitation at temperatures above 65°C. Various ambient-temperature operation methodologies have also been proposed, but the effects of temperature reduction on product stability, and on the extent of isomorphous substitution (in terms of x in Me xFe 3-xO 4, Me representing a non-iron metal), have not been adequately quantified. At ambient temperature precipitation, maximal x of Zn 2+, Co 2+, Ni 2+ and Cd 2+ was found in the current study to be approximately 0.73, 0.67, 0.39 and 0.17, respectively. These values are 73% to 50% of the corresponding values attained by precipitation at 90°C. The chemical stability of the ferrites produced under ambient temperatures was found to deteriorate upon high Me 2+ incorporation levels, in stark contrast with the trend observed in ferrites precipitated at 90°C. Both observations were ascribed to the increased importance of Fe 2+-Fe 3+ interaction under ambient conditions in driving spinel ordering. In the presence of high Me to Fe ratio in the initial solution, this interaction is weaker, resulting in impeded dehydration.
KW - Co-precipitation
KW - Ferrite process
KW - Heavy metals
KW - Isomorphous substitution
KW - Substituted magnetite
UR - http://www.scopus.com/inward/record.url?scp=80053221892&partnerID=8YFLogxK
U2 - 10.1016/j.jhazmat.2011.07.023
DO - 10.1016/j.jhazmat.2011.07.023
M3 - 文章
C2 - 21803496
AN - SCOPUS:80053221892
VL - 193
SP - 59
EP - 64
JO - Journal of Hazardous Materials
JF - Journal of Hazardous Materials
SN - 0304-3894
ER -