TY - JOUR
T1 - Influence of aluminate and silicate on selenate immobilization using alkaline-earth metal oxides and ferrous salt
AU - Tian, Quanzhi
AU - Bai, Yingchu
AU - Pan, Yinhai
AU - Yao, Shuo
AU - Chen, Changshuai
AU - Zhang, Haijun
AU - Sasaki, Keiko
N1 - Funding Information:
This research was supported by the NSFC (National Natural Science Foundation of China) projects (No. 52104404 , No. U21A20325 ), and the JSPS (Japan Society for the Promotion of Science) KAKENHI (A) [No. JP19F19393 ] and Kyushu University (Progress 100).
Publisher Copyright:
© 2022 Elsevier B.V.
PY - 2022/12/10
Y1 - 2022/12/10
N2 - Effects of aluminate and silicate species on the SeO42− immobilization using alkali-earth metal oxides and ferrous species have not been clearly elucidated. In the present study, Al and Si species were separately added into MgO/Fe(II) and CaO/Fe(II) reactions containing SeO42−, studied by toxicity characteristic leaching procedure (TCLP), X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), X-ray absorption fine structure (XAFS), and PHREEQC simulation. Approximately 42 % of SeO42− was reduced to SeO32− for MgO/Fe(II) reaction in the presence of Al species, being consistent with the case without Al species. The Al species only showed slight inhibition of Se leaching for the MgO/Fe(II) reaction. Most of Se oxyanions were adsorbed onto Mg(OH)2 through outer-sphere complexation. For CaO/Fe(II) reaction, all of SeO42− was reduced to SeO32− with or without Al species. However, the Se leaching amount (3 %) of sample added with Al species (CE3) is much lower than that (12 %) of sample without Al species (CE2). This is mainly because SeO32− can be sorbed onto the iron-based minerals through binuclear bidentate corner-sharing (2C) complexation instead of monodentate mononuclear corner-sharing (1V) complexation of the case without Al species. On the other hand, SeO42− was not reduced to SeO32− in the presence of silicate, and almost all of Se was leached out for silicate-contained samples except CaO/Fe(II) reaction with the addition of Al species. This is due to the polymerization of Al and Si species under a high-alkalinity environment, thereby stabilizing SeO42− in the amorphous silicon-aluminum structure and contributing to the decrease of Se leaching.
AB - Effects of aluminate and silicate species on the SeO42− immobilization using alkali-earth metal oxides and ferrous species have not been clearly elucidated. In the present study, Al and Si species were separately added into MgO/Fe(II) and CaO/Fe(II) reactions containing SeO42−, studied by toxicity characteristic leaching procedure (TCLP), X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), X-ray absorption fine structure (XAFS), and PHREEQC simulation. Approximately 42 % of SeO42− was reduced to SeO32− for MgO/Fe(II) reaction in the presence of Al species, being consistent with the case without Al species. The Al species only showed slight inhibition of Se leaching for the MgO/Fe(II) reaction. Most of Se oxyanions were adsorbed onto Mg(OH)2 through outer-sphere complexation. For CaO/Fe(II) reaction, all of SeO42− was reduced to SeO32− with or without Al species. However, the Se leaching amount (3 %) of sample added with Al species (CE3) is much lower than that (12 %) of sample without Al species (CE2). This is mainly because SeO32− can be sorbed onto the iron-based minerals through binuclear bidentate corner-sharing (2C) complexation instead of monodentate mononuclear corner-sharing (1V) complexation of the case without Al species. On the other hand, SeO42− was not reduced to SeO32− in the presence of silicate, and almost all of Se was leached out for silicate-contained samples except CaO/Fe(II) reaction with the addition of Al species. This is due to the polymerization of Al and Si species under a high-alkalinity environment, thereby stabilizing SeO42− in the amorphous silicon-aluminum structure and contributing to the decrease of Se leaching.
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U2 - 10.1016/j.scitotenv.2022.158126
DO - 10.1016/j.scitotenv.2022.158126
M3 - Article
C2 - 35987217
AN - SCOPUS:85136279678
VL - 851
JO - Science of the Total Environment
JF - Science of the Total Environment
SN - 0048-9697
M1 - 158126
ER -