Arsenic (III) Removal from a High-Concentration Arsenic (III) Solution by Forming Ferric Arsenite on Red Mud Surface
Arsenic (As) is considered one of the most serious inorganic pollutants, and the wastewater produced in some smelters contains a high concentration of arsenic. In this paper, we purified the high-concentration arsenic solution with red mud and Fe<sup>3+</sup> synergistically. In this sys...
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MDPI AG
2020-06-01
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author | Dongdong He Yuming Xiong Li Wang Wei Sun Runqing Liu Tong Yue |
author_facet | Dongdong He Yuming Xiong Li Wang Wei Sun Runqing Liu Tong Yue |
author_sort | Dongdong He |
collection | DOAJ |
description | Arsenic (As) is considered one of the most serious inorganic pollutants, and the wastewater produced in some smelters contains a high concentration of arsenic. In this paper, we purified the high-concentration arsenic solution with red mud and Fe<sup>3+</sup> synergistically. In this system, arsenite anions reacted with Fe(III) ions to form ferric arsenite, which attached on the surface of red mud particles. The generated red mud/Fe<sub>1−x</sub>(As)<sub>x</sub>(OH)<sub>3</sub> showed a better sedimentation performance than the pure ferric arsenite, which is beneficial to the separation of arsenic from the solution. The red mud not only served as the carrier, but also as the alkaline agent and adsorbent for arsenic treatment. The effects of red mud dosage, dosing order, pH, and molar ratio of Fe/As on arsenic removal were investigated. The efficiency of arsenic removal increased from a pH of 2 to 6 and reached equilibrium at a pH of 7. At the Fe/As molar ratio of 3, the removal efficiency of arsenic ions with an initial concentration of 500 mg/L reached 98%. In addition, the crystal structure, chemical composition, and morphological properties of red mud and arsenic removal residues (red mud/Fe<sub>1−x</sub>(As)<sub>x</sub>(OH)<sub>3</sub>) were characterized by XRD, XPS, X-ray fluorescence (XRF), SEM-EDS, and Raman spectroscopy to study the mechanism of arsenic removal. The results indicated that most of the arsenic was removed from the solution by forming Fe<sub>1−x</sub>(As)<sub>x</sub>(OH)<sub>3</sub> precipitates on the red mud surface, while the remaining arsenic was adsorbed by the red mud and ferric hydroxide. |
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spelling | doaj.art-9cd13b16ea3845f6b3e9ce04bbd1f2382023-11-20T05:11:38ZengMDPI AGMinerals2075-163X2020-06-0110758310.3390/min10070583Arsenic (III) Removal from a High-Concentration Arsenic (III) Solution by Forming Ferric Arsenite on Red Mud SurfaceDongdong He0Yuming Xiong1Li Wang2Wei Sun3Runqing Liu4Tong Yue5School of Minerals Processing and Bioengineering, Central South University, Changsha 410083, ChinaSchool of Minerals Processing and Bioengineering, Central South University, Changsha 410083, ChinaSchool of Minerals Processing and Bioengineering, Central South University, Changsha 410083, ChinaSchool of Minerals Processing and Bioengineering, Central South University, Changsha 410083, ChinaSchool of Minerals Processing and Bioengineering, Central South University, Changsha 410083, ChinaSchool of Minerals Processing and Bioengineering, Central South University, Changsha 410083, ChinaArsenic (As) is considered one of the most serious inorganic pollutants, and the wastewater produced in some smelters contains a high concentration of arsenic. In this paper, we purified the high-concentration arsenic solution with red mud and Fe<sup>3+</sup> synergistically. In this system, arsenite anions reacted with Fe(III) ions to form ferric arsenite, which attached on the surface of red mud particles. The generated red mud/Fe<sub>1−x</sub>(As)<sub>x</sub>(OH)<sub>3</sub> showed a better sedimentation performance than the pure ferric arsenite, which is beneficial to the separation of arsenic from the solution. The red mud not only served as the carrier, but also as the alkaline agent and adsorbent for arsenic treatment. The effects of red mud dosage, dosing order, pH, and molar ratio of Fe/As on arsenic removal were investigated. The efficiency of arsenic removal increased from a pH of 2 to 6 and reached equilibrium at a pH of 7. At the Fe/As molar ratio of 3, the removal efficiency of arsenic ions with an initial concentration of 500 mg/L reached 98%. In addition, the crystal structure, chemical composition, and morphological properties of red mud and arsenic removal residues (red mud/Fe<sub>1−x</sub>(As)<sub>x</sub>(OH)<sub>3</sub>) were characterized by XRD, XPS, X-ray fluorescence (XRF), SEM-EDS, and Raman spectroscopy to study the mechanism of arsenic removal. The results indicated that most of the arsenic was removed from the solution by forming Fe<sub>1−x</sub>(As)<sub>x</sub>(OH)<sub>3</sub> precipitates on the red mud surface, while the remaining arsenic was adsorbed by the red mud and ferric hydroxide.https://www.mdpi.com/2075-163X/10/7/583arsenic removalred mudferric arsenitesynergistic effect |
spellingShingle | Dongdong He Yuming Xiong Li Wang Wei Sun Runqing Liu Tong Yue Arsenic (III) Removal from a High-Concentration Arsenic (III) Solution by Forming Ferric Arsenite on Red Mud Surface Minerals arsenic removal red mud ferric arsenite synergistic effect |
title | Arsenic (III) Removal from a High-Concentration Arsenic (III) Solution by Forming Ferric Arsenite on Red Mud Surface |
title_full | Arsenic (III) Removal from a High-Concentration Arsenic (III) Solution by Forming Ferric Arsenite on Red Mud Surface |
title_fullStr | Arsenic (III) Removal from a High-Concentration Arsenic (III) Solution by Forming Ferric Arsenite on Red Mud Surface |
title_full_unstemmed | Arsenic (III) Removal from a High-Concentration Arsenic (III) Solution by Forming Ferric Arsenite on Red Mud Surface |
title_short | Arsenic (III) Removal from a High-Concentration Arsenic (III) Solution by Forming Ferric Arsenite on Red Mud Surface |
title_sort | arsenic iii removal from a high concentration arsenic iii solution by forming ferric arsenite on red mud surface |
topic | arsenic removal red mud ferric arsenite synergistic effect |
url | https://www.mdpi.com/2075-163X/10/7/583 |
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