Arsenopyrite Bio-Oxidization Behavior in Bioleaching Process: Evidence From Laser Microscopy, SEM-EDS, and XPS
In arsenopyrite bioleaching, the interfacial reaction between mineral and cells is one of the most important factors. The energy of the interface is influenced by the mineralogical and microbiological characteristics. In this paper, the interfacial energy was calculated, and the surface of arsenopyr...
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2020-08-01
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doaj-d5177935875540d4a3722be61a84320d2020-11-25T03:31:57ZengFrontiers Media S.A.Frontiers in Microbiology1664-302X2020-08-011110.3389/fmicb.2020.01773527324Arsenopyrite Bio-Oxidization Behavior in Bioleaching Process: Evidence From Laser Microscopy, SEM-EDS, and XPSLu Yin0Lu Yin1Hong-ying Yang2Hong-ying Yang3Lin-lin Tong4Lin-lin Tong5Peng-cheng Ma6Qin Zhang7Qin Zhang8Miao-miao Zhao9Miao-miao Zhao10Key Laboratory for Ecological Metallurgy of Multimetallic Mineral (Ministry of Education), Northeastern University, Shenyang, ChinaSchool of Metallurgy, Northeastern University, Shenyang, ChinaKey Laboratory for Ecological Metallurgy of Multimetallic Mineral (Ministry of Education), Northeastern University, Shenyang, ChinaSchool of Metallurgy, Northeastern University, Shenyang, ChinaKey Laboratory for Ecological Metallurgy of Multimetallic Mineral (Ministry of Education), Northeastern University, Shenyang, ChinaSchool of Metallurgy, Northeastern University, Shenyang, ChinaZhaojin Group Co., Ltd., Zhaoyuan, ChinaKey Laboratory for Ecological Metallurgy of Multimetallic Mineral (Ministry of Education), Northeastern University, Shenyang, ChinaSchool of Metallurgy, Northeastern University, Shenyang, ChinaKey Laboratory for Ecological Metallurgy of Multimetallic Mineral (Ministry of Education), Northeastern University, Shenyang, ChinaSchool of Metallurgy, Northeastern University, Shenyang, ChinaIn arsenopyrite bioleaching, the interfacial reaction between mineral and cells is one of the most important factors. The energy of the interface is influenced by the mineralogical and microbiological characteristics. In this paper, the interfacial energy was calculated, and the surface of arsenopyrite during the bioleaching process was characterized by 3D laser microscopy, scanning electron microscopy with energy-dispersive X-ray spectroscopy, and X-ray photoelectron spectroscopy, in order to assess the dissolution and oxidation behavior of arsenopyrite during bioleaching. The results showed that the contact angles of arsenopyrite were 22 ± 2° when covered with biofilms, but the reaction surface of arsenopyrite turned 103 ± 2°. However, the angle was 45–50° when covered by passive layer, which was half as that of arsenopyrite surface. The interfacial energy of arsenopyrite without biofilms increased from 45 to 62 mJ/m2, while it decreased to 5 ± 1 mJ/m2 when covered by biofilms during the leaching process. The surface was separated into fresh surface, oxidized surface, and (corrosion) pits. The interfacial energy was influenced by the fresh and oxidized surfaces. Surface roughness increased from 0.03 ± 0.01 to 5.89 ± 1.97 μm, and dissolution volume increased from 6.31 ± 0.47 × 104 to 2.72 ± 0.49 × 106 μm3. The dissolution kinetics of arsenopyrite followed the model of Kt = lnX, and the dissolution mechanisms were mixed controlled: surface reaction control and diffusion through sulfur layer. On the surface of arsenopyrite crystal, the oxidation steps of each element can be described as: for Fe, Fe(II)–(AsS)→Fe(III)–(AsS)→Fe(III)–OH or Fe(III)–SO; for S, As–S(-1) or Fe–S(-1)→polysulfide S→intermediate S–O→sulfate; and for As, As–1–S→As0→As+1–O→As+3–O→As+5–O.https://www.frontiersin.org/article/10.3389/fmicb.2020.01773/fulldissolution kineticsinterfacial energyXPSbioleachinghydrophobicitypassive layer |
collection |
DOAJ |
language |
English |
format |
Article |
sources |
DOAJ |
author |
Lu Yin Lu Yin Hong-ying Yang Hong-ying Yang Lin-lin Tong Lin-lin Tong Peng-cheng Ma Qin Zhang Qin Zhang Miao-miao Zhao Miao-miao Zhao |
spellingShingle |
Lu Yin Lu Yin Hong-ying Yang Hong-ying Yang Lin-lin Tong Lin-lin Tong Peng-cheng Ma Qin Zhang Qin Zhang Miao-miao Zhao Miao-miao Zhao Arsenopyrite Bio-Oxidization Behavior in Bioleaching Process: Evidence From Laser Microscopy, SEM-EDS, and XPS Frontiers in Microbiology dissolution kinetics interfacial energy XPS bioleaching hydrophobicity passive layer |
author_facet |
Lu Yin Lu Yin Hong-ying Yang Hong-ying Yang Lin-lin Tong Lin-lin Tong Peng-cheng Ma Qin Zhang Qin Zhang Miao-miao Zhao Miao-miao Zhao |
author_sort |
Lu Yin |
title |
Arsenopyrite Bio-Oxidization Behavior in Bioleaching Process: Evidence From Laser Microscopy, SEM-EDS, and XPS |
title_short |
Arsenopyrite Bio-Oxidization Behavior in Bioleaching Process: Evidence From Laser Microscopy, SEM-EDS, and XPS |
title_full |
Arsenopyrite Bio-Oxidization Behavior in Bioleaching Process: Evidence From Laser Microscopy, SEM-EDS, and XPS |
title_fullStr |
Arsenopyrite Bio-Oxidization Behavior in Bioleaching Process: Evidence From Laser Microscopy, SEM-EDS, and XPS |
title_full_unstemmed |
Arsenopyrite Bio-Oxidization Behavior in Bioleaching Process: Evidence From Laser Microscopy, SEM-EDS, and XPS |
title_sort |
arsenopyrite bio-oxidization behavior in bioleaching process: evidence from laser microscopy, sem-eds, and xps |
publisher |
Frontiers Media S.A. |
series |
Frontiers in Microbiology |
issn |
1664-302X |
publishDate |
2020-08-01 |
description |
In arsenopyrite bioleaching, the interfacial reaction between mineral and cells is one of the most important factors. The energy of the interface is influenced by the mineralogical and microbiological characteristics. In this paper, the interfacial energy was calculated, and the surface of arsenopyrite during the bioleaching process was characterized by 3D laser microscopy, scanning electron microscopy with energy-dispersive X-ray spectroscopy, and X-ray photoelectron spectroscopy, in order to assess the dissolution and oxidation behavior of arsenopyrite during bioleaching. The results showed that the contact angles of arsenopyrite were 22 ± 2° when covered with biofilms, but the reaction surface of arsenopyrite turned 103 ± 2°. However, the angle was 45–50° when covered by passive layer, which was half as that of arsenopyrite surface. The interfacial energy of arsenopyrite without biofilms increased from 45 to 62 mJ/m2, while it decreased to 5 ± 1 mJ/m2 when covered by biofilms during the leaching process. The surface was separated into fresh surface, oxidized surface, and (corrosion) pits. The interfacial energy was influenced by the fresh and oxidized surfaces. Surface roughness increased from 0.03 ± 0.01 to 5.89 ± 1.97 μm, and dissolution volume increased from 6.31 ± 0.47 × 104 to 2.72 ± 0.49 × 106 μm3. The dissolution kinetics of arsenopyrite followed the model of Kt = lnX, and the dissolution mechanisms were mixed controlled: surface reaction control and diffusion through sulfur layer. On the surface of arsenopyrite crystal, the oxidation steps of each element can be described as: for Fe, Fe(II)–(AsS)→Fe(III)–(AsS)→Fe(III)–OH or Fe(III)–SO; for S, As–S(-1) or Fe–S(-1)→polysulfide S→intermediate S–O→sulfate; and for As, As–1–S→As0→As+1–O→As+3–O→As+5–O. |
topic |
dissolution kinetics interfacial energy XPS bioleaching hydrophobicity passive layer |
url |
https://www.frontiersin.org/article/10.3389/fmicb.2020.01773/full |
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