Chemical and surface analysis during evolution of arsenopyrite oxidation by Acidithiobacillus thiooxidans in the presence and absence of supplementary arsenic.
Chemical and surface analysis during evolution of arsenopyrite oxidation by Acidithiobacillus thiooxidans in the presence and absence of supplementary arsenic.
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DOI：
10.1016/j.scitotenv.2016.05.143
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发表时间：
2016-10
期刊：
影响因子：
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通讯作者：
Hugo Ramírez-Aldaba;O. P. Valles;J. Vazquez‐Arenas;J. Rojas-Contreras;D. Valdez-Pérez;E. Ruiz-Baca
中科院分区：
文献类型：
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作者：
Hugo Ramírez-Aldaba;O. P. Valles;J. Vazquez‐Arenas;J. Rojas-Contreras;D. Valdez-Pérez;E. Ruiz-Baca
毒砂的生物浸出由于回收有价金属和环境问题而引起了人们的极大兴趣。本研究旨在评价在补充和不补充砷的情况下，酸性硫氧化硫杆菌在240 h内对毒砂的氧化作用。利用拉曼光谱、原子力显微镜、SEM-EDS、循环伏安法、EIS、电泳和附着力等进行了化学和电化学表征，综合评价了该矿物的表面行为和生物氧化机制。这些分析表明，在非生物控制表面上形成了类黄铁矿的次级相，而在生物氧化表面上则形成了类黄铁矿（FeS2）、类黄铁矿（As2S3）和元素硫和多硫化物（Sn2−/S0）相。伏安结果表明毒砂由于（生物）氧化而发生了显著的变化。EIS测定的电阻过程与（生物）氧化介导的化学和电化学反应有关，导致毒砂表面的转化和生物膜的直接附着。在补充砷存在的情况下进行（生物）氧化时，电荷转移电阻增加，而在没有补充砷的情况下获得的非生物控制电阻降低；强化了As(V)在体系中产生更稳定的表面产物的观点。生物膜结构主要由微菌落组成，逐渐被二级化合物包围。在补充砷的存在下，发现了一种更紧凑的生物膜结构，增强了二级化合物的形成，其中可变的毒砂反应性与这些二级化合物有关，包括Sn2−/S0，类黄铁矿和类黄铁矿相。
Bioleaching of arsenopyrite presents a great interest due to recovery of valuable metals and environmental issues. The current study aims to evaluate the arsenopyrite oxidation byAcidithiobacillus thiooxidansduring 240 h at different time intervals, in the presence and absence of supplementary arsenic. Chemical and electrochemical characterizations are carried out using Raman, AFM, SEM-EDS, Cyclic Voltammetry, EIS, electrophoretic and adhesion forces to comprehensively assess the surface behavior and biooxidation mechanism of this mineral. These analyses evidence the formation of pyrite-like secondary phase on abiotic control surfaces, which contrast with the formation of pyrite (FeS2)-like, orpiment (As2S3)-like and elementary sulfur and polysulfide (Sn2 −/S0) phases found on biooxidized surfaces. Voltammetric results indicate a significant alteration of arsenopyrite due to (bio)oxidation. Resistive processes determined with EIS are associated with chemical and electrochemical reactions mediated by (bio)oxidation, resulting in the transformation of arsenopyrite surface and biofilm direct attachment. Charge transfer resistance is increased when (bio)oxidation is performed in the presence of supplementary arsenic, in comparison with lowered abiotic control resistances obtained in its absence; reinforcing the idea that more stable surface products are generated when As(V) is in the system. Biofilm structure is mainly comprised of micro-colonies, progressively enclosed in secondary compounds. A more compact biofilm structure with enhanced formation of secondary compounds is identified in the presence of supplementary arsenic, whereby variable arsenopyrite reactivity is linked and attributed to these secondary compounds, including Sn2 −/S0, pyrite-like and orpiment-like phases.