Chemical and surface analysis during evolution of arsenopyrite oxidation by Acidithiobacillus thiooxidans in the presence and absence of supplementary arsenic.
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 by Acidithiobacillus thiooxidans during 240h 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 (Sn(2-)/S(0)) 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 Sn(2-)/S(0), pyrite-like and orpiment-like phases.
Facultad de Ciencias Químicas, Departamento de Ciencia de Materiales, Universidad Juárez del Estado de Durango (UJED), Av. Veterinaria S/N, Circuito Universitario, Col. Valle del Sur, 34120 Durango, Dgo, Mexico.
Hugo
H
Ramírez-Aldaba
Facultad de Ciencias Químicas, Departamento de Ciencia de Materiales, Universidad Juárez del Estado de Durango (UJED), Av. Veterinaria S/N, Circuito Universitario, Col. Valle del Sur, 34120 Durango, Dgo, Mexico; Instituto Tecnológico de Durando, UPIDET, Av. Felipe Pescador 1830 Ote. Col. Nueva Vizcaya, 34080 Durango, Dgo, Mexico.
O Paola
OP
Valles
Departamento de Química, Universidad Autónoma Metropolitana-Iztapalapa, Av. San Rafael Atlixco 186, Col. Vicentina, Iztapalapa, México DF 09340, Mexico.
Jorge
J
Vazquez-Arenas
Instituto Tecnológico de Durando, UPIDET, Av. Felipe Pescador 1830 Ote. Col. Nueva Vizcaya, 34080 Durango, Dgo, Mexico.
J Antonio
JA
Rojas-Contreras
Instituto Politécnico Nacional, UPALM, Edif. Z-4 3er Piso, CP 07738 México D.F, Mexico.
Donato
D
Valdez-Pérez
Facultad de Ciencias Químicas, Departamento de Ciencia de Materiales, Universidad Juárez del Estado de Durango (UJED), Av. Veterinaria S/N, Circuito Universitario, Col. Valle del Sur, 34120 Durango, Dgo, Mexico.
Estela
E
Ruiz-Baca
Departamento de Biotecnología, Universidad Autónoma Metropolitana-Iztapalapa, Av. San Rafael Atlixco 186, Col. Vicentina, Iztapalapa, México DF 09340, Mexico.
Mónica
M
Meraz-Rodríguez
Universidad Autónoma Metropolitana-Azcapotzalco, Área de Crecimiento Económico y Medio Ambiente, Departamento de Economía, Av. San Pablo 180, Azcapotzalco, México DF 02200, Mexico.
Fabiola S
FS
Sosa-Rodríguez
CIACyT, Universidad Autónoma de San Luis Potosí, Av. Sierra Leona 550, Lomas 2da sección, 78230 San Luis Potosí, SLP, Mexico.
Ángel G
ÁG
Rodríguez
Facultad de Ciencias Químicas, Departamento de Ciencia de Materiales, Universidad Juárez del Estado de Durango (UJED), Av. Veterinaria S/N, Circuito Universitario, Col. Valle del Sur, 34120 Durango, Dgo, Mexico. Electronic address: lcrh75@ujed.mx.
René H
RH
Lara
D013856:Acidithiobacillus thiooxidans / Q000502:physiology*; D001151:Arsenic / Q000737:chemistry*; D001152:Arsenicals / Q000378:metabolism*; D001673:Biodegradation, Environmental; D018441:Biofilms; D058085:Iron Compounds / Q000378:metabolism*; D008903:Minerals / Q000378:metabolism*; D010084:Oxidation-Reduction; D013440:Sulfides / Q000378:metabolism*; D013997:Time Factors; D014874:Water Pollutants, Chemical / Q000378:metabolism*
D001152:Arsenicals; D058085:Iron Compounds; D008903:Minerals; D013440:Sulfides; D014874:Water Pollutants, Chemical; C064510:arsenopyrite; D001151:Arsenic
Acidithiobacillus thiooxidans; Arsenopyrite biooxidation; Biofilm modification; Direct cell attachment; Electrochemical impedance spectroscopy; Toxic arsenic