Arsenopyrite weathering under conditions of simulated calcareous soil.
Mining activities release arsenopyrite into calcareous soils where it undergoes weathering generating toxic compounds. The research evaluates the environmental impacts of these processes under semi-alkaline carbonated conditions. Electrochemical (cyclic voltammetry, chronoamperometry, EIS), spectroscopic (Raman, XPS), and microscopic (SEM, AFM, TEM) techniques are combined along with chemical analyses of leachates collected from simulated arsenopyrite weathering to comprehensively examine the interfacial mechanisms. Early oxidation stages enhance mineral reactivity through the formation of surface sulfur phases (e.g., S n (2-)/S(0)) with semiconductor properties, leading to oscillatory mineral reactivity. Subsequent steps entail the generation of intermediate siderite (FeCO3)-like, followed by the formation of low-compact mass sub-micro ferric oxyhydroxides (α, γ-FeOOH) with adsorbed arsenic (mainly As(III), and lower amounts of As(V)). In addition, weathering reactions can be influenced by accessible arsenic resulting in the formation of a symplesite (Fe3(AsO4)3)-like compound which is dependent on the amount of accessible arsenic in the system. It is proposed that arsenic release occurs via diffusion across secondary α, γ-FeOOH structures during arsenopyrite weathering. We suggest weathering mechanisms of arsenopyrite in calcareous soil and environmental implications based on experimental data.
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, Mexico. lcrh75@ujed.mx.
René H
RH
Lara
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, Mexico.
Leticia J
LJ
Velázquez
Departamento de Química, Universidad Autónoma Metropolitana, Iztapalapa, Av. San Rafael Atlixco 186, Col. Vicentina, Iztapalapa, México, DF, 09340, Mexico.
Jorge
J
Vazquez-Arenas
Laboratoire de Chimie Physique et Microbiologie pour l'Environnement (LCPME), UMR 7564 CNRS-Université de Lorraine, 405 rue de Vandœuvre, F-54600, Villers-lès-Nancy, France.
Martine
M
Mallet
Laboratoire de Chimie Physique et Microbiologie pour l'Environnement (LCPME), UMR 7564 CNRS-Université de Lorraine, 405 rue de Vandœuvre, F-54600, Villers-lès-Nancy, France.
Manuel
M
Dossot
Departamento de Energía, Universidad Autónoma Metropolitana, Azcapotzalco, Av. San Pablo 180, Azcapotzalco, México, DF, 02200, Mexico.
Israel
I
Labastida
Crecimiento Económico y Medio Ambiente, Departamento Economía, Universidad Autónoma Metropolitana, Azcapotzalco, Av. San Pablo 180, Azcapotzalco, México, DF, 02200, Mexico.
Fabiola S
FS
Sosa-Rodríguez
Universidad Autónoma de Ciudad Juárez, ICB, Av. Benjamín Franklin 4650, Zona PRONAF, 32315, Cd. Juárez, Chihuahua, Mexico.
León F
LF
Espinosa-Cristóbal
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, Mexico.
Miguel A
MA
Escobedo-Bretado
Instituto de Metalurgia, Facultad de Ingeniería, UASLP, Av. Sierra Leona 550, Lomas 2a. Sección, 78210, San Luis Potosí, SLP, Mexico.
Roel
R
Cruz
D001152:Arsenicals / Q000032:analysis*; D002119:Calcium Carbonate / Q000737:chemistry*; D002254:Carbonates / Q000032:analysis; D004563:Electrochemistry; D004784:Environmental Monitoring / Q000379:methods*; D005290:Ferric Compounds / Q000032:analysis; D058085:Iron Compounds / Q000032:analysis*; D008855:Microscopy, Electron, Scanning; D046529:Microscopy, Electron, Transmission; D008903:Minerals / Q000032:analysis*; D008906:Mining; D008962:Models, Theoretical; D010084:Oxidation-Reduction; D012987:Soil / Q000737:chemistry*; D012989:Soil Pollutants / Q000032:analysis*; D013440:Sulfides / Q000032:analysis*; D013455:Sulfur / Q000032:analysis; D013499:Surface Properties; D014887:Weather
D001152:Arsenicals; D002254:Carbonates; D005290:Ferric Compounds; D058085:Iron Compounds; D008903:Minerals; D012987:Soil; D012989:Soil Pollutants; D013440:Sulfides; C064510:arsenopyrite; D013455:Sulfur; C092844:ferric oxyhydroxide; D002119:Calcium Carbonate; C486982:siderite
Arsenic release; Arsenopyrite weathering; Calcareous soil; Electrochemical impedance; Oscillatory mineral reactivity; Surface analysis