title: Biologically-induced precipitation of sphalerite-wurtzite nanoparticles by sulfate-reducing bacteria: implications for acid mine drainage treatment.
abstract: Several experiments were conducted to evaluate zinc-tolerance of sulfate-reducing bacteria (SRB) obtained from three environmental samples, two inocula from sulfide-mining districts and another inoculum from a wastewater treatment plant. The populations of SRB resisted zinc concentrations of 260 mg/L for 42 days in a sulfate-rich medium. During the experiments, sulfate was reduced to sulfide and concentrations in solution decreased. Zinc concentrations also decreased from 260 mg/L to values below detection limit. Both decreases were consistent with the precipitation of newly-formed sphalerite and wurtzite, two polymorphs of ZnS, forming <2.5-μm-diameter spherical aggregates identified by microscopy and synchrotron-μ-XRD. Sulfate and zinc are present in high concentrations in acid mine drainage (AMD) even after passive treatments based on limestone dissolution. The implementation of a SRB-based zinc removal step in these systems could completely reduce the mobility of all metals, which would improve the quality of stream sediments, water and soils in AMD-affected landscapes.
authors.affiliation: Department of Geology, University of Huelva, Campus El Carmen, 21071, Huelva, Spain.
authors.forename: Julio
authors.initials: J
authors.lastname: Castillo
authors.forename: Rafael
authors.initials: R
authors.lastname: Pérez-López
authors.forename: Manuel A
authors.initials: MA
authors.lastname: Caraballo
authors.forename: José M
authors.initials: JM
authors.lastname: Nieto
authors.forename: Mónica
authors.initials: M
authors.lastname: Martins
authors.forename: M Clara
authors.initials: MC
authors.lastname: Costa
authors.forename: Manuel
authors.initials: M
authors.lastname: Olías
authors.forename: Juan C
authors.initials: JC
authors.lastname: Cerón
authors.forename: Rémi
authors.initials: R
authors.lastname: Tucoulou
mesh_terms: D001421:Bacteria, Anaerobic / Q000378:metabolism*; D001673:Biodegradation, Environmental; D011232:Chemical Precipitation; D004785:Environmental Pollutants / Q000737:chemistry*; D007220:Industrial Waste; D008906:Mining; D053758:Nanoparticles / Q000737:chemistry*; D010084:Oxidation-Reduction; D010316:Particle Size; D013440:Sulfides / Q000737:chemistry*; D018505:Waste Management / Q000379:methods*; D015032:Zinc / Q000737:chemistry; D017967:Zinc Compounds / Q000737:chemistry*
chemical_list: D004785:Environmental Pollutants; D007220:Industrial Waste; D013440:Sulfides; D017967:Zinc Compounds; D015032:Zinc; C031238:zinc sulfide