title: Two-step bioleaching of copper and gold from discarded printed circuit boards (PCB).
abstract: An effective strategy for environmentally sound biological recovery of copper and gold from discarded printed circuit boards (PCB) in a two-step bioleaching process was experimented. In the first step, chemolithotrophic acidophilic Acidithiobacillus ferrivorans and Acidithiobacillus thiooxidans were used. In the second step, cyanide-producing heterotrophic Pseudomonas fluorescens and Pseudomonas putida were used. Results showed that at a 1% pulp density (10g/L PCB concentration), 98.4% of the copper was bioleached by a mixture of A. ferrivorans and A. thiooxidans at pH 1.0-1.6 and ambient temperature (23±2°C) in 7days. A pure culture of P. putida (strain WCS361) produced 21.5 (±1.5)mg/L cyanide with 10g/L glycine as the substrate. This gold complexing agent was used in the subsequent bioleaching step using the Cu-leached (by A. ferrivorans and A. thiooxidans) PCB material, 44.0% of the gold was mobilized in alkaline conditions at pH 7.3-8.6, and 30°C in 2days. This study provided a proof-of-concept of a two-step approach in metal bioleaching from PCB, by bacterially produced lixiviants.
authors.affiliation: UNESCO-IHE Institute for Water Education, 2611 AX Delft, The Netherlands. Electronic address: a.isildar@unesco-ihe.org.
authors.forename: Arda
authors.initials: A
authors.lastname: Işıldar
authors.affiliation: UNESCO-IHE Institute for Water Education, 2611 AX Delft, The Netherlands.
authors.forename: Jack
authors.initials: J
authors.lastname: van de Vossenberg
authors.affiliation: UNESCO-IHE Institute for Water Education, 2611 AX Delft, The Netherlands.
authors.forename: Eldon R
authors.initials: ER
authors.lastname: Rene
authors.affiliation: Université Paris-Est, Laboratoire Geomatériaux et Environnement (LGE), EA 4508, UPEM, 77454 Marne-la-Vallée, France.
authors.forename: Eric D
authors.initials: ED
authors.lastname: van Hullebusch
authors.affiliation: UNESCO-IHE Institute for Water Education, 2611 AX Delft, The Netherlands; Department of Chemistry and Bioengineering, Tampere University of Technology, PO Box 541, Tampere, Finland.
authors.forename: Piet N L
authors.initials: PN
authors.lastname: Lens
mesh_terms: D042763:Acidithiobacillus / Q000378:metabolism; D013856:Acidithiobacillus thiooxidans; D001709:Biotechnology / Q000379:methods*; D003300:Copper / Q000302:isolation & purification*; D003486:Cyanides / Q000378:metabolism; D059029:Electronic Waste; D005998:Glycine / Q000378:metabolism; D006046:Gold / Q000302:isolation & purification*; D008855:Microscopy, Electron, Scanning; D011551:Pseudomonas fluorescens; D016958:Pseudomonas putida / Q000378:metabolism; D059027:Recycling / Q000379:methods*; D014961:X-Ray Diffraction
chemical_list: D003486:Cyanides; D006046:Gold; D003300:Copper; D005998:Glycine
keywords: Bioleaching; Copper; Gold; PCB; Secondary resource; Two-step; WEEE