title: A new approach for the recovery of precious metals from solution and from leachates derived from electronic scrap.
abstract: A new approach is described for the recovery of precious metals (PMs: Au, Pd and Ag) with >99% efficiency from aqueous solution utilising biogas produced during the aerobic growth of Klebsiella pneumoniae. Gold was recovered from electronic scrap leachate ( approximately 95%) by this method, with some selectivity against Cu. The recovered PM solids all contained metal and sulphur as determined by energy dispersive X-ray microanalysis (EDX). X-ray powder diffraction analysis (XRD) showed no crystalline metal sulphur compounds but a crystalline palladium amine was recorded. Silver was recovered as a sulphide (found by EDX), carbonate and oxide (found by XRD). EDX analysis of the Au-precipitate showed mainly gold and sulphur, with some metallic Au(0) detected by XRD. The gold compound was shock-sensitive; upon grinding it detonated to leave a sooty black deposit.
authors.affiliation: School of Biosciences, The University of Birmingham, Edgbaston, Birmingham B15 2TT, UK. l.e.macaskie@bham.ac.uk
authors.forename: L E
authors.initials: LE
authors.lastname: Macaskie
authors.forename: N J
authors.initials: NJ
authors.lastname: Creamer
authors.forename: A M M
authors.initials: AM
authors.lastname: Essa
authors.forename: N L
authors.initials: NL
authors.lastname: Brown
mesh_terms: D000332:Aerobiosis / Q000502:physiology; D001673:Biodegradation, Environmental; D011232:Chemical Precipitation; D003247:Conservation of Natural Resources; D004577:Electron Probe Microanalysis; D004581:Electronics; D006046:Gold / Q000302:isolation & purification*; D007220:Industrial Waste; D007711:Klebsiella pneumoniae / Q000254:growth & development / Q000378:metabolism*; D010165:Palladium / Q000302:isolation & purification*; D012834:Silver / Q000302:isolation & purification*; D013440:Sulfides / Q000302:isolation & purification*; D014865:Waste Disposal, Fluid; D014961:X-Ray Diffraction
chemical_list: D007220:Industrial Waste; D013440:Sulfides; D012834:Silver; D010165:Palladium; D006046:Gold