Computer-munching microbes: Metal leaching from electronic scrap by bacteria and fungi
1999; Elsevier BV; Linguagem: Inglês
10.1016/s1572-4409(99)80146-1
ISSN2212-084X
AutoresH. Brandl, René Bosshard, M. Wegmann,
Tópico(s)Recycling and Waste Management Techniques
ResumoWe applied microbiological processes to mobilize metals from electronic waste materials. Bacteria (Thiobacillus thiooxidans, T. ferrooxidans) and fungi (Aspergillus niger, Penicillium simplicissimum) were grown in the presence of electronic scrap. The formation of inorganic and organic acids caused the mobilization of metals. Initial experiments showed that above a concentration of 1% (w/v) of scrap in the medium microbial growth was inhibited. However, after a prolonged adaptation time, fungi grew also at concentrations of 10% (w/v). Both fungal strains were able to mobilize Cu and Sn by 65%, and Al, Ni, Pb. and Zn by >95%. At scrap concentrations of 0.5% Thiobacilli were able to leach >90 % of the available Cu, Zn, Ni, and Al. Pb precipitated as PbSO4, Sn probably precipitated as SnO. For a more efficient metal mobilization a two-step leaching process is proposed where biomass growth is separated from metal leaching.
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