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- Innovative combination of chemical and biological strategies for the recovery of metals from metal-bearing wastewaters and leachatesPublication . Nobahar, Amir; Costa, Maria Clara; Carlier, JorgeThis dissertation applied pioneering approaches that benefits the potential of both solvent extraction (SX) and bio-recovery strategies based on the use of bacterial communities and plant extracts as metal separation and recovery technique. In this regard, metal recovery from an extreme acid mine drainage (AMD) was initially performed for Cu SX with Acorga M5640 that was then stripped with 2M sulfuric acid, allowing to rise the Cu concentration to over 46 g/l, which was then recovered as CuS nanoparticles through the addition of biogenic sulfide. Thereafter, the rafiinate from the mentioned SX process, was subjected to Zn recovery studies. In these studies, Fe3+ was found to be nuisance in Zn recovery and was separated from the solution by SX with AliCy followed by alkalinization of its aqueous raffinate to pH 3.25 or 3.50. Thereafter, Zn was recovered as ZnS nanoparticles through precipitation by biogenic sulfide at pH=3.5. In addition, AMD remediation studies were investigated by applying acidophilic SRB consortium that was obtained from the enrichment of sediments of an inactive Cu mine at pH 4.00 with methanol as carbon source. The metal removal from AMD by the mentioned consortium revealed promising results when a 20% (v/v) supplement of Postgate B base (except lactate) was added to AMD. Metataxonomic analysis showed the presence of Desulfosporosinus genus in all enrichment and AMD remediation studies, with highest relative abundances in cultures enriched with methanol at pH 4.00 and in AMD remediation tests with lowest Postgate base supplements. Another part of this study investigated the potential of plant extracts in PGMs and precious metals recovery from different leachates. These studies revealed the high potential of red raspberry (Rubus Idaeus L.) leaves hydroalcoholic extract in Pd precipitation (>60%) from spent autocatalytic converters leachates as nanoparticles and also in Au precipitation (~96%,) from printed circuit boards leachates as microparticle clusters of Au nanoparticles. Contribution of functional groups of the phytochemicals present in the extracts were studied in the Pd and Au ions’ bio-reduction and bio-stabilization. Keywords: acid mine drainage, metal leachate, metal bio-recovery, solvent extraction, sulfate-reducing bacteria, nanoparticles green synthesis