Platinum Recovery from Synthetic Extreme Environments by Halophilic Bacteria

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• 作者：Synthia Maes ; Ruben Props ; Jeffrey P. Fitts ; Rebecca De Smet ; Ramiro Vilchez-Vargas ; Marius Vital ; Dietmar H. Pieper ; Frank Vanhaecke ; Nico Boon ; Tom Hennebel
• 刊名：Environmental Science & Technology
• 出版年：2016
• 出版时间：March 1, 2016
• 年：2016
• 卷：50
• 期：5
• 页码：2619-2626
• 全文大小：418K
• ISSN：1520-5851

文摘

Metal recycling based on urban mining needs to be established to tackle the increasing supply risk of critical metals such as platinum. Presently, efficient strategies are missing for the recovery of platinum from diluted industrial process streams, often characterized by extremely low pHs and high salt concentrations. In this research, halophilic mixed cultures were employed for the biological recovery of platinum (Pt). Halophilic bacteria were enriched from Artemia cysts, living in salt lakes, in different salt matrices (sea salt mixture and NH₄Cl; 20–210 g Lp>–1p> salts) and at low to neutral pH (pH 3–7). The main taxonomic families present in the halophilic cultures were Halomonadaceae, Bacillaceae, and Idiomarinaceae. The halophilic cultures were able to recover >98% Pt(II) and >97% Pt(IV) at pH 2 within 3–21 h (4–453 mg Pt_recovered hp>–1p> gp>–1p> biomass). X-ray absorption spectroscopy confirmed the reduction to Pt(0) and transmission electron microscopy revealed both intra- and extracellular Pt precipitates, with median diameters of 9–30 nm and 11–13 nm, for Pt(II) and Pt(IV), respectively. Flow cytometric membrane integrity staining demonstrated the preservation of cell viability during platinum recovery. This study demonstrates the Pt recovery potential of halophilic mixed cultures in acidic saline conditions.