The accumulation of metals in the environment has several negative impacts, which tend to be aggravated by their intensive demand and utilization. This situation is accompanied by the depletion of some primary resources, namely those of platinum group metals (PGMs). Hence, their recovery from secondary sources, namely wastes and wastewaters, using economically and environmentally sustainable techniques is a top priority. In this regard, the present project aims the recovery of strategic metals (Cu, Zn and Fe) from two highly metals-contaminated effluents (an extreme contaminated acid mine drainage, AMD, and spent solutions from Zn plating industries) and the recovery of PGMs (e.g. Pd, Pt) from leachates from spent automotive catalysts.

For that purpose, a pioneering approach that combines the potential of liquid-liquid extraction as separation technique with the versatility of bio-recovery strategies based on the use of bacterial communities, solutions from their activity or plant extracts, are being tested. The use of diverse biologic agents (and conditions) that can act through several mechanisms such as bio-reduction or bio-precipitation, allows the metal to be recovered in a non-combined or combined form, and may result on different products or particles sizes, thus broadening with advantage their possible properties and applications.