Towards “Precision Mining” of wastewater: Selective recovery of Cu from acid mine drainage onto diatomite supported nanoscale zerovalent iron particles
© 2018 Published by Elsevier Ltd.
Reason for embargo
Under embargo until 8 March 2019 in compliance with publisher policy.
This paper introduces the concept of ‘Precision Mining’ of metals which can be defined as a process for the selective in situ uptake of a metal from a material or media, with subsequent retrieval and recovery of the target metal. In order to demonstrate this concept nanoscale zerovalent iron (nZVI) was loaded onto diatomaceous earth (DE) and tested for the selective uptake of Cu from acid mine drainage (AMD) and subsequent release. Batch experiments were conducted using the AMD and nZVI-DE at 4.0–16.0 g/L. Results demonstrate nZVI-DE as highly selective for Cu removal with >99% uptake recorded after 0.25 h when using nZVI-DE concentrations ≥12.0 g/L, despite appreciable concentrations of numerous other metals in the AMD, namely: Co, Ni, Mn and Zn. Cu uptake was maintained in excess of 4 and 24 h when using nZVI-DE concentrations of 12.0 and 16.0 g/L respectively. Near-total Cu release from the nZVI-DE was then recorded and attributed to the depletion of the nZVI component and the subsequent Eh, DO and pH recovery. This novel Cu uptake and release mechanism, once appropriately engineered, holds great promise as a novel ‘Precision Mining’ process for the rapid and selective Cu recovery from acidic wastewater, process effluents and leach liquors.
We would like to thank Mr Jeff Rowlands and Mr Marco Santonastaso from the School of Engineering, Cardiff University for their technical support. We would also like to thank Mr Phillip Goodman from Natural Resources Wales for his help organising the mine water sample collection. We would also like to thank Dr Thomas Davies from the Cardiff Catalysis Institute and the Cardiff Electron Microscopy Facility for the HRTEM-EDS analysis, Dr David Morgan from the School of Chemistry, Cardiff University for the XPS and BET surface area analysis and Dr Iain McDonald from the ELEMENT Facility within the School of Earth Sciences for the ICP-MS analysis. This work was financially supported by the Natural Environment Research Council (grant number: NE/L013908/1) and the Camborne School of Mines Trust.
This is the author accepted manuscript. The final version is available from Elsevier via the DOI in this record.
Available online 7 March 2018