Nanoscale zerovalent iron (nZVI) has been investigated for the selective formation of Cu
nanoparticles from acid mine drainage (AMD) taken from a legacy mine site in the UK. Batch
experiments were conducted containing unbuffered (pH 2.67 at t=0) and pH buffered (pH <3.1)
AMD which were exposed to nZVI at 0.1-2.0 g/L. Results demonstrate ...
Nanoscale zerovalent iron (nZVI) has been investigated for the selective formation of Cu
nanoparticles from acid mine drainage (AMD) taken from a legacy mine site in the UK. Batch
experiments were conducted containing unbuffered (pH 2.67 at t=0) and pH buffered (pH <3.1)
AMD which were exposed to nZVI at 0.1-2.0 g/L. Results demonstrate that nZVI is selective
for Cu, Cd and Al removal (>99.9% removal of all metals within 1 h when nZVI ≥1.0 g/L) from
unbuffered AMD despite the coexistent of numerous other metals in the AMD, namely: Na,
Ca, Mg, K, Mn and Zn. An acidic pH buffer enabled similarly high Cu removal but maximum
removal of only <1.5% and <0.5% Cd and Al respectively. HRTEM-EDS confirmed the
formation of discrete spherical nanoparticles comprised of up to 68% wt. Cu, with a relatively
narrow size distribution (typically 20-100 nm diameter). XPS confirmed such nanoparticles as
containing Cu0, with the Cu removal mechanism therefore likely via cementation with Fe0.
Overall the results demonstrate nZVI as effective for the one-pot and selective formation of
Cu0-bearing nanoparticles from acidic wastewater, with the technique therefore potentially
highly useful for the selective upcycling of dissolved Cu in wastewater into high value
nanomaterials.