Tunable formation of copper metal, oxide, chloride and hydroxyl chloride nanoparticles from aqueous copper solutions using nanoscale zerovalent iron particles

The influence of different parameters (solid–liquid ratio, initial pH, initial Cu concentration and anion type) on the cementation of aqueous copper (Cu) with nanoscale zerovalent iron (nZVI) has been studied. The work has been established to study both the influence such parameters have on the kinetics and efficacy of the cementation process but also the physicochemical composition of resultant Cu-bearing products. The nZVI exhibited high Cu removal capacity (maximum removal 905.2 mg/g) due to its high surface area. X-ray diffraction determined the most common Cu-bearing precipitates were Cu2O, CuCl2 and Cu2(OH)3Cl for solutions containing Cl− counterions (CuCl2 salt precursor), while Cu0 and Cu2O were the most common phases for those containing SO2−4 counterions (CuSO4 salt precursor). Transmission electron microscopy determined such precipitates were discrete nanoparticles of relatively high purity Cu (e.g. >80 wt% Cu or ≥99.9 wt% Cu and O). Overall the results demonstrate nZVI as effective for the one-pot transformation of aqueous Cu into a range of different high purity Cu-bearing nanoparticles. The methodology developed herein is therefore likely to have important application in the recovery of Cu from wastewater and process solutions where the direct upcycling to high-value Cu-bearing nanoparticles is an advantageous form in which to recover Cu