The recovery of metals as high value powders and nanopowders from industrial wastewaters using potential-controlled electrolysis

The objective of the presented study was the recovery of Zn, Cr, Cu and Co in the form of powders and nanopowders from various types of industrial wastewaters. Powders and nanopowders as products of high added value find a wide applications in nanotechnology and material science and engineering. The metallic powders were obtained using potentiostatic electroreduction (potential-controlled electrolysis). The chosen method offers better control of the purity and structure of the products. The structure and size of crystallites depend on the value of electrolysis potentials and time, cathode material, concentrations of metal ions. In this investigation, the powders of different sizes ranging from 90 to 230 nm for Cr, 100–4000 nm for Zn, 25–100 nm for Co and 40–660 nm for Cu were deposited. The compositions, purity and size of the cathode deposits were confirmed by scanning electron microscopy and energy-dispersive X-ray spectroscopy. Presented metal recovery method is a promising technique for industrial application, given its simplicity, economic viability and environmental sustainability. It can be used on a wide range of solutions and help in reducing the problem of the growing amounts of industrial wastewater.