Desalination combined with copper(II) removal in a novel microbial desalination cell

• Copper(II) removal and salt water desalination were realized in a FMDC.
• Copper(II) acted as electron acceptor in the FMDC and was reduced to Cu/Cu2O.
• The initial copper(II) concentration affected the performance of the FMDC.
• Small external resistance was beneficial to copper(II) removal.
• Copper(II) removal efficiency above 90% was observed in the FMDC.

A novel four-chamber microbial desalination cell (FMDC) was proposed to treat synthetic Cu(II)-containing wastewater in the cathode chamber and simultaneously desalinate brine or seawater in the desalination chamber. In this study, two anion exchange membranes (AEMs) and one cation exchange membrane (CEM) were used as separators between the four different function chambers of the FMDC. Below a pH value of 3.0, the maximum current density was 2.0 A/m2 with the initial Cu2 + concentration of 800 mg/L and an external resistance of 10 Ω. The copper removal rate, salt removal rate and total desalination rate, all conducted simultaneously, were 94.1 ± 1.2%, 43.9 ± 0.9% and 5.1 ± 0.6 mg/h in a batch-fed cycle, respectively. Scanning electron microscope–energy dispersive spectrometer (SEM–EDS) analysis indicated that the Cu(II) was reduced to Cu2O plus Cu, which deposited on the cathode surface. These results suggested a novel approach to remove and recover Cu(II) from Cu(II)-containing wastewater and to desalinate salt water by using an FMDC reactor.

The construction of a novel four chamber microbial desalination cell (FMDC).Figure optionsDownload as PowerPoint slide