Copper Recovery Combined with Electricity Production in a Microbial Fuel Cell

Abstract

A metallurgical microbial fuel cell (MFC) is an attractive alternative for recovery of copper from copper containing waste streams, as the metal is recovered in its metallic form at the cathode, while the energy for metal reduction can be obtained from oxidation of organic materials at the anode with possible additional production of electricity. We studied the recovery of copper in an MFC using a bipolar membrane as a pH separator. Under anaerobic conditions, the maximum power density was 0.43 W/m(2) at a current density of 1.7 A/m(2). In the presence of oxygen, MFC performance improved considerably to a maximum power density of 0.80 W/m(2) at a current density of 3.2 A/m(2). Pure copper crystals were formed on the cathode, and no CuO or Cu(2)O was detected. Removal efficiencies of >99.88% were obtained. The cathodic recovery of copper compared to the produced electricity was 84% (anaerobic) and 43% (aerobic). The metallurgy MFC with the Cu(2+) reducing cathode further enlarges the application range of MFCs.

Gas diffusion electrodes improve hydrogen gas mass transfer for a hydrogen oxidizing bioanode

“…Figure 2 shows the current density produced with acetate and hydrogen gas as an electron donor at different hydrogen gas inflow rates and anolyte recirculation speed. For acetate, the maximum current density was 6.8 A m ‐ 2 at an anode potential of –0.30 V, which is comparable with values reported in the literature 3, 4, 21. For hydrogen gas as electron donor supplied at 3 mL min ‐1 , the maximum current density was 1.5 A m ‐ 2 at –0.20 V anode potential, for the highest anolyte recirculation speed of 200 mL min ‐1 .…”

“…In practice, industrial copper plating requires 2.7 kWh kg ‐1 Cu when water is used as electron donor due to a high overpotential for this reaction 1, 2. Previously it has been shown that bioelectrochemical systems (BESs) can be used for the recovery of metals, using electron donors present in wastewater such as acetate 3. The oxidation of organics such as acetate, gives an energetic advantage over water oxidation and even results in power production combined with copper recovery.…”

Bioelectrochemical metal recovery with microbial fuel cells

“…23,25,26 . Ter Heijne et al (2010) were the first to use a BES, with acetate as an electron donor, and Cu 2+ as the electrode acceptor in the cathode. They showed the possibility to remove copper from wastewater and production of pure plated copper, in combination with electricity production (Figure 1.2).…”

“…They showed the possibility to remove copper from wastewater and production of pure plated copper, in combination with electricity production (Figure 1.2). The novelty of the application of BES for the recovery of metal waste was that this provides an energy-efficient alternative to conventional electrowinning processes, because the electron donor (wastewater) provides (part of) the energy to drive the reduction reaction [27][28][29][30][31][32] .…”

“…The voltage and the power are also relevant to understand how efficient the process is from an energetic point of view. Copper and Chromium are the most studied metals in BESs, but other metals can be used such as silver, gold and mercury [27][28][29][30][31][37][38][39] . Wang et al (2008) published one of the first papers on MFC technology in which Cr (VI) in wastewaters was reduced to a less toxic aqueous species.…”