Cathodic reduction of hexavalent chromium [Cr(VI)] coupled with electricity generation in microbial fuel cells

Abstract

A novel approach to Cr(VI)-contaminated wastewater treatment was investigated using microbial fuel cell technologies in fed-batch mode. By using synthetic Cr(VI)-containing wastewater as catholyte and anaerobic microorganisms as anodic biocatalyst, Cr(VI) at 100 mg/l was completely removed during 150 h (initial pH 2). The maximum power density of 150 mW/m(2) (0.04 mA/cm(2)) and the maximum open circuit voltage of 0.91 V were generated with Cr(VI) at 200 mg/l as electron acceptor. This work verifies the possibility of simultaneous electricity production and cathodic Cr(VI) reduction.

Impact of Fe(III) as an effective electron-shuttle mediator for enhanced Cr(VI) reduction in microbial fuel cells: Reduction of diffusional resistances and cathode overpotentials

“…In addition, the rate of Cr(VI) reduction observed in Fig. 2A was more than one order of magnitude higher than those observed at an initial Cr(VI) concentration of 100 mg/L after 150 h [4] and at an initial Cr(VI) concentration of 250 mg/L after 240 h, respectively [7].…”

“…shown promising results for the reduction of Cr(VI) since they couple reduced sludge generation with the production of renewable energy [3][4]. In MFCs, electrons are released from reductive organic matters in the anode in the presence of exoelectrogens.…”

“…Here Table 1 Species having the properties of displaying reversible redox reactions to function as electron mediators, are potentially effective to eliminate the electrical repulsion between the negatively charged cathode and Cr 2 O 7 2-or CrO 4 2-anions, and this is essential to achieve enhanced Cr(VI) reduction. Solid-phase mediating species such as rutile TiO 2 under light irradiation or conductive polymers of pyrrole/ClO 4 -and pyrrole/9,10-anthraquinone-2-sulfonate can facilitate the reduction of Cr(VI) in MFCs [5,8].…”

Enhanced Performance of Hexavalent Chromium Reducing Cathodes in the Presence ofShewanella oneidensisMR-1 and Lactate

“…Removal options include ion-exchange, adsorption and electrodialysis 3 ; however in many of these applications chromium keeps its toxic hexavalent state. Reduction of Cr(VI) to the considerably 3 less toxic trivalent form Cr(III) and its subsequent precipitation at neutral pH could be considered a more effective remediation strategy 4 .A possible method for Cr(VI) reduction using a microbial fuel cell (MFC) has recently been proposed, where Cr(VI) was used as an oxidant in the cathode to generate an electrical energy output 5,6 . At low pH values where H + is abundant, cathodic Cr(VI) reduction has been demonstrated at relatively fast rates and without the use of a catalyst 5,6 .…”

Bioelectrochemical metal recovery with microbial fuel cells

“…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] .…”