Hydrogen as electron donor for copper removal in bioelectrochemical systems

Hydrogen gas is an attractive alternative electron donor since it is produced in large quantities as a side product in the metallurgical industry. Aim of this study was to demonstrate that microbial anodic hydrogen oxidation on a non-catalyzed graphite electrode can be coupled with cathodic copper reduction in a BES to simultaneously recover copper and produce power. The strategy was to first grow an anodic biofilm on acetate, then replace the acetate with hydrogen as electron donor, and finally combine hydrogen oxidation with copper reduction in the cathode. The maximum current density was 1.8 A/m2 at -250 mV anode potential vs Ag/AgCl. When coupled with Cu2+ reduction, the maximum power density was 0.25 W/m2 at a current density of 0.48 A/m2. Anode overpotentials were higher compared to acetate oxidation, probably a result of limited hydrogen solubility and transfer.</p

Prototype of a scaled-up microbial fuel cell for copper recovery

Background: Bioelectrochemical systems (BESs) enable recovery of electrical energy through oxidation of a wide range of substrates at an anode and simultaneous recovery of metals at a cathode. Scale-up of BESs from the laboratory to pilot scale is a challenging step in the development of the process, and there are only a few successful experiences to build on. This paper presents a prototype BES for the recovery of copper. Results: The cell design presented here had removable electrodes, similar to those in electroplating baths. The anode and cathode in this design could be replaced independently. The prototype bioelectrochemical cell consisted of an 835 cm2 bioanode fed with acetate, and a 700 cm2 cathode fed with copper. A current density of 1.2 A/−2 was achieved with 48 mW m−2 of power production. The contribution of each component (anode, electrolytes, cathode and membrane) was evaluated through the analysis of the internal resistance distribution. This revealed that major losses occurred at the anode, and that the design with removable electrodes results in higher internal resistance compared with other systems. To further assess the practical applicability of BES for copper recovery, an economic evaluation was performed. Conclusion: Analysis shows that the internal resistance of several lab-scale BESs is already sufficiently low to make the system economic, while the internal resistance for scaled-up systems still needs to be improved considerably to become economically applicable

High rate copper and energy recovery in microbial fuel cells

Bioelectrochemicalsystems(BESs)areanovel,promisingtechnologyfortherecoveryofmetals.Theprerequisiteforupscalingfromlaboratorytoindustrialsizeisthathighcurrentandhighpowerdensitiescanbeproduced.Inthisstudywereporttherecoveryofcopperfromacoppersulfatestream(2gL-1Cu2+)usingalaboratoryscaleBESathighrate.Toachievethis,weusedanovelcellconfigurationtoreducetheinternalvoltagelossesofthesystem.Attheanode,electroactivemicroorganismsproduceelectronsatthesurfaceofanelectrode,whichgeneratesastablecellvoltageof485mVwhencombinedwithacathodewherecopperisreduced.Inthissystem,amaximumcurrentdensityof23Am-2incombinationwithapowerdensityof5.5Wm-2wasproduced.XRDanalysisconfirmed99%purityincopperofcopperdepositedontocathodesurface.Analysisofvoltagelossesshowedthatatthehighestcurrent,mostvoltagelossesoccurredatthecathode,andmembrane,whileanodelosseshadthelowestcontributiontothetotalvoltageloss.TheseresultsencouragefurtherdevelopmentofBESsforbioelectrochemicalmetalrecover

Prototype of a scaled-up microbial fuel cell for copper recovery

Background: Bioelectrochemical systems (BESs) enable recovery of electrical energy through oxidation of a wide range of substrates at an anode and simultaneous recovery of metals at a cathode. Scale-up of BESs from the laboratory to pilot scale is a challenging step in the development of the process, and there are only a few successful experiences to build on. This paper presents a prototype BES for the recovery of copper. Results: The cell design presented here had removable electrodes, similar to those in electroplating baths. The anode and cathode in this design could be replaced independently. The prototype bioelectrochemical cell consisted of an 835 cm2 bioanode fed with acetate, and a 700 cm2 cathode fed with copper. A current density of 1.2 A/−2 was achieved with 48 mW m−2 of power production. The contribution of each component (anode, electrolytes, cathode and membrane) was evaluated through the analysis of the internal resistance distribution. This revealed that major losses occurred at the anode, and that the design with removable electrodes results in higher internal resistance compared with other systems. To further assess the practical applicability of BES for copper recovery, an economic evaluation was performed. Conclusion: Analysis shows that the internal resistance of several lab-scale BESs is already sufficiently low to make the system economic, while the internal resistance for scaled-up systems still needs to be improved considerably to become economically applicable.</p

Resource Recovery From Wastes and Wastewaters Using Bioelectrochemical Systems.

Recent scientific and technological advancements in bioelectrochemical system (BES) research have opened up several avenues for realizing the concept of bio-based economy. Current research within this area has been directed toward exploring their applicability to generate a wastewater biorefinery. Valorization of resources in the form of energy, nutrients, metals, and chemicals has been actively exhibited using this technology. This chapter highlights the fundamentals and technological aspects of bioelectrochemical resource recovery from wastes and wastewaters with detailed emphasis on the latest trends of bioelectrorecovery systems (BERSs). Several wastes and wastewater feedstocks are enlisted and classified based on their prospects for resource and energy recovery. Two representative case studies, existing challenges, and a brief overview of the relative advantages and disadvantages of BERSs over alternative resource recovery options are also included. Further, an outlook is given for realizing resource recovery using BESs as a sustainable technology in the domain of energy and resource management