Microcellular Electrode Material for Microbial Bioelectrochemical Systems Synthesized by Hydrothermal Carbonization of Biomass Derived Precursors

V.F. acknowledges a UQ Postdoctoral Fellowship. This work was supported by the Australian Research Council Grant DP110100539. The authors acknowledge the facilities and the scientific and technical assistance of the Australian Microscopy & Microanalysis Research Facility at the Centre for Microscopy and Microanalysis (The University of Queensland). The Ghent University Special Research Fund (BOF) is acknowledged for the postdoctoral grant of M.N.B

Flame oxidation of stainless steel felt enhances anodic biofilm formation and current output in bioelectrochemical systems

Stainless steel (SS) can be an attractive material to create large electrodes for microbial bioelectrochemical systems (BESs), due to its low cost and high conductivity. However, poor biocompatibility limits its successful application today. Here we report a simple and effective method to make SS electrodes biocompatible by means of flame oxidation. Physicochemical characterization of electrode surface indicated that iron oxide nanoparticles (IONPs) were generated in situ on an SS felt surface by flame oxidation. IONPs-coating dramatically enhanced the biocompatibility of SS felt and consequently resulted in a robust electroactive biofilm formation at its surface in BESs. The maximum current densities reached at IONPs-coated SS felt electrodes were 16.5 times and 4.8 times higher than the untreated SS felts and carbon felts, respectively. Furthermore, the maximum current density achieved with the IONPs-coated SS felt (1.92 mA/cm2, 27.42 mA/cm3) is one of the highest current densities reported thus far. These results demonstrate for the first time that flame oxidized SS felts could be a good alternative to carbon-based electrodes for achieving high current densities in BESs. Most importantly, high conductivity, excellent mechanical strength, strong chemical stability, large specific surface area, and comparatively low cost of flame oxidized SS felts offer exciting opportunities for scaling-up of the anodes for BESs. © 2014 American Chemical Society

Surface modification of materials to encourage beneficial biofilm formation

Biofilms are communities of sessile microorganisms that grow and produce extrapolymeric substances on an abiotic or biotic surface. Although biofilms are often associated with negative impacts, the role of beneficial biofilms is wide and include applications in bioremediation, wastewater treatment and microbial fuel cells. Microbial adhesion to a surface, which is highly dependent on the physicochemical properties of the cells and surfaces, is an essential step in biofilm formation. Surface modification therefore represents an important way to modulate microbial attachment and ultimately biofilm formation by microorganisms. In this review different surface modification processes such as organosilane surface modification, plasma treatment, and chemical modification of carbon nanotubes, electro-oxidation and covalent-immobilization with neutral red and methylene blue molecules are outlined. The effectiveness of these modifications and their industrial applications are also discussed. There is inadequate literature on surface modification as a process to enhance beneficial biofilm formation. These methods need to be safe, economically viable, scalable and environmental friendly and their potential to fulfil these criteria for many applications has yet to be determined