Plasma treatment of electrodes significantly enhances the development of anodic electrochemically active biofilms

VICTORIA FLEXER; MARQUE, M.; DONOSE, B.C.; VIRDIS, B.; KELLER, J.

ELECTROCHIMICA ACTA

PERGAMON-ELSEVIER SCIENCE LTD

Lugar: Amsterdam; Año: 2013 vol. 108 p. 566 - 574

0013-4686

Surface modifications of electrode materials are important for improved performance of microbial bio-electrochemical systems. Here, we studied the effect of pre-treating both glassy carbon and graphitefelt electrodes with either an oxygen or a nitrogen plasma before reactor inoculation with a mixedmicrobial consortia. The plasma produces chemical modifications at the electrode surface level. X-rayphotoelectron spectroscopy and water contact angle analysis showed that the plasma removes sur-face contamination, produces ion implantation and renders the hydrophobic surfaces highly hydrophilic.Plasma pre-treatment considerably accelerated the generation of a bio-electrochemical anodic currentafter inoculation. Nitrogen plasma pre-treatment yielded the best performance, followed closely by oxy-gen plasma. Plasma pre-treated electrodes reached a plateau of maximum current density twice as fastas untreated electrodes. Analysis of the current development profiles suggests that the plasma pre-treatment is neither producing a preferential attachment of certain types of bacteria over others noraccelerating the extracellular electron transfer rate. The results indicate that the plasma treatment con-siderably enhances the initial cell adhesion, which results in subsequently faster biofilm development.Plasma pre-treatment of electrodes is an inexpensive, fast, safe and straightforward technique to achievemore rapid start-up of bio-electrochemical processes.