es6b06339_si_001.pdf (2.43 MB)
Influence of Electric Fields on Biofouling of Carbonaceous Electrodes
journal contribution
posted on 2017-07-25, 00:00 authored by Soumya Pandit, Sneha Shanbhag, Meagan Mauter, Yoram Oren, Moshe HerzbergBiofouling
commonly occurs on carbonaceous capacitive deionization electrodes
in the process of treating natural waters. Although previous work
reported the effect of electric fields on bacterial mortality for
a variety of medical and engineered applications, the effect of electrode
surface properties and the magnitude and polarity of applied electric
fields on biofilm development has not been comprehensively investigated.
This paper studies the formation of a Pseudomonas aeruginosa biofilm on a Papyex graphite (PA) and a carbon aerogel (CA) in the
presence and the absence of an electric field. The experiments were
conducted using a two-electrode flow cell with a voltage window of
±0.9 V. The CA was less susceptible to biofilm formation compared
to the PA due to its lower surface roughness, lower hydrophobicity,
and significant antimicrobial properties. For both positive and negative
applied potentials, we observed an inverse relationship between biofilm
formation and the magnitude of the applied potential. The effect is
particularly strong for the CA electrodes and may be a result of cumulative
effects between material toxicity and the stress experienced by cells
at high applied potentials. Under the applied potentials for both
electrodes, high production of endogenous reactive oxygen species
(ROS) was indicative of bacterial stress. For both electrodes, the
elevated specific ROS activity was lowest for the open circuit potential
condition, elevated when cathodically and anodically polarized, and
highest for the ±0.9 V cases. These high applied potentials are
believed to affect the redox potential across the cell membrane and
disrupt redox homeostasis, thereby inhibiting bacterial growth.