Role of Near-Electrode Solution Chemistry on Bacteria Attachment and Poration at Low Applied Potentials
At a Glance
Section titled āAt a Glanceā| Metadata | Details |
|---|---|
| Publication Date | 2019-12-03 |
| Journal | Environmental Science & Technology |
| Authors | MengāHsuan Lin, Shafigh Mehraeen, Gang Cheng, Cory A. Rusinek, Brian P. Chaplin |
| Institutions | University of Illinois Chicago, Fraunhofer USA |
| Citations | 17 |
Abstract
Section titled āAbstractāThis research investigated mechanisms for biofouling control at boron-doped diamond (BDD) electrode surfaces polarized at low applied potentials (e.g., -0.2 to 1.0 V vs Ag/AgCl), using <i>Pseudomonas aeruginosa</i> as a model organism. Results indicated that electrostatic interactions between bacteria and ionic electrode functional groups facilitated bacteria attachment at the open-circuit potential (OCP). However, under polarization, the applied potential governed these electrostatic interactions and electrochemical reactions resulted in surface bubble formation and near-surface pH modulation that decreased surface attachment under anodic conditions. The poration of the attached bacteria occurred at OCP conditions and increased with the applied potential. Scanning electrochemical microscopy (SECM) provided near-surface pH and oxidant formation measurements under anodic and cathodic polarizations. The near-surface pH was 3.1 at 1.0 V vs Ag/AgCl and 8.0 at -0.2 V vs Ag/AgCl and was possibly a contributor to bacteria poration. Interpretation of SECM data using a reactive transport model allowed for a better understanding of the near-electrode chemistry. Under cathodic conditions, the primary oxidant formed was H<sub>2</sub>O<sub>2</sub>, and under anodic conditions, a combination of H<sub>2</sub>O<sub>2</sub>, Cl<sup>ā¢</sup>, HO<sub>2</sub><sup>ā¢</sup>, Cl<sub>2</sub><sup>ā¢-</sup>, and Cl<sub>2</sub> formations likely contributed to bacteria poration at potentials as low as 0.5 V vs Ag/AgCl.