Understanding the Relationship between Electrochemical Fouling Control and Electrode Surface Coverage

Abstract

Fouling limits the performance of membrane-based water treatment processes and accounts for up to 25% of the operational expenses of membrane-based water treatment processes. Electrically conductive membranes have been proposed as cheaper and more energy efficient alternatives to reduce and remove fouling. In this study, we investigate the relationship between the surface coverage with an electrode and fouling control levels. We use direct laser scribing for the printing of electrodes with varying surface coverage and measure the removal of bacterial foulants across a range of applied potentials. We find that partial substrate coverage with conductive materials can result in effective electrical fouling control and uncover a surprising relationship between the current density and fouling control. At a given applied potential, biofilm control was not correlated with current density, which indicates that factors other than current density or electrode coverage, such as the shape of the electrode or the particular pattern, might also be critical factors that control biofilm removal levels. These results provide guiding principles for the design of active fouling removal from membranes and other surfaces by using electrochemical reactions.

In Situ Oxidative, Catalytic Oxidative, and Nonoxidative Electrocleaning of Fouled Conductive Membranes

“…When both nonoxidative and catalytic oxidative are used consecutively, a small fraction of the fouling is removed while the rest can be taken care of by the catalytic oxidative electrocleaning. Some studies have reported that hydrogen evolution can also contribute to the electrocleaning. , However, in the case of nonoxidative electrocleaning, the cleaning solution is DI water with no electrolyte to facilitate electron transfer. Thus, in DI water, the electrochemical redox reactions are inhibited and the generation of hydrogen gas bubbles is negligible.…”

“…Some studies have reported that hydrogen evolution can also contribute to the electrocleaning. 69,70 However, in the case of nonoxidative electrocleaning, the cleaning solution is DI water with no electrolyte to facilitate electron transfer. Thus, in DI water, the electrochemical redox reactions are inhibited and the generation of hydrogen gas bubbles is negligible.…”