Electrochemical impedance spectroscopy study of membrane fouling and electrochemical regeneration at a sub-stoichiometric TiO2 reactive electrochemical membrane

By Jing, Yin; Guo, Lun; Chaplin, Brian P.
Published in Journal of Membrane Science NULL 2016

Abstract

Abstract In this study, a novel sub-stoichiometric TiO2 ultrafiltration reactive electrochemical membrane (REM) was synthesized and used for electrochemical regeneration of membranes fouled by humic acid (HA) and polystyrene beads (PS). A non-invasive and non-destructive electrochemical impedance spectroscopy (EIS) characterization technique was used to spatially characterize fouling at the {REM} and data were successfully interpreted by a transmission line model. Based on these analyses, a chemical free electrochemical regeneration (CFER) scheme in backwash mode was developed. The {CFER} in anodic treatment mode recovered the flux of a {HA} fouled {REM} from 3.0% to between 76% and 99% of the initial flux over 5 continuous fouling/regeneration cycles. Full flux recovery of a {PS} fouled {REM} (fouling 31% to 38%) was achieved when using either cathodic or anodic CFER. By contrast, regeneration without an applied potential showed only partial flux recovery of 66% and 62% on {HA} fouled and {PS} fouled membranes, respectively. The operating cost of {CFER} was $0.04 m?2 to $0.06 m?2 per regeneration cycle, which is only 1.3% the cost of NaOH cleaning. Results suggest that the {REM} can provide an efficient and cost effective regeneration scheme that allows it to function in a diverse set of water treatment applications.

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