Deposition of fine iron oxide particles in tap water using electrophoretic deposition (EPD) technique

Abstract

An investigation of using the electrophoretic deposition (EPD) technique to deposit negatively charged fine iron oxide particles in tap water samples on a counter charge electrode (anode) was conducted. Characterizations of fine iron oxide particles in tap water from two different locations, i.e. commercial and residential areas, were identified. After centrifuging the tap water samples, a particle analyzer was used to analyze the particle sizes and zeta potential values. The average particle sizes for the supernatant region from the commercial and residential areas were 230±22.30 and 260±3.68nm, respectively. The zeta potential value from the residential area was higher than the commercial area, i.e. −42.27±0.12 and −34.83±0.23mV, respectively. X-ray diffraction (XRD) analysis indicated that the tap water samples consisted of iron oxide polymorphs, namely goethite (α-FeOOH), hematite (α-Fe2O3), magnetite (Fe3O4), and maghemite (γ-Fe2O3). During the removal of fine iron oxide particles using the EPD technique, the direct current (DC) voltage was varied from 5 to 25V at a constant electrode distance of 30mm. By increasing the surface area of the electrode from the carbon plate (64.87cm2/g) to the carbon fiber (679.35cm2/g), a higher percentage of fine iron oxide particles deposition was obtained from the carbon fiber than the carbon plate electrode. Thus, the removal of fine iron oxide particles at 5V was 96%±1.42 and 58%±2.17 for carbon fiber and carbon plate, respectively. EDX analysis confirmed that fine iron oxide particles were deposited on the anode electrode. The results proved that EPD was effective at removing fine iron oxide particles in tap water.