Electrophoretic Deposition of Titanium Dioxide Thin Films for Photocatalytic Water Purification Systems

Francis Nyongesa

doi:10.11648/j.am.20170604.11

Abstract

In this study, electrophoretic deposition (EPD) technique was used to deposit titanium dioxide (TiO2) thin films on conducting glass substrates for application in water purification from organic contaminants. Phenol was used as a model pollutant. The EPD suspension related parameters and deposition conditions were first optimized for good quality film deposits. The suspension stability and deposition conditions that result in good adherence of TiO2 particles to the substrate with homogeneous film coatings, is ethanol with a pH of 3.0, a TiO2 solid loading of 4.0 wt%, a 0.2 wt% iodine concentration in the solvent and a deposition voltage of 20.0V in a time of 210.0s. The photocatalytic activity of TiO2 thin films decreases exponentially with the ultraviolet light (UV) illumination time and it is also dependent on film thickness, sintering temperature and the intensity of the UV light. Highest rate of photocatalytic activity is observed at an optimal film thickness of 95.0 ± 2.0µm sintered at 300.0°C. The implications of these results are discussed for design of inexpensive waste water purification systems for light industries before discharge into the ecosystem.

Highlights

In recent years, industrial and agricultural activities have caused significant increase of organic contaminants such as phenol in natural waterways, presenting a toxicological hazard to plants, marine and animal lives
Optimization of electrophoretic deposition (EPD) Suspension Related Parameters Glass substrates coated with a conducting layer of fluorine doped tin oxide (FTO) were used as the electrodes in EPD cell
Higher iodine concentrations > 0.3 wt% resulted in undisolved iodine in the solvent with most of the iodine settling at the bottom of the Notably, higher voltages (> 20.0 V) cause high currents resulting in rapid deposit formation with growth of TiO2 clusters as shown in the scanning electron microscope (SEM) micrograph of Figure 3(a)

Summary

Introduction

Industrial and agricultural activities have caused significant increase of organic contaminants such as phenol in natural waterways, presenting a toxicological hazard to plants, marine and animal lives. In the anatase form, exhibits higher photocatalytic activity under ultraviolet (UV) irradiation and has a strong oxidizing power, to decompose organic contaminants into environmentally harmless compounds such as water and carbon dioxide [2,3,4]. Complete inactivation of microorganisms such as bacteria, viruses and protozoa can be achieved [5]. This method eliminates the foul odor and improves water turbidity [6]

Methods

Results

Conclusion