Oily wastewater treatment using a zirconia ceramic membrane - a literature review

The goal of this article was to review the literature which discusses the problem of oily wastewater purification by membrane filtration. The authors focused on membranes containing zirconium compounds, mainly ZrO2, used in pressure driven membrane processes. The efficiency of the oil removal processes for various membranes (ceramic and composite), usually above 95% for the oil contaminated sewage, was compared. The influence of zirconium compounds on the properties of ceramic membranes was also discussed. The methods of producing ceramic membranes have been briefly characterized as well. Ceramic membranes are usually obtained by sol-gel technique but also by isostatic compression, reverse phase technique, or hydrothermal crystallization. Ceramic membranes are formed with zirconia, which cause an increase in filtration efficiency by improvement of hydrophilic properties of the membrane. Moreover, the addition of ZrO2 results in increased chemical and hydrothermal membrane stability. The efficiency of the filtration processes using the presented membranes was high, suggesting that membrane filtration processes are highly effective purification methods.