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 purifi cation by membrane fi ltration. The authors focused on membranes containing zirconium compounds, mainly ZrO2, used in pressure driven membrane processes. The effi ciency of the oil removal processes for various membranes (ceramic and composite), usually above 95% for the oil contaminated sewage, was compared. The infl uence of zirconium compounds on the properties of ceramic membranes was also discussed. The methods of producing ceramic membranes have been briefl y 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 fi ltration effi ciency by improvement of hydrophilic properties of the membrane. Moreover, the addition of ZrO2 results in increased chemical and hydrothermal membrane stability. The effi ciency of the fi ltration processes using the presented membranes was high, suggesting that membrane fi ltration processes are highly effective purifi cation methods.