Coupled ozonation with nanofiltration and catalytic nanofiltration for the removal of micropollutants from secondary effluent
摘要
Emerging contaminants have become a global concern in recent years. Ozonation is an effective treatment for their degradation. However, it may generate toxic by-products under certain conditions. Catalytic ozonation is an option for improved contaminant oxidation, which can be enhanced by incorporating a filtering membrane, adding the advantages of retaining molecules, ions, and colloids. Recent studies have demonstrated the catalytic potential of a nanofiltration membrane functionalized with a thin layer of mesoporous maghemite (γ-Fe2O3). However, they have not tested its efficiency in real environmental matrices. In this study, the efficiency of a ceramic membrane functionalized with maghemite was tested for the removal of seven contaminants (carbamazepine, acetaminophen, sulfamethoxazole, caffeine, sodium diclofenac, diuron, and ketoprofen). The performance of ozonation and nanofiltration and the combination of both, with and without the functionalized γ-Fe2O3 layer, were compared for ultrapure water and secondary effluent with contaminants at a concentration of 0.5 mgL−1. The coupling of ozonation and functionalized membrane had around 20% higher removal for the most resistant compounds, using 70% less ozone than the configuration that used a commercial membrane. Although the initial samples did not show toxicity, there was an emergence and growth of toxicity, possibly due to the formation of toxic by-products.