Control of Membrane Fouling in Organics Filtration Using Ce-Doped Zirconia and Visible Light

• Published in: Nanomaterials (Basel, Switzerland) Vol. 9; no. 4; p. 534
• Main Authors: Bortot Coelho, Fabrício Eduardo, Gionco, Chiara, Paganini, Maria Cristina, Calza, Paola, Magnacca, Giuliana
• Format: Journal Article
• Language: English
• Published: Switzerland MDPI 03-04-2019; MDPI AG
• Subjects: cerium; fouling; humic acid; LED; membrane filtration; photocatalysts; visible light; zirconium dioxide; zirconium dioxide; membrane filtration; cerium; photocatalysts; humic acid; LED; fouling; visible light
• ISSN: 2079-4991; 2079-4991
• DOI: 10.3390/nano9040534

Membrane fouling has been a major issue in the development of more efficient water treatment processes. Specifically in surface waters filtration, organic matter, such as humic-like substances, can cause irreversible fouling. Therefore, this study evaluates the activity of a photocatalytic layer composed of Ce-doped zirconia nanoparticles in improving the fouling resistance during filtration of an aqueous solution of humic acid (HA). These nanoparticles were prepared by hydrothermal and sol-gel processes and then characterized. Before the filtration experiments, the photodegradation of HA catalyzed by Ce-doped zirconia nanoparticles in dispersion was studied. It was observed that the sol-gel prepared Ce-ZrO₂ exhibited higher HA removal in practically neutral pH, achieving 93% efficiency in 180 min of adsorption in the dark followed by 180 min under visible-light irradiation using light-emitting diodes (LEDs). Changes in spectral properties and in total organic carbon confirmed HA degradation and contributed to the proposal of a mechanism for HA photodegradation. Finally, in HA filtration tests, Ce-ZrO₂ photocatalytic membranes were able to recover the flux in a fouled membrane using visible-light by degrading HA. The present findings point to the further development of anti-fouling membranes, in which solar light can be used to degrade fouling compounds and possibly contaminants of emerging concern, which will have important environmental implications.