Stability of polymeric membranes to UV exposure before and after coating with TiO2 nanoparticles

Acknowledgments: Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP, Nº 2019/ 04319-9), Associate Laboratory for Green Chemistry—LAQV, Unidade de Tecnologia de Células Animais do iBET e à Paula Alves, iNOVA4Health—UIDB/Multi/04462/2020, a program financially supported by Fundação para a Ciência e Tecnologia/Ministério da Educação e Ciência, through national funds is acknowledged. Funding from INTERFACE Program, through the Innovation, Technology and Circular Economy Fund (FITEC), is also gratefully acknowledged. Funding Information: Funding: Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP, Nº 2019/04319-9), Associate Laboratory for Green Chemistry—LAQV (through projects UIDB/50006/2020 and UIDP/ 50006/2020), Fundação para a Ciência e a Tecnologia through the project PTDC/EAM-AMB/30989/2017, Unidade de Tecnologia de Células Animais do iBET, iNOVA4Health—UIDB/Multi/04462/2020. Funding Information: Funda??o de Amparo ? Pesquisa do Estado de S?o Paulo (FAPESP, N? 2019/04319-9), Associate Laboratory for Green Chemistry?LAQV (through projects UIDB/50006/2020 and UIDP/ 50006/2020), Funda??o para a Ci?ncia e a Tecnologia through the project PTDC/EAM-AMB/30989/2017, Unidade de Tecnologia de C?lulas Animais do iBET, iNOVA4Health?UIDB/Multi/04462/2020. Publisher Copyright: © 2021 by the authors. Licensee MDPI, Basel, Switzerland.The combination of photocatalysis and membrane filtration in a single reactor has been proposed, since the photocatalytic treatment may degrade the pollutants retained by the membrane and reduce fouling. However, polymeric membranes can be susceptible to degradation by UV radiation and free radicals. In the present study, five commercial polymeric membranes were exposed to ultraviolet (UV) radiation before and after applying a sol–gel coating with TiO2 nanoparticles. Membrane stability was characterized by changes in hydrophilicity as well as analysis of soluble substances and nanoparticles detached into the aqueous medium, and by Fourier transform infrared spectroscopy (FTIR), scanning electron microscope (SEM), and energy-dispersive X-ray spectrometry (EDS) for structural, morphological, and elemental distribution analysis, respectively. The TiO2 coating conferred photocatalytic properties to the membranes and protected them during 6 h of UV radiation exposures, reducing or eliminating chemical and morphological changes, and in some cases, improving their mechanical resistance. A selected commercial nanofiltration membrane was coated with TiO2 and used in a hybrid reactor with a low-pressure UV lamp, promoting photocatalysis coupled with cross-flow filtration in order to remove 17α-ethinylestradiol spiked into an aqueous matrix, achieving an efficiency close to 100% after 180 min of combined filtration and photocatalysis, and almost 80% after 90 min.publishersversionpublishe