Tube-in-tube membrane reactor for heterogeneous TiO2 photocatalysis with radial addition of H2O2

• Published in: Chemical engineering journal (Lausanne, Switzerland : 1996) Vol. 395; p. 124998
• Main Authors: Castellanos, Reynel M., Paulo Bassin, João, Dezotti, Márcia, Boaventura, Rui A.R., Vilar, Vítor J.P.
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01.09.2020
• Subjects: H2O2 radial permeation; Heterogeneous H2O2/TiO2 Photocatalysis; Process Intensification; Tube-in-Tube Membrane Reactor; UVC/H2O2/TiO2; Process Intensification; Tube-in-Tube Membrane Reactor; H2O2 radial permeation; Heterogeneous H2O2/TiO2 Photocatalysis; UVC/H2O2/TiO2
• ISSN: 1385-8947; 1873-3212
• DOI: 10.1016/j.cej.2020.124998

[Display omitted] •Tube-in-tube membrane reactor for heterogeneous TiO2 photocatalysis.•Ceramic membrane as oxidant dosing system and as catalyst support.•Radial addition of H2O2 through the membrane porous into the active catalyst sites.•Radial addition of H2O2 through the membrane porous into the annular reaction zone.•Integration of membrane, photocatalysis and photochemical systems within a single unit. A tube-in-tube membrane reactor, operating with radial addition of H2O2, was employed for the intensification of heterogeneous H2O2/TiO2 photocatalytic processes. Polluted water is continuously fed into the annular space between the shell side of an ultrafiltration membrane and an outer quartz tube. The membrane shell-side surface is coated with a thin-film of TiO2-P25. The oxidant (H2O2) is internally fed to the membrane, which permeates through the membrane pores, being dosed and uniformly delivered to the active catalyst sites. Radiation is externally supplied via four UVC or UVA lamps. The helical movement of water around the membrane shell side improves the radial dispersion of the oxidant, promoting efficiently its UVC photolytic cleavage into OH within the annular reaction zone. Tests were performed using pure water and a secondary effluent from a wastewater treatment plant, both spiked with 100 µg L−1 of 17β-estradiol (E2) and 17α-ethinylestradiol (EE2). The efficiency of the photochemical (UVC and UVC/H2O2) processes was first assessed as a function of H2O2 dose. Then, E2 and EE2 photocatalytic oxidation efficiency by UV/TiO2 and UV/H2O2/TiO2 was evaluated according to the amount of TiO2-P25 deposited on the outer surface of the membrane, H2O2 dose, H2O2 addition mode, light source and aqueous solution matrix. The UVC/H2O2/TiO2 system with radial H2O2 addition showed the highest oxidation ability, resulting in E2 and EE2 removal percentages of 51/32% and 48/30%, respectively, for the synthetic/real matrices, using a low UVC fluence (45 mJ cm−2).