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Application of a micro-meso-structured reactor (NETmix) to promote photochemical UVC/H2O2 processes – oxidation of As(III) to As(V)

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Abstract

A micro-meso-structured reactor (NETmix) was used for the first time to promote photochemical UVC/H2O2 processes. The NETmix photoreactor consists of a network of chambers and channels, where the liquid flows, sealed with a quartz slab with high UVC transparency. Due to the small size of channels and chambers, the NETmix presents a uniform irradiance through the entire reactor depth, short molecular diffusion distances and large specific interfacial areas, maximizing the pollutant/oxidant contact. In this study, the NETmix photoreactor was evaluated for As(III) oxidation to As(V) using a photochemical UVC/H2O2 system. The effect of the UVC lamp power (4, 6 or 11 W), the number of UVC lamps (2 or 3 lamps) and the UVC lamp layout (parallel or perpendicular to the flow direction) was evaluated, in order to ensure uniform irradiation of the entire reaction mixture. The optimum H2O2 concentration for each light distribution system was also evaluated. At the best configuration, 3 lamps of 11 W positioned parallel to the flow direction, total As(III) oxidation ([As(III)]0 = 1.33 × 10−2 mM) was achieved in 15 min with an absorbed photon flux density of 1.9 × 10−1 einstein per m3 per s. Significant differences were highlighted between the photon flux actually received in the photoreactor and the radiant power emitted by the lamp. A kinetic model able to represent the As(III) oxidation employing UVC radiation and H2O2 in a micro-meso-structured reactor was presented. The photochemical space time yield (PSTY) values obtained for the micro-meso-structured reactor are higher than for conventional batch reactors, showing that the NETmix technology can be a good solution for application in photochemical processes.

Graphical abstract: Application of a micro-meso-structured reactor (NETmix) to promote photochemical UVC/H2O2 processes – oxidation of As(iii) to As(v)

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Publication details

The article was received on 08 Jan 2018, accepted on 11 Jul 2018 and first published on 13 Jul 2018


Article type: Paper
DOI: 10.1039/C8PP00006A
Citation: Photochem. Photobiol. Sci., 2018, Advance Article
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    Application of a micro-meso-structured reactor (NETmix) to promote photochemical UVC/H2O2 processes – oxidation of As(III) to As(V)

    B. A. Marinho, M. J. Martín de Vidales, L. P. Mazur, L. Paulista, R. O. Cristóvão, D. A. Mayer, J. M. Loureiro, R. A. R. Boaventura, M. M. Dias, J. C. B. Lopes and V. J. P. Vilar, Photochem. Photobiol. Sci., 2018, Advance Article , DOI: 10.1039/C8PP00006A

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