Towards the Configuration of a Photoelectrocatalytic Reactor: Part 1—Determination of Photoelectrode Geometry and Optical Thickness by a Numerical Approach

• Published in: Nanomaterials (Basel, Switzerland) Vol. 12; no. 14; p. 2385
• Main Authors: Borrás-Jiménez, Daniel, Silva-López, Wilber, Nieto-Londoño, César
• Format: Journal Article
• Language: English
• Published: Basel MDPI AG 12.07.2022; MDPI
• Subjects: Computational fluid dynamics; Computer applications; Configurations; Dyes; Electrodes; Finite element method; Flow rates; Flow velocity; Fluid dynamics; Hydrodynamics; Inlet flow; Kinetics; Mass transfer; Mathematical models; Mineralization; Optical thickness; Oxidation; Photocatalysis; photoelectrocatalytic reactor design; Radiant flux density; Radiation; radiation absorption; Reactors; Semiconductors; Spectroscopy; Tertiary wastewater treatment; tertiary wastewater treatments; Textile industry; Textiles; TiO2 nanotube photocatalyst; Titanium; Titanium dioxide; Ultraviolet spectroscopy; Wastewater treatment; Water treatment
• ISSN: 2079-4991; 2079-4991
• DOI: 10.3390/nano12142385

Photoelectrocatalysis has been highlighted as a tertiary wastewater treatment in the textile industry due to its high dye mineralisation capacity. However, design improvements are necessary to overcome photo-reactors limitations. The present work proposes a preliminary configuration of a photoelectrocatalytic reactor to degrade Reactive Red 239 (RR239) textile dye, using computational fluid dynamics (CFD) to analyse the mass transfer rate, radiation intensity loss (RIL), and its effect on kinetics degradation, over a photoelectrode based on a TiO2 nanotube. A study to increase the space-time yield (STY) was carried out through mass transfer rate and kinetic analysis, varying the optical thickness (δ) between the radiation entrance and the photocatalytic surface, photoelectrode geometry, inlet flow rate, and the surface radiation intensity. The RIL was determined using a 1D Beer–Lambert-based model, and an extinction coefficient experimentally determined by UV-Vis spectroscopy. The results show that in RR239 solutions below concentrations of 6 mg/L, a woven mesh photoelectrode and an optimal optical thickness δ of 1 cm is enough to keep the RIL below 15% and maximise the mass transfer and the STY in around 110 g/m3-day.