关键词: 微反应器, 微通道, 光催化, 降解, 稳定性

Abstract:

Photofluidics can combine photocatalytic reaction with microfluidic technology, greatly improve light utilization and reaction rate, and achieve efficient enhancement of photocatalytic water treatment. The design and optimization of microreactor structure is one of the research focuses. In this work, we first use computational fluid dynamics simulation to optimize the number of channels, and design a 5-level tree-shaped microfluidic planar reactor. The planar microreactor has a 12 mm × 12 mm reaction chamber enclosed by TiO₂ coated glass slide as bottom substrate and polydimethylsiloxane board as the top cover, and a microstructured UV-cured NOA-81 layer is as the sealant and flow input/output. Subsequently, photocatalytic performance is investigated by tuning the microreactor overall height. This is evidenced by our findings in this paper that the degradation and continuous operation performance of the 50 μm microreactor is better than that of 100 μm microreactor. In the photocatalysis experiment, the methylene blue is used as a simulated wastewater to study the performance of planar microreactors and tank reactors, including reaction kinetics, microreactor pollution problems and continuous operation performance. It is shown that when the microreactors operate at different flow rates, the methylene blue can achieve continuous and high-efficiency photocatalytic degradation, and the degradation rate is much higher than the tank reactor. When the flow rate is 55 μl/min, the degradation rate of 5×10^-5 mol/L methylene blue can reach 95%, which means that the planar microreactors can maintain good continuous operation performance and reusability. Planar micreactor inherits the merits of microfluidics, such as huge specific surface area, efficient and stable reaction, and easy control, and offers an efficient and feasible scheme for water treatment.

Key words: microreactor, microchannels, photocatalysis, degradation, stability