新型多级串联槽式光微反应器及其在光催化反应中的应用

Performing photocatalysis in continuous microflow offers great advantages including uniform light distribution, high mass transfer rate and improved safety. Nevertheless, the solids that involved in photocatalytic reactions will possibly block the microreactor. A new photo-microreactor, multistage consecutive stirred-tank microreactor, is developed in this paper to manipulate solids occurring in photocatalytic reactions. The microreactor has 16 miniaturized stirred-tanks connected in series, each of which possesses a volume of 390 µL and contains a micro stirred-bar. By applying a magnetic stirrer below the reactor, good mixing was achieved in each unit stirred-tank. The residence time distribution curves for both liquid single-phase flow and liquid-solid two-phase flow almost overlapped and exhibited satisfying symmetry, indicating solid particles were able to be suspended homogeneously in the flow in the new photo-microreactor. The degradation of methylene blue photo-catalyzed by TiO₂ particles (about 400 nm) was conducted in a multistage consecutive stirred-tank microreactor made of glass. No clogging was observed during long time operation in the photo-microreactor (about 10 h). Moreover, the photocatalytic reaction rate was accelerated by about 24 times as compared to the batch reactor and the reaction rate was not slowed down as the content of TiO₂ particles was decreased in the photo-microreactor. The multistage consecutive stirred-tank reactor developed in this work can be applied to photocatalytic reactions involving or not involving solids, and help to push forward the development of continuous microflow photocatalysis.