No abstract

In this work, a spiral microchannel reactor was used to study the photocatalytic degradation process of oxytetracycline (OTC) in a titanium dioxide (TiO2) slurry system. The influence of parameters such as residence time, TiO2 dosage, OTC concentration, light intensity, and concentration of added ions (NO3 –, SO4 2–, Ca2+, Fe3+) on OTC removal was systematically investigated, and the degradation stability of OTC in the microreactor was evaluated. The results show that under the best experimental conditions, the degradation rate of OTC can reach 99.33%, the initial stage apparent reaction rate constant is 7.7124 min–1, and the space–time yield is 142.79 m3 pollutants/(m3 reactor day). In addition, the results prove the high efficiency and stability of OTC degradation in the microreactor. OTC can be efficiently degraded under high TiO2 dosage, high initial OTC concentration, and low light intensity, which demonstrates the outstanding advantages of spiral microchannels for OTC degradation in slurry systems. This study has a guiding significance for the efficient photocatalytic degradation of tetracycline antibiotics in slurry systems.

The combination of a photocatalytic reaction and microfluidic technology is an increasingly popular method utilized to continuously degrade wastewater. In this work, a novel photocatalytic microreactor with TiO 2 loaded on the channel center insert was designed and the photocatalytic degradation process of oxytetracycline (OTC) was investigated. Parameters such as TiO 2 loading, OTC initial concentration, light intensity, and ion (NO 3 − and SO 4 2−) concentrations were systematically investigated. The results show that the degradation efficiency of OTC was 56% under the optimal experimental conditions. Compared with the conventional miniaturized photocatalytic reactors, the reaction rate constant and space−time degradation efficiency of the plug-in three-dimensional photocatalytic microreactor proposed in this work were 1−2 orders of magnitude higher. In addition, dimensionless correlation was obtained to predict the degradation efficiency. This work provides a promising microfluidic technology for the process intensification of photocatalytic reaction and wastewater treatment.