Evaluation of Kinetic Pseudo-Order in the Photocatalytic Degradation of Ofloxacin

Catalysts

Giora Rytwo¹  Arye Lev Zelkind¹ 

[1] Environmental Sciences & Water Sciences Departments, Tel Hai College, Upper Galilee 1220800, Israel;

关键词: ofloxacin;    rate-law;    pseudo-order;    half-life time;    homogeneous catalysis;    heterogeneous catalysis;   

DOI  :  10.3390/catal12010024

来源: DOAJ

【 摘 要 】

Ofloxacin is a highly efficient and widely used antibiotic drug. It is classified as a refractory pollutant due to its poor biodegradability. Consequently, it is commonly found in water sources, requiring efficient methods for its removal. Advanced oxidation processes (AOPs) offer efficient alternatives since those yield complete degradation not achieved in adsorption or membrane processes. Previous studies suggest ofloxacin degradation follows a pseudo-first or -second order processes, whereas for full removal of refractory pollutants—lower pseudo-orders are required. Monitoring the actual “pseudo-order” degradation kinetics of ofloxacin is needed to evaluate any proposed AOP process. This study presents a simple procedure to evaluate pseudo-orders of AOPs. Photolysis of 20 μM ofloxacin solutions follow pseudo-zero order kinetics, with half-life times (t_1/2) of approx. 60 min. TiO₂ heterogenous catalysts have been shown to have no influence at low concentrations (0.2 mg L⁻¹), but a significant reduction of half-life time (t_1/2 = 20 min) and increase in pseudo-order (0.8) is measured at 2.0 mg L⁻¹. Similar results are obtained with homogenous catalysis by 2.0 mg L⁻¹ H₂O₂. The combination of H₂O₂ and TiO₂ catalysts shows additional reduction in half-time life with increase in the pseudo-order to 1.2. The conclusions are (1) heterogenous and homogenous photocatalysis can effectively degrade ofloxacin, (2) combined photocatalysis yields higher pseudo-order, being less prone to achieve full removal, and (3) analysis of specific pseudo-orders in AOPs of refractory pollutants helps to further elucidate the efficiency of the processes.

【 授权许可】

Unknown