Fabrication of a novel MoB/BiOCl photocatalyst for losartan and Escherichia coli removal

Abstract

In this work, various MoB/BiOCl (0.5–2.0% wt. MoB) photocatalysts were fabricated, characterized using X-ray diffraction, diffuse reflectance spectroscopy, scanning electron microscopy/energy dispersive spectrometer (SEM/EDS) and chronoamperometry, and their photocatalytic activity was assessed for the degradation of the persistent contaminant losartan (LOS) in aqueous solutions under simulated solar irradiation. The 0.5MoB/BiOCl catalyst exhibited the highest efficiency, achieving complete degradation of 500 μg/L LOS in less than 10 min. Interestingly, the 0.5MoB/BiOCl sample also showed remarkable efficiency under visible irradiation (>420 nm), achieving 80% removal in 30 min. The decomposition kinetics followed pseudo-first-order, while the efficiency significantly decreased under alkaline conditions. According to the scavenging experiments, both h+, O2•− and 1O2 participate in the decomposition of LOS, while the role of •OH is minor. A slight increase in degradation was observed in the presence of NaCl, and a small retardation occurred in the presence of humic acid. On the contrary, the presence of bicarbonates significantly delayed the reaction. Although significant inhibition was observed for secondary effluent, the system was capable of completely degrading LOS in less than 15 min when pH was adjusted to 3.8. The process demonstrated promising results for the simultaneous removal of E. coli and micropollutants, achieving complete LOS removal in 15 min and 99.999% inactivation of E. coli after 180 min.