Photocatalytic degradation of ciprofloxacin·HCl using Aeroxide® P-25 TiO2 photocatalyst: Comparative evaluation of solar and artificial radiation

Abstract

The photocatalytic degradation of ciprofloxacin (CFX) has been investigated using Aeroxide^® P-25 TiO₂ photocatalyst in the presence of solar as well as artificial radiation. The effects of different operating parameters like initial concentration of CFX, catalyst loading, pH of solution and effect of co-existing ions on photocatalytic degradation of CFX have been investigated with a view to establish the optimum operating conditions. It is observed that as the initial concentration of CFX increases, the rate of photocatalytic degradation decreases. Optimum catalyst loading is observed at 1 g L^-1 for CFX concentration of 100 mg L^-1. Over the pH range 3-11, maximum degradation rate occurs at pH 9. The mechanism and intermediates formed during the photocatalytic degradation of CFX are discussed based on UPLC-MS/MS analysis. From kinetic studies, it is found that the photocatalytic degradation obeys pseudo-first order kinetics. The degradation rate constant using solar radiation is about 1.7 times higher than that under artificial radiation.