Gold-decorated Fe3O4 nanoparticles for efficient photocatalytic degradation of ampicillin: a chemometrics investigation

Abstract

Wastewater treatment for lowering down the amount of antibiotic drugs in environment is essential for preventing their harmful effects in the ecosystem and for diminishing the growing bacterial resistance. Here, gold-decorated Fe3O4 nanoparticles (NPs) were used for efficient photocatalytic degradation of ampicillin, investigated by UV/Vis absorbance spectrometry. The absorbance data matrices recorded in the course of reactions were analyzed using multivariate curve resolution-alternative least squares as a power chemometrics method. The resolved concentration profiles were composed of three intermediate species and one final product. The concentration profiles were fitted to a first-order kinetics and for the photodegradation experiments run (1) in the absence of photocatalyst, (2) in the presence of Fe3O4 NPs and (3) in the presence of Au-decorated Fe3O4 NPs, the rate constants of 0.023, 0.041 and 0.055 min−1 were obtained, respectively. We found that ampicillin undergoes fast photocatalytic degradation reaction, so that, in the presence of Fe3O4 NPs and Au-decorated magnetic NPs, it was completely converted to its photodegradation product in a few min (35 and 25 min, respectively). The results obtained by chemometrics analysis of the absorbance data agreed with those obtained by capillary electrophoresis.