Multivariate-Parameter Optimization for Photodegradation of Tetracycline by Fe(III)-Citrate Complexes at Near-Neutral pH

Abstract

Tetracycline antibiotics have been extensively used in pharmaceutical and veterinary therapies, and they are widely present in natural waters. Although Fe(III)-citrate complexes are known to be highly photoreactive, the optimal conditions for treatment of pollutants at near-neutral pH are not fully understood. In this study, the photochemical removal of tetracycline (TC) in the Fe(III)-citrate solution under simulated sunlight was investigated. A central composite design was employed to explore the effects of the initial concentrations of TC (0–90 μM), Fe(III) (0–40 μM), citrate (0–400 μM), and pH (5.0–9.0) on the photodegradation of TC in aqueous solution. Five levels of each factor were included in the design. The photodegradation of TC in the Fe(III)-citrate solution was observed to follow pseudo-first-order kinetics. According to the multivariate effects analysis, the optimal photodegradation condition was achieved at pH 6.9 and