Performance of Iron-Doped Titanium Dioxide-Loaded Activated Carbon Composite Synthesized by Simplified Sol–Gel Method for Ciprofloxacin Degradation under Ultraviolet Light

Abstract

Low-concentration antibiotic wastewater is difficult to treat rapidly using conventional photocatalysts. For this reason, this paper simplified the traditional sol–gel method to prepare Fe3+-TiO2/AC composites and characterized the properties of the composites using FT-IR, XRD, SEM, BET, and TEM. The results demonstrated that iron was uniformly dispersed on the surface of the composites, and the activated carbon (AC) was successfully loaded with iron-doped titanium dioxide. Afterward, ciprofloxacin (CIP) was used as the target degradant, and the effects of different activated carbon loadings, iron-doping, pH, initial concentrations, and UV light intensities on the removal of ciprofloxacin were investigated. The repetitive photocatalytic stability of the composites was studied, and the reaction mechanism was explored by using free radical quenching experiments. The results demonstrated that while iron doping reduced the rate at which photogenerated electrons and holes could combine, loading AC increased the usage efficiency of the composites’ adsorption and catalytic active sites. According to the parameter tests, the circumstances that led to the highest CIP degradation efficiency (94.59%) were as follows: 10 mg/L CIP, 0.5 g/L 0.2%Fe3+-TiO2/20%AC, and solution pH of 7 under 40 min of UV light irradiation. In addition, the Fe3+-TiO2/AC composite material has excellent cyclic stability, the degradation rate of CIP can still reach 87.73% at 60 min after four repeated degradation tests under the same conditions. The applicability of this method could be expanded to the treatment of various industrial organic pollutants in water.