Facile synthesis of iron(II) doped carbonaceous aerogel as a three-dimensional cathode and its excellent performance in electro-Fenton degradation of ceftazidime from water solution

Abstract

• Synthesis of iron(II) doped carbonaceous aerogel (FCA) as a three-dimensional cathode electrode for electro-Fenton (EF) system. • Degradation of ceftazidime using FCA cathode in EF process. • Optimization of the operational condition by response surface methodology. • Identification of the produced intermediates through the ceftazidime degradation. • Developing a safe, environmentally friendly, and cost-effective method by using FCA and EF process. In the present study, the electro-Fenton (EF) process has been used to remove ceftazidime (CAZ) from an aqueous solution. In the first part of this study, the iron(II) doped carbonaceous aerogel (denote as FCA) as a three-dimensional cathode was synthesized as a cathode electrode. For this purpose, resorcinol–formaldehyde polymers containing iron(II) salt were prepared by sol–gel method and after drying by ambient drying method, the resulting polymer was finally carbonized in a furnace with inert nitrogen medium at 800 °C and the resulting composite properties examined by Field Emission Scanning Electron Microscopy, Energy Dispersive X-ray, Brunaur-Emmett-Teller, X-ray Diffraction, Fourier Transform Infrared Spectroscopy, and cyclic voltammetry analyses. In the last part of this study, the prepared carbonaceous aerogel was employed as a cathode electrode in the EF system to remove CAZ from an aqueous medium. The influence of key factors such as applied current (mA), initial pH of the solution, initial CAZ concentration (mg/L), and process time (min) on the CAZ removal efficiency (RE (%)) under the EF process was assessed. The mineralization current efficiency (MCE) was found as 60.66% in 200 min. Response surface methodology (RSM) was used to optimize the process. The results showed that the optimal values for the variables of applied current intensity, pH, initial CAZ concentration, and process time were 400 mA, 4, 40 mg/L, and 110 min, respectively. The intermediates of CAZ removal were identified by gas chromatography-mass spectrometry analysis. Moreover, the possible removal mechanism of CAZ was proposed. The reusability and stability of the FCA cathode was assessed and revealed an approximately 4% decline in CAZ removal efficiency after eight consecutive cycles. The amount of organic carbon degraded by this process was investigated by chemical oxygen demand test and it was 99% after 200 min of reaction time.