Removal of Tetracycline from water by Electro-Fenton technique based on graphite felt electrode

To overcome the limitations of the traditional homogeneous Electro-Fenton technique—including a narrow working pH range, generation of iron sludge, and the requirement for aeration—a novel GF@CB@FeOCl composite material was synthesized by loading carbon black (CB) and ferric oxychloride (FeOCl) onto graphite felt (GF) using an impregnation-calcination method. This composite served as the cathode in a heterogeneous Electro-Fenton system aimed at removing tetracycline (TC) from aqueous solutions. Scanning electron microscopy (SEM), X-ray diffraction (XRD), linear scanning voltammetry (LSV) and cyclic voltammetry (CV) were used to characterize the morphology as well as electrochemical properties of the materials, and the results showed that the loading of CB and FeOCl enhanced the electrocatalytic activity of two-electron oxygen reduction reaction (ORR). Experimental results demonstrated that under the conditions of an applied current density of 18 mA·cm−2, pH=6, initial TC concentration of 40 mg·L−1, and no aeration, GF@CB @FeOCl cathode can degrade 92.4% of TC in the Electro-Fenton system. Free radical quenching experiments further revealed that while hydroxyl radicals (·OH) contributed auxiliary effects, singlet oxygen (1O2) played a predominant role in the degradation of TC within this heterogeneous Electro-Fenton system.