Fe3O4-CeO2 loaded on modified activated carbon as efficient heterogeneous catalyst

Abstract

A novel Fe3O4-CeO2/activated carbon (AC) composite was synthesized by an immersion-precipitation process. The Fe3O4-CeO2/AC composite was characterized by BET surface area measurement, Fourier Transform infrared (FTIR), X-ray diffraction (XRD), scanning electron microscope (SEM), high-resolution transmission electron microscopy (HRTEM), X-ray photoelectron spectroscopic (XPS), and vibrating sample magnetometer (VSM). Its catalytic activity was evaluated by azo organic dye Orange G (OG) oxidation in heterogeneous Fenton system. Due to excellent performance of AC in adsorption and conductivity, the catalyst exhibited enhanced catalytic activity compared with AC-Fe3O4, CeO2-AC, Fe3O4-CeO2 and AC. Some parameters, such as initial concentration of OG, pH, catalyst loading, H2O2 dosage, were studied. At pH 2.5, H2O2 18 mM, OG 50 mg L−1, Fe3O4-CeO2/AC 0.4 g L−1 and 35 °C, the OG removal rate and the total organic carbon (TOC) removal reached 98.8% and 56.3% within 60 min. The stability and reusability of the Fe3O4-CeO2/AC were also tested. Besides a possible OG degradation pathway was proposed and eight intermediates were determined.