Mechanistic Study of Tetracycline Removal and Degradation in Water Using nCo@nZVI Composite Materials within a Fenton System

Abstract

In response to the increasingly severe antibiotic pollution in water bodies, this study developed a new type of magnetic nano cobalt @ nano zero valent iron that is easy to prepare and inexpensive( nCo@nZVI ) Composite materials. The magnetic sheet-like nZVI was prepared using a rheological phase inversion method, followed by the synthesis of nCo@nZVI through liquid-phase reduction. The material's physical and chemical properties, along with its structure, were meticulously characterized through the utilization of various techniques, including BET, FESEM, XRD, HRTEM, EDS, XPS, and FTIR. Batch experiments were conducted to evaluate the adsorption-degradation mechanism of TC by the material in the Fenton system, and to investigate the effects of factors such as temperature, pH value, and initial TC ion concentration on removal efficiency. The results indicated that under conditions of pH 7 and temperature of 20°C, the nCo@nZVI material could reduce the TC concentration in wastewater from an initial 20mg/L to trace levels within 120 minutes. Adsorption kinetics and isotherm analysis revealed that the adsorption process of TC by nCo@nZVI followed a pseudo-second-order kinetic model and Langmuir isotherm model, indicating predominantly chemical adsorption with an adsorption capacity of 25.33mg/g. Thermodynamic studies have shown that the adsorption of TC by nCo@nZVI occurs spontaneously. Furthermore, the nCo@nZVI composite material is environmentally friendly and cost-effective. It has the advantages of being recyclable and reusable under external magnetic fields, showing great potential in the remediation of antibiotic contaminated sites, and this method has guiding significance for the recovery of cobalt containing wastewater.