Contamination from emerging pollutants such as antibiotics, organic dyes, pesticides, and herbicides is an ongoing issue in much of the world. Low cost and fast-acting methods for removal and degradation of emerging pollutants is an ongoing area of research and carbon nanomaterials and their composites have shown promise for the removal of many pollutants. Radical oxidation using peroxymonosulfate (PMS) is a potent method for removing pollutants and acts by forming the sulfate and hydroxy radicals, which degrade organic materials. PMS activation is used to enhance the formation of radical species, resulting in faster and more complete degradation; activated carbon and cobalt ferrite have both been found to be effective PMS activators. In this study, we report the development of a new magnetic carbon/CoFe₂O₄ composite for use in the efficient removal of emerging pollutants including the antibiotics trimethoprim and sulfamethoxazole. The simple acid dehydration of glycerol was first used to produce carbon nanoparticles which were then co-precipitated with adsorbed Co²⁺ and Fe³⁺ under basic conditions to produce a magnetic carbon nanocomposite. Composite samples were analyzed by several techniques including scanning electron microscopy (SEM), infrared spectroscopy, Raman spectroscopy, X-ray powder diffraction (XRD), and thermal gravimetric analysis (TGA). SEM analysis indicated micron-sized aggregates composed of smaller nanoparticles. This material was found to be an effective adsorbent for both trimethoprim and sulfamethoxazole and the adsorption isotherms were determined using both the Langmuir and Freundlich models. The composite was tested to activate PMS for the oxidative degradation of both antibiotics and the dependance of pH, catalyst amount and PMS concentration was evaluated. Degradation products resulting from radical oxidation were determined by liquid chromatography – mass spectrometry (LC-MS). The kinetics for both adsorption and catalytic degradation were fit to standard kinetic models. In all studies, the antibiotic concentrations were determined using UV-vis spectroscopy and high-performance liquid chromatography (HPLC).

Francis Webster

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