Síntese e caracterização de adsorventes para remoção de diclofenaco de sódio em solução aquosa

Abstract

Several environmental problems are caused by the growing population demand associated with meeting basic needs. In general, the traditional productive activities have corroborated this problematic. Amid the dispersion of so many pollutants in the environment, a category of compounds gets special attention and are called emerging pollutants, PE. Such compounds are not susceptible to conventional treatment methods, since they may present low biodegradability, bioaccumulation, and recalcitrance. Among them we can cite diclofenac sodium, which is a drug widely used on a global scale in the reduction of inflammation and nociceptive pain, which have been detected in various analyses of aquatic environments causing numerous environmental disorders and health risks. Therefore, the adsorptive process has gained prominence due to its high efficiency in the removal of pollutants harmful to the environment, since the conventional treatments have not been sufficient to eliminate these contaminants. The use of magnetic adsorbents allows an easy separation of the adsorbent and the adsorbate, reducing the costs with the use of centrifuge, besides being efficient in several treatments of persistent pollutants. In this context, we aimed to evaluate Simonkolleite (Zn5(OH)8Cl2.H2O) as an adsorbent material because it is a layered single metal hydroxide (LSHs), due to its unique properties, stability, high surface area and enhanced capacity for charge transfer associated with Manganese Ferrite for the production of a magnetic composite. Through the characterization techniques employed, such as Scanning Electron Microscopy (SEM), Transmission Electron Microscopy - Energy Dispersive (MET-EDS), X-ray Diffractometry (XRD), Zero Charge pH (PCZ), the chemical and morphological characteristics of the adsorbent were analyzed. The adsorption kinetics can evaluate the interference of the variations of adsorbent mass and adsorbate concentration and influence of pH. In the affinity tests it was found that in natural pH, the removal was greater than 89% against 0.1g of Diclofenac sodium at 50 ppm. In the test performed in real water, according to the analyses in water directly from the tap, the percentage of reduction was approximately 75% removal of diclofenac sodium and in mineral water a percentage greater than 90% and in the kinetic study it was observed that in 720 min the adsorptive capacity was reached in approximately 85% for SK/C 0.5g and 89% for SK/C 1.0g. Given the above and the results obtained, this work aimed to optimize the adsorptive properties of SK, associating it with the magnetic material manganese ferrite (MnFe2O4), facilitating the separation process and minimizing the losses in the operation, and confirm the use of this material as an alternative in processes of pollutant removal in aqueous phase.