Fatores intervenientes e cinética da adsorção de diclofenaco sódico em carvão ativado pulverizado

Abstract

The removal of drugs from sources is one of the main challenges of water treatment plants, which are not able to completely remove these emerging contaminants. Among these drugs, the classes of anti-inflammatory drugs have been commonly found in water sources, the sodium diclofenac belonging to this class are one of the most detected anti-inflammatory drugs in aquatic matrices, around 940 tons / year are consumed in the world. The fact that these micropollutants are bioaccumulative can cause damage to both humans and the environment, to remove them it is necessary to use efficient alternative processes and techniques, such as adsorption. In this context, the objective of this work is to study the kinetics of the adsorption of sodium diclofenac in synthetic water using pulverized activated carbon, through mathematical models and to analyze the behavior of the factors that interfere in the adsorptive process such as pH, contact time, concentration of sodium diclofenac and mass of the pulverized activated carbon. The determination of kinetic parameters was obtained using mathematical models of pseudo-first order, pseudo-second order and intraparticle diffusion. Several factors affect the adsorptive process, they are the influence of pH, adsorbent mass, contact time and adsorvate concentration. The results showed that the powdered activated carbon had maximum adsorptive capacity at the concentration of the adsorbate of 450 mg.l ^ (- 1), a contact time of 35 minutes, pH 5 and masses of 0.2 g ^ (- 1) . There was a decrease in the adsorption capacity with an increase in the adsorbent mass and an increase in pH. The coefficient of determination (R²) pointed to the pseudo-second order model as the one that best suits the generated kinetics. Therefore, the adsorption on pulverized activated carbon indicates that chemical type adsorption occurred, in the study of intraparticle diffusion the external diffusion proved to be determinant in the speed and mass transfer of the adsorption process.