Utilização de sílica mesoporosa magnética modificada para adsorção do fármaco tetraciclina

Abstract

Antibiotics belong to the class of drugs used on a large scale for the treatment and prevention of diseases. The antibiotic tetracycline (TC) is widely used as a bactericide and in animal therapy and when improperly discarded can lead to irreversible and long-term changes in the genome of microorganisms, making them resistant to its presence. Thus, in this work the use of magnetic particles covered by mesoporous silica, modified by CTAB (cetyltrimethyl ammonium bromide) for the removal of the TC drug in aqueous solutions was studied. For this, the variables pH, adsorbent mass and TC contaminant concentration were optimized by means of an experimental design and its effect on the adsorption process was evaluated for subsequent adsorption tests, evaluating the kinetics, isotherms, nature of the interaction and reuse of the adsorbent. The optimization indicated that the optimal experimental conditions for the process were mass equal to 0.029 g of magnetic particle, pH equal to 4.4 and concentration of contaminant TC of 16 ppm, predicting a maximum removal percentage of 71.99% .The contact time to reach the equilibrium of the process was 960 minutes, resulting in an efficiency of 83.23% removing 1.78 mg g -1. The experimental data were adequate to the kinetic model of pseudo-second order. For adsorption isotherms, the Freundlich model best described experimental data, indicating an efficiency of 72.35% by removing 17.85 mg g-1 at a temperature of 31.2 ° C, and with parameter RL between 0 <RL <1 characterizing favorable adsorption.