Adsorção de diclofenaco sódico a partir do resíduo da produção de silicato de sódio

Abstract

Rice husk (RH), as it has no nutritional value in human and animal nutrition, is an agricultural by-product in abundance in countries that produce this grain. This is because with population growth, the production of grains and cereals, the chain in which rice is inserted, is increasing exponentially to meet global demand. In the literature there are several studies focused on the reuse of AC, with the greatest emphasis being its use in the energy generation process, through combustion, where the remaining ash has a high percentage of silicon dioxide. To recover this silica, research has proposed the use of alkaline leaching, where this unitary operation has proven to be economically viable and efficient. In this process, two distinct materials used in various industrial areas are obtained, namely sodium silicate and residual material, which can be used as a low-cost adsorbent material. Adsorbents are widely used in the removal of various pollutants, which includes the drug diclofenac sodium (DCF), a non-steroidal anti inflammatory drug used to relieve pain and inflammation. They are classified as emerging contaminants, as there is no specific environmental legislation that regulates the presence of these compounds in water resources. In view of this, the objective of this course conclusion work was to study the adsorption of DCF using the residual material of sodium silicate. To this end, the characterization of the residual material, kinetic tests and adsorption isotherms were carried out. As a result, the characterizations by DRX and TGA revealed a crystalline structure and loss of mass due to water evaporation respectively. The kinetic studies demonstrated that the model that best fit the experimental data was the pseudo-second order model, with an adsorption capacity of 0.02305 mg/g. Regarding the isotherm tests, the model that best described the experiments was the Redlich-Peterson model and the percentage of drug removal varied between 38% and 63% for the masses of residual material tested. Therefore, the analyzed material has great potential in removing diclofenac sodium, as it was proven through the experiments carried out.