Banca de DEFESA: ERNANI DIAS DA SILVA FILHO

Uma banca de DEFESA de DOUTORADO foi cadastrada pelo programa.
STUDENT : ERNANI DIAS DA SILVA FILHO
DATE: 11/08/2023
TIME: 09:30
LOCAL: videoconferência
TITLE:

Sorption of emerging contaminants in magnetic composites and chitosan particles

KEY WORDS:

water pollution; textile industry; medication disposal; drug adsorption; dyes

PAGES: 129
BIG AREA: Ciências Exatas e da Terra
AREA: Química
SUBÁREA: Química Orgânica
SPECIALTY: Polímeros e Colóides
SUMMARY:

The pollution of water resources caused by the textile industry and the improper disposal of medicines are serious environmental problems that require immediate attention. Dyes used in the textile industry are highly soluble in water, contaminating water resources and making removal difficult. On the other hand, improper disposal of medicines can contaminate soil and water, representing a significant risk to public health and the environment. These emerging contaminants are being detected at increasing levels in the environment and which still do not have regulations or established control standards. It is crucial that the population is aware of the risks associated with the inappropriate disposal of medicines and that they take steps for their safe and responsible disposal, and through programs to collect expired or unused  medications.  In  this  context,  this  thesis  proposes  the  study  of  the  sorption  of  drugs  sodium  cromoglycate  and  tetracycline  hydrochloride  on magnetic composites, and the development of a numerical method applied to the adsorption of dyes, acid blue 260 (AA), and methyl orange (AM), on crosslinked chitosan to individually and simultaneously identify the concentration of these dyes in aqueous solutions. For this purpose, techniques such as thermogravimetric analysis, molecular absorption spectroscopy in the ultraviolet and visible region, infrared absorption spectroscopy, X-ray diffraction, and adsorption equilibrium studies were employed. The study on drugs revealed that sorption occurred in multiple layers, reaching saturation at concentrations of 0.2 mmol of drug per gram of composite for tetracycline hydrochloride (HTCCl) in both positive and negative magnetic composites. The anionic drug was adsorbed with similar intensity in both composites, with saturation in the negatively charged composite achieved at a value of approximately 0.05 mmol per gram of composite. The Gibbs free energy of adsorption was estimated under dilute solution conditions, ranging from ‒17 to ‒3 kJ/mol. The analysis of thermal degradation kinetics using the isoconversional approach revealed that the presence of magnetite in the magnetic composites reduced the apparent activation energy. Values obtained reached up to 400 kJ/mol for the degradation of the organic phase. This phenomenon demonstrated that magnetite increased the surface area available for drug adsorption. As for the developed method applied to the dyes, it demonstrated more effective sorption for AA, which could be characterized by determining different isothermic parameters, estimation of the Gibbs free energy of adsorption as well as competitive sorption by itself.

COMMITTEE MEMBERS:
Externo ao Programa - 1753094 - ALCIDES DE OLIVEIRA WANDERLEY NETO - nullExterna à Instituição - ANDARAIR GOMES DOS SANTOS - UFERSA
Presidente - 1198847 - JOSE LUIS CARDOZO FONSECA
Externo à Instituição - JOÃO MARIA SOARES - UERN
Interna - 1149440 - ROSANGELA DE CARVALHO BALABAN