Análise da adsorção de contaminantes orgânico e inorgânicos de amostras aquosas em diferentes biossorventes
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Data
2019-07-05
Autores
Chiachia Pasta, Paula
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Universidade Estadual Paulista (Unesp)
Resumo
A identificação e quantificação de diferentes contaminantes em águas naturais têm sido amplamente divulgadas em meios científicos. Nas duas últimas décadas, a remoção, em meio aquoso, de fármacos e seus metabólitos, também designados contaminantes emergentes, tem recebido destaque. O problema da existência destes compostos no ambiente, além da sua persistência, relaciona-se com a ocorrência de bactérias mais resistentes, sendo um grave risco para a saúde. Desta forma, os objetivos desse projeto foram caracterização das folhas da taboa, Typha angustifolia L. in natura, e aplicação desse biossorvente para remoção do antibiótico cloranfenicol em amostras aquosas. O material foi caracterizado por Espectroscopia na Região do Infravermelho (FTIR), Ponto de Carga Zero (PZC), Ressonância Magnética Nuclear (RMN), Microscopia Eletrônica de Varredura (MEV), Espectroscopia de Energia Dispersiva de raios X (EDX), análise elementar de nitrogênio e enxofre, além da medida de área superficial (Brunauer, Emmett, Teller - BET). Foram realizados experimentos em batelada em função do pH, tempo de contato e concentração do analito, cuja solução sobrenadante foi quantificada por Ultra Performance Liquid Chromatography (UPLC). Resultados referentes ao espectro de FTIR, bem como as análises de RMN, corroboraram ao identificar grupos químicos funcionais que promovem interação entre o biossorvente e analito. O pHPZC, calculado em torno de 5,75, foi considerado para escolher pH ideal do meio que favoreça a adsorção. Por imagens de MEV, o material caracterizou-se por placas paralelas com grande quantidade de canais (superfície heterogênea). A isoterma do tipo II foi obtida a partir do método BET, apresentando baixa área superficial, não porosa ou macroporosa, adsorção mono e multicamadas. Pseudo-segunda ordem foi o modelo que mais se ajustou à cinética de adsorção, enquanto que, para determinação da capacidade máxima, o modelo de Freundlich apresentou maior concordância.
The identification and quantification of different contaminants in natural waters have been widely disseminated in scientific journals. In the last two decades, removal from aqueous samples of drugs and their metabolites, also called emerging contaminants, have been highlighted. The problem of their existence in the environment, besides its persistence, is related to the occurrence of more resistant bacteria, being a serious risk to health. Thus, the objectives of this project were characterization of cattail leaves, Typha angustifolia L. in natura, and its application for the removal of the antibiotic chloramphenicol in aqueous samples. The material was characterized by Fourier Transform in the Infrared Region (FTIR), Point of Zero Charge (PZC), Nuclear Magnetic Resonance (NMR), Scanning Electron Microscopy (SEM), Energy Dispersive X-ray Spectroscopy (EDX), elemental analysis of nitrogen and sulfur, as well as surface area measurements (Brunauer, Emmett, Teller-BET). Batch experiments were performed considering the influence of pH, contact time and analyte concentration, whose supernatant solution was quantified by Ultra Performance Liquid Chromatography (UPLC). Both results, regarding FTIR spectrum and NMR analysis, corroborated by identifying functional chemical groups that promote interaction between biosorbent and analyte. The pHPZC, estimated around 5.75, was considered to choose the ideal pH of the medium that favors adsorption. By means of SEM images, the material was characterized by parallel plates with large number of channels (heterogeneous surface). Type II isotherm was obtained from BET method, with low surface area, nonporous or macroporous, mono and multilayer adsorption. Pseudo-second order was the model that best fit the adsorption kinetics, while for determining the maximum capacity, the Freundlich model showed the highest agreement.
The identification and quantification of different contaminants in natural waters have been widely disseminated in scientific journals. In the last two decades, removal from aqueous samples of drugs and their metabolites, also called emerging contaminants, have been highlighted. The problem of their existence in the environment, besides its persistence, is related to the occurrence of more resistant bacteria, being a serious risk to health. Thus, the objectives of this project were characterization of cattail leaves, Typha angustifolia L. in natura, and its application for the removal of the antibiotic chloramphenicol in aqueous samples. The material was characterized by Fourier Transform in the Infrared Region (FTIR), Point of Zero Charge (PZC), Nuclear Magnetic Resonance (NMR), Scanning Electron Microscopy (SEM), Energy Dispersive X-ray Spectroscopy (EDX), elemental analysis of nitrogen and sulfur, as well as surface area measurements (Brunauer, Emmett, Teller-BET). Batch experiments were performed considering the influence of pH, contact time and analyte concentration, whose supernatant solution was quantified by Ultra Performance Liquid Chromatography (UPLC). Both results, regarding FTIR spectrum and NMR analysis, corroborated by identifying functional chemical groups that promote interaction between biosorbent and analyte. The pHPZC, estimated around 5.75, was considered to choose the ideal pH of the medium that favors adsorption. By means of SEM images, the material was characterized by parallel plates with large number of channels (heterogeneous surface). Type II isotherm was obtained from BET method, with low surface area, nonporous or macroporous, mono and multilayer adsorption. Pseudo-second order was the model that best fit the adsorption kinetics, while for determining the maximum capacity, the Freundlich model showed the highest agreement.
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Palavras-chave
adsorção de antibióticos, taboa, biorremediação, biotecnologia ambiental, antibiotic adsorption, bioremediation, environmental biotechnology, reaproveitamento, caranguejo, biossorção de metais, reuse, crab, metal biosorption