RESUMO
Bisphenol-A is widely used chemical in industry and unfortunately often detected in natural waters. Considered as an emerging pollutant, bisphenol-A represents an environmental problem due to its endocrine-disrupting behavior. The production of activated carbon from alternative precursors has shown to be attractive in the removal of emerging pollutants from the water. Activated carbon was produced from waste coffee by physical and chemical activation and applied in the removal of bisphenol-A. The samples were characterized by elemental analysis, scanning electron microscopy, X-ray diffraction, Fourier transform infrared spectroscopy, and analysis of textural properties. Bisphenol-A adsorption experiments showed that the chemically activated carbon was more efficient due to its high specific surface area (1039 m2/g) compared to the physically activated carbon (4.0 m2/g). The bisphenol-A adsorption data followed the pseudo-second-order model and Langmuir isotherm, which indicated a maximum adsorption capacity of 123.22 mg/g for chemically activated carbon. The results demonstrated a potential use of the coffee grounds as a sustainable raw material for the production of chemically activated carbon that could be used in water treatment.
Assuntos
Compostos Benzidrílicos/isolamento & purificação , Carvão Vegetal/química , Café , Fenóis/isolamento & purificação , Poluentes Químicos da Água/isolamento & purificação , Adsorção , Compostos Benzidrílicos/química , Cloretos/química , Cinética , Microscopia Eletrônica de Varredura , Fenóis/química , Espectroscopia de Infravermelho com Transformada de Fourier , Resíduos , Poluentes Químicos da Água/química , Purificação da Água/métodos , Difração de Raios X , Compostos de Zinco/químicaRESUMO
In this study, a simple, efficient, and reusable device based on cellulose membranes modified with polypyrrole was developed to extract 14 emerging contaminants from aqueous matrices. For chemical polymerization, a low-cost cellulose membrane was immersed in 0.1 mol/L pyrrole and 0.5 mol/L ammonium persulfate for 40 min in an ice/water bath. The cellulose membranes modified with polypyrrole were accommodated in a polycarbonate holder suitable for solid-phase extraction disks. Solid-phase extraction parameters that affect extraction efficiency, such as sample volume, pH, flow rate, and desorption were optimized. Subsequently, determination of target compounds was performed by gas chromatography with mass spectrometry. The linear range for analytes ranged from 0.05 to 500 µg/L, with coefficients of determination above 0.990. The limits of quantification varied between 0.05 and 10 µg/L, with relative standard deviations lower than 17%. The performance of the proposed cellulose membranes modified with polypyrrole device for real samples was evaluated after extraction of emerging contaminants from a river water sample from the city of Curitiba, Brazil. Bisphenol A (6.39 µg/L), caffeine (17.83 µg/L), and paracetamol (19.28 µg/L) were found in these samples.
Assuntos
Celulose/química , Cromatografia Gasosa-Espectrometria de Massas/métodos , Extração em Fase Sólida/métodos , Poluentes Químicos da Água/análise , Poluentes Químicos da Água/isolamento & purificação , Acetaminofen/análise , Acetaminofen/isolamento & purificação , Compostos Benzidrílicos/análise , Compostos Benzidrílicos/isolamento & purificação , Brasil , Cafeína/análise , Cafeína/isolamento & purificação , Fenóis/análise , Fenóis/isolamento & purificação , Polímeros/química , Pirróis/química , Rios/química , Extração em Fase Sólida/instrumentaçãoRESUMO
Endocrine Disrupter Compounds (EDCs) are responsible for alterations in the endocrine system functions. Aquatic organisms are able to accumulate EDCs residues, being the major source of contamination for top predators and human consumers. This study aimed to develop and validate a method for the determination of 40 EDCs in fish fillet using modified QuEChERS and Gas Chromatography coupled with Mass Spectrometry in tandem (GC-MS/MS). A factorial design was used to optimize the extraction procedure. Method validation presented recoveries from 70.1% to 120.0% with RSD<20% and method limit of detection ranged from 0.3 to 7.5 µg kg(-1), showing good accuracy and precision. This method was successfully applied to the analysis of fish fillet from different species and residues of bisphenol A, chlorpyrifos and bifenthrin were detected. The proposed method proved to be effective for the determination of EDCs in fish fillet at very low concentration levels.