RESUMO
The adsorption of Pb2+ by a compost obtained from the treatment of tobacco from smuggled cigarettes (SCT) and industrial sewage sludge (ISS) was investigated. The Pb2+ adsorption process was evaluated as function of different concentrations of adsorbent and adsorbate, pH variations, and contact time. Fourier transformed infrared spectroscopy (FTIR) and energy dispersive X-ray spectrometry (EDX) were adopted to obtain information regarding structural changes and a better understanding of the adsorption mechanism. The adsorbent maximum adsorption capacity for Pb2+, calculated using the Sips equation, was 21.454 mg/g with 3 g/L adsorbent at pH 5. The adsorption kinetics best adjustment was obtained using the pseudo-second-order model with a time of 240 min to reach the adsorption equilibrium. FTIR and EDX results suggest that Pb2+ might have bonded to phenolic, carboxylic, hydroxyl, and amine groups; they also show formation of organometallic complexes and cationic exchange between the compost and the solution. The study confirmed that the compost evaluated can be used as a potential adsorbent in environments contaminated with Pb2+.
Assuntos
Compostagem/métodos , Chumbo/química , Nicotiana , Poluentes Químicos da Água/química , Adsorção , Concentração de Íons de Hidrogênio , Cinética , Chumbo/análise , Esgotos/química , Espectrometria por Raios X , Espectroscopia de Infravermelho com Transformada de Fourier , Produtos do Tabaco , Poluentes Químicos da Água/análiseRESUMO
This study aims to develop and validate a method to determine OCPs in fish tissues, minimizing the consumption of sample and reagents, by using a modified QuEChERS along with ultrasound, d-SPE and gas chromatography with an electron capture detector (GC-ECD), refraining the pooling. Different factorial designs were employed to optimize the sample preparation phase. The validation method presented a recovery of around 77.3% and 110.8%, with RSD lower than 13% and the detection limits were between 0.24 and 2.88 µgkg-1, revealing good sensitiveness and accuracy. The method was satisfactorily applied to the analysis of tissues from different species of fish and OCPs residues were detected. The proposed method was shown effective to determine OCPs low concentrations in fish tissues, using small sample mass (0.5 g), making the sample analyses viable without the need for grouping (pool).
Assuntos
Contaminação de Alimentos/análise , Hidrocarbonetos Clorados/análise , Praguicidas/análise , Alimentos Marinhos/análise , Animais , Peixes , Cromatografia Gasosa-Espectrometria de Massas , Limite de Detecção , Reprodutibilidade dos Testes , Tamanho da AmostraRESUMO
This paper presents a study on the translocation factors (TFs) and bioconcentration factors (BCFs) of copper (Cu), manganese (Mn), zinc (Zn), cobalt (Co), chromium (Cr), cadmium (Cd), lead (Pb), iron (Fe), nickel (Ni), and arsenic (As) ions in roots, stems, and leaves of tobacco. The results revealed that during the tobacco growth, the roots are able to increase the sensitiveness of the physiological control, reducing the translocation of the metals Ni (0.38) and Pb (0.48) to the leaves. Cd and Zn presented factors TF and BCF >1 in the three tissues under analysis, which indicates the high potential for transportation and accumulation of these metals in all plant tissues. The TF values for Cr (0.65) and As (0.63) revealed low translocation of these ions to the aerial parts, indicating low mobility of ions from the roots. Therefore, tobacco can be considered an efficient accumulator of Ni, Cr, As and Pb in roots and Cd and Zn in all plant parts.
Assuntos
Monitoramento Ambiental/métodos , Metais Pesados/análise , Nicotiana/química , Raízes de Plantas/química , Poluentes do Solo/análise , Solo/química , Biodegradação Ambiental , Cádmio/análise , Cromo/análise , Cobalto/análise , Cobre/análise , Íons/análise , Níquel/análise , Folhas de Planta/química , Folhas de Planta/crescimento & desenvolvimento , Raízes de Plantas/crescimento & desenvolvimento , Caules de Planta/química , Caules de Planta/crescimento & desenvolvimento , Nicotiana/crescimento & desenvolvimento , Zinco/análiseRESUMO
This study proposes a new facultative reactor configuration for the treatment of organic household waste and pine sawdust. The process was monitored and the compost characterized by conventional (temperature, moisture, pH, ash content and ratio C/N) conjugated with spectroscopic analyses (ultraviolet (UV)/visible (Vis) and infrared (IR)) and germination index. The spectroscopy results revealed enrichment of carbon-carbon unsaturation structures and a degradation of the aliphatic structures. The results showed that stability of the final product was reached after 90 days and that the compost obtained presents substantial richness of stabilized organic matter and an absence of toxicity, so it may be considered as an organic fertilizer. Finally, this study led to the conclusion that the reactor proposed can be a promising technology for the management of organic household waste and sawdust.