Irajá do Nascimento Filho

Quantitative analysis of plasticizers in a wastewater treatment plant: influence of the suspended solids parameter

A ocorrencia de ftalato de di(2-etilhexila) (DEHP) e bisfenol A (BPA) em aguas residuais da estacao de tratamento da Universidade de Caxias do sul (ETE-UCS) foi investigada neste trabalho. Durante cinco meses, cinco amostras dos pontos de entrada e saida da ETE-UCS foram coletadas e submetidas a extracao liquido-liquido (LLE). Os extratos orgânicos foram analisados por cromatografia a gas com deteccao por ionizacao em chama (GC/FID). As eficiencias de remocao da ETE-UCS foram de 37,79 e 19,90% para BPA e DEHP, respectivamente. As concentracoes medias no ponto de saida foram 52,52 e 20,00 mg L-1 para BPA e DEHP, respectivamente. As concentracoes altas dos analitos, no ponto de saida da ETE podem estar relacionadas com a remocao baixa dos solidos suspensos das amostras brutas. Para confirmar esta hipotese, outras cinco amostras dos pontos de entrada e saida da ETE-UCS tambem foram submetidas a LLE, com e sem o procedimento de pre-filtracao. A remocao de DEHP foi de 74,44% sendo a concentracao media no ponto de saida de 6,01 mg L-1. Para as amostras nao pre-filtradas a remocao de DEHP foi de 40,96% sendo a concentracao media no ponto de saida de 17,04 mg L-1

Volatilization of monoaromatic compounds (benzene, toluene, and xylenes; BTX) from gasoline: effect of the ethanol.

The main objective of present study was to assess the evaporation profile of monoaromatic compounds, namely, benzene, toluene, and xylenes (BTX) from gasoline-ethanol-blend fuels. The vapors from two river sand columns contaminated with gasoline and gasoline-ethanol were monitored for 77 d. Standards mixtures (batch tests) of benzene, toluene, and xylenes with different ethanol contents were also analyzed for evaporation rates studies. The instrumental analysis was performed via gas chromatography. The concentration of benzene in the vapor phase of the gasoline-ethanol column was decreased by 89.09%, considering the entire experimental period, whereas the toluene and xylenes concentrations were increased by 239.34 and 251.78%, respectively. In the batch tests, the benzene concentration in the vapor phase varied from 0.4 to 0.9 mg/L for ethanol concentrations (v/v) of 5 and 10%, respectively. For ethanol concentrations higher than 10%, no important changes in the benzene concentration were observed. The toluene exponentially increases between 20 and 30% ethanol concentration. and the maximum concentration of xylenes was observed when the ethanol concentration was 20% (v/v). These results suggest that the benzene evaporation behavior is preferentially affected by the interactions among ethanol and other aromatic compounds rather than the ethanol concentration itself. The evaporation behaviors of toluene and xylenes are directly dependent on the ethanol content.

Variabilidade química de compostos orgânicos voláteis e semivoláteis de populações nativas de Maytenus ilicifolia

This work is focused on the chemical distribution of volatile and semi-volatile compounds of 18 native populations of Maytenus ilicifolia collected all over Brazil. The extracts of bulk samples (30 plants) of each population were obtained by supercritical CO2 extraction technique, and analyzed by GC/MS. The quantification of compounds (phytol, squalene, vitamin E, limonene, stigmasterol, friedelan-3-ol, friedelin, fridelan-3-one, palmitic acid and geranyl acetate) showed significant variations within the different populations, which could be related tom microclimate characteristics.

Two Generations of Fall Armyworm (Lepidoptera: Noctuidae) Contamination by Di-n-Butylphthalate

The effects of di-n-butylphthalate (DnBP) were investigated with respect to bioaccumulation and whether these effects occurred over a second generation in the fall armyworm Spodoptera frugiperda (J.E. Smith, 1797). The concentrations of DnBP in males and females of the second generation were higher than those in first one. However, frequency of mortality of exposed individuals in the second generation was approximately 57% less but the reduction in size and weight was more pronounced than in the first generation.

Head Space Solid Phase Micro-Extraction (HS - SPME) of volatile organic compounds produced by Sporidiobolus salmonicolor (CBS 2636)

O objetivo do presente estudo foi avaliar os compostos orgânicos volateis produzidos por Sporidiobolus salmonicolor (CBS 2636) utilizando metil e etil ricinoleato, acido ricinoleico e oleo de mamona como precursores. A analise dos compostos volateis produzidos foi conduzida por Micro-Extracao em Fase Solida (MEFS). A tecnica de planejamento experimental foi utilizada na avaliacao das condicoes de extracao, na qual se avaliaram a agitacao (0-400 rpm), a temperatura (25-60 oC), o tempo de extracao (10-30 minutos) e o volume da amostra (2-3 mL). A identificacao dos compostos foi realizada por Cromatografia a Gas com deteccao por Espectrometria de Massas (CG/EM). As condicoes que resultaram na maxima extracao foram: 60 oC, 10 minutos de extracao, sem agitacao, volume de amostra de 2,0 mL e adicao de solucao de KCl saturada (1:10 v/v). Na bioproducao dos compostos volateis, o efeito da agitacao (120-200 rpm), da temperatura (23-33 oC), do pH (4,0-8,0), da concentracao do precursor (0,02 a 0,1%), da concentracao de manitol (0 a 6%) e de asparagina (0 a 0,2%) foi avaliado. Na condicao de 28 oC, 160 rpm, pH 6,0 e com a adicao de 0,02% de acido ricinoleico ao meio, foi atingida a maxima producao dos compostos volateis, identificados como: 1,4-butanodiol, 1,2,2-trimetilciclopropilamina, beta-ionona; 2,3-butanodiona, pentanal, tetradecano, 2-isononenal, 4-octen-3-ona, acido propanoico e octadecano.

Study of odor compounds in gaseous effluents generated during production of poultry feather and viscera meal using headspace solid phase microextraction

This work reports the screening and characterization of odor compounds in gaseous effluents generated during the production of poultry feather and viscera meal, the by-products of the poultry meat industry. Chemical analysis was carried out by solid phase microextraction in the headspace (HS-SPME) mode. Exhaust air of thermal processing of poultry feather and viscera were sampled online from a bench-scale digester, condensed, and collected in sampling flasks. Both volatile and semivolatile organic compounds present in the condensed gases were extracted under agitation at constant temperature. The extracts were analyzed with a gas chromatograph coupled to a mass spectrometric detector (GC/MSD). The identification of compounds was carried out by comparing the mass spectra obtained with those from the Wiley library and quantification was accomplished through authentic analytical standards. For the determination of the best extraction conditions and analysis, extraction fibers of different coatings and polarities were tested: divinylbenzene/carboxen/polydimethyilsiloxane (DVB/CAR/PDMS), carbowax/divinylbenzene (CW/DVB), and polydimethylsiloxane (PDMS) and chromatography columns of different polarities: DB-WAX (polar) and DB-5 (nonpolar). The best extraction conditions and analysis of the compounds of interest were obtained by the use of the SPME fiber with DVB/CAR/PDMS coating and analysis by GC/MSD with polar capillary column. Several carboxylic acids were identified, as well as mercaptans, amines, and aldehydes of great environmental importance.

Analysis of BTEX in experimental columns containing neat gasoline and gasoline-ethanol

The main objective of the present study was to assess the evaporation profile of BTEX (benzene, toluene, ethylbenzene and xylenes) in neat gasoline and gasoline-ethanol blend fuels. The vapors from two sealed columns containing river sand and distilled water were monitored during 18 days by SPME (solid-phase microextraction). BTEX that remained in the water and sand phases were extracted by SPE (solid-phase extraction) and Soxhlet, respectively. Instrumental analysis was performed by gas chromatography using a flame ionization detector (GC/FID). Toluene and ethylbenzene showed the highest volatilizations in the gasoline-ethanol column and the occurrence of attractive intermolecular forces among ethanol and BTEX molecules can be responsible for this distribution. Benzene showed the lowest reduction of concentration in the sand compartment in the gasoline-ethanol column.

Determinação de bromato em melhoradores de farinha por cromatografia de troca iônica com detecção espectrofotométrica

KBrO3 is registered by the FAO/OMS as a genotoxic and carcinogenic compound. In spite of this, KBrO3 is still employed by Brazilian bakeries. Nowadays ion exchange chromatography (IEC) is the most rapid and trustful method for BrO3- analysis. When at high concentrations, chloride ions can interfere in the BrO3- analysis, if the detection is performed by electrical conductivity. On the other hand, spectrophotometric detection, presented here is based on the absorption of BrO3- in the ultraviolet region (210 - 230 nm) where the absortion of chloride ions is very low, thus making possible the qualitative and quantitative analysis of BrO3- in flour improver samples.

The environmental aspects of the evaporation of BTEX from gasoline with and without ethanol

In this work the vapours from two columns simulating gasoline-contaminated soils (with and without ethanol) were monitored. Standards mixtures of BTEX, containing different ethanol contents were also analysed. The instrumental analysis was performed by Gas Chromatography with a Flame Ionisation Detector. Among BTEX, except benzene, in both columns the evaporation rate increases with time. In the gasoline/ethanol column this effect is higher particularly for the xylenes. Although the benzene concentrations were reduced in both columns, this reduction was less marked in the gasoline/ethanol column. The toluene concentrations were higher in the pure gasoline column.

The importance of the suspended solids parameter on the quantitative analysis of di-n-butyl phthalate in a wastewater treatment system.

The present study has investigated the influence of the filtration step of the liquid-liquid extraction (LLE) on the quantitative analysis of di-n-butyl phthalate (DnBP) in the wastewater treatment system of the University of Caxias do Sul (WWTS-UCS). During five months, five wastewater samples from the inflow and outflow points were collected and submitted to LLE with and without the filtration step. The organic extracts were analyzed by Gas Chromatography with Flame Ionization Detection (GC/FID). The DnBP removal in the filtered samples was 36%, and the median DnBP concentration at the outflow point was 17.45 μg/mL. For the unfiltered samples, the DnBP removal was 39%, and the median DnBP concentration at the outflow point was 21.45 μg/mL. According to these results, an important fraction of the contaminant is retained in the LLE filtration step leading to considerable errors in the quantification of the target compounds.