Andreia Neves Fernandes

Development of a new adsorbent from agro-industrial waste and its potential use in endocrine disruptor compound removal

A new activated carbon (AC) material was prepared by pyrolysis of a mixture of coffee grounds, eucalyptus sawdust, calcium hydroxide and soybean oil at 800°C. This material was used as adsorbent for the removal of the endocrine disruptor compounds 17β-estradiol (E2) and 17α-ethinylestradiol (EE2) from aqueous solutions. The carbon material was characterized by scanning electron microscopy (SEM), infrared spectroscopy (FTIR), N2 adsorption/desorption curves and point of zero charge (pHPZC). Variables including the initial pH of the adsorbate solutions, adsorbent masses and contact time were optimized. The optimum range of initial pH for removal of endocrine disruptor compounds (EDC) was 2.0-11.0. The kinetics of adsorption were investigated using general order, pseudo first-order and pseudo-second order kinetic models. The Sips isotherm model gave the best fits of the equilibrium data (298K). The maximum amounts of E2 and EE2 removed at 298K were 7.584 (E2) and 7.883mgg(-1) (EE2) using the AC as adsorbent. The carbon adsorbent was employed in SPE (solid phase extraction) of E2 and EE2 from aqueous solutions.

A preliminary nationwide survey of the presence of emerging contaminants in drinking and source waters in Brazil

This is the first nationwide survey of emerging contaminants in Brazilian waters. One hundred drinking water samples were investigated in 22 Brazilian state capitals. In addition, seven source water samples from two of the most populous regions of the country were evaluated. Samples were collected from June to September of 2011 and again during the same period in 2012. The study covered emerging contaminants of different classes, including hormones, plasticizers, herbicides, triclosan and caffeine. The analytical method for the determination of the compounds was based on solid-phase extraction followed by analysis via liquid chromatography electrospray triple-quadrupole mass spectrometry (LC-MS/MS). Caffeine, triclosan, atrazine, phenolphthalein and bisphenol A were found in at least one of the samples collected in the two sampling campaigns. Caffeine and atrazine were the most frequently detected substances in both drinking and source water. Caffeine concentrations in drinking water ranged from 1.8ngL-1 to values above 2.0μgL-1 while source-water concentrations varied from 40ngL-1 to about 19μgL-1. For atrazine, concentrations were found in the range from 2.0 to 6.0ngL-1 in drinking water and at concentrations of up to 15ngL-1 in source water. The widespread presence of caffeine in samples of treated water is an indication of the presence of domestic sewage in the source water, considering that caffeine is a compound of anthropogenic origin.

Remoção dos hormônios 17β-estradiol e 17α-etinilestradiol de soluções aquosas empregando turfa decomposta como material adsorvente

This paper describes the adsorption of 17β-estradiol (E2) and 17α-ethinylestradiol (EE2) from aqueous solution by decomposed peat. The peat presented a good adsorption process, close to 76.2% for E2 removal and approximately 55.0% for EE2. Moreover, the results indicated a probable multi-layered process. Adsorption isotherms were well fitted by Freundlich model. The data were evaluated considering the pseudo-first-order and pseudo-second-order approaches, being the second more significant mechanism in the rate-controlling step. Thermodynamic data revealed that hormones adsorption onto peat is spontaneous under the employed experimental conditions. The results confirmed the potential of this adsorbent to be employed for effluents treatment.

Nutrient contents in bottom sediment samples from a southern Brazilian microbasin

The nutrients, carbon, nitrogen and phosphorus, significantly affect the quality of aquatic environments, especially when present at concentrations above natural levels. In this context, the sedimentary column can act as an environment for storage or accumulation of these nutrients and for the reprocessing of such substances in the water column and aquatic biota. In this context, this study aimed to estimate the concentration of total organic carbon (TOC), total nitrogen (TN), total phosphorus (TP), inorganic phosphorus (IP) and organic phosphorus (OP) in seven sediment samples that were collected from the Marrecas Stream microbasin (Caxias do Sul, Rio Grande do Sul State, Brazil). The relationships among the sediment nutrient concentrations and the levels of organic matter (OM), fine material (silt–clay) and the concentration of the metal species, Al, Fe and Mn, as well as the possible nutrient sources to the stream studied were also evaluated. The data set suggest that the TOC and IP appear to have a direct correlation with the vast riparian vegetation present in areas adjacent to the sampling points and to the physico-chemical properties of the water and sedimentary column. Moreover, the results obtained for TN suggest that its concentration possibly suffers interference from the temperature of the water and its oxygenation, in addition to other biological activities. On the other hand, one cannot rule out human interference, mainly in the levels of OP, possibly due to the inflow of domestic sewage to the stream.

Titanium dioxide nanoparticles induce genotoxicity but not mutagenicity in golden mussel Limnoperna fortunei

The widespread use of titanium dioxide nanoparticles (TiO2-NP) in consumer products is the cause of its appearance in wastewater and effluents, reaching the aquatic environment. The evaluation of the biological impact of TiO2-NP and the need to understand its ecotoxicological impact to the aquatic ecosystem are of major concern. Bivalve mollusks may represent a target group for nanoparticle toxicity. Limnoperna fortunei (golden mussel), a freshwater bivalve organism that has been employed in biomonitoring environmental conditions. Comet assay, micronucleus test and oxidative damage to lipids and proteins were performed after the golden mussel was exposed to TiO2-NP (1, 5, 10 and 50μgmL(-1)). The results demonstrate that TiO2-NP can damage the DNA of haemocytes after 2h of exposure and the genotoxic activity significantly increased after 4h exposure to TiO2-NP, at all the TiO2-NP concentrations. TiO2-NP was ineffective in causing mutagenicity in the haemolymph cells of golden mussel. The increase in the lipid peroxidation levels and carbonyl proteins after the exposure to TiO2-NP indicates the induction of oxidative stress at 2h exposure with similar results to all TiO2-NP concentrations, but these effects did not occur at 4h exposure. These results demonstrated that, although TiO2-NP is not mutagenic to golden mussel, it does induce DNA damage and oxidative stress in these organisms.

REMOVAL OF CIBACRON BRILLIANT YELLOW 3G-P DYE FROM AQUEOUS SOLUTIONS BY BRAZILIAN PEATS AS BIOSORBENTS

Two Brazilian peat samples in different stages of decomposition, fibrous peat (FP) and decomposed peat (DP), were used as biosorbents for the removal of the textile dye Cibacron Brilliant Yellow 3G-P (CBY) from aqueous solutions. These biosorbents were characterized by Fourier transform-infrared spectroscopy (FT-IR) and scanning electron microscopy (SEM). The effects of initial pH of dye solution and contact time between the dye and the biosorbents on the biosorption capacities were studied. Based on an error function (Ferror ) the general-order kinetic model provided the best fit to the experimental data compared with the pseudo-first-order and pseudo-second-order kinetic biosorption models. The equilibrium data were fitted to Langmuir, Freundlich, and Liu isotherm models. For both biosorbents the equilibrium data were best fitted to the Liu isotherm model. Simulated dye house effluents were used to check the applicability of the proposed biosorbents for effluent treatment.

Antioxidant defences and haemocyte internalization in Limnoperna fortunei exposed to TiO2 nanoparticles

TiO2 nanoparticles (TiO2-NP) have been incorporated into a large range of materials for different applications in the last decades and are very likely to appear in wastewater and effluents, eventually reaching the aquatic environment. Therefore, the assessment of the biological impact of TiO2-NP on aquatic ecosystem is of a major concern. The mussels represent a target group for TiO2-NP toxicity, as they are filter feeders and are capable of bioaccumulating toxic compounds. Furthermore, the exotic organism Limnoperna fortunei, golden mussel, is a freshwater bivalve that has been used in biomonitoring environmental conditions. In this work, the TiO2-NPs ability to interact with haemocytes of golden mussel was assessed by transmission electron microscopy. The enzymatic and non-enzymatic antioxidant defenses were evaluated by superoxide dismutase (Sod) and catalase (Cat) activities and protein sulfhydryl content, which were measured after the golden mussel was exposed to TiO2-NP (1, 5, 10 and 50μgmL(-1)). Results demonstrate that TiO2-NP was internalized by cells, causing alterations in haemocytes membrane. Antioxidant activity of Sod and Cat decreased after 2h TiO2-NP exposure. After 4h exposure, the enzymatic antioxidant activity was restored. Notably, the protein sulfhydryl content decreased after 2h to all the TiO2-NP concentrations and no alterations were observed after 4h of TiO2-NP exposure. These results demonstrate the potential of golden mussel as sentinel organism to TiO2-NP exposure.

Removal of pyrene from aqueous solutions by adsorption onto Brazilian peat samples

Pyrene is a polycyclic aromatic hydrocarbon, classified as a priority pollutant. Aiming to minimize the presence of this polycyclic aromatic hydrocarbon in aquatic ecosystems, it is important to develop and consider new alternatives that enable its partial or total removal by different mechanisms and/or processes. In this sense, several techniques have been used for this purpose. Among them, adsorption techniques employing natural adsorbents as peat represent an attractive alternative due to its low cost and high removal efficiency. In the present study, two samples (decomposed peat – DP, and fibrous peat – FP) were used to remove pyrene at concentrations of 1.0, 2.0, 3.0, 4.0, and 5.0 µg L−1 for up to 72 h. The removal percentages with DP were between 75.5 and 91.0%, while for FP these values were in the range of 77.7 to 92.1%. The experimental data showed that the adsorption kinetics were better described using a pseudo-second-order model. Regarding the adsorption equilibrium, the experimental data were adequately fitted by the Freundlich equation for both peat samples. Finally, the adsorption capacity depended on thermodynamic parameters, indicating that the adsorption process was spontaneous and occurred by physisorption.

Optimization of an analytical protocol for the extraction, fractionation and determination of aromatic and aliphatic hydrocarbons in sediments

Neste trabalho foram aperfeicoadas as etapas para determinacao de hidrocarbonetos alifaticos e aromaticos em sedimentos. Durante as etapas de extracao e concentracao foram avaliados fatores determinantes como tempo, solvente extrator e sistema de resfriamento. Quanto ao cleanup, foram estudados diferentes volumes e misturas de solventes de eluicao. Os resultados obtidos foram considerados aceitaveis (70-120%). A linearidade, limites de deteccao e quantificacao foram estudados construindo-se curvas analiticas (R > 0,99) com valores que demonstraram grande sensibilidade do metodo. A precisao e exatidao foram avaliadas com ensaios envolvendo material de referencia certificado e adicao e recuperacao de analitos em sulfato de sodio. Nos testes de adicao e recuperacao os desvios ficaram abaixo de 20%, com recuperacao dos alifaticos e aromaticos de 59-105% e 55-113%, respectivamente. Para os sedimentos de referencia, os desvios obtidos foram inferiores aos valores certificados, com recuperacoes satisfatorias. O presente trabalho proporcionou a melhoria de um metodo ja consolidado, possibilitando obter resultados com elevada confiabilidade analitica.

Potentiometric quantification and speciation of oxygenated groups in humic substances using BEST7 software

In this study the BEST7 software was employed to quantify different classes of functional groups and to model the proton titration behavior of humic substances. To illustrate the process, the Suwannee River fulvic acid of the IHSS (International Humic Substances Society) was used. Five categories - two classes of phenolic groups (phenol and cathecol), two classes of carboxylic groups (benzoic and phtalic) and the combination between them (salicylic) - of oxygenated groups were considered as being responsible for the potentiometric behavior of the sample and were quantitatively determined. The most and the least abundant groups were cathecol (3.300 ± 0.010 mmol g-1) and phenol (1.225 ± 0.070 mmol g-1), respectively. The estimated equilibrium constants were also determined and were in good agreement with the literature values for phenol and cathecol groups and for benzoic, phtalic and salicylic acids. Distribution diagrams of the species were generated with the software SPE and SPEPLOT.